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