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 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 Klass::Klass() : _kind(UnknownKlassKind) {
205 assert(CDSConfig::is_dumping_static_archive() || UseSharedSpaces, "only for cds");
206 }
207
208 // "Normal" instantiation is preceded by a MetaspaceObj allocation
209 // which zeros out memory - calloc equivalent.
210 // The constructor is also used from CppVtableCloner,
211 // which doesn't zero out the memory before calling the constructor.
212 Klass::Klass(KlassKind kind) : _kind(kind),
213 _prototype_header(make_prototype(this)),
214 _shared_class_path_index(-1) {
215 CDS_ONLY(_shared_class_flags = 0;)
216 CDS_JAVA_HEAP_ONLY(_archived_mirror_index = -1;)
217 _primary_supers[0] = this;
218 set_super_check_offset(in_bytes(primary_supers_offset()));
219 }
220
221 jint Klass::array_layout_helper(BasicType etype) {
222 assert(etype >= T_BOOLEAN && etype <= T_OBJECT, "valid etype");
223 // Note that T_ARRAY is not allowed here.
224 int hsize = arrayOopDesc::base_offset_in_bytes(etype);
225 int esize = type2aelembytes(etype);
226 bool isobj = (etype == T_OBJECT);
227 int tag = isobj ? _lh_array_tag_obj_value : _lh_array_tag_type_value;
228 int lh = array_layout_helper(tag, hsize, etype, exact_log2(esize));
229
230 assert(lh < (int)_lh_neutral_value, "must look like an array layout");
231 assert(layout_helper_is_array(lh), "correct kind");
232 assert(layout_helper_is_objArray(lh) == isobj, "correct kind");
233 assert(layout_helper_is_typeArray(lh) == !isobj, "correct kind");
234 assert(layout_helper_header_size(lh) == hsize, "correct decode");
235 assert(layout_helper_element_type(lh) == etype, "correct decode");
236 assert(1 << layout_helper_log2_element_size(lh) == esize, "correct decode");
237
238 return lh;
239 }
240
241 bool Klass::can_be_primary_super_slow() const {
242 if (super() == nullptr)
243 return true;
244 else if (super()->super_depth() >= primary_super_limit()-1)
245 return false;
246 else
247 return true;
248 }
249
250 void Klass::initialize_supers(Klass* k, Array<InstanceKlass*>* transitive_interfaces, TRAPS) {
251 if (k == nullptr) {
252 set_super(nullptr);
253 _primary_supers[0] = this;
254 assert(super_depth() == 0, "Object must already be initialized properly");
255 } else if (k != super() || k == vmClasses::Object_klass()) {
256 assert(super() == nullptr || super() == vmClasses::Object_klass(),
257 "initialize this only once to a non-trivial value");
258 set_super(k);
259 Klass* sup = k;
260 int sup_depth = sup->super_depth();
261 juint my_depth = MIN2(sup_depth + 1, (int)primary_super_limit());
262 if (!can_be_primary_super_slow())
263 my_depth = primary_super_limit();
264 for (juint i = 0; i < my_depth; i++) {
265 _primary_supers[i] = sup->_primary_supers[i];
266 }
267 Klass* *super_check_cell;
268 if (my_depth < primary_super_limit()) {
269 _primary_supers[my_depth] = this;
270 super_check_cell = &_primary_supers[my_depth];
271 } else {
272 // Overflow of the primary_supers array forces me to be secondary.
273 super_check_cell = &_secondary_super_cache;
274 }
275 set_super_check_offset(u4((address)super_check_cell - (address) this));
276
277 #ifdef ASSERT
278 {
279 juint j = super_depth();
280 assert(j == my_depth, "computed accessor gets right answer");
281 Klass* t = this;
282 while (!t->can_be_primary_super()) {
283 t = t->super();
284 j = t->super_depth();
285 }
286 for (juint j1 = j+1; j1 < primary_super_limit(); j1++) {
287 assert(primary_super_of_depth(j1) == nullptr, "super list padding");
288 }
289 while (t != nullptr) {
290 assert(primary_super_of_depth(j) == t, "super list initialization");
291 t = t->super();
292 --j;
293 }
294 assert(j == (juint)-1, "correct depth count");
295 }
296 #endif
297 }
298
299 if (secondary_supers() == nullptr) {
300
301 // Now compute the list of secondary supertypes.
302 // Secondaries can occasionally be on the super chain,
303 // if the inline "_primary_supers" array overflows.
304 int extras = 0;
305 Klass* p;
306 for (p = super(); !(p == nullptr || p->can_be_primary_super()); p = p->super()) {
307 ++extras;
308 }
309
310 ResourceMark rm(THREAD); // need to reclaim GrowableArrays allocated below
311
312 // Compute the "real" non-extra secondaries.
313 GrowableArray<Klass*>* secondaries = compute_secondary_supers(extras, transitive_interfaces);
314 if (secondaries == nullptr) {
315 // secondary_supers set by compute_secondary_supers
316 return;
317 }
318
319 GrowableArray<Klass*>* primaries = new GrowableArray<Klass*>(extras);
320
321 for (p = super(); !(p == nullptr || p->can_be_primary_super()); p = p->super()) {
322 int i; // Scan for overflow primaries being duplicates of 2nd'arys
323
324 // This happens frequently for very deeply nested arrays: the
325 // primary superclass chain overflows into the secondary. The
326 // secondary list contains the element_klass's secondaries with
327 // an extra array dimension added. If the element_klass's
328 // secondary list already contains some primary overflows, they
329 // (with the extra level of array-ness) will collide with the
330 // normal primary superclass overflows.
331 for( i = 0; i < secondaries->length(); i++ ) {
332 if( secondaries->at(i) == p )
333 break;
334 }
335 if( i < secondaries->length() )
336 continue; // It's a dup, don't put it in
337 primaries->push(p);
338 }
339 // Combine the two arrays into a metadata object to pack the array.
340 // The primaries are added in the reverse order, then the secondaries.
341 int new_length = primaries->length() + secondaries->length();
342 Array<Klass*>* s2 = MetadataFactory::new_array<Klass*>(
343 class_loader_data(), new_length, CHECK);
344 int fill_p = primaries->length();
345 for (int j = 0; j < fill_p; j++) {
346 s2->at_put(j, primaries->pop()); // add primaries in reverse order.
347 }
348 for( int j = 0; j < secondaries->length(); j++ ) {
349 s2->at_put(j+fill_p, secondaries->at(j)); // add secondaries on the end.
350 }
351
352 #ifdef ASSERT
353 // We must not copy any null placeholders left over from bootstrap.
354 for (int j = 0; j < s2->length(); j++) {
355 assert(s2->at(j) != nullptr, "correct bootstrapping order");
356 }
357 #endif
358
359 set_secondary_supers(s2);
360 }
361 }
362
363 GrowableArray<Klass*>* Klass::compute_secondary_supers(int num_extra_slots,
364 Array<InstanceKlass*>* transitive_interfaces) {
365 assert(num_extra_slots == 0, "override for complex klasses");
366 assert(transitive_interfaces == nullptr, "sanity");
367 set_secondary_supers(Universe::the_empty_klass_array());
368 return nullptr;
369 }
370
371
372 // superklass links
373 InstanceKlass* Klass::superklass() const {
374 assert(super() == nullptr || super()->is_instance_klass(), "must be instance klass");
375 return _super == nullptr ? nullptr : InstanceKlass::cast(_super);
376 }
377
378 // subklass links. Used by the compiler (and vtable initialization)
379 // May be cleaned concurrently, so must use the Compile_lock.
380 // The log parameter is for clean_weak_klass_links to report unlinked classes.
381 Klass* Klass::subklass(bool log) const {
382 // Need load_acquire on the _subklass, because it races with inserts that
383 // publishes freshly initialized data.
384 for (Klass* chain = Atomic::load_acquire(&_subklass);
385 chain != nullptr;
386 // Do not need load_acquire on _next_sibling, because inserts never
387 // create _next_sibling edges to dead data.
388 chain = Atomic::load(&chain->_next_sibling))
389 {
390 if (chain->is_loader_alive()) {
391 return chain;
392 } else if (log) {
393 if (log_is_enabled(Trace, class, unload)) {
394 ResourceMark rm;
395 log_trace(class, unload)("unlinking class (subclass): %s", chain->external_name());
396 }
397 }
398 }
399 return nullptr;
400 }
401
402 Klass* Klass::next_sibling(bool log) const {
403 // Do not need load_acquire on _next_sibling, because inserts never
404 // create _next_sibling edges to dead data.
405 for (Klass* chain = Atomic::load(&_next_sibling);
406 chain != nullptr;
407 chain = Atomic::load(&chain->_next_sibling)) {
408 // Only return alive klass, there may be stale klass
409 // in this chain if cleaned concurrently.
410 if (chain->is_loader_alive()) {
411 return chain;
412 } else if (log) {
413 if (log_is_enabled(Trace, class, unload)) {
414 ResourceMark rm;
415 log_trace(class, unload)("unlinking class (sibling): %s", chain->external_name());
416 }
417 }
418 }
419 return nullptr;
420 }
421
422 void Klass::set_subklass(Klass* s) {
423 assert(s != this, "sanity check");
424 Atomic::release_store(&_subklass, s);
425 }
426
427 void Klass::set_next_sibling(Klass* s) {
428 assert(s != this, "sanity check");
429 // Does not need release semantics. If used by cleanup, it will link to
430 // already safely published data, and if used by inserts, will be published
431 // safely using cmpxchg.
432 Atomic::store(&_next_sibling, s);
433 }
434
435 void Klass::append_to_sibling_list() {
436 if (Universe::is_fully_initialized()) {
437 assert_locked_or_safepoint(Compile_lock);
438 }
439 debug_only(verify();)
440 // add ourselves to superklass' subklass list
441 InstanceKlass* super = superklass();
442 if (super == nullptr) return; // special case: class Object
443 assert((!super->is_interface() // interfaces cannot be supers
444 && (super->superklass() == nullptr || !is_interface())),
445 "an interface can only be a subklass of Object");
446
447 // Make sure there is no stale subklass head
448 super->clean_subklass();
449
450 for (;;) {
451 Klass* prev_first_subklass = Atomic::load_acquire(&_super->_subklass);
452 if (prev_first_subklass != nullptr) {
453 // set our sibling to be the superklass' previous first subklass
454 assert(prev_first_subklass->is_loader_alive(), "May not attach not alive klasses");
455 set_next_sibling(prev_first_subklass);
456 }
457 // Note that the prev_first_subklass is always alive, meaning no sibling_next links
458 // are ever created to not alive klasses. This is an important invariant of the lock-free
459 // cleaning protocol, that allows us to safely unlink dead klasses from the sibling list.
460 if (Atomic::cmpxchg(&super->_subklass, prev_first_subklass, this) == prev_first_subklass) {
461 return;
462 }
463 }
464 debug_only(verify();)
465 }
466
467 void Klass::clean_subklass() {
468 for (;;) {
469 // Need load_acquire, due to contending with concurrent inserts
470 Klass* subklass = Atomic::load_acquire(&_subklass);
471 if (subklass == nullptr || subklass->is_loader_alive()) {
472 return;
473 }
474 // Try to fix _subklass until it points at something not dead.
475 Atomic::cmpxchg(&_subklass, subklass, subklass->next_sibling());
476 }
477 }
478
479 void Klass::clean_weak_klass_links(bool unloading_occurred, bool clean_alive_klasses) {
480 if (!ClassUnloading || !unloading_occurred) {
481 return;
482 }
483
484 Klass* root = vmClasses::Object_klass();
485 Stack<Klass*, mtGC> stack;
486
487 stack.push(root);
488 while (!stack.is_empty()) {
489 Klass* current = stack.pop();
490
491 assert(current->is_loader_alive(), "just checking, this should be live");
492
493 // Find and set the first alive subklass
494 Klass* sub = current->subklass(true);
495 current->clean_subklass();
496 if (sub != nullptr) {
497 stack.push(sub);
498 }
499
500 // Find and set the first alive sibling
501 Klass* sibling = current->next_sibling(true);
502 current->set_next_sibling(sibling);
503 if (sibling != nullptr) {
504 stack.push(sibling);
505 }
506
507 // Clean the implementors list and method data.
508 if (clean_alive_klasses && current->is_instance_klass()) {
509 InstanceKlass* ik = InstanceKlass::cast(current);
510 ik->clean_weak_instanceklass_links();
511
512 // JVMTI RedefineClasses creates previous versions that are not in
513 // the class hierarchy, so process them here.
514 while ((ik = ik->previous_versions()) != nullptr) {
515 ik->clean_weak_instanceklass_links();
516 }
517 }
518 }
519 }
520
521 void Klass::metaspace_pointers_do(MetaspaceClosure* it) {
522 if (log_is_enabled(Trace, cds)) {
523 ResourceMark rm;
524 log_trace(cds)("Iter(Klass): %p (%s)", this, external_name());
525 }
526
527 it->push(&_name);
528 it->push(&_secondary_super_cache);
529 it->push(&_secondary_supers);
530 for (int i = 0; i < _primary_super_limit; i++) {
531 it->push(&_primary_supers[i]);
532 }
533 it->push(&_super);
534 if (!CDSConfig::is_dumping_archive()) {
535 // If dumping archive, these may point to excluded classes. There's no need
536 // to follow these pointers anyway, as they will be set to null in
537 // remove_unshareable_info().
538 it->push((Klass**)&_subklass);
539 it->push((Klass**)&_next_sibling);
540 it->push(&_next_link);
541 }
542
543 vtableEntry* vt = start_of_vtable();
544 for (int i=0; i<vtable_length(); i++) {
545 it->push(vt[i].method_addr());
546 }
547 }
548
549 #if INCLUDE_CDS
550 void Klass::remove_unshareable_info() {
551 assert(CDSConfig::is_dumping_archive(),
552 "only called during CDS dump time");
553 JFR_ONLY(REMOVE_ID(this);)
554 if (log_is_enabled(Trace, cds, unshareable)) {
555 ResourceMark rm;
556 log_trace(cds, unshareable)("remove: %s", external_name());
557 }
558
559 set_subklass(nullptr);
560 set_next_sibling(nullptr);
561 set_next_link(nullptr);
562
563 // Null out class_loader_data because we don't share that yet.
564 set_class_loader_data(nullptr);
565 set_is_shared();
566 }
567
568 void Klass::remove_java_mirror() {
569 assert(CDSConfig::is_dumping_archive(), "sanity");
570 if (log_is_enabled(Trace, cds, unshareable)) {
571 ResourceMark rm;
572 log_trace(cds, unshareable)("remove java_mirror: %s", external_name());
573 }
574 // Just null out the mirror. The class_loader_data() no longer exists.
575 clear_java_mirror_handle();
576 }
577
578 void Klass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) {
579 assert(is_klass(), "ensure C++ vtable is restored");
580 assert(is_shared(), "must be set");
581 JFR_ONLY(RESTORE_ID(this);)
582 if (log_is_enabled(Trace, cds, unshareable)) {
583 ResourceMark rm(THREAD);
584 oop class_loader = loader_data->class_loader();
585 log_trace(cds, unshareable)("restore: %s with class loader: %s", external_name(),
586 class_loader != nullptr ? class_loader->klass()->external_name() : "boot");
587 }
588
589 // If an exception happened during CDS restore, some of these fields may already be
590 // set. We leave the class on the CLD list, even if incomplete so that we don't
591 // modify the CLD list outside a safepoint.
592 if (class_loader_data() == nullptr) {
593 set_class_loader_data(loader_data);
594
595 // Add to class loader list first before creating the mirror
596 // (same order as class file parsing)
597 loader_data->add_class(this);
598 }
599
600 Handle loader(THREAD, loader_data->class_loader());
601 ModuleEntry* module_entry = nullptr;
602 Klass* k = this;
603 if (k->is_objArray_klass()) {
604 k = ObjArrayKlass::cast(k)->bottom_klass();
605 }
606 // Obtain klass' module.
607 if (k->is_instance_klass()) {
608 InstanceKlass* ik = (InstanceKlass*) k;
609 module_entry = ik->module();
610 } else {
611 module_entry = ModuleEntryTable::javabase_moduleEntry();
612 }
613 // Obtain java.lang.Module, if available
614 Handle module_handle(THREAD, ((module_entry != nullptr) ? module_entry->module() : (oop)nullptr));
615
616 if (this->has_archived_mirror_index()) {
617 ResourceMark rm(THREAD);
618 log_debug(cds, mirror)("%s has raw archived mirror", external_name());
619 if (ArchiveHeapLoader::is_in_use()) {
620 bool present = java_lang_Class::restore_archived_mirror(this, loader, module_handle,
621 protection_domain,
622 CHECK);
623 if (present) {
624 return;
625 }
626 }
627
628 // No archived mirror data
629 log_debug(cds, mirror)("No archived mirror data for %s", external_name());
630 clear_java_mirror_handle();
631 this->clear_archived_mirror_index();
632 }
633
634 // Only recreate it if not present. A previous attempt to restore may have
635 // gotten an OOM later but keep the mirror if it was created.
636 if (java_mirror() == nullptr) {
637 ResourceMark rm(THREAD);
638 log_trace(cds, mirror)("Recreate mirror for %s", external_name());
639 java_lang_Class::create_mirror(this, loader, module_handle, protection_domain, Handle(), CHECK);
640 }
641 }
642 #endif // INCLUDE_CDS
643
644 #if INCLUDE_CDS_JAVA_HEAP
645 oop Klass::archived_java_mirror() {
646 assert(has_archived_mirror_index(), "must have archived mirror");
647 return HeapShared::get_root(_archived_mirror_index);
648 }
649
650 void Klass::clear_archived_mirror_index() {
651 if (_archived_mirror_index >= 0) {
652 HeapShared::clear_root(_archived_mirror_index);
653 }
654 _archived_mirror_index = -1;
655 }
656
657 // No GC barrier
658 void Klass::set_archived_java_mirror(int mirror_index) {
659 assert(CDSConfig::is_dumping_heap(), "sanity");
660 _archived_mirror_index = mirror_index;
661 }
662 #endif // INCLUDE_CDS_JAVA_HEAP
663
664 void Klass::check_array_allocation_length(int length, int max_length, TRAPS) {
665 if (length > max_length) {
666 if (!THREAD->in_retryable_allocation()) {
667 report_java_out_of_memory("Requested array size exceeds VM limit");
668 JvmtiExport::post_array_size_exhausted();
669 THROW_OOP(Universe::out_of_memory_error_array_size());
670 } else {
671 THROW_OOP(Universe::out_of_memory_error_retry());
672 }
673 } else if (length < 0) {
674 THROW_MSG(vmSymbols::java_lang_NegativeArraySizeException(), err_msg("%d", length));
675 }
676 }
677
678 // Replace the last '+' char with '/'.
679 static char* convert_hidden_name_to_java(Symbol* name) {
680 size_t name_len = name->utf8_length();
681 char* result = NEW_RESOURCE_ARRAY(char, name_len + 1);
682 name->as_klass_external_name(result, (int)name_len + 1);
683 for (int index = (int)name_len; index > 0; index--) {
684 if (result[index] == '+') {
685 result[index] = JVM_SIGNATURE_SLASH;
686 break;
687 }
688 }
689 return result;
690 }
691
692 // In product mode, this function doesn't have virtual function calls so
693 // there might be some performance advantage to handling InstanceKlass here.
694 const char* Klass::external_name() const {
695 if (is_instance_klass()) {
696 const InstanceKlass* ik = static_cast<const InstanceKlass*>(this);
697 if (ik->is_hidden()) {
698 char* result = convert_hidden_name_to_java(name());
699 return result;
700 }
701 } else if (is_objArray_klass() && ObjArrayKlass::cast(this)->bottom_klass()->is_hidden()) {
702 char* result = convert_hidden_name_to_java(name());
703 return result;
704 }
705 if (name() == nullptr) return "<unknown>";
706 return name()->as_klass_external_name();
707 }
708
709 const char* Klass::signature_name() const {
710 if (name() == nullptr) return "<unknown>";
711 if (is_objArray_klass() && ObjArrayKlass::cast(this)->bottom_klass()->is_hidden()) {
712 size_t name_len = name()->utf8_length();
713 char* result = NEW_RESOURCE_ARRAY(char, name_len + 1);
714 name()->as_C_string(result, (int)name_len + 1);
715 for (int index = (int)name_len; index > 0; index--) {
716 if (result[index] == '+') {
717 result[index] = JVM_SIGNATURE_DOT;
718 break;
719 }
720 }
721 return result;
722 }
723 return name()->as_C_string();
724 }
725
726 const char* Klass::external_kind() const {
727 if (is_interface()) return "interface";
728 if (is_abstract()) return "abstract class";
729 return "class";
730 }
731
732 // Unless overridden, jvmti_class_status has no flags set.
733 jint Klass::jvmti_class_status() const {
734 return 0;
735 }
736
737
738 // Printing
739
740 void Klass::print_on(outputStream* st) const {
741 ResourceMark rm;
742 // print title
743 st->print("%s", internal_name());
744 print_address_on(st);
745 st->cr();
746 }
747
748 #define BULLET " - "
749
750 // Caller needs ResourceMark
751 void Klass::oop_print_on(oop obj, outputStream* st) {
752 // print title
753 st->print_cr("%s ", internal_name());
754 obj->print_address_on(st);
755
756 if (WizardMode) {
757 // print header
758 obj->mark().print_on(st);
759 st->cr();
760 if (UseCompactObjectHeaders) {
761 st->print(BULLET"prototype_header: " INTPTR_FORMAT, _prototype_header.value());
762 st->cr();
763 }
764 }
765
766 // print class
767 st->print(BULLET"klass: ");
768 obj->klass()->print_value_on(st);
769 st->cr();
770 }
771
772 void Klass::oop_print_value_on(oop obj, outputStream* st) {
773 // print title
774 ResourceMark rm; // Cannot print in debug mode without this
775 st->print("%s", internal_name());
776 obj->print_address_on(st);
777 }
778
779 // Verification
780
781 void Klass::verify_on(outputStream* st) {
782
783 // This can be expensive, but it is worth checking that this klass is actually
784 // in the CLD graph but not in production.
785 assert(Metaspace::contains((address)this), "Should be");
786
787 guarantee(this->is_klass(),"should be klass");
788
789 if (super() != nullptr) {
790 guarantee(super()->is_klass(), "should be klass");
791 }
792 if (secondary_super_cache() != nullptr) {
793 Klass* ko = secondary_super_cache();
794 guarantee(ko->is_klass(), "should be klass");
795 }
796 for ( uint i = 0; i < primary_super_limit(); i++ ) {
797 Klass* ko = _primary_supers[i];
798 if (ko != nullptr) {
799 guarantee(ko->is_klass(), "should be klass");
800 }
801 }
802
803 if (java_mirror_no_keepalive() != nullptr) {
804 guarantee(java_lang_Class::is_instance(java_mirror_no_keepalive()), "should be instance");
805 }
806 }
807
808 void Klass::oop_verify_on(oop obj, outputStream* st) {
809 guarantee(oopDesc::is_oop(obj), "should be oop");
810 guarantee(obj->klass()->is_klass(), "klass field is not a klass");
811 }
812
813 bool Klass::is_valid(Klass* k) {
814 if (!is_aligned(k, sizeof(MetaWord))) return false;
815 if ((size_t)k < os::min_page_size()) return false;
816
817 if (!os::is_readable_range(k, k + 1)) return false;
818 if (!Metaspace::contains(k)) return false;
819
820 if (!Symbol::is_valid(k->name())) return false;
821 return ClassLoaderDataGraph::is_valid(k->class_loader_data());
822 }
823
824 Method* Klass::method_at_vtable(int index) {
825 #ifndef PRODUCT
826 assert(index >= 0, "valid vtable index");
827 if (DebugVtables) {
828 verify_vtable_index(index);
829 }
830 #endif
831 return start_of_vtable()[index].method();
832 }
833
834
835 #ifndef PRODUCT
836
837 bool Klass::verify_vtable_index(int i) {
838 int limit = vtable_length()/vtableEntry::size();
839 assert(i >= 0 && i < limit, "index %d out of bounds %d", i, limit);
840 return true;
841 }
842
843 #endif // PRODUCT
844
845 // Caller needs ResourceMark
846 // joint_in_module_of_loader provides an optimization if 2 classes are in
847 // the same module to succinctly print out relevant information about their
848 // module name and class loader's name_and_id for error messages.
849 // Format:
850 // <fully-qualified-external-class-name1> and <fully-qualified-external-class-name2>
851 // are in module <module-name>[@<version>]
852 // of loader <loader-name_and_id>[, parent loader <parent-loader-name_and_id>]
853 const char* Klass::joint_in_module_of_loader(const Klass* class2, bool include_parent_loader) const {
854 assert(module() == class2->module(), "classes do not have the same module");
855 const char* class1_name = external_name();
856 size_t len = strlen(class1_name) + 1;
857
858 const char* class2_description = class2->class_in_module_of_loader(true, include_parent_loader);
859 len += strlen(class2_description);
860
861 len += strlen(" and ");
862
863 char* joint_description = NEW_RESOURCE_ARRAY_RETURN_NULL(char, len);
864
865 // Just return the FQN if error when allocating string
866 if (joint_description == nullptr) {
867 return class1_name;
868 }
869
870 jio_snprintf(joint_description, len, "%s and %s",
871 class1_name,
872 class2_description);
873
874 return joint_description;
875 }
876
877 // Caller needs ResourceMark
878 // class_in_module_of_loader provides a standard way to include
879 // relevant information about a class, such as its module name as
880 // well as its class loader's name_and_id, in error messages and logging.
881 // Format:
882 // <fully-qualified-external-class-name> is in module <module-name>[@<version>]
883 // of loader <loader-name_and_id>[, parent loader <parent-loader-name_and_id>]
884 const char* Klass::class_in_module_of_loader(bool use_are, bool include_parent_loader) const {
885 // 1. fully qualified external name of class
886 const char* klass_name = external_name();
887 size_t len = strlen(klass_name) + 1;
888
889 // 2. module name + @version
890 const char* module_name = "";
891 const char* version = "";
892 bool has_version = false;
893 bool module_is_named = false;
894 const char* module_name_phrase = "";
895 const Klass* bottom_klass = is_objArray_klass() ?
896 ObjArrayKlass::cast(this)->bottom_klass() : this;
897 if (bottom_klass->is_instance_klass()) {
898 ModuleEntry* module = InstanceKlass::cast(bottom_klass)->module();
899 if (module->is_named()) {
900 module_is_named = true;
901 module_name_phrase = "module ";
902 module_name = module->name()->as_C_string();
903 len += strlen(module_name);
904 // Use version if exists and is not a jdk module
905 if (module->should_show_version()) {
906 has_version = true;
907 version = module->version()->as_C_string();
908 // Include stlen(version) + 1 for the "@"
909 len += strlen(version) + 1;
910 }
911 } else {
912 module_name = UNNAMED_MODULE;
913 len += UNNAMED_MODULE_LEN;
914 }
915 } else {
916 // klass is an array of primitives, module is java.base
917 module_is_named = true;
918 module_name_phrase = "module ";
919 module_name = JAVA_BASE_NAME;
920 len += JAVA_BASE_NAME_LEN;
921 }
922
923 // 3. class loader's name_and_id
924 ClassLoaderData* cld = class_loader_data();
925 assert(cld != nullptr, "class_loader_data should not be null");
926 const char* loader_name_and_id = cld->loader_name_and_id();
927 len += strlen(loader_name_and_id);
928
929 // 4. include parent loader information
930 const char* parent_loader_phrase = "";
931 const char* parent_loader_name_and_id = "";
932 if (include_parent_loader &&
933 !cld->is_builtin_class_loader_data()) {
934 oop parent_loader = java_lang_ClassLoader::parent(class_loader());
935 ClassLoaderData *parent_cld = ClassLoaderData::class_loader_data_or_null(parent_loader);
936 // The parent loader's ClassLoaderData could be null if it is
937 // a delegating class loader that has never defined a class.
938 // In this case the loader's name must be obtained via the parent loader's oop.
939 if (parent_cld == nullptr) {
940 oop cl_name_and_id = java_lang_ClassLoader::nameAndId(parent_loader);
941 if (cl_name_and_id != nullptr) {
942 parent_loader_name_and_id = java_lang_String::as_utf8_string(cl_name_and_id);
943 }
944 } else {
945 parent_loader_name_and_id = parent_cld->loader_name_and_id();
946 }
947 parent_loader_phrase = ", parent loader ";
948 len += strlen(parent_loader_phrase) + strlen(parent_loader_name_and_id);
949 }
950
951 // Start to construct final full class description string
952 len += ((use_are) ? strlen(" are in ") : strlen(" is in "));
953 len += strlen(module_name_phrase) + strlen(" of loader ");
954
955 char* class_description = NEW_RESOURCE_ARRAY_RETURN_NULL(char, len);
956
957 // Just return the FQN if error when allocating string
958 if (class_description == nullptr) {
959 return klass_name;
960 }
961
962 jio_snprintf(class_description, len, "%s %s in %s%s%s%s of loader %s%s%s",
963 klass_name,
964 (use_are) ? "are" : "is",
965 module_name_phrase,
966 module_name,
967 (has_version) ? "@" : "",
968 (has_version) ? version : "",
969 loader_name_and_id,
970 parent_loader_phrase,
971 parent_loader_name_and_id);
972
973 return class_description;
974 }