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 oop Klass::java_mirror_no_keepalive() const {
61 return _java_mirror.peek();
62 }
63
64 bool Klass::is_cloneable() const {
65 return _access_flags.is_cloneable_fast() ||
66 is_subtype_of(SystemDictionary::Cloneable_klass());
67 }
68
69 void Klass::set_is_cloneable() {
70 if (name() == vmSymbols::java_lang_invoke_MemberName()) {
71 assert(is_final(), "no subclasses allowed");
72 // MemberName cloning should not be intrinsified and always happen in JVM_Clone.
73 } else if (is_instance_klass() && InstanceKlass::cast(this)->reference_type() != REF_NONE) {
74 // Reference cloning should not be intrinsified and always happen in JVM_Clone.
75 } else {
76 _access_flags.set_is_cloneable_fast();
77 }
78 }
79
80 void Klass::set_name(Symbol* n) {
81 _name = n;
82 if (_name != NULL) _name->increment_refcount();
83 }
84
85 bool Klass::is_subclass_of(const Klass* k) const {
86 // Run up the super chain and check
87 if (this == k) return true;
88
89 Klass* t = const_cast<Klass*>(this)->super();
90
91 while (t != NULL) {
92 if (t == k) return true;
93 t = t->super();
94 }
95 return false;
96 }
97
98 bool Klass::search_secondary_supers(Klass* k) const {
99 // Put some extra logic here out-of-line, before the search proper.
100 // This cuts down the size of the inline method.
101
102 // This is necessary, since I am never in my own secondary_super list.
103 if (this == k)
104 return true;
105 // Scan the array-of-objects for a match
106 int cnt = secondary_supers()->length();
107 for (int i = 0; i < cnt; i++) {
108 if (secondary_supers()->at(i) == k) {
109 ((Klass*)this)->set_secondary_super_cache(k);
110 return true;
111 }
112 }
113 return false;
114 }
115
116 // Return self, except for abstract classes with exactly 1
117 // implementor. Then return the 1 concrete implementation.
118 Klass *Klass::up_cast_abstract() {
119 Klass *r = this;
120 while( r->is_abstract() ) { // Receiver is abstract?
121 Klass *s = r->subklass(); // Check for exactly 1 subklass
122 if( !s || s->next_sibling() ) // Oops; wrong count; give up
123 return this; // Return 'this' as a no-progress flag
124 r = s; // Loop till find concrete class
125 }
126 return r; // Return the 1 concrete class
127 }
128
129 // Find LCA in class hierarchy
130 Klass *Klass::LCA( Klass *k2 ) {
131 Klass *k1 = this;
132 while( 1 ) {
133 if( k1->is_subtype_of(k2) ) return k2;
134 if( k2->is_subtype_of(k1) ) return k1;
135 k1 = k1->super();
136 k2 = k2->super();
137 }
138 }
139
140
141 void Klass::check_valid_for_instantiation(bool throwError, TRAPS) {
142 ResourceMark rm(THREAD);
143 THROW_MSG(throwError ? vmSymbols::java_lang_InstantiationError()
144 : vmSymbols::java_lang_InstantiationException(), external_name());
145 }
146
147
148 void Klass::copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS) {
149 ResourceMark rm(THREAD);
150 assert(s != NULL, "Throw NPE!");
151 THROW_MSG(vmSymbols::java_lang_ArrayStoreException(),
152 err_msg("arraycopy: source type %s is not an array", s->klass()->external_name()));
153 }
154
155
156 void Klass::initialize(TRAPS) {
157 ShouldNotReachHere();
158 }
159
160 bool Klass::compute_is_subtype_of(Klass* k) {
161 assert(k->is_klass(), "argument must be a class");
162 return is_subclass_of(k);
163 }
164
165 Klass* Klass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
166 #ifdef ASSERT
167 tty->print_cr("Error: find_field called on a klass oop."
168 " Likely error: reflection method does not correctly"
169 " wrap return value in a mirror object.");
170 #endif
171 ShouldNotReachHere();
172 return NULL;
173 }
174
175 Method* Klass::uncached_lookup_method(const Symbol* name, const Symbol* signature,
176 OverpassLookupMode overpass_mode,
177 PrivateLookupMode private_mode) const {
178 #ifdef ASSERT
179 tty->print_cr("Error: uncached_lookup_method called on a klass oop."
180 " Likely error: reflection method does not correctly"
181 " wrap return value in a mirror object.");
182 #endif
183 ShouldNotReachHere();
184 return NULL;
185 }
186
187 void* Klass::operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, TRAPS) throw() {
188 return Metaspace::allocate(loader_data, word_size, MetaspaceObj::ClassType, THREAD);
189 }
190
191 // "Normal" instantiation is preceeded by a MetaspaceObj allocation
192 // which zeros out memory - calloc equivalent.
193 // The constructor is also used from CppVtableCloner,
194 // which doesn't zero out the memory before calling the constructor.
195 // Need to set the _java_mirror field explicitly to not hit an assert that the field
196 // should be NULL before setting it.
197 Klass::Klass(KlassID id) : _id(id),
198 _prototype_header(markOopDesc::prototype()),
199 _shared_class_path_index(-1),
200 _java_mirror(NULL) {
201 CDS_ONLY(_shared_class_flags = 0;)
202 CDS_JAVA_HEAP_ONLY(_archived_mirror = 0;)
203 _primary_supers[0] = this;
204 set_super_check_offset(in_bytes(primary_supers_offset()));
205 }
206
207 jint Klass::array_layout_helper(BasicType etype) {
208 assert(etype >= T_BOOLEAN && etype <= T_OBJECT, "valid etype");
209 // Note that T_ARRAY is not allowed here.
210 int hsize = arrayOopDesc::base_offset_in_bytes(etype);
211 int esize = type2aelembytes(etype);
212 bool isobj = (etype == T_OBJECT);
213 int tag = isobj ? _lh_array_tag_obj_value : _lh_array_tag_type_value;
214 int lh = array_layout_helper(tag, hsize, etype, exact_log2(esize));
215
216 assert(lh < (int)_lh_neutral_value, "must look like an array layout");
217 assert(layout_helper_is_array(lh), "correct kind");
218 assert(layout_helper_is_objArray(lh) == isobj, "correct kind");
219 assert(layout_helper_is_typeArray(lh) == !isobj, "correct kind");
220 assert(layout_helper_header_size(lh) == hsize, "correct decode");
221 assert(layout_helper_element_type(lh) == etype, "correct decode");
222 assert(1 << layout_helper_log2_element_size(lh) == esize, "correct decode");
223
224 return lh;
225 }
226
227 bool Klass::can_be_primary_super_slow() const {
228 if (super() == NULL)
229 return true;
230 else if (super()->super_depth() >= primary_super_limit()-1)
231 return false;
232 else
233 return true;
234 }
235
236 void Klass::initialize_supers(Klass* k, Array<Klass*>* transitive_interfaces, TRAPS) {
237 if (FastSuperclassLimit == 0) {
238 // None of the other machinery matters.
239 set_super(k);
240 return;
241 }
242 if (k == NULL) {
243 set_super(NULL);
244 _primary_supers[0] = this;
245 assert(super_depth() == 0, "Object must already be initialized properly");
246 } else if (k != super() || k == SystemDictionary::Object_klass()) {
247 assert(super() == NULL || super() == SystemDictionary::Object_klass(),
248 "initialize this only once to a non-trivial value");
249 set_super(k);
250 Klass* sup = k;
251 int sup_depth = sup->super_depth();
252 juint my_depth = MIN2(sup_depth + 1, (int)primary_super_limit());
253 if (!can_be_primary_super_slow())
254 my_depth = primary_super_limit();
255 for (juint i = 0; i < my_depth; i++) {
256 _primary_supers[i] = sup->_primary_supers[i];
257 }
258 Klass* *super_check_cell;
259 if (my_depth < primary_super_limit()) {
260 _primary_supers[my_depth] = this;
261 super_check_cell = &_primary_supers[my_depth];
262 } else {
263 // Overflow of the primary_supers array forces me to be secondary.
264 super_check_cell = &_secondary_super_cache;
265 }
266 set_super_check_offset((address)super_check_cell - (address) this);
267
268 #ifdef ASSERT
269 {
270 juint j = super_depth();
271 assert(j == my_depth, "computed accessor gets right answer");
272 Klass* t = this;
273 while (!t->can_be_primary_super()) {
274 t = t->super();
275 j = t->super_depth();
276 }
277 for (juint j1 = j+1; j1 < primary_super_limit(); j1++) {
278 assert(primary_super_of_depth(j1) == NULL, "super list padding");
279 }
280 while (t != NULL) {
281 assert(primary_super_of_depth(j) == t, "super list initialization");
282 t = t->super();
283 --j;
284 }
285 assert(j == (juint)-1, "correct depth count");
286 }
287 #endif
288 }
289
290 if (secondary_supers() == NULL) {
291
292 // Now compute the list of secondary supertypes.
293 // Secondaries can occasionally be on the super chain,
294 // if the inline "_primary_supers" array overflows.
295 int extras = 0;
296 Klass* p;
297 for (p = super(); !(p == NULL || p->can_be_primary_super()); p = p->super()) {
298 ++extras;
299 }
300
301 ResourceMark rm(THREAD); // need to reclaim GrowableArrays allocated below
302
303 // Compute the "real" non-extra secondaries.
304 GrowableArray<Klass*>* secondaries = compute_secondary_supers(extras, transitive_interfaces);
305 if (secondaries == NULL) {
306 // secondary_supers set by compute_secondary_supers
307 return;
308 }
309
310 GrowableArray<Klass*>* primaries = new GrowableArray<Klass*>(extras);
311
312 for (p = super(); !(p == NULL || p->can_be_primary_super()); p = p->super()) {
313 int i; // Scan for overflow primaries being duplicates of 2nd'arys
314
315 // This happens frequently for very deeply nested arrays: the
316 // primary superclass chain overflows into the secondary. The
317 // secondary list contains the element_klass's secondaries with
318 // an extra array dimension added. If the element_klass's
319 // secondary list already contains some primary overflows, they
320 // (with the extra level of array-ness) will collide with the
321 // normal primary superclass overflows.
322 for( i = 0; i < secondaries->length(); i++ ) {
323 if( secondaries->at(i) == p )
324 break;
325 }
326 if( i < secondaries->length() )
327 continue; // It's a dup, don't put it in
328 primaries->push(p);
329 }
330 // Combine the two arrays into a metadata object to pack the array.
331 // The primaries are added in the reverse order, then the secondaries.
332 int new_length = primaries->length() + secondaries->length();
333 Array<Klass*>* s2 = MetadataFactory::new_array<Klass*>(
334 class_loader_data(), new_length, CHECK);
335 int fill_p = primaries->length();
336 for (int j = 0; j < fill_p; j++) {
337 s2->at_put(j, primaries->pop()); // add primaries in reverse order.
338 }
339 for( int j = 0; j < secondaries->length(); j++ ) {
340 s2->at_put(j+fill_p, secondaries->at(j)); // add secondaries on the end.
341 }
342
343 #ifdef ASSERT
344 // We must not copy any NULL placeholders left over from bootstrap.
345 for (int j = 0; j < s2->length(); j++) {
346 assert(s2->at(j) != NULL, "correct bootstrapping order");
347 }
348 #endif
349
350 set_secondary_supers(s2);
351 }
352 }
353
354 GrowableArray<Klass*>* Klass::compute_secondary_supers(int num_extra_slots,
355 Array<Klass*>* transitive_interfaces) {
356 assert(num_extra_slots == 0, "override for complex klasses");
357 assert(transitive_interfaces == NULL, "sanity");
358 set_secondary_supers(Universe::the_empty_klass_array());
359 return NULL;
360 }
361
362
363 InstanceKlass* Klass::superklass() const {
364 assert(super() == NULL || super()->is_instance_klass(), "must be instance klass");
365 return _super == NULL ? NULL : InstanceKlass::cast(_super);
366 }
367
368 void Klass::set_subklass(Klass* s) {
369 assert(s != this, "sanity check");
370 _subklass = s;
371 }
372
373 void Klass::set_next_sibling(Klass* s) {
374 assert(s != this, "sanity check");
375 _next_sibling = s;
376 }
377
378 void Klass::append_to_sibling_list() {
379 debug_only(verify();)
380 // add ourselves to superklass' subklass list
381 InstanceKlass* super = superklass();
382 if (super == NULL) return; // special case: class Object
383 assert((!super->is_interface() // interfaces cannot be supers
384 && (super->superklass() == NULL || !is_interface())),
385 "an interface can only be a subklass of Object");
386 Klass* prev_first_subklass = super->subklass();
387 if (prev_first_subklass != NULL) {
388 // set our sibling to be the superklass' previous first subklass
389 set_next_sibling(prev_first_subklass);
390 }
391 // make ourselves the superklass' first subklass
392 super->set_subklass(this);
393 debug_only(verify();)
394 }
395
396 oop Klass::holder_phantom() const {
397 return class_loader_data()->holder_phantom();
398 }
399
400 void Klass::clean_weak_klass_links(bool unloading_occurred, bool clean_alive_klasses) {
401 if (!ClassUnloading || !unloading_occurred) {
402 return;
403 }
404
405 Klass* root = SystemDictionary::Object_klass();
406 Stack<Klass*, mtGC> stack;
407
408 stack.push(root);
409 while (!stack.is_empty()) {
410 Klass* current = stack.pop();
411
412 assert(current->is_loader_alive(), "just checking, this should be live");
413
414 // Find and set the first alive subklass
415 Klass* sub = current->subklass();
416 while (sub != NULL && !sub->is_loader_alive()) {
417 #ifndef PRODUCT
418 if (log_is_enabled(Trace, class, unload)) {
419 ResourceMark rm;
420 log_trace(class, unload)("unlinking class (subclass): %s", sub->external_name());
421 }
422 #endif
423 sub = sub->next_sibling();
424 }
425 current->set_subklass(sub);
426 if (sub != NULL) {
427 stack.push(sub);
428 }
429
430 // Find and set the first alive sibling
431 Klass* sibling = current->next_sibling();
432 while (sibling != NULL && !sibling->is_loader_alive()) {
433 if (log_is_enabled(Trace, class, unload)) {
434 ResourceMark rm;
435 log_trace(class, unload)("[Unlinking class (sibling) %s]", sibling->external_name());
436 }
437 sibling = sibling->next_sibling();
438 }
439 current->set_next_sibling(sibling);
440 if (sibling != NULL) {
441 stack.push(sibling);
442 }
443
444 // Clean the implementors list and method data.
445 if (clean_alive_klasses && current->is_instance_klass()) {
446 InstanceKlass* ik = InstanceKlass::cast(current);
447 ik->clean_weak_instanceklass_links();
448
449 // JVMTI RedefineClasses creates previous versions that are not in
450 // the class hierarchy, so process them here.
451 while ((ik = ik->previous_versions()) != NULL) {
452 ik->clean_weak_instanceklass_links();
453 }
454 }
455 }
456 }
457
458 void Klass::metaspace_pointers_do(MetaspaceClosure* it) {
459 if (log_is_enabled(Trace, cds)) {
460 ResourceMark rm;
461 log_trace(cds)("Iter(Klass): %p (%s)", this, external_name());
462 }
463
464 it->push(&_name);
465 it->push(&_secondary_super_cache);
466 it->push(&_secondary_supers);
467 for (int i = 0; i < _primary_super_limit; i++) {
468 it->push(&_primary_supers[i]);
469 }
470 it->push(&_super);
471 it->push(&_subklass);
472 it->push(&_next_sibling);
473 it->push(&_next_link);
474
475 vtableEntry* vt = start_of_vtable();
476 for (int i=0; i<vtable_length(); i++) {
477 it->push(vt[i].method_addr());
478 }
479 }
480
481 void Klass::remove_unshareable_info() {
482 assert (DumpSharedSpaces, "only called for DumpSharedSpaces");
483 JFR_ONLY(REMOVE_ID(this);)
484 if (log_is_enabled(Trace, cds, unshareable)) {
485 ResourceMark rm;
486 log_trace(cds, unshareable)("remove: %s", external_name());
487 }
488
489 set_subklass(NULL);
490 set_next_sibling(NULL);
491 set_next_link(NULL);
492
493 // Null out class_loader_data because we don't share that yet.
494 set_class_loader_data(NULL);
495 set_is_shared();
496 }
497
498 void Klass::remove_java_mirror() {
499 assert (DumpSharedSpaces, "only called for DumpSharedSpaces");
500 if (log_is_enabled(Trace, cds, unshareable)) {
501 ResourceMark rm;
502 log_trace(cds, unshareable)("remove java_mirror: %s", external_name());
503 }
504 // Just null out the mirror. The class_loader_data() no longer exists.
505 _java_mirror = NULL;
506 }
507
508 void Klass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) {
509 assert(is_klass(), "ensure C++ vtable is restored");
510 assert(is_shared(), "must be set");
511 JFR_ONLY(RESTORE_ID(this);)
512 if (log_is_enabled(Trace, cds, unshareable)) {
513 ResourceMark rm;
514 log_trace(cds, unshareable)("restore: %s", external_name());
515 }
516
517 // If an exception happened during CDS restore, some of these fields may already be
518 // set. We leave the class on the CLD list, even if incomplete so that we don't
519 // modify the CLD list outside a safepoint.
520 if (class_loader_data() == NULL) {
521 // Restore class_loader_data to the null class loader data
522 set_class_loader_data(loader_data);
523
524 // Add to null class loader list first before creating the mirror
525 // (same order as class file parsing)
526 loader_data->add_class(this);
527 }
528
529 Handle loader(THREAD, loader_data->class_loader());
530 ModuleEntry* module_entry = NULL;
531 Klass* k = this;
532 if (k->is_objArray_klass()) {
533 k = ObjArrayKlass::cast(k)->bottom_klass();
534 }
535 // Obtain klass' module.
536 if (k->is_instance_klass()) {
537 InstanceKlass* ik = (InstanceKlass*) k;
538 module_entry = ik->module();
539 } else {
540 module_entry = ModuleEntryTable::javabase_moduleEntry();
541 }
542 // Obtain java.lang.Module, if available
543 Handle module_handle(THREAD, ((module_entry != NULL) ? module_entry->module() : (oop)NULL));
544
545 if (this->has_raw_archived_mirror()) {
546 ResourceMark rm;
547 log_debug(cds, mirror)("%s has raw archived mirror", external_name());
548 if (MetaspaceShared::open_archive_heap_region_mapped()) {
549 bool present = java_lang_Class::restore_archived_mirror(this, loader, module_handle,
550 protection_domain,
551 CHECK);
552 if (present) {
553 return;
554 }
555 }
556
557 // No archived mirror data
558 log_debug(cds, mirror)("No archived mirror data for %s", external_name());
559 _java_mirror = NULL;
560 this->clear_has_raw_archived_mirror();
561 }
562
563 // Only recreate it if not present. A previous attempt to restore may have
564 // gotten an OOM later but keep the mirror if it was created.
565 if (java_mirror() == NULL) {
566 log_trace(cds, mirror)("Recreate mirror for %s", external_name());
567 java_lang_Class::create_mirror(this, loader, module_handle, protection_domain, CHECK);
568 }
569 }
570
571 #if INCLUDE_CDS_JAVA_HEAP
572 // Used at CDS dump time to access the archived mirror. No GC barrier.
573 oop Klass::archived_java_mirror_raw() {
574 assert(has_raw_archived_mirror(), "must have raw archived mirror");
575 return CompressedOops::decode(_archived_mirror);
576 }
577
578 // No GC barrier
579 void Klass::set_archived_java_mirror_raw(oop m) {
580 assert(DumpSharedSpaces, "called only during runtime");
581 _archived_mirror = CompressedOops::encode(m);
582 }
583 #endif // INCLUDE_CDS_JAVA_HEAP
584
585 Klass* Klass::array_klass_or_null(int rank) {
586 EXCEPTION_MARK;
587 // No exception can be thrown by array_klass_impl when called with or_null == true.
588 // (In anycase, the execption mark will fail if it do so)
589 return array_klass_impl(true, rank, THREAD);
590 }
591
592
593 Klass* Klass::array_klass_or_null() {
594 EXCEPTION_MARK;
595 // No exception can be thrown by array_klass_impl when called with or_null == true.
596 // (In anycase, the execption mark will fail if it do so)
597 return array_klass_impl(true, THREAD);
598 }
599
600
601 Klass* Klass::array_klass_impl(bool or_null, int rank, TRAPS) {
602 fatal("array_klass should be dispatched to InstanceKlass, ObjArrayKlass or TypeArrayKlass");
603 return NULL;
604 }
605
606
607 Klass* Klass::array_klass_impl(bool or_null, TRAPS) {
608 fatal("array_klass should be dispatched to InstanceKlass, ObjArrayKlass or TypeArrayKlass");
609 return NULL;
610 }
611
612 oop Klass::class_loader() const { return class_loader_data()->class_loader(); }
613
614 // In product mode, this function doesn't have virtual function calls so
615 // there might be some performance advantage to handling InstanceKlass here.
616 const char* Klass::external_name() const {
617 if (is_instance_klass()) {
618 const InstanceKlass* ik = static_cast<const InstanceKlass*>(this);
619 if (ik->is_anonymous()) {
620 char addr_buf[20];
621 jio_snprintf(addr_buf, 20, "/" INTPTR_FORMAT, p2i(ik));
622 size_t addr_len = strlen(addr_buf);
623 size_t name_len = name()->utf8_length();
624 char* result = NEW_RESOURCE_ARRAY(char, name_len + addr_len + 1);
625 name()->as_klass_external_name(result, (int) name_len + 1);
626 assert(strlen(result) == name_len, "");
627 strcpy(result + name_len, addr_buf);
628 assert(strlen(result) == name_len + addr_len, "");
629 return result;
630 }
631 }
632 if (name() == NULL) return "<unknown>";
633 return name()->as_klass_external_name();
634 }
635
636 const char* Klass::signature_name() const {
637 if (name() == NULL) return "<unknown>";
638 return name()->as_C_string();
639 }
640
641 const char* Klass::external_kind() const {
642 if (is_interface()) return "interface";
643 if (is_abstract()) return "abstract class";
644 return "class";
645 }
646
647 // Unless overridden, modifier_flags is 0.
648 jint Klass::compute_modifier_flags(TRAPS) const {
649 return 0;
650 }
651
652 int Klass::atomic_incr_biased_lock_revocation_count() {
653 return (int) Atomic::add(1, &_biased_lock_revocation_count);
654 }
655
656 // Unless overridden, jvmti_class_status has no flags set.
657 jint Klass::jvmti_class_status() const {
658 return 0;
659 }
660
661
662 // Printing
663
664 void Klass::print_on(outputStream* st) const {
665 ResourceMark rm;
666 // print title
667 st->print("%s", internal_name());
668 print_address_on(st);
669 st->cr();
670 }
671
672 void Klass::oop_print_on(oop obj, outputStream* st) {
673 ResourceMark rm;
674 // print title
675 st->print_cr("%s ", internal_name());
676 obj->print_address_on(st);
677
678 if (WizardMode) {
679 // print header
680 obj->mark()->print_on(st);
681 }
682
683 // print class
684 st->print(" - klass: ");
685 obj->klass()->print_value_on(st);
686 st->cr();
687 }
688
689 void Klass::oop_print_value_on(oop obj, outputStream* st) {
690 // print title
691 ResourceMark rm; // Cannot print in debug mode without this
692 st->print("%s", internal_name());
693 obj->print_address_on(st);
694 }
695
696 #if INCLUDE_SERVICES
697 // Size Statistics
698 void Klass::collect_statistics(KlassSizeStats *sz) const {
699 sz->_klass_bytes = sz->count(this);
700 sz->_mirror_bytes = sz->count(java_mirror_no_keepalive());
701 sz->_secondary_supers_bytes = sz->count_array(secondary_supers());
702
703 sz->_ro_bytes += sz->_secondary_supers_bytes;
704 sz->_rw_bytes += sz->_klass_bytes + sz->_mirror_bytes;
705 }
706 #endif // INCLUDE_SERVICES
707
708 // Verification
709
710 void Klass::verify_on(outputStream* st) {
711
712 // This can be expensive, but it is worth checking that this klass is actually
713 // in the CLD graph but not in production.
714 assert(Metaspace::contains((address)this), "Should be");
715
716 guarantee(this->is_klass(),"should be klass");
717
718 if (super() != NULL) {
719 guarantee(super()->is_klass(), "should be klass");
720 }
721 if (secondary_super_cache() != NULL) {
722 Klass* ko = secondary_super_cache();
723 guarantee(ko->is_klass(), "should be klass");
724 }
725 for ( uint i = 0; i < primary_super_limit(); i++ ) {
726 Klass* ko = _primary_supers[i];
727 if (ko != NULL) {
728 guarantee(ko->is_klass(), "should be klass");
729 }
730 }
731
732 if (java_mirror_no_keepalive() != NULL) {
733 guarantee(oopDesc::is_oop(java_mirror_no_keepalive()), "should be instance");
734 }
735 }
736
737 void Klass::oop_verify_on(oop obj, outputStream* st) {
738 guarantee(oopDesc::is_oop(obj), "should be oop");
739 guarantee(obj->klass()->is_klass(), "klass field is not a klass");
740 }
741
742 Klass* Klass::decode_klass_raw(narrowKlass narrow_klass) {
743 return (Klass*)(void*)( (uintptr_t)Universe::narrow_klass_base() +
744 ((uintptr_t)narrow_klass << Universe::narrow_klass_shift()));
745 }
746
747 bool Klass::is_valid(Klass* k) {
748 if (!is_aligned(k, sizeof(MetaWord))) return false;
749 if ((size_t)k < os::min_page_size()) return false;
750
751 if (!os::is_readable_range(k, k + 1)) return false;
752 if (!MetaspaceUtils::is_range_in_committed(k, k + 1)) return false;
753
754 if (!Symbol::is_valid(k->name())) return false;
755 return ClassLoaderDataGraph::is_valid(k->class_loader_data());
756 }
757
758 klassVtable Klass::vtable() const {
759 return klassVtable(const_cast<Klass*>(this), start_of_vtable(), vtable_length() / vtableEntry::size());
760 }
761
762 vtableEntry* Klass::start_of_vtable() const {
763 return (vtableEntry*) ((address)this + in_bytes(vtable_start_offset()));
764 }
765
766 Method* Klass::method_at_vtable(int index) {
767 #ifndef PRODUCT
768 assert(index >= 0, "valid vtable index");
769 if (DebugVtables) {
770 verify_vtable_index(index);
771 }
772 #endif
773 return start_of_vtable()[index].method();
774 }
775
776 ByteSize Klass::vtable_start_offset() {
777 return in_ByteSize(InstanceKlass::header_size() * wordSize);
778 }
779
780 #ifndef PRODUCT
781
782 bool Klass::verify_vtable_index(int i) {
783 int limit = vtable_length()/vtableEntry::size();
784 assert(i >= 0 && i < limit, "index %d out of bounds %d", i, limit);
785 return true;
786 }
787
788 bool Klass::verify_itable_index(int i) {
789 assert(is_instance_klass(), "");
790 int method_count = klassItable::method_count_for_interface(this);
791 assert(i >= 0 && i < method_count, "index out of bounds");
792 return true;
793 }
794
795 #endif // PRODUCT
796
797 // Caller needs ResourceMark
798 // joint_in_module_of_loader provides an optimization if 2 classes are in
799 // the same module to succinctly print out relevant information about their
800 // module name and class loader's name_and_id for error messages.
801 // Format:
802 // <fully-qualified-external-class-name1> and <fully-qualified-external-class-name2>
803 // are in module <module-name>[@<version>]
804 // of loader <loader-name_and_id>[, parent loader <parent-loader-name_and_id>]
805 const char* Klass::joint_in_module_of_loader(const Klass* class2, bool include_parent_loader) const {
806 assert(module() == class2->module(), "classes do not have the same module");
807 const char* class1_name = external_name();
808 size_t len = strlen(class1_name) + 1;
809
810 const char* class2_description = class2->class_in_module_of_loader(true, include_parent_loader);
811 len += strlen(class2_description);
812
813 len += strlen(" and ");
814
815 char* joint_description = NEW_RESOURCE_ARRAY_RETURN_NULL(char, len);
816
817 // Just return the FQN if error when allocating string
818 if (joint_description == NULL) {
819 return class1_name;
820 }
821
822 jio_snprintf(joint_description, len, "%s and %s",
823 class1_name,
824 class2_description);
825
826 return joint_description;
827 }
828
829 // Caller needs ResourceMark
830 // class_in_module_of_loader provides a standard way to include
831 // relevant information about a class, such as its module name as
832 // well as its class loader's name_and_id, in error messages and logging.
833 // Format:
834 // <fully-qualified-external-class-name> is in module <module-name>[@<version>]
835 // of loader <loader-name_and_id>[, parent loader <parent-loader-name_and_id>]
836 const char* Klass::class_in_module_of_loader(bool use_are, bool include_parent_loader) const {
837 // 1. fully qualified external name of class
838 const char* klass_name = external_name();
839 size_t len = strlen(klass_name) + 1;
840
841 // 2. module name + @version
842 const char* module_name = "";
843 const char* version = "";
844 bool has_version = false;
845 bool module_is_named = false;
846 const char* module_name_phrase = "";
847 const Klass* bottom_klass = is_objArray_klass() ?
848 ObjArrayKlass::cast(this)->bottom_klass() : this;
849 if (bottom_klass->is_instance_klass()) {
850 ModuleEntry* module = InstanceKlass::cast(bottom_klass)->module();
851 if (module->is_named()) {
852 module_is_named = true;
853 module_name_phrase = "module ";
854 module_name = module->name()->as_C_string();
855 len += strlen(module_name);
856 // Use version if exists and is not a jdk module
857 if (module->should_show_version()) {
858 has_version = true;
859 version = module->version()->as_C_string();
860 // Include stlen(version) + 1 for the "@"
861 len += strlen(version) + 1;
862 }
863 } else {
864 module_name = UNNAMED_MODULE;
865 len += UNNAMED_MODULE_LEN;
866 }
867 } else {
868 // klass is an array of primitives, module is java.base
869 module_is_named = true;
870 module_name_phrase = "module ";
871 module_name = JAVA_BASE_NAME;
872 len += JAVA_BASE_NAME_LEN;
873 }
874
875 // 3. class loader's name_and_id
876 ClassLoaderData* cld = class_loader_data();
877 assert(cld != NULL, "class_loader_data should not be null");
878 const char* loader_name_and_id = cld->loader_name_and_id();
879 len += strlen(loader_name_and_id);
880
881 // 4. include parent loader information
882 const char* parent_loader_phrase = "";
883 const char* parent_loader_name_and_id = "";
884 if (include_parent_loader &&
885 !cld->is_builtin_class_loader_data()) {
886 oop parent_loader = java_lang_ClassLoader::parent(class_loader());
887 ClassLoaderData *parent_cld = ClassLoaderData::class_loader_data_or_null(parent_loader);
888 // The parent loader's ClassLoaderData could be null if it is
889 // a delegating class loader that has never defined a class.
890 // In this case the loader's name must be obtained via the parent loader's oop.
891 if (parent_cld == NULL) {
892 oop cl_name_and_id = java_lang_ClassLoader::nameAndId(parent_loader);
893 if (cl_name_and_id != NULL) {
894 parent_loader_name_and_id = java_lang_String::as_utf8_string(cl_name_and_id);
895 }
896 } else {
897 parent_loader_name_and_id = parent_cld->loader_name_and_id();
898 }
899 parent_loader_phrase = ", parent loader ";
900 len += strlen(parent_loader_phrase) + strlen(parent_loader_name_and_id);
901 }
902
903 // Start to construct final full class description string
904 len += ((use_are) ? strlen(" are in ") : strlen(" is in "));
905 len += strlen(module_name_phrase) + strlen(" of loader ");
906
907 char* class_description = NEW_RESOURCE_ARRAY_RETURN_NULL(char, len);
908
909 // Just return the FQN if error when allocating string
910 if (class_description == NULL) {
911 return klass_name;
912 }
913
914 jio_snprintf(class_description, len, "%s %s in %s%s%s%s of loader %s%s%s",
915 klass_name,
916 (use_are) ? "are" : "is",
917 module_name_phrase,
918 module_name,
919 (has_version) ? "@" : "",
920 (has_version) ? version : "",
921 loader_name_and_id,
922 parent_loader_phrase,
923 parent_loader_name_and_id);
924
925 return class_description;
926 }