1 /*
2 * Copyright (c) 1997, 2019, 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/classLoaderDataGraph.inline.hpp"
28 #include "classfile/dictionary.hpp"
29 #include "classfile/javaClasses.hpp"
30 #include "classfile/moduleEntry.hpp"
31 #include "classfile/systemDictionary.hpp"
32 #include "classfile/vmSymbols.hpp"
33 #include "gc/shared/collectedHeap.inline.hpp"
34 #include "logging/log.hpp"
35 #include "memory/heapInspection.hpp"
36 #include "memory/heapShared.hpp"
37 #include "memory/metadataFactory.hpp"
38 #include "memory/metaspaceClosure.hpp"
39 #include "memory/metaspaceShared.hpp"
40 #include "memory/oopFactory.hpp"
41 #include "memory/resourceArea.hpp"
42 #include "memory/universe.hpp"
43 #include "oops/compressedOops.inline.hpp"
44 #include "oops/instanceKlass.hpp"
45 #include "oops/klass.inline.hpp"
46 #include "oops/oop.inline.hpp"
47 #include "oops/oopHandle.inline.hpp"
48 #include "runtime/atomic.hpp"
49 #include "runtime/handles.inline.hpp"
50 #include "runtime/orderAccess.hpp"
51 #include "utilities/macros.hpp"
52 #include "utilities/stack.inline.hpp"
53
54 void Klass::set_java_mirror(Handle m) {
55 assert(!m.is_null(), "New mirror should never be null.");
56 assert(_java_mirror.resolve() == NULL, "should only be used to initialize mirror");
57 _java_mirror = class_loader_data()->add_handle(m);
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 == NULL || s->next_sibling() != NULL) // 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 Klass* Klass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
161 #ifdef ASSERT
162 tty->print_cr("Error: find_field called on a klass oop."
163 " Likely error: reflection method does not correctly"
164 " wrap return value in a mirror object.");
165 #endif
166 ShouldNotReachHere();
167 return NULL;
168 }
169
170 Method* Klass::uncached_lookup_method(const Symbol* name, const Symbol* signature,
171 OverpassLookupMode overpass_mode,
172 PrivateLookupMode private_mode) const {
173 #ifdef ASSERT
174 tty->print_cr("Error: uncached_lookup_method called on a klass oop."
175 " Likely error: reflection method does not correctly"
176 " wrap return value in a mirror object.");
177 #endif
178 ShouldNotReachHere();
179 return NULL;
180 }
181
182 void* Klass::operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, TRAPS) throw() {
183 return Metaspace::allocate(loader_data, word_size, MetaspaceObj::ClassType, THREAD);
184 }
185
186 // "Normal" instantiation is preceeded by a MetaspaceObj allocation
187 // which zeros out memory - calloc equivalent.
188 // The constructor is also used from CppVtableCloner,
189 // which doesn't zero out the memory before calling the constructor.
190 // Need to set the _java_mirror field explicitly to not hit an assert that the field
191 // should be NULL before setting it.
192 Klass::Klass(KlassID id) : _id(id),
193 _java_mirror(NULL),
194 _prototype_header(markWord::prototype()),
195 _shared_class_path_index(-1) {
196 CDS_ONLY(_shared_class_flags = 0;)
197 CDS_JAVA_HEAP_ONLY(_archived_mirror = 0;)
198 _primary_supers[0] = this;
199 set_super_check_offset(in_bytes(primary_supers_offset()));
200 }
201
202 jint Klass::array_layout_helper(BasicType etype) {
203 assert(etype >= T_BOOLEAN && etype <= T_OBJECT, "valid etype");
204 // Note that T_ARRAY is not allowed here.
205 int hsize = arrayOopDesc::base_offset_in_bytes(etype);
206 int esize = type2aelembytes(etype);
207 bool isobj = (etype == T_OBJECT);
208 int tag = isobj ? _lh_array_tag_obj_value : _lh_array_tag_type_value;
209 int lh = array_layout_helper(tag, hsize, etype, exact_log2(esize));
210
211 assert(lh < (int)_lh_neutral_value, "must look like an array layout");
212 assert(layout_helper_is_array(lh), "correct kind");
213 assert(layout_helper_is_objArray(lh) == isobj, "correct kind");
214 assert(layout_helper_is_typeArray(lh) == !isobj, "correct kind");
215 assert(layout_helper_header_size(lh) == hsize, "correct decode");
216 assert(layout_helper_element_type(lh) == etype, "correct decode");
217 assert(1 << layout_helper_log2_element_size(lh) == esize, "correct decode");
218
219 return lh;
220 }
221
222 bool Klass::can_be_primary_super_slow() const {
223 if (super() == NULL)
224 return true;
225 else if (super()->super_depth() >= primary_super_limit()-1)
226 return false;
227 else
228 return true;
229 }
230
231 void Klass::initialize_supers(Klass* k, Array<InstanceKlass*>* transitive_interfaces, TRAPS) {
232 if (k == NULL) {
233 set_super(NULL);
234 _primary_supers[0] = this;
235 assert(super_depth() == 0, "Object must already be initialized properly");
236 } else if (k != super() || k == SystemDictionary::Object_klass()) {
237 assert(super() == NULL || super() == SystemDictionary::Object_klass(),
238 "initialize this only once to a non-trivial value");
239 set_super(k);
240 Klass* sup = k;
241 int sup_depth = sup->super_depth();
242 juint my_depth = MIN2(sup_depth + 1, (int)primary_super_limit());
243 if (!can_be_primary_super_slow())
244 my_depth = primary_super_limit();
245 for (juint i = 0; i < my_depth; i++) {
246 _primary_supers[i] = sup->_primary_supers[i];
247 }
248 Klass* *super_check_cell;
249 if (my_depth < primary_super_limit()) {
250 _primary_supers[my_depth] = this;
251 super_check_cell = &_primary_supers[my_depth];
252 } else {
253 // Overflow of the primary_supers array forces me to be secondary.
254 super_check_cell = &_secondary_super_cache;
255 }
256 set_super_check_offset((address)super_check_cell - (address) this);
257
258 #ifdef ASSERT
259 {
260 juint j = super_depth();
261 assert(j == my_depth, "computed accessor gets right answer");
262 Klass* t = this;
263 while (!t->can_be_primary_super()) {
264 t = t->super();
265 j = t->super_depth();
266 }
267 for (juint j1 = j+1; j1 < primary_super_limit(); j1++) {
268 assert(primary_super_of_depth(j1) == NULL, "super list padding");
269 }
270 while (t != NULL) {
271 assert(primary_super_of_depth(j) == t, "super list initialization");
272 t = t->super();
273 --j;
274 }
275 assert(j == (juint)-1, "correct depth count");
276 }
277 #endif
278 }
279
280 if (secondary_supers() == NULL) {
281
282 // Now compute the list of secondary supertypes.
283 // Secondaries can occasionally be on the super chain,
284 // if the inline "_primary_supers" array overflows.
285 int extras = 0;
286 Klass* p;
287 for (p = super(); !(p == NULL || p->can_be_primary_super()); p = p->super()) {
288 ++extras;
289 }
290
291 ResourceMark rm(THREAD); // need to reclaim GrowableArrays allocated below
292
293 // Compute the "real" non-extra secondaries.
294 GrowableArray<Klass*>* secondaries = compute_secondary_supers(extras, transitive_interfaces);
295 if (secondaries == NULL) {
296 // secondary_supers set by compute_secondary_supers
297 return;
298 }
299
300 GrowableArray<Klass*>* primaries = new GrowableArray<Klass*>(extras);
301
302 for (p = super(); !(p == NULL || p->can_be_primary_super()); p = p->super()) {
303 int i; // Scan for overflow primaries being duplicates of 2nd'arys
304
305 // This happens frequently for very deeply nested arrays: the
306 // primary superclass chain overflows into the secondary. The
307 // secondary list contains the element_klass's secondaries with
308 // an extra array dimension added. If the element_klass's
309 // secondary list already contains some primary overflows, they
310 // (with the extra level of array-ness) will collide with the
311 // normal primary superclass overflows.
312 for( i = 0; i < secondaries->length(); i++ ) {
313 if( secondaries->at(i) == p )
314 break;
315 }
316 if( i < secondaries->length() )
317 continue; // It's a dup, don't put it in
318 primaries->push(p);
319 }
320 // Combine the two arrays into a metadata object to pack the array.
321 // The primaries are added in the reverse order, then the secondaries.
322 int new_length = primaries->length() + secondaries->length();
323 Array<Klass*>* s2 = MetadataFactory::new_array<Klass*>(
324 class_loader_data(), new_length, CHECK);
325 int fill_p = primaries->length();
326 for (int j = 0; j < fill_p; j++) {
327 s2->at_put(j, primaries->pop()); // add primaries in reverse order.
328 }
329 for( int j = 0; j < secondaries->length(); j++ ) {
330 s2->at_put(j+fill_p, secondaries->at(j)); // add secondaries on the end.
331 }
332
333 #ifdef ASSERT
334 // We must not copy any NULL placeholders left over from bootstrap.
335 for (int j = 0; j < s2->length(); j++) {
336 assert(s2->at(j) != NULL, "correct bootstrapping order");
337 }
338 #endif
339
340 set_secondary_supers(s2);
341 }
342 }
343
344 GrowableArray<Klass*>* Klass::compute_secondary_supers(int num_extra_slots,
345 Array<InstanceKlass*>* transitive_interfaces) {
346 assert(num_extra_slots == 0, "override for complex klasses");
347 assert(transitive_interfaces == NULL, "sanity");
348 set_secondary_supers(Universe::the_empty_klass_array());
349 return NULL;
350 }
351
352
353 // superklass links
354 InstanceKlass* Klass::superklass() const {
355 assert(super() == NULL || super()->is_instance_klass(), "must be instance klass");
356 return _super == NULL ? NULL : InstanceKlass::cast(_super);
357 }
358
359 // subklass links. Used by the compiler (and vtable initialization)
360 // May be cleaned concurrently, so must use the Compile_lock.
361 // The log parameter is for clean_weak_klass_links to report unlinked classes.
362 Klass* Klass::subklass(bool log) const {
363 // Need load_acquire on the _subklass, because it races with inserts that
364 // publishes freshly initialized data.
365 for (Klass* chain = Atomic::load_acquire(&_subklass);
366 chain != NULL;
367 // Do not need load_acquire on _next_sibling, because inserts never
368 // create _next_sibling edges to dead data.
369 chain = Atomic::load(&chain->_next_sibling))
370 {
371 if (chain->is_loader_alive()) {
372 return chain;
373 } else if (log) {
374 if (log_is_enabled(Trace, class, unload)) {
375 ResourceMark rm;
376 log_trace(class, unload)("unlinking class (subclass): %s", chain->external_name());
377 }
378 }
379 }
380 return NULL;
381 }
382
383 Klass* Klass::next_sibling(bool log) const {
384 // Do not need load_acquire on _next_sibling, because inserts never
385 // create _next_sibling edges to dead data.
386 for (Klass* chain = Atomic::load(&_next_sibling);
387 chain != NULL;
388 chain = Atomic::load(&chain->_next_sibling)) {
389 // Only return alive klass, there may be stale klass
390 // in this chain if cleaned concurrently.
391 if (chain->is_loader_alive()) {
392 return chain;
393 } else if (log) {
394 if (log_is_enabled(Trace, class, unload)) {
395 ResourceMark rm;
396 log_trace(class, unload)("unlinking class (sibling): %s", chain->external_name());
397 }
398 }
399 }
400 return NULL;
401 }
402
403 void Klass::set_subklass(Klass* s) {
404 assert(s != this, "sanity check");
405 Atomic::release_store(&_subklass, s);
406 }
407
408 void Klass::set_next_sibling(Klass* s) {
409 assert(s != this, "sanity check");
410 // Does not need release semantics. If used by cleanup, it will link to
411 // already safely published data, and if used by inserts, will be published
412 // safely using cmpxchg.
413 Atomic::store(&_next_sibling, s);
414 }
415
416 void Klass::append_to_sibling_list() {
417 assert_locked_or_safepoint(Compile_lock);
418 debug_only(verify();)
419 // add ourselves to superklass' subklass list
420 InstanceKlass* super = superklass();
421 if (super == NULL) return; // special case: class Object
422 assert((!super->is_interface() // interfaces cannot be supers
423 && (super->superklass() == NULL || !is_interface())),
424 "an interface can only be a subklass of Object");
425
426 // Make sure there is no stale subklass head
427 super->clean_subklass();
428
429 for (;;) {
430 Klass* prev_first_subklass = Atomic::load_acquire(&_super->_subklass);
431 if (prev_first_subklass != NULL) {
432 // set our sibling to be the superklass' previous first subklass
433 assert(prev_first_subklass->is_loader_alive(), "May not attach not alive klasses");
434 set_next_sibling(prev_first_subklass);
435 }
436 // Note that the prev_first_subklass is always alive, meaning no sibling_next links
437 // are ever created to not alive klasses. This is an important invariant of the lock-free
438 // cleaning protocol, that allows us to safely unlink dead klasses from the sibling list.
439 if (Atomic::cmpxchg(this, &super->_subklass, prev_first_subklass) == prev_first_subklass) {
440 return;
441 }
442 }
443 debug_only(verify();)
444 }
445
446 void Klass::clean_subklass() {
447 for (;;) {
448 // Need load_acquire, due to contending with concurrent inserts
449 Klass* subklass = Atomic::load_acquire(&_subklass);
450 if (subklass == NULL || subklass->is_loader_alive()) {
451 return;
452 }
453 // Try to fix _subklass until it points at something not dead.
454 Atomic::cmpxchg(subklass->next_sibling(), &_subklass, subklass);
455 }
456 }
457
458 void Klass::clean_weak_klass_links(bool unloading_occurred, bool clean_alive_klasses) {
459 if (!ClassUnloading || !unloading_occurred) {
460 return;
461 }
462
463 Klass* root = SystemDictionary::Object_klass();
464 Stack<Klass*, mtGC> stack;
465
466 stack.push(root);
467 while (!stack.is_empty()) {
468 Klass* current = stack.pop();
469
470 assert(current->is_loader_alive(), "just checking, this should be live");
471
472 // Find and set the first alive subklass
473 Klass* sub = current->subklass(true);
474 current->clean_subklass();
475 if (sub != NULL) {
476 stack.push(sub);
477 }
478
479 // Find and set the first alive sibling
480 Klass* sibling = current->next_sibling(true);
481 current->set_next_sibling(sibling);
482 if (sibling != NULL) {
483 stack.push(sibling);
484 }
485
486 // Clean the implementors list and method data.
487 if (clean_alive_klasses && current->is_instance_klass()) {
488 InstanceKlass* ik = InstanceKlass::cast(current);
489 ik->clean_weak_instanceklass_links();
490
491 // JVMTI RedefineClasses creates previous versions that are not in
492 // the class hierarchy, so process them here.
493 while ((ik = ik->previous_versions()) != NULL) {
494 ik->clean_weak_instanceklass_links();
495 }
496 }
497 }
498 }
499
500 void Klass::metaspace_pointers_do(MetaspaceClosure* it) {
501 if (log_is_enabled(Trace, cds)) {
502 ResourceMark rm;
503 log_trace(cds)("Iter(Klass): %p (%s)", this, external_name());
504 }
505
506 it->push(&_name);
507 it->push(&_secondary_super_cache);
508 it->push(&_secondary_supers);
509 for (int i = 0; i < _primary_super_limit; i++) {
510 it->push(&_primary_supers[i]);
511 }
512 it->push(&_super);
513 it->push((Klass**)&_subklass);
514 it->push((Klass**)&_next_sibling);
515 it->push(&_next_link);
516
517 vtableEntry* vt = start_of_vtable();
518 for (int i=0; i<vtable_length(); i++) {
519 it->push(vt[i].method_addr());
520 }
521 }
522
523 void Klass::remove_unshareable_info() {
524 assert (Arguments::is_dumping_archive(),
525 "only called during CDS dump time");
526 JFR_ONLY(REMOVE_ID(this);)
527 if (log_is_enabled(Trace, cds, unshareable)) {
528 ResourceMark rm;
529 log_trace(cds, unshareable)("remove: %s", external_name());
530 }
531
532 set_subklass(NULL);
533 set_next_sibling(NULL);
534 set_next_link(NULL);
535
536 // Null out class_loader_data because we don't share that yet.
537 set_class_loader_data(NULL);
538 set_is_shared();
539 }
540
541 void Klass::remove_java_mirror() {
542 Arguments::assert_is_dumping_archive();
543 if (log_is_enabled(Trace, cds, unshareable)) {
544 ResourceMark rm;
545 log_trace(cds, unshareable)("remove java_mirror: %s", external_name());
546 }
547 // Just null out the mirror. The class_loader_data() no longer exists.
548 _java_mirror = NULL;
549 }
550
551 void Klass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) {
552 assert(is_klass(), "ensure C++ vtable is restored");
553 assert(is_shared(), "must be set");
554 JFR_ONLY(RESTORE_ID(this);)
555 if (log_is_enabled(Trace, cds, unshareable)) {
556 ResourceMark rm;
557 log_trace(cds, unshareable)("restore: %s", external_name());
558 }
559
560 // If an exception happened during CDS restore, some of these fields may already be
561 // set. We leave the class on the CLD list, even if incomplete so that we don't
562 // modify the CLD list outside a safepoint.
563 if (class_loader_data() == NULL) {
564 // Restore class_loader_data to the null class loader data
565 set_class_loader_data(loader_data);
566
567 // Add to null class loader list first before creating the mirror
568 // (same order as class file parsing)
569 loader_data->add_class(this);
570 }
571
572 Handle loader(THREAD, loader_data->class_loader());
573 ModuleEntry* module_entry = NULL;
574 Klass* k = this;
575 if (k->is_objArray_klass()) {
576 k = ObjArrayKlass::cast(k)->bottom_klass();
577 }
578 // Obtain klass' module.
579 if (k->is_instance_klass()) {
580 InstanceKlass* ik = (InstanceKlass*) k;
581 module_entry = ik->module();
582 } else {
583 module_entry = ModuleEntryTable::javabase_moduleEntry();
584 }
585 // Obtain java.lang.Module, if available
586 Handle module_handle(THREAD, ((module_entry != NULL) ? module_entry->module() : (oop)NULL));
587
588 if (this->has_raw_archived_mirror()) {
589 ResourceMark rm;
590 log_debug(cds, mirror)("%s has raw archived mirror", external_name());
591 if (HeapShared::open_archive_heap_region_mapped()) {
592 bool present = java_lang_Class::restore_archived_mirror(this, loader, module_handle,
593 protection_domain,
594 CHECK);
595 if (present) {
596 return;
597 }
598 }
599
600 // No archived mirror data
601 log_debug(cds, mirror)("No archived mirror data for %s", external_name());
602 _java_mirror = NULL;
603 this->clear_has_raw_archived_mirror();
604 }
605
606 // Only recreate it if not present. A previous attempt to restore may have
607 // gotten an OOM later but keep the mirror if it was created.
608 if (java_mirror() == NULL) {
609 log_trace(cds, mirror)("Recreate mirror for %s", external_name());
610 java_lang_Class::create_mirror(this, loader, module_handle, protection_domain, CHECK);
611 }
612 }
613
614 #if INCLUDE_CDS_JAVA_HEAP
615 // Used at CDS dump time to access the archived mirror. No GC barrier.
616 oop Klass::archived_java_mirror_raw() {
617 assert(has_raw_archived_mirror(), "must have raw archived mirror");
618 return CompressedOops::decode(_archived_mirror);
619 }
620
621 narrowOop Klass::archived_java_mirror_raw_narrow() {
622 assert(has_raw_archived_mirror(), "must have raw archived mirror");
623 return _archived_mirror;
624 }
625
626 // No GC barrier
627 void Klass::set_archived_java_mirror_raw(oop m) {
628 assert(DumpSharedSpaces, "called only during runtime");
629 _archived_mirror = CompressedOops::encode(m);
630 }
631 #endif // INCLUDE_CDS_JAVA_HEAP
632
633 Klass* Klass::array_klass_or_null(int rank) {
634 EXCEPTION_MARK;
635 // No exception can be thrown by array_klass_impl when called with or_null == true.
636 // (In anycase, the execption mark will fail if it do so)
637 return array_klass_impl(true, rank, THREAD);
638 }
639
640
641 Klass* Klass::array_klass_or_null() {
642 EXCEPTION_MARK;
643 // No exception can be thrown by array_klass_impl when called with or_null == true.
644 // (In anycase, the execption mark will fail if it do so)
645 return array_klass_impl(true, THREAD);
646 }
647
648
649 Klass* Klass::array_klass_impl(bool or_null, int rank, TRAPS) {
650 fatal("array_klass should be dispatched to InstanceKlass, ObjArrayKlass or TypeArrayKlass");
651 return NULL;
652 }
653
654
655 Klass* Klass::array_klass_impl(bool or_null, TRAPS) {
656 fatal("array_klass should be dispatched to InstanceKlass, ObjArrayKlass or TypeArrayKlass");
657 return NULL;
658 }
659
660 void Klass::check_array_allocation_length(int length, int max_length, TRAPS) {
661 if (length > max_length) {
662 if (!THREAD->in_retryable_allocation()) {
663 report_java_out_of_memory("Requested array size exceeds VM limit");
664 JvmtiExport::post_array_size_exhausted();
665 THROW_OOP(Universe::out_of_memory_error_array_size());
666 } else {
667 THROW_OOP(Universe::out_of_memory_error_retry());
668 }
669 } else if (length < 0) {
670 THROW_MSG(vmSymbols::java_lang_NegativeArraySizeException(), err_msg("%d", length));
671 }
672 }
673
674 // In product mode, this function doesn't have virtual function calls so
675 // there might be some performance advantage to handling InstanceKlass here.
676 const char* Klass::external_name() const {
677 if (is_instance_klass()) {
678 const InstanceKlass* ik = static_cast<const InstanceKlass*>(this);
679 if (ik->is_unsafe_anonymous()) {
680 char addr_buf[20];
681 jio_snprintf(addr_buf, 20, "/" INTPTR_FORMAT, p2i(ik));
682 size_t addr_len = strlen(addr_buf);
683 size_t name_len = name()->utf8_length();
684 char* result = NEW_RESOURCE_ARRAY(char, name_len + addr_len + 1);
685 name()->as_klass_external_name(result, (int) name_len + 1);
686 assert(strlen(result) == name_len, "");
687 strcpy(result + name_len, addr_buf);
688 assert(strlen(result) == name_len + addr_len, "");
689 return result;
690 }
691 }
692 if (name() == NULL) return "<unknown>";
693 return name()->as_klass_external_name();
694 }
695
696 const char* Klass::signature_name() const {
697 if (name() == NULL) return "<unknown>";
698 return name()->as_C_string();
699 }
700
701 const char* Klass::external_kind() const {
702 if (is_interface()) return "interface";
703 if (is_abstract()) return "abstract class";
704 return "class";
705 }
706
707 // Unless overridden, modifier_flags is 0.
708 jint Klass::compute_modifier_flags(TRAPS) const {
709 return 0;
710 }
711
712 int Klass::atomic_incr_biased_lock_revocation_count() {
713 return (int) Atomic::add(1, &_biased_lock_revocation_count);
714 }
715
716 // Unless overridden, jvmti_class_status has no flags set.
717 jint Klass::jvmti_class_status() const {
718 return 0;
719 }
720
721
722 // Printing
723
724 void Klass::print_on(outputStream* st) const {
725 ResourceMark rm;
726 // print title
727 st->print("%s", internal_name());
728 print_address_on(st);
729 st->cr();
730 }
731
732 #define BULLET " - "
733
734 void Klass::oop_print_on(oop obj, outputStream* st) {
735 // print title
736 st->print_cr("%s ", internal_name());
737 obj->print_address_on(st);
738
739 if (WizardMode) {
740 // print header
741 obj->mark().print_on(st);
742 st->cr();
743 st->print(BULLET"prototype_header: " INTPTR_FORMAT, _prototype_header.value());
744 st->cr();
745 }
746
747 // print class
748 st->print(BULLET"klass: ");
749 obj->klass()->print_value_on(st);
750 st->cr();
751 }
752
753 void Klass::oop_print_value_on(oop obj, outputStream* st) {
754 // print title
755 ResourceMark rm; // Cannot print in debug mode without this
756 st->print("%s", internal_name());
757 obj->print_address_on(st);
758 }
759
760 #if INCLUDE_SERVICES
761 // Size Statistics
762 void Klass::collect_statistics(KlassSizeStats *sz) const {
763 sz->_klass_bytes = sz->count(this);
764 sz->_mirror_bytes = sz->count(java_mirror_no_keepalive());
765 sz->_secondary_supers_bytes = sz->count_array(secondary_supers());
766
767 sz->_ro_bytes += sz->_secondary_supers_bytes;
768 sz->_rw_bytes += sz->_klass_bytes + sz->_mirror_bytes;
769 }
770 #endif // INCLUDE_SERVICES
771
772 // Verification
773
774 void Klass::verify_on(outputStream* st) {
775
776 // This can be expensive, but it is worth checking that this klass is actually
777 // in the CLD graph but not in production.
778 assert(Metaspace::contains((address)this), "Should be");
779
780 guarantee(this->is_klass(),"should be klass");
781
782 if (super() != NULL) {
783 guarantee(super()->is_klass(), "should be klass");
784 }
785 if (secondary_super_cache() != NULL) {
786 Klass* ko = secondary_super_cache();
787 guarantee(ko->is_klass(), "should be klass");
788 }
789 for ( uint i = 0; i < primary_super_limit(); i++ ) {
790 Klass* ko = _primary_supers[i];
791 if (ko != NULL) {
792 guarantee(ko->is_klass(), "should be klass");
793 }
794 }
795
796 if (java_mirror_no_keepalive() != NULL) {
797 guarantee(oopDesc::is_oop(java_mirror_no_keepalive()), "should be instance");
798 }
799 }
800
801 void Klass::oop_verify_on(oop obj, outputStream* st) {
802 guarantee(oopDesc::is_oop(obj), "should be oop");
803 guarantee(obj->klass()->is_klass(), "klass field is not a klass");
804 }
805
806 bool Klass::is_valid(Klass* k) {
807 if (!is_aligned(k, sizeof(MetaWord))) return false;
808 if ((size_t)k < os::min_page_size()) return false;
809
810 if (!os::is_readable_range(k, k + 1)) return false;
811 if (!Metaspace::contains(k)) return false;
812
813 if (!Symbol::is_valid(k->name())) return false;
814 return ClassLoaderDataGraph::is_valid(k->class_loader_data());
815 }
816
817 Method* Klass::method_at_vtable(int index) {
818 #ifndef PRODUCT
819 assert(index >= 0, "valid vtable index");
820 if (DebugVtables) {
821 verify_vtable_index(index);
822 }
823 #endif
824 return start_of_vtable()[index].method();
825 }
826
827
828 #ifndef PRODUCT
829
830 bool Klass::verify_vtable_index(int i) {
831 int limit = vtable_length()/vtableEntry::size();
832 assert(i >= 0 && i < limit, "index %d out of bounds %d", i, limit);
833 return true;
834 }
835
836 #endif // PRODUCT
837
838 // Caller needs ResourceMark
839 // joint_in_module_of_loader provides an optimization if 2 classes are in
840 // the same module to succinctly print out relevant information about their
841 // module name and class loader's name_and_id for error messages.
842 // Format:
843 // <fully-qualified-external-class-name1> and <fully-qualified-external-class-name2>
844 // are in module <module-name>[@<version>]
845 // of loader <loader-name_and_id>[, parent loader <parent-loader-name_and_id>]
846 const char* Klass::joint_in_module_of_loader(const Klass* class2, bool include_parent_loader) const {
847 assert(module() == class2->module(), "classes do not have the same module");
848 const char* class1_name = external_name();
849 size_t len = strlen(class1_name) + 1;
850
851 const char* class2_description = class2->class_in_module_of_loader(true, include_parent_loader);
852 len += strlen(class2_description);
853
854 len += strlen(" and ");
855
856 char* joint_description = NEW_RESOURCE_ARRAY_RETURN_NULL(char, len);
857
858 // Just return the FQN if error when allocating string
859 if (joint_description == NULL) {
860 return class1_name;
861 }
862
863 jio_snprintf(joint_description, len, "%s and %s",
864 class1_name,
865 class2_description);
866
867 return joint_description;
868 }
869
870 // Caller needs ResourceMark
871 // class_in_module_of_loader provides a standard way to include
872 // relevant information about a class, such as its module name as
873 // well as its class loader's name_and_id, in error messages and logging.
874 // Format:
875 // <fully-qualified-external-class-name> is in module <module-name>[@<version>]
876 // of loader <loader-name_and_id>[, parent loader <parent-loader-name_and_id>]
877 const char* Klass::class_in_module_of_loader(bool use_are, bool include_parent_loader) const {
878 // 1. fully qualified external name of class
879 const char* klass_name = external_name();
880 size_t len = strlen(klass_name) + 1;
881
882 // 2. module name + @version
883 const char* module_name = "";
884 const char* version = "";
885 bool has_version = false;
886 bool module_is_named = false;
887 const char* module_name_phrase = "";
888 const Klass* bottom_klass = is_objArray_klass() ?
889 ObjArrayKlass::cast(this)->bottom_klass() : this;
890 if (bottom_klass->is_instance_klass()) {
891 ModuleEntry* module = InstanceKlass::cast(bottom_klass)->module();
892 if (module->is_named()) {
893 module_is_named = true;
894 module_name_phrase = "module ";
895 module_name = module->name()->as_C_string();
896 len += strlen(module_name);
897 // Use version if exists and is not a jdk module
898 if (module->should_show_version()) {
899 has_version = true;
900 version = module->version()->as_C_string();
901 // Include stlen(version) + 1 for the "@"
902 len += strlen(version) + 1;
903 }
904 } else {
905 module_name = UNNAMED_MODULE;
906 len += UNNAMED_MODULE_LEN;
907 }
908 } else {
909 // klass is an array of primitives, module is java.base
910 module_is_named = true;
911 module_name_phrase = "module ";
912 module_name = JAVA_BASE_NAME;
913 len += JAVA_BASE_NAME_LEN;
914 }
915
916 // 3. class loader's name_and_id
917 ClassLoaderData* cld = class_loader_data();
918 assert(cld != NULL, "class_loader_data should not be null");
919 const char* loader_name_and_id = cld->loader_name_and_id();
920 len += strlen(loader_name_and_id);
921
922 // 4. include parent loader information
923 const char* parent_loader_phrase = "";
924 const char* parent_loader_name_and_id = "";
925 if (include_parent_loader &&
926 !cld->is_builtin_class_loader_data()) {
927 oop parent_loader = java_lang_ClassLoader::parent(class_loader());
928 ClassLoaderData *parent_cld = ClassLoaderData::class_loader_data_or_null(parent_loader);
929 // The parent loader's ClassLoaderData could be null if it is
930 // a delegating class loader that has never defined a class.
931 // In this case the loader's name must be obtained via the parent loader's oop.
932 if (parent_cld == NULL) {
933 oop cl_name_and_id = java_lang_ClassLoader::nameAndId(parent_loader);
934 if (cl_name_and_id != NULL) {
935 parent_loader_name_and_id = java_lang_String::as_utf8_string(cl_name_and_id);
936 }
937 } else {
938 parent_loader_name_and_id = parent_cld->loader_name_and_id();
939 }
940 parent_loader_phrase = ", parent loader ";
941 len += strlen(parent_loader_phrase) + strlen(parent_loader_name_and_id);
942 }
943
944 // Start to construct final full class description string
945 len += ((use_are) ? strlen(" are in ") : strlen(" is in "));
946 len += strlen(module_name_phrase) + strlen(" of loader ");
947
948 char* class_description = NEW_RESOURCE_ARRAY_RETURN_NULL(char, len);
949
950 // Just return the FQN if error when allocating string
951 if (class_description == NULL) {
952 return klass_name;
953 }
954
955 jio_snprintf(class_description, len, "%s %s in %s%s%s%s of loader %s%s%s",
956 klass_name,
957 (use_are) ? "are" : "is",
958 module_name_phrase,
959 module_name,
960 (has_version) ? "@" : "",
961 (has_version) ? version : "",
962 loader_name_and_id,
963 parent_loader_phrase,
964 parent_loader_name_and_id);
965
966 return class_description;
967 }