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