1 /*
2 * Copyright (c) 1997, 2023, 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 "cds/archiveHeapLoader.hpp"
27 #include "cds/heapShared.hpp"
28 #include "classfile/classLoaderData.inline.hpp"
29 #include "classfile/classLoaderDataGraph.inline.hpp"
30 #include "classfile/javaClasses.inline.hpp"
31 #include "classfile/moduleEntry.hpp"
32 #include "classfile/systemDictionary.hpp"
33 #include "classfile/systemDictionaryShared.hpp"
34 #include "classfile/vmClasses.hpp"
35 #include "classfile/vmSymbols.hpp"
36 #include "gc/shared/collectedHeap.inline.hpp"
37 #include "jvm_io.h"
38 #include "logging/log.hpp"
39 #include "memory/metadataFactory.hpp"
40 #include "memory/metaspaceClosure.hpp"
41 #include "memory/oopFactory.hpp"
42 #include "memory/resourceArea.hpp"
43 #include "memory/universe.hpp"
44 #include "oops/compressedOops.inline.hpp"
45 #include "oops/instanceKlass.hpp"
46 #include "oops/klass.inline.hpp"
47 #include "oops/objArrayKlass.hpp"
48 #include "oops/oop.inline.hpp"
49 #include "oops/oopHandle.inline.hpp"
50 #include "prims/jvmtiExport.hpp"
51 #include "runtime/arguments.hpp"
52 #include "runtime/atomic.hpp"
53 #include "runtime/handles.inline.hpp"
54 #include "utilities/macros.hpp"
55 #include "utilities/powerOfTwo.hpp"
56 #include "utilities/stack.inline.hpp"
57
58 void Klass::set_java_mirror(Handle m) {
59 assert(!m.is_null(), "New mirror should never be null.");
60 assert(_java_mirror.is_empty(), "should only be used to initialize mirror");
61 _java_mirror = class_loader_data()->add_handle(m);
62 }
63
64 bool Klass::is_cloneable() const {
65 return _access_flags.is_cloneable_fast() ||
66 is_subtype_of(vmClasses::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 != nullptr) _name->increment_refcount();
83
84 if (Arguments::is_dumping_archive() && is_instance_klass()) {
85 SystemDictionaryShared::init_dumptime_info(InstanceKlass::cast(this));
86 }
87 }
88
89 bool Klass::is_subclass_of(const Klass* k) const {
90 // Run up the super chain and check
91 if (this == k) return true;
92
93 Klass* t = const_cast<Klass*>(this)->super();
94
95 while (t != nullptr) {
96 if (t == k) return true;
97 t = t->super();
98 }
99 return false;
100 }
101
102 void Klass::release_C_heap_structures(bool release_constant_pool) {
103 if (_name != nullptr) _name->decrement_refcount();
104 }
105
106 bool Klass::search_secondary_supers(Klass* k) const {
107 // Put some extra logic here out-of-line, before the search proper.
108 // This cuts down the size of the inline method.
109
110 // This is necessary, since I am never in my own secondary_super list.
111 if (this == k)
112 return true;
113 // Scan the array-of-objects for a match
114 int cnt = secondary_supers()->length();
115 for (int i = 0; i < cnt; i++) {
116 if (secondary_supers()->at(i) == k) {
117 ((Klass*)this)->set_secondary_super_cache(k);
118 return true;
119 }
120 }
121 return false;
122 }
123
124 // Return self, except for abstract classes with exactly 1
125 // implementor. Then return the 1 concrete implementation.
126 Klass *Klass::up_cast_abstract() {
127 Klass *r = this;
128 while( r->is_abstract() ) { // Receiver is abstract?
129 Klass *s = r->subklass(); // Check for exactly 1 subklass
130 if (s == nullptr || s->next_sibling() != nullptr) // Oops; wrong count; give up
131 return this; // Return 'this' as a no-progress flag
132 r = s; // Loop till find concrete class
133 }
134 return r; // Return the 1 concrete class
135 }
136
137 // Find LCA in class hierarchy
138 Klass *Klass::LCA( Klass *k2 ) {
139 Klass *k1 = this;
140 while( 1 ) {
141 if( k1->is_subtype_of(k2) ) return k2;
142 if( k2->is_subtype_of(k1) ) return k1;
143 k1 = k1->super();
144 k2 = k2->super();
145 }
146 }
147
148
149 void Klass::check_valid_for_instantiation(bool throwError, TRAPS) {
150 ResourceMark rm(THREAD);
151 THROW_MSG(throwError ? vmSymbols::java_lang_InstantiationError()
152 : vmSymbols::java_lang_InstantiationException(), external_name());
153 }
154
155
156 void Klass::copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS) {
157 ResourceMark rm(THREAD);
158 assert(s != nullptr, "Throw NPE!");
159 THROW_MSG(vmSymbols::java_lang_ArrayStoreException(),
160 err_msg("arraycopy: source type %s is not an array", s->klass()->external_name()));
161 }
162
163
164 void Klass::initialize(TRAPS) {
165 ShouldNotReachHere();
166 }
167
168 Klass* Klass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
169 #ifdef ASSERT
170 tty->print_cr("Error: find_field called on a klass oop."
171 " Likely error: reflection method does not correctly"
172 " wrap return value in a mirror object.");
173 #endif
174 ShouldNotReachHere();
175 return nullptr;
176 }
177
178 Method* Klass::uncached_lookup_method(const Symbol* name, const Symbol* signature,
179 OverpassLookupMode overpass_mode,
180 PrivateLookupMode private_mode) const {
181 #ifdef ASSERT
182 tty->print_cr("Error: uncached_lookup_method called on a klass oop."
183 " Likely error: reflection method does not correctly"
184 " wrap return value in a mirror object.");
185 #endif
186 ShouldNotReachHere();
187 return nullptr;
188 }
189
190 void* Klass::operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, TRAPS) throw() {
191 return Metaspace::allocate(loader_data, word_size, MetaspaceObj::ClassType, THREAD);
192 }
193
194 static markWord make_prototype(Klass* kls) {
195 markWord prototype = markWord::prototype();
196 #ifdef _LP64
197 if (UseCompactObjectHeaders) {
198 prototype = prototype.set_klass(kls);
199 }
200 #endif
201 return prototype;
202 }
203
204 // "Normal" instantiation is preceded by a MetaspaceObj allocation
205 // which zeros out memory - calloc equivalent.
206 // The constructor is also used from CppVtableCloner,
207 // which doesn't zero out the memory before calling the constructor.
208 Klass::Klass(KlassKind kind) : _kind(kind),
209 _prototype_header(make_prototype(this)),
210 _shared_class_path_index(-1) {
211 CDS_ONLY(_shared_class_flags = 0;)
212 CDS_JAVA_HEAP_ONLY(_archived_mirror_index = -1;)
213 _primary_supers[0] = this;
214 set_super_check_offset(in_bytes(primary_supers_offset()));
215 }
216
217 jint Klass::array_layout_helper(BasicType etype) {
218 assert(etype >= T_BOOLEAN && etype <= T_OBJECT, "valid etype");
219 // Note that T_ARRAY is not allowed here.
220 int hsize = arrayOopDesc::base_offset_in_bytes(etype);
221 int esize = type2aelembytes(etype);
222 bool isobj = (etype == T_OBJECT);
223 int tag = isobj ? _lh_array_tag_obj_value : _lh_array_tag_type_value;
224 int lh = array_layout_helper(tag, hsize, etype, exact_log2(esize));
225
226 assert(lh < (int)_lh_neutral_value, "must look like an array layout");
227 assert(layout_helper_is_array(lh), "correct kind");
228 assert(layout_helper_is_objArray(lh) == isobj, "correct kind");
229 assert(layout_helper_is_typeArray(lh) == !isobj, "correct kind");
230 assert(layout_helper_header_size(lh) == hsize, "correct decode");
231 assert(layout_helper_element_type(lh) == etype, "correct decode");
232 assert(1 << layout_helper_log2_element_size(lh) == esize, "correct decode");
233
234 return lh;
235 }
236
237 bool Klass::can_be_primary_super_slow() const {
238 if (super() == nullptr)
239 return true;
240 else if (super()->super_depth() >= primary_super_limit()-1)
241 return false;
242 else
243 return true;
244 }
245
246 void Klass::initialize_supers(Klass* k, Array<InstanceKlass*>* transitive_interfaces, TRAPS) {
247 if (k == nullptr) {
248 set_super(nullptr);
249 _primary_supers[0] = this;
250 assert(super_depth() == 0, "Object must already be initialized properly");
251 } else if (k != super() || k == vmClasses::Object_klass()) {
252 assert(super() == nullptr || super() == vmClasses::Object_klass(),
253 "initialize this only once to a non-trivial value");
254 set_super(k);
255 Klass* sup = k;
256 int sup_depth = sup->super_depth();
257 juint my_depth = MIN2(sup_depth + 1, (int)primary_super_limit());
258 if (!can_be_primary_super_slow())
259 my_depth = primary_super_limit();
260 for (juint i = 0; i < my_depth; i++) {
261 _primary_supers[i] = sup->_primary_supers[i];
262 }
263 Klass* *super_check_cell;
264 if (my_depth < primary_super_limit()) {
265 _primary_supers[my_depth] = this;
266 super_check_cell = &_primary_supers[my_depth];
267 } else {
268 // Overflow of the primary_supers array forces me to be secondary.
269 super_check_cell = &_secondary_super_cache;
270 }
271 set_super_check_offset(u4((address)super_check_cell - (address) this));
272
273 #ifdef ASSERT
274 {
275 juint j = super_depth();
276 assert(j == my_depth, "computed accessor gets right answer");
277 Klass* t = this;
278 while (!t->can_be_primary_super()) {
279 t = t->super();
280 j = t->super_depth();
281 }
282 for (juint j1 = j+1; j1 < primary_super_limit(); j1++) {
283 assert(primary_super_of_depth(j1) == nullptr, "super list padding");
284 }
285 while (t != nullptr) {
286 assert(primary_super_of_depth(j) == t, "super list initialization");
287 t = t->super();
288 --j;
289 }
290 assert(j == (juint)-1, "correct depth count");
291 }
292 #endif
293 }
294
295 if (secondary_supers() == nullptr) {
296
297 // Now compute the list of secondary supertypes.
298 // Secondaries can occasionally be on the super chain,
299 // if the inline "_primary_supers" array overflows.
300 int extras = 0;
301 Klass* p;
302 for (p = super(); !(p == nullptr || p->can_be_primary_super()); p = p->super()) {
303 ++extras;
304 }
305
306 ResourceMark rm(THREAD); // need to reclaim GrowableArrays allocated below
307
308 // Compute the "real" non-extra secondaries.
309 GrowableArray<Klass*>* secondaries = compute_secondary_supers(extras, transitive_interfaces);
310 if (secondaries == nullptr) {
311 // secondary_supers set by compute_secondary_supers
312 return;
313 }
314
315 GrowableArray<Klass*>* primaries = new GrowableArray<Klass*>(extras);
316
317 for (p = super(); !(p == nullptr || p->can_be_primary_super()); p = p->super()) {
318 int i; // Scan for overflow primaries being duplicates of 2nd'arys
319
320 // This happens frequently for very deeply nested arrays: the
321 // primary superclass chain overflows into the secondary. The
322 // secondary list contains the element_klass's secondaries with
323 // an extra array dimension added. If the element_klass's
324 // secondary list already contains some primary overflows, they
325 // (with the extra level of array-ness) will collide with the
326 // normal primary superclass overflows.
327 for( i = 0; i < secondaries->length(); i++ ) {
328 if( secondaries->at(i) == p )
329 break;
330 }
331 if( i < secondaries->length() )
332 continue; // It's a dup, don't put it in
333 primaries->push(p);
334 }
335 // Combine the two arrays into a metadata object to pack the array.
336 // The primaries are added in the reverse order, then the secondaries.
337 int new_length = primaries->length() + secondaries->length();
338 Array<Klass*>* s2 = MetadataFactory::new_array<Klass*>(
339 class_loader_data(), new_length, CHECK);
340 int fill_p = primaries->length();
341 for (int j = 0; j < fill_p; j++) {
342 s2->at_put(j, primaries->pop()); // add primaries in reverse order.
343 }
344 for( int j = 0; j < secondaries->length(); j++ ) {
345 s2->at_put(j+fill_p, secondaries->at(j)); // add secondaries on the end.
346 }
347
348 #ifdef ASSERT
349 // We must not copy any null placeholders left over from bootstrap.
350 for (int j = 0; j < s2->length(); j++) {
351 assert(s2->at(j) != nullptr, "correct bootstrapping order");
352 }
353 #endif
354
355 set_secondary_supers(s2);
356 }
357 }
358
359 GrowableArray<Klass*>* Klass::compute_secondary_supers(int num_extra_slots,
360 Array<InstanceKlass*>* transitive_interfaces) {
361 assert(num_extra_slots == 0, "override for complex klasses");
362 assert(transitive_interfaces == nullptr, "sanity");
363 set_secondary_supers(Universe::the_empty_klass_array());
364 return nullptr;
365 }
366
367
368 // superklass links
369 InstanceKlass* Klass::superklass() const {
370 assert(super() == nullptr || super()->is_instance_klass(), "must be instance klass");
371 return _super == nullptr ? nullptr : InstanceKlass::cast(_super);
372 }
373
374 // subklass links. Used by the compiler (and vtable initialization)
375 // May be cleaned concurrently, so must use the Compile_lock.
376 // The log parameter is for clean_weak_klass_links to report unlinked classes.
377 Klass* Klass::subklass(bool log) const {
378 // Need load_acquire on the _subklass, because it races with inserts that
379 // publishes freshly initialized data.
380 for (Klass* chain = Atomic::load_acquire(&_subklass);
381 chain != nullptr;
382 // Do not need load_acquire on _next_sibling, because inserts never
383 // create _next_sibling edges to dead data.
384 chain = Atomic::load(&chain->_next_sibling))
385 {
386 if (chain->is_loader_alive()) {
387 return chain;
388 } else if (log) {
389 if (log_is_enabled(Trace, class, unload)) {
390 ResourceMark rm;
391 log_trace(class, unload)("unlinking class (subclass): %s", chain->external_name());
392 }
393 }
394 }
395 return nullptr;
396 }
397
398 Klass* Klass::next_sibling(bool log) const {
399 // Do not need load_acquire on _next_sibling, because inserts never
400 // create _next_sibling edges to dead data.
401 for (Klass* chain = Atomic::load(&_next_sibling);
402 chain != nullptr;
403 chain = Atomic::load(&chain->_next_sibling)) {
404 // Only return alive klass, there may be stale klass
405 // in this chain if cleaned concurrently.
406 if (chain->is_loader_alive()) {
407 return chain;
408 } else if (log) {
409 if (log_is_enabled(Trace, class, unload)) {
410 ResourceMark rm;
411 log_trace(class, unload)("unlinking class (sibling): %s", chain->external_name());
412 }
413 }
414 }
415 return nullptr;
416 }
417
418 void Klass::set_subklass(Klass* s) {
419 assert(s != this, "sanity check");
420 Atomic::release_store(&_subklass, s);
421 }
422
423 void Klass::set_next_sibling(Klass* s) {
424 assert(s != this, "sanity check");
425 // Does not need release semantics. If used by cleanup, it will link to
426 // already safely published data, and if used by inserts, will be published
427 // safely using cmpxchg.
428 Atomic::store(&_next_sibling, s);
429 }
430
431 void Klass::append_to_sibling_list() {
432 if (Universe::is_fully_initialized()) {
433 assert_locked_or_safepoint(Compile_lock);
434 }
435 debug_only(verify();)
436 // add ourselves to superklass' subklass list
437 InstanceKlass* super = superklass();
438 if (super == nullptr) return; // special case: class Object
439 assert((!super->is_interface() // interfaces cannot be supers
440 && (super->superklass() == nullptr || !is_interface())),
441 "an interface can only be a subklass of Object");
442
443 // Make sure there is no stale subklass head
444 super->clean_subklass();
445
446 for (;;) {
447 Klass* prev_first_subklass = Atomic::load_acquire(&_super->_subklass);
448 if (prev_first_subklass != nullptr) {
449 // set our sibling to be the superklass' previous first subklass
450 assert(prev_first_subklass->is_loader_alive(), "May not attach not alive klasses");
451 set_next_sibling(prev_first_subklass);
452 }
453 // Note that the prev_first_subklass is always alive, meaning no sibling_next links
454 // are ever created to not alive klasses. This is an important invariant of the lock-free
455 // cleaning protocol, that allows us to safely unlink dead klasses from the sibling list.
456 if (Atomic::cmpxchg(&super->_subklass, prev_first_subklass, this) == prev_first_subklass) {
457 return;
458 }
459 }
460 debug_only(verify();)
461 }
462
463 void Klass::clean_subklass() {
464 for (;;) {
465 // Need load_acquire, due to contending with concurrent inserts
466 Klass* subklass = Atomic::load_acquire(&_subklass);
467 if (subklass == nullptr || subklass->is_loader_alive()) {
468 return;
469 }
470 // Try to fix _subklass until it points at something not dead.
471 Atomic::cmpxchg(&_subklass, subklass, subklass->next_sibling());
472 }
473 }
474
475 void Klass::clean_weak_klass_links(bool unloading_occurred, bool clean_alive_klasses) {
476 if (!ClassUnloading || !unloading_occurred) {
477 return;
478 }
479
480 Klass* root = vmClasses::Object_klass();
481 Stack<Klass*, mtGC> stack;
482
483 stack.push(root);
484 while (!stack.is_empty()) {
485 Klass* current = stack.pop();
486
487 assert(current->is_loader_alive(), "just checking, this should be live");
488
489 // Find and set the first alive subklass
490 Klass* sub = current->subklass(true);
491 current->clean_subklass();
492 if (sub != nullptr) {
493 stack.push(sub);
494 }
495
496 // Find and set the first alive sibling
497 Klass* sibling = current->next_sibling(true);
498 current->set_next_sibling(sibling);
499 if (sibling != nullptr) {
500 stack.push(sibling);
501 }
502
503 // Clean the implementors list and method data.
504 if (clean_alive_klasses && current->is_instance_klass()) {
505 InstanceKlass* ik = InstanceKlass::cast(current);
506 ik->clean_weak_instanceklass_links();
507
508 // JVMTI RedefineClasses creates previous versions that are not in
509 // the class hierarchy, so process them here.
510 while ((ik = ik->previous_versions()) != nullptr) {
511 ik->clean_weak_instanceklass_links();
512 }
513 }
514 }
515 }
516
517 void Klass::metaspace_pointers_do(MetaspaceClosure* it) {
518 if (log_is_enabled(Trace, cds)) {
519 ResourceMark rm;
520 log_trace(cds)("Iter(Klass): %p (%s)", this, external_name());
521 }
522
523 it->push(&_name);
524 it->push(&_secondary_super_cache);
525 it->push(&_secondary_supers);
526 for (int i = 0; i < _primary_super_limit; i++) {
527 it->push(&_primary_supers[i]);
528 }
529 it->push(&_super);
530 if (!Arguments::is_dumping_archive()) {
531 // If dumping archive, these may point to excluded classes. There's no need
532 // to follow these pointers anyway, as they will be set to null in
533 // remove_unshareable_info().
534 it->push((Klass**)&_subklass);
535 it->push((Klass**)&_next_sibling);
536 it->push(&_next_link);
537 }
538
539 vtableEntry* vt = start_of_vtable();
540 for (int i=0; i<vtable_length(); i++) {
541 it->push(vt[i].method_addr());
542 }
543 }
544
545 #if INCLUDE_CDS
546 void Klass::remove_unshareable_info() {
547 assert (Arguments::is_dumping_archive(),
548 "only called during CDS dump time");
549 JFR_ONLY(REMOVE_ID(this);)
550 if (log_is_enabled(Trace, cds, unshareable)) {
551 ResourceMark rm;
552 log_trace(cds, unshareable)("remove: %s", external_name());
553 }
554
555 set_subklass(nullptr);
556 set_next_sibling(nullptr);
557 set_next_link(nullptr);
558
559 // Null out class_loader_data because we don't share that yet.
560 set_class_loader_data(nullptr);
561 set_is_shared();
562 }
563
564 void Klass::remove_java_mirror() {
565 Arguments::assert_is_dumping_archive();
566 if (log_is_enabled(Trace, cds, unshareable)) {
567 ResourceMark rm;
568 log_trace(cds, unshareable)("remove java_mirror: %s", external_name());
569 }
570 // Just null out the mirror. The class_loader_data() no longer exists.
571 clear_java_mirror_handle();
572 }
573
574 void Klass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) {
575 assert(is_klass(), "ensure C++ vtable is restored");
576 assert(is_shared(), "must be set");
577 JFR_ONLY(RESTORE_ID(this);)
578 if (log_is_enabled(Trace, cds, unshareable)) {
579 ResourceMark rm(THREAD);
580 log_trace(cds, unshareable)("restore: %s", external_name());
581 }
582
583 // If an exception happened during CDS restore, some of these fields may already be
584 // set. We leave the class on the CLD list, even if incomplete so that we don't
585 // modify the CLD list outside a safepoint.
586 if (class_loader_data() == nullptr) {
587 set_class_loader_data(loader_data);
588
589 // Add to class loader list first before creating the mirror
590 // (same order as class file parsing)
591 loader_data->add_class(this);
592 }
593
594 Handle loader(THREAD, loader_data->class_loader());
595 ModuleEntry* module_entry = nullptr;
596 Klass* k = this;
597 if (k->is_objArray_klass()) {
598 k = ObjArrayKlass::cast(k)->bottom_klass();
599 }
600 // Obtain klass' module.
601 if (k->is_instance_klass()) {
602 InstanceKlass* ik = (InstanceKlass*) k;
603 module_entry = ik->module();
604 } else {
605 module_entry = ModuleEntryTable::javabase_moduleEntry();
606 }
607 // Obtain java.lang.Module, if available
608 Handle module_handle(THREAD, ((module_entry != nullptr) ? module_entry->module() : (oop)nullptr));
609
610 if (this->has_archived_mirror_index()) {
611 ResourceMark rm(THREAD);
612 log_debug(cds, mirror)("%s has raw archived mirror", external_name());
613 if (ArchiveHeapLoader::is_in_use()) {
614 bool present = java_lang_Class::restore_archived_mirror(this, loader, module_handle,
615 protection_domain,
616 CHECK);
617 if (present) {
618 return;
619 }
620 }
621
622 // No archived mirror data
623 log_debug(cds, mirror)("No archived mirror data for %s", external_name());
624 clear_java_mirror_handle();
625 this->clear_archived_mirror_index();
626 }
627
628 // Only recreate it if not present. A previous attempt to restore may have
629 // gotten an OOM later but keep the mirror if it was created.
630 if (java_mirror() == nullptr) {
631 ResourceMark rm(THREAD);
632 log_trace(cds, mirror)("Recreate mirror for %s", external_name());
633 java_lang_Class::create_mirror(this, loader, module_handle, protection_domain, Handle(), CHECK);
634 }
635 }
636 #endif // INCLUDE_CDS
637
638 #if INCLUDE_CDS_JAVA_HEAP
639 oop Klass::archived_java_mirror() {
640 assert(has_archived_mirror_index(), "must have archived mirror");
641 return HeapShared::get_root(_archived_mirror_index);
642 }
643
644 void Klass::clear_archived_mirror_index() {
645 if (_archived_mirror_index >= 0) {
646 HeapShared::clear_root(_archived_mirror_index);
647 }
648 _archived_mirror_index = -1;
649 }
650
651 // No GC barrier
652 void Klass::set_archived_java_mirror(int mirror_index) {
653 assert(DumpSharedSpaces, "called only during dumptime");
654 _archived_mirror_index = mirror_index;
655 }
656 #endif // INCLUDE_CDS_JAVA_HEAP
657
658 void Klass::check_array_allocation_length(int length, int max_length, TRAPS) {
659 if (length > max_length) {
660 if (!THREAD->in_retryable_allocation()) {
661 report_java_out_of_memory("Requested array size exceeds VM limit");
662 JvmtiExport::post_array_size_exhausted();
663 THROW_OOP(Universe::out_of_memory_error_array_size());
664 } else {
665 THROW_OOP(Universe::out_of_memory_error_retry());
666 }
667 } else if (length < 0) {
668 THROW_MSG(vmSymbols::java_lang_NegativeArraySizeException(), err_msg("%d", length));
669 }
670 }
671
672 // Replace the last '+' char with '/'.
673 static char* convert_hidden_name_to_java(Symbol* name) {
674 size_t name_len = name->utf8_length();
675 char* result = NEW_RESOURCE_ARRAY(char, name_len + 1);
676 name->as_klass_external_name(result, (int)name_len + 1);
677 for (int index = (int)name_len; index > 0; index--) {
678 if (result[index] == '+') {
679 result[index] = JVM_SIGNATURE_SLASH;
680 break;
681 }
682 }
683 return result;
684 }
685
686 // In product mode, this function doesn't have virtual function calls so
687 // there might be some performance advantage to handling InstanceKlass here.
688 const char* Klass::external_name() const {
689 if (is_instance_klass()) {
690 const InstanceKlass* ik = static_cast<const InstanceKlass*>(this);
691 if (ik->is_hidden()) {
692 char* result = convert_hidden_name_to_java(name());
693 return result;
694 }
695 } else if (is_objArray_klass() && ObjArrayKlass::cast(this)->bottom_klass()->is_hidden()) {
696 char* result = convert_hidden_name_to_java(name());
697 return result;
698 }
699 if (name() == nullptr) return "<unknown>";
700 return name()->as_klass_external_name();
701 }
702
703 const char* Klass::signature_name() const {
704 if (name() == nullptr) return "<unknown>";
705 if (is_objArray_klass() && ObjArrayKlass::cast(this)->bottom_klass()->is_hidden()) {
706 size_t name_len = name()->utf8_length();
707 char* result = NEW_RESOURCE_ARRAY(char, name_len + 1);
708 name()->as_C_string(result, (int)name_len + 1);
709 for (int index = (int)name_len; index > 0; index--) {
710 if (result[index] == '+') {
711 result[index] = JVM_SIGNATURE_DOT;
712 break;
713 }
714 }
715 return result;
716 }
717 return name()->as_C_string();
718 }
719
720 const char* Klass::external_kind() const {
721 if (is_interface()) return "interface";
722 if (is_abstract()) return "abstract class";
723 return "class";
724 }
725
726 // Unless overridden, jvmti_class_status has no flags set.
727 jint Klass::jvmti_class_status() const {
728 return 0;
729 }
730
731
732 // Printing
733
734 void Klass::print_on(outputStream* st) const {
735 ResourceMark rm;
736 // print title
737 st->print("%s", internal_name());
738 print_address_on(st);
739 st->cr();
740 }
741
742 #define BULLET " - "
743
744 // Caller needs ResourceMark
745 void Klass::oop_print_on(oop obj, outputStream* st) {
746 // print title
747 st->print_cr("%s ", internal_name());
748 obj->print_address_on(st);
749
750 if (WizardMode) {
751 // print header
752 obj->mark().print_on(st);
753 st->cr();
754 if (UseCompactObjectHeaders) {
755 st->print(BULLET"prototype_header: " INTPTR_FORMAT, _prototype_header.value());
756 st->cr();
757 }
758 }
759
760 // print class
761 st->print(BULLET"klass: ");
762 obj->klass()->print_value_on(st);
763 st->cr();
764 }
765
766 void Klass::oop_print_value_on(oop obj, outputStream* st) {
767 // print title
768 ResourceMark rm; // Cannot print in debug mode without this
769 st->print("%s", internal_name());
770 obj->print_address_on(st);
771 }
772
773 // Verification
774
775 void Klass::verify_on(outputStream* st) {
776
777 // This can be expensive, but it is worth checking that this klass is actually
778 // in the CLD graph but not in production.
779 assert(Metaspace::contains((address)this), "Should be");
780
781 guarantee(this->is_klass(),"should be klass");
782
783 if (super() != nullptr) {
784 guarantee(super()->is_klass(), "should be klass");
785 }
786 if (secondary_super_cache() != nullptr) {
787 Klass* ko = secondary_super_cache();
788 guarantee(ko->is_klass(), "should be klass");
789 }
790 for ( uint i = 0; i < primary_super_limit(); i++ ) {
791 Klass* ko = _primary_supers[i];
792 if (ko != nullptr) {
793 guarantee(ko->is_klass(), "should be klass");
794 }
795 }
796
797 if (java_mirror_no_keepalive() != nullptr) {
798 guarantee(java_lang_Class::is_instance(java_mirror_no_keepalive()), "should be instance");
799 }
800 }
801
802 void Klass::oop_verify_on(oop obj, outputStream* st) {
803 guarantee(oopDesc::is_oop(obj), "should be oop");
804 guarantee(obj->klass()->is_klass(), "klass field is not a klass");
805 }
806
807 bool Klass::is_valid(Klass* k) {
808 if (!is_aligned(k, sizeof(MetaWord))) return false;
809 if ((size_t)k < os::min_page_size()) return false;
810
811 if (!os::is_readable_range(k, k + 1)) return false;
812 if (!Metaspace::contains(k)) return false;
813
814 if (!Symbol::is_valid(k->name())) return false;
815 return ClassLoaderDataGraph::is_valid(k->class_loader_data());
816 }
817
818 Method* Klass::method_at_vtable(int index) {
819 #ifndef PRODUCT
820 assert(index >= 0, "valid vtable index");
821 if (DebugVtables) {
822 verify_vtable_index(index);
823 }
824 #endif
825 return start_of_vtable()[index].method();
826 }
827
828
829 #ifndef PRODUCT
830
831 bool Klass::verify_vtable_index(int i) {
832 int limit = vtable_length()/vtableEntry::size();
833 assert(i >= 0 && i < limit, "index %d out of bounds %d", i, limit);
834 return true;
835 }
836
837 #endif // PRODUCT
838
839 // Caller needs ResourceMark
840 // joint_in_module_of_loader provides an optimization if 2 classes are in
841 // the same module to succinctly print out relevant information about their
842 // module name and class loader's name_and_id for error messages.
843 // Format:
844 // <fully-qualified-external-class-name1> and <fully-qualified-external-class-name2>
845 // are in module <module-name>[@<version>]
846 // of loader <loader-name_and_id>[, parent loader <parent-loader-name_and_id>]
847 const char* Klass::joint_in_module_of_loader(const Klass* class2, bool include_parent_loader) const {
848 assert(module() == class2->module(), "classes do not have the same module");
849 const char* class1_name = external_name();
850 size_t len = strlen(class1_name) + 1;
851
852 const char* class2_description = class2->class_in_module_of_loader(true, include_parent_loader);
853 len += strlen(class2_description);
854
855 len += strlen(" and ");
856
857 char* joint_description = NEW_RESOURCE_ARRAY_RETURN_NULL(char, len);
858
859 // Just return the FQN if error when allocating string
860 if (joint_description == nullptr) {
861 return class1_name;
862 }
863
864 jio_snprintf(joint_description, len, "%s and %s",
865 class1_name,
866 class2_description);
867
868 return joint_description;
869 }
870
871 // Caller needs ResourceMark
872 // class_in_module_of_loader provides a standard way to include
873 // relevant information about a class, such as its module name as
874 // well as its class loader's name_and_id, in error messages and logging.
875 // Format:
876 // <fully-qualified-external-class-name> is in module <module-name>[@<version>]
877 // of loader <loader-name_and_id>[, parent loader <parent-loader-name_and_id>]
878 const char* Klass::class_in_module_of_loader(bool use_are, bool include_parent_loader) const {
879 // 1. fully qualified external name of class
880 const char* klass_name = external_name();
881 size_t len = strlen(klass_name) + 1;
882
883 // 2. module name + @version
884 const char* module_name = "";
885 const char* version = "";
886 bool has_version = false;
887 bool module_is_named = false;
888 const char* module_name_phrase = "";
889 const Klass* bottom_klass = is_objArray_klass() ?
890 ObjArrayKlass::cast(this)->bottom_klass() : this;
891 if (bottom_klass->is_instance_klass()) {
892 ModuleEntry* module = InstanceKlass::cast(bottom_klass)->module();
893 if (module->is_named()) {
894 module_is_named = true;
895 module_name_phrase = "module ";
896 module_name = module->name()->as_C_string();
897 len += strlen(module_name);
898 // Use version if exists and is not a jdk module
899 if (module->should_show_version()) {
900 has_version = true;
901 version = module->version()->as_C_string();
902 // Include stlen(version) + 1 for the "@"
903 len += strlen(version) + 1;
904 }
905 } else {
906 module_name = UNNAMED_MODULE;
907 len += UNNAMED_MODULE_LEN;
908 }
909 } else {
910 // klass is an array of primitives, module is java.base
911 module_is_named = true;
912 module_name_phrase = "module ";
913 module_name = JAVA_BASE_NAME;
914 len += JAVA_BASE_NAME_LEN;
915 }
916
917 // 3. class loader's name_and_id
918 ClassLoaderData* cld = class_loader_data();
919 assert(cld != nullptr, "class_loader_data should not be null");
920 const char* loader_name_and_id = cld->loader_name_and_id();
921 len += strlen(loader_name_and_id);
922
923 // 4. include parent loader information
924 const char* parent_loader_phrase = "";
925 const char* parent_loader_name_and_id = "";
926 if (include_parent_loader &&
927 !cld->is_builtin_class_loader_data()) {
928 oop parent_loader = java_lang_ClassLoader::parent(class_loader());
929 ClassLoaderData *parent_cld = ClassLoaderData::class_loader_data_or_null(parent_loader);
930 // The parent loader's ClassLoaderData could be null if it is
931 // a delegating class loader that has never defined a class.
932 // In this case the loader's name must be obtained via the parent loader's oop.
933 if (parent_cld == nullptr) {
934 oop cl_name_and_id = java_lang_ClassLoader::nameAndId(parent_loader);
935 if (cl_name_and_id != nullptr) {
936 parent_loader_name_and_id = java_lang_String::as_utf8_string(cl_name_and_id);
937 }
938 } else {
939 parent_loader_name_and_id = parent_cld->loader_name_and_id();
940 }
941 parent_loader_phrase = ", parent loader ";
942 len += strlen(parent_loader_phrase) + strlen(parent_loader_name_and_id);
943 }
944
945 // Start to construct final full class description string
946 len += ((use_are) ? strlen(" are in ") : strlen(" is in "));
947 len += strlen(module_name_phrase) + strlen(" of loader ");
948
949 char* class_description = NEW_RESOURCE_ARRAY_RETURN_NULL(char, len);
950
951 // Just return the FQN if error when allocating string
952 if (class_description == nullptr) {
953 return klass_name;
954 }
955
956 jio_snprintf(class_description, len, "%s %s in %s%s%s%s of loader %s%s%s",
957 klass_name,
958 (use_are) ? "are" : "is",
959 module_name_phrase,
960 module_name,
961 (has_version) ? "@" : "",
962 (has_version) ? version : "",
963 loader_name_and_id,
964 parent_loader_phrase,
965 parent_loader_name_and_id);
966
967 return class_description;
968 }