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 oop Klass::java_mirror_no_keepalive() const {
65 return _java_mirror.peek();
66 }
67
68 bool Klass::is_cloneable() const {
69 return _access_flags.is_cloneable_fast() ||
70 is_subtype_of(vmClasses::Cloneable_klass());
71 }
72
73 void Klass::set_is_cloneable() {
74 if (name() == vmSymbols::java_lang_invoke_MemberName()) {
75 assert(is_final(), "no subclasses allowed");
76 // MemberName cloning should not be intrinsified and always happen in JVM_Clone.
77 } else if (is_instance_klass() && InstanceKlass::cast(this)->reference_type() != REF_NONE) {
78 // Reference cloning should not be intrinsified and always happen in JVM_Clone.
79 } else {
80 _access_flags.set_is_cloneable_fast();
81 }
82 }
83
84 void Klass::set_name(Symbol* n) {
85 _name = n;
86 if (_name != nullptr) _name->increment_refcount();
87
88 if (Arguments::is_dumping_archive() && is_instance_klass()) {
89 SystemDictionaryShared::init_dumptime_info(InstanceKlass::cast(this));
90 }
91 }
92
93 bool Klass::is_subclass_of(const Klass* k) const {
94 // Run up the super chain and check
95 if (this == k) return true;
96
97 Klass* t = const_cast<Klass*>(this)->super();
98
99 while (t != nullptr) {
100 if (t == k) return true;
101 t = t->super();
102 }
103 return false;
104 }
105
106 void Klass::release_C_heap_structures(bool release_constant_pool) {
107 if (_name != nullptr) _name->decrement_refcount();
108 }
109
110 bool Klass::search_secondary_supers(Klass* k) const {
111 // Put some extra logic here out-of-line, before the search proper.
112 // This cuts down the size of the inline method.
113
114 // This is necessary, since I am never in my own secondary_super list.
115 if (this == k)
116 return true;
117 // Scan the array-of-objects for a match
118 int cnt = secondary_supers()->length();
119 for (int i = 0; i < cnt; i++) {
120 if (secondary_supers()->at(i) == k) {
121 ((Klass*)this)->set_secondary_super_cache(k);
122 return true;
123 }
124 }
125 return false;
126 }
127
128 // Return self, except for abstract classes with exactly 1
129 // implementor. Then return the 1 concrete implementation.
130 Klass *Klass::up_cast_abstract() {
131 Klass *r = this;
132 while( r->is_abstract() ) { // Receiver is abstract?
133 Klass *s = r->subklass(); // Check for exactly 1 subklass
134 if (s == nullptr || s->next_sibling() != nullptr) // Oops; wrong count; give up
135 return this; // Return 'this' as a no-progress flag
136 r = s; // Loop till find concrete class
137 }
138 return r; // Return the 1 concrete class
139 }
140
141 // Find LCA in class hierarchy
142 Klass *Klass::LCA( Klass *k2 ) {
143 Klass *k1 = this;
144 while( 1 ) {
145 if( k1->is_subtype_of(k2) ) return k2;
146 if( k2->is_subtype_of(k1) ) return k1;
147 k1 = k1->super();
148 k2 = k2->super();
149 }
150 }
151
152
153 void Klass::check_valid_for_instantiation(bool throwError, TRAPS) {
154 ResourceMark rm(THREAD);
155 THROW_MSG(throwError ? vmSymbols::java_lang_InstantiationError()
156 : vmSymbols::java_lang_InstantiationException(), external_name());
157 }
158
159
160 void Klass::copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS) {
161 ResourceMark rm(THREAD);
162 assert(s != nullptr, "Throw NPE!");
163 THROW_MSG(vmSymbols::java_lang_ArrayStoreException(),
164 err_msg("arraycopy: source type %s is not an array", s->klass()->external_name()));
165 }
166
167
168 void Klass::initialize(TRAPS) {
169 ShouldNotReachHere();
170 }
171
172 Klass* Klass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
173 #ifdef ASSERT
174 tty->print_cr("Error: find_field called on a klass oop."
175 " Likely error: reflection method does not correctly"
176 " wrap return value in a mirror object.");
177 #endif
178 ShouldNotReachHere();
179 return nullptr;
180 }
181
182 Method* Klass::uncached_lookup_method(const Symbol* name, const Symbol* signature,
183 OverpassLookupMode overpass_mode,
184 PrivateLookupMode private_mode) const {
185 #ifdef ASSERT
186 tty->print_cr("Error: uncached_lookup_method called on a klass oop."
187 " Likely error: reflection method does not correctly"
188 " wrap return value in a mirror object.");
189 #endif
190 ShouldNotReachHere();
191 return nullptr;
192 }
193
194 void* Klass::operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, TRAPS) throw() {
195 return Metaspace::allocate(loader_data, word_size, MetaspaceObj::ClassType, THREAD);
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 _shared_class_path_index(-1) {
204 CDS_ONLY(_shared_class_flags = 0;)
205 CDS_JAVA_HEAP_ONLY(_archived_mirror_index = -1;)
206 _primary_supers[0] = this;
207 set_super_check_offset(in_bytes(primary_supers_offset()));
208 }
209
210 jint Klass::array_layout_helper(BasicType etype) {
211 assert(etype >= T_BOOLEAN && etype <= T_OBJECT, "valid etype");
212 // Note that T_ARRAY is not allowed here.
213 int hsize = arrayOopDesc::base_offset_in_bytes(etype);
214 int esize = type2aelembytes(etype);
215 bool isobj = (etype == T_OBJECT);
216 int tag = isobj ? _lh_array_tag_obj_value : _lh_array_tag_type_value;
217 int lh = array_layout_helper(tag, hsize, etype, exact_log2(esize));
218
219 assert(lh < (int)_lh_neutral_value, "must look like an array layout");
220 assert(layout_helper_is_array(lh), "correct kind");
221 assert(layout_helper_is_objArray(lh) == isobj, "correct kind");
222 assert(layout_helper_is_typeArray(lh) == !isobj, "correct kind");
223 assert(layout_helper_header_size(lh) == hsize, "correct decode");
224 assert(layout_helper_element_type(lh) == etype, "correct decode");
225 assert(1 << layout_helper_log2_element_size(lh) == esize, "correct decode");
226
227 return lh;
228 }
229
230 bool Klass::can_be_primary_super_slow() const {
231 if (super() == nullptr)
232 return true;
233 else if (super()->super_depth() >= primary_super_limit()-1)
234 return false;
235 else
236 return true;
237 }
238
239 void Klass::initialize_supers(Klass* k, Array<InstanceKlass*>* transitive_interfaces, TRAPS) {
240 if (k == nullptr) {
241 set_super(nullptr);
242 _primary_supers[0] = this;
243 assert(super_depth() == 0, "Object must already be initialized properly");
244 } else if (k != super() || k == vmClasses::Object_klass()) {
245 assert(super() == nullptr || super() == vmClasses::Object_klass(),
246 "initialize this only once to a non-trivial value");
247 set_super(k);
248 Klass* sup = k;
249 int sup_depth = sup->super_depth();
250 juint my_depth = MIN2(sup_depth + 1, (int)primary_super_limit());
251 if (!can_be_primary_super_slow())
252 my_depth = primary_super_limit();
253 for (juint i = 0; i < my_depth; i++) {
254 _primary_supers[i] = sup->_primary_supers[i];
255 }
256 Klass* *super_check_cell;
257 if (my_depth < primary_super_limit()) {
258 _primary_supers[my_depth] = this;
259 super_check_cell = &_primary_supers[my_depth];
260 } else {
261 // Overflow of the primary_supers array forces me to be secondary.
262 super_check_cell = &_secondary_super_cache;
263 }
264 set_super_check_offset(u4((address)super_check_cell - (address) this));
265
266 #ifdef ASSERT
267 {
268 juint j = super_depth();
269 assert(j == my_depth, "computed accessor gets right answer");
270 Klass* t = this;
271 while (!t->can_be_primary_super()) {
272 t = t->super();
273 j = t->super_depth();
274 }
275 for (juint j1 = j+1; j1 < primary_super_limit(); j1++) {
276 assert(primary_super_of_depth(j1) == nullptr, "super list padding");
277 }
278 while (t != nullptr) {
279 assert(primary_super_of_depth(j) == t, "super list initialization");
280 t = t->super();
281 --j;
282 }
283 assert(j == (juint)-1, "correct depth count");
284 }
285 #endif
286 }
287
288 if (secondary_supers() == nullptr) {
289
290 // Now compute the list of secondary supertypes.
291 // Secondaries can occasionally be on the super chain,
292 // if the inline "_primary_supers" array overflows.
293 int extras = 0;
294 Klass* p;
295 for (p = super(); !(p == nullptr || p->can_be_primary_super()); p = p->super()) {
296 ++extras;
297 }
298
299 ResourceMark rm(THREAD); // need to reclaim GrowableArrays allocated below
300
301 // Compute the "real" non-extra secondaries.
302 GrowableArray<Klass*>* secondaries = compute_secondary_supers(extras, transitive_interfaces);
303 if (secondaries == nullptr) {
304 // secondary_supers set by compute_secondary_supers
305 return;
306 }
307
308 GrowableArray<Klass*>* primaries = new GrowableArray<Klass*>(extras);
309
310 for (p = super(); !(p == nullptr || p->can_be_primary_super()); p = p->super()) {
311 int i; // Scan for overflow primaries being duplicates of 2nd'arys
312
313 // This happens frequently for very deeply nested arrays: the
314 // primary superclass chain overflows into the secondary. The
315 // secondary list contains the element_klass's secondaries with
316 // an extra array dimension added. If the element_klass's
317 // secondary list already contains some primary overflows, they
318 // (with the extra level of array-ness) will collide with the
319 // normal primary superclass overflows.
320 for( i = 0; i < secondaries->length(); i++ ) {
321 if( secondaries->at(i) == p )
322 break;
323 }
324 if( i < secondaries->length() )
325 continue; // It's a dup, don't put it in
326 primaries->push(p);
327 }
328 // Combine the two arrays into a metadata object to pack the array.
329 // The primaries are added in the reverse order, then the secondaries.
330 int new_length = primaries->length() + secondaries->length();
331 Array<Klass*>* s2 = MetadataFactory::new_array<Klass*>(
332 class_loader_data(), new_length, CHECK);
333 int fill_p = primaries->length();
334 for (int j = 0; j < fill_p; j++) {
335 s2->at_put(j, primaries->pop()); // add primaries in reverse order.
336 }
337 for( int j = 0; j < secondaries->length(); j++ ) {
338 s2->at_put(j+fill_p, secondaries->at(j)); // add secondaries on the end.
339 }
340
341 #ifdef ASSERT
342 // We must not copy any null placeholders left over from bootstrap.
343 for (int j = 0; j < s2->length(); j++) {
344 assert(s2->at(j) != nullptr, "correct bootstrapping order");
345 }
346 #endif
347
348 set_secondary_supers(s2);
349 }
350 }
351
352 GrowableArray<Klass*>* Klass::compute_secondary_supers(int num_extra_slots,
353 Array<InstanceKlass*>* transitive_interfaces) {
354 assert(num_extra_slots == 0, "override for complex klasses");
355 assert(transitive_interfaces == nullptr, "sanity");
356 set_secondary_supers(Universe::the_empty_klass_array());
357 return nullptr;
358 }
359
360
361 // superklass links
362 InstanceKlass* Klass::superklass() const {
363 assert(super() == nullptr || super()->is_instance_klass(), "must be instance klass");
364 return _super == nullptr ? nullptr : InstanceKlass::cast(_super);
365 }
366
367 // subklass links. Used by the compiler (and vtable initialization)
368 // May be cleaned concurrently, so must use the Compile_lock.
369 // The log parameter is for clean_weak_klass_links to report unlinked classes.
370 Klass* Klass::subklass(bool log) const {
371 // Need load_acquire on the _subklass, because it races with inserts that
372 // publishes freshly initialized data.
373 for (Klass* chain = Atomic::load_acquire(&_subklass);
374 chain != nullptr;
375 // Do not need load_acquire on _next_sibling, because inserts never
376 // create _next_sibling edges to dead data.
377 chain = Atomic::load(&chain->_next_sibling))
378 {
379 if (chain->is_loader_alive()) {
380 return chain;
381 } else if (log) {
382 if (log_is_enabled(Trace, class, unload)) {
383 ResourceMark rm;
384 log_trace(class, unload)("unlinking class (subclass): %s", chain->external_name());
385 }
386 }
387 }
388 return nullptr;
389 }
390
391 Klass* Klass::next_sibling(bool log) const {
392 // Do not need load_acquire on _next_sibling, because inserts never
393 // create _next_sibling edges to dead data.
394 for (Klass* chain = Atomic::load(&_next_sibling);
395 chain != nullptr;
396 chain = Atomic::load(&chain->_next_sibling)) {
397 // Only return alive klass, there may be stale klass
398 // in this chain if cleaned concurrently.
399 if (chain->is_loader_alive()) {
400 return chain;
401 } else if (log) {
402 if (log_is_enabled(Trace, class, unload)) {
403 ResourceMark rm;
404 log_trace(class, unload)("unlinking class (sibling): %s", chain->external_name());
405 }
406 }
407 }
408 return nullptr;
409 }
410
411 void Klass::set_subklass(Klass* s) {
412 assert(s != this, "sanity check");
413 Atomic::release_store(&_subklass, s);
414 }
415
416 void Klass::set_next_sibling(Klass* s) {
417 assert(s != this, "sanity check");
418 // Does not need release semantics. If used by cleanup, it will link to
419 // already safely published data, and if used by inserts, will be published
420 // safely using cmpxchg.
421 Atomic::store(&_next_sibling, s);
422 }
423
424 void Klass::append_to_sibling_list() {
425 if (Universe::is_fully_initialized()) {
426 assert_locked_or_safepoint(Compile_lock);
427 }
428 debug_only(verify();)
429 // add ourselves to superklass' subklass list
430 InstanceKlass* super = superklass();
431 if (super == nullptr) return; // special case: class Object
432 assert((!super->is_interface() // interfaces cannot be supers
433 && (super->superklass() == nullptr || !is_interface())),
434 "an interface can only be a subklass of Object");
435
436 // Make sure there is no stale subklass head
437 super->clean_subklass();
438
439 for (;;) {
440 Klass* prev_first_subklass = Atomic::load_acquire(&_super->_subklass);
441 if (prev_first_subklass != nullptr) {
442 // set our sibling to be the superklass' previous first subklass
443 assert(prev_first_subklass->is_loader_alive(), "May not attach not alive klasses");
444 set_next_sibling(prev_first_subklass);
445 }
446 // Note that the prev_first_subklass is always alive, meaning no sibling_next links
447 // are ever created to not alive klasses. This is an important invariant of the lock-free
448 // cleaning protocol, that allows us to safely unlink dead klasses from the sibling list.
449 if (Atomic::cmpxchg(&super->_subklass, prev_first_subklass, this) == prev_first_subklass) {
450 return;
451 }
452 }
453 debug_only(verify();)
454 }
455
456 void Klass::clean_subklass() {
457 for (;;) {
458 // Need load_acquire, due to contending with concurrent inserts
459 Klass* subklass = Atomic::load_acquire(&_subklass);
460 if (subklass == nullptr || subklass->is_loader_alive()) {
461 return;
462 }
463 // Try to fix _subklass until it points at something not dead.
464 Atomic::cmpxchg(&_subklass, subklass, subklass->next_sibling());
465 }
466 }
467
468 void Klass::clean_weak_klass_links(bool unloading_occurred, bool clean_alive_klasses) {
469 if (!ClassUnloading || !unloading_occurred) {
470 return;
471 }
472
473 Klass* root = vmClasses::Object_klass();
474 Stack<Klass*, mtGC> stack;
475
476 stack.push(root);
477 while (!stack.is_empty()) {
478 Klass* current = stack.pop();
479
480 assert(current->is_loader_alive(), "just checking, this should be live");
481
482 // Find and set the first alive subklass
483 Klass* sub = current->subklass(true);
484 current->clean_subklass();
485 if (sub != nullptr) {
486 stack.push(sub);
487 }
488
489 // Find and set the first alive sibling
490 Klass* sibling = current->next_sibling(true);
491 current->set_next_sibling(sibling);
492 if (sibling != nullptr) {
493 stack.push(sibling);
494 }
495
496 // Clean the implementors list and method data.
497 if (clean_alive_klasses && current->is_instance_klass()) {
498 InstanceKlass* ik = InstanceKlass::cast(current);
499 ik->clean_weak_instanceklass_links();
500
501 // JVMTI RedefineClasses creates previous versions that are not in
502 // the class hierarchy, so process them here.
503 while ((ik = ik->previous_versions()) != nullptr) {
504 ik->clean_weak_instanceklass_links();
505 }
506 }
507 }
508 }
509
510 void Klass::metaspace_pointers_do(MetaspaceClosure* it) {
511 if (log_is_enabled(Trace, cds)) {
512 ResourceMark rm;
513 log_trace(cds)("Iter(Klass): %p (%s)", this, external_name());
514 }
515
516 it->push(&_name);
517 it->push(&_secondary_super_cache);
518 it->push(&_secondary_supers);
519 for (int i = 0; i < _primary_super_limit; i++) {
520 it->push(&_primary_supers[i]);
521 }
522 it->push(&_super);
523 if (!Arguments::is_dumping_archive()) {
524 // If dumping archive, these may point to excluded classes. There's no need
525 // to follow these pointers anyway, as they will be set to null in
526 // remove_unshareable_info().
527 it->push((Klass**)&_subklass);
528 it->push((Klass**)&_next_sibling);
529 it->push(&_next_link);
530 }
531
532 vtableEntry* vt = start_of_vtable();
533 for (int i=0; i<vtable_length(); i++) {
534 it->push(vt[i].method_addr());
535 }
536 }
537
538 #if INCLUDE_CDS
539 void Klass::remove_unshareable_info() {
540 assert (Arguments::is_dumping_archive(),
541 "only called during CDS dump time");
542 JFR_ONLY(REMOVE_ID(this);)
543 if (log_is_enabled(Trace, cds, unshareable)) {
544 ResourceMark rm;
545 log_trace(cds, unshareable)("remove: %s", external_name());
546 }
547
548 set_subklass(nullptr);
549 set_next_sibling(nullptr);
550 set_next_link(nullptr);
551
552 // Null out class_loader_data because we don't share that yet.
553 set_class_loader_data(nullptr);
554 set_is_shared();
555 }
556
557 void Klass::remove_java_mirror() {
558 Arguments::assert_is_dumping_archive();
559 if (log_is_enabled(Trace, cds, unshareable)) {
560 ResourceMark rm;
561 log_trace(cds, unshareable)("remove java_mirror: %s", external_name());
562 }
563 // Just null out the mirror. The class_loader_data() no longer exists.
564 clear_java_mirror_handle();
565 }
566
567 void Klass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) {
568 assert(is_klass(), "ensure C++ vtable is restored");
569 assert(is_shared(), "must be set");
570 JFR_ONLY(RESTORE_ID(this);)
571 if (log_is_enabled(Trace, cds, unshareable)) {
572 ResourceMark rm(THREAD);
573 log_trace(cds, unshareable)("restore: %s", external_name());
574 }
575
576 // If an exception happened during CDS restore, some of these fields may already be
577 // set. We leave the class on the CLD list, even if incomplete so that we don't
578 // modify the CLD list outside a safepoint.
579 if (class_loader_data() == nullptr) {
580 set_class_loader_data(loader_data);
581
582 // Add to class loader list first before creating the mirror
583 // (same order as class file parsing)
584 loader_data->add_class(this);
585 }
586
587 Handle loader(THREAD, loader_data->class_loader());
588 ModuleEntry* module_entry = nullptr;
589 Klass* k = this;
590 if (k->is_objArray_klass()) {
591 k = ObjArrayKlass::cast(k)->bottom_klass();
592 }
593 // Obtain klass' module.
594 if (k->is_instance_klass()) {
595 InstanceKlass* ik = (InstanceKlass*) k;
596 module_entry = ik->module();
597 } else {
598 module_entry = ModuleEntryTable::javabase_moduleEntry();
599 }
600 // Obtain java.lang.Module, if available
601 Handle module_handle(THREAD, ((module_entry != nullptr) ? module_entry->module() : (oop)nullptr));
602
603 if (this->has_archived_mirror_index()) {
604 ResourceMark rm(THREAD);
605 log_debug(cds, mirror)("%s has raw archived mirror", external_name());
606 if (ArchiveHeapLoader::is_in_use()) {
607 bool present = java_lang_Class::restore_archived_mirror(this, loader, module_handle,
608 protection_domain,
609 CHECK);
610 if (present) {
611 return;
612 }
613 }
614
615 // No archived mirror data
616 log_debug(cds, mirror)("No archived mirror data for %s", external_name());
617 clear_java_mirror_handle();
618 this->clear_archived_mirror_index();
619 }
620
621 // Only recreate it if not present. A previous attempt to restore may have
622 // gotten an OOM later but keep the mirror if it was created.
623 if (java_mirror() == nullptr) {
624 ResourceMark rm(THREAD);
625 log_trace(cds, mirror)("Recreate mirror for %s", external_name());
626 java_lang_Class::create_mirror(this, loader, module_handle, protection_domain, Handle(), CHECK);
627 }
628 }
629 #endif // INCLUDE_CDS
630
631 #if INCLUDE_CDS_JAVA_HEAP
632 oop Klass::archived_java_mirror() {
633 assert(has_archived_mirror_index(), "must have archived mirror");
634 return HeapShared::get_root(_archived_mirror_index);
635 }
636
637 void Klass::clear_archived_mirror_index() {
638 if (_archived_mirror_index >= 0) {
639 HeapShared::clear_root(_archived_mirror_index);
640 }
641 _archived_mirror_index = -1;
642 }
643
644 // No GC barrier
645 void Klass::set_archived_java_mirror(int mirror_index) {
646 assert(DumpSharedSpaces, "called only during dumptime");
647 _archived_mirror_index = mirror_index;
648 }
649 #endif // INCLUDE_CDS_JAVA_HEAP
650
651 void Klass::check_array_allocation_length(int length, int max_length, TRAPS) {
652 if (length > max_length) {
653 if (!THREAD->in_retryable_allocation()) {
654 report_java_out_of_memory("Requested array size exceeds VM limit");
655 JvmtiExport::post_array_size_exhausted();
656 THROW_OOP(Universe::out_of_memory_error_array_size());
657 } else {
658 THROW_OOP(Universe::out_of_memory_error_retry());
659 }
660 } else if (length < 0) {
661 THROW_MSG(vmSymbols::java_lang_NegativeArraySizeException(), err_msg("%d", length));
662 }
663 }
664
665 // Replace the last '+' char with '/'.
666 static char* convert_hidden_name_to_java(Symbol* name) {
667 size_t name_len = name->utf8_length();
668 char* result = NEW_RESOURCE_ARRAY(char, name_len + 1);
669 name->as_klass_external_name(result, (int)name_len + 1);
670 for (int index = (int)name_len; index > 0; index--) {
671 if (result[index] == '+') {
672 result[index] = JVM_SIGNATURE_SLASH;
673 break;
674 }
675 }
676 return result;
677 }
678
679 // In product mode, this function doesn't have virtual function calls so
680 // there might be some performance advantage to handling InstanceKlass here.
681 const char* Klass::external_name() const {
682 if (is_instance_klass()) {
683 const InstanceKlass* ik = static_cast<const InstanceKlass*>(this);
684 if (ik->is_hidden()) {
685 char* result = convert_hidden_name_to_java(name());
686 return result;
687 }
688 } else if (is_objArray_klass() && ObjArrayKlass::cast(this)->bottom_klass()->is_hidden()) {
689 char* result = convert_hidden_name_to_java(name());
690 return result;
691 }
692 if (name() == nullptr) return "<unknown>";
693 return name()->as_klass_external_name();
694 }
695
696 const char* Klass::signature_name() const {
697 if (name() == nullptr) return "<unknown>";
698 if (is_objArray_klass() && ObjArrayKlass::cast(this)->bottom_klass()->is_hidden()) {
699 size_t name_len = name()->utf8_length();
700 char* result = NEW_RESOURCE_ARRAY(char, name_len + 1);
701 name()->as_C_string(result, (int)name_len + 1);
702 for (int index = (int)name_len; index > 0; index--) {
703 if (result[index] == '+') {
704 result[index] = JVM_SIGNATURE_DOT;
705 break;
706 }
707 }
708 return result;
709 }
710 return name()->as_C_string();
711 }
712
713 const char* Klass::external_kind() const {
714 if (is_interface()) return "interface";
715 if (is_abstract()) return "abstract class";
716 return "class";
717 }
718
719 // Unless overridden, jvmti_class_status has no flags set.
720 jint Klass::jvmti_class_status() const {
721 return 0;
722 }
723
724
725 // Printing
726
727 void Klass::print_on(outputStream* st) const {
728 ResourceMark rm;
729 // print title
730 st->print("%s", internal_name());
731 print_address_on(st);
732 st->cr();
733 }
734
735 #define BULLET " - "
736
737 // Caller needs ResourceMark
738 void Klass::oop_print_on(oop obj, outputStream* st) {
739 // print title
740 st->print_cr("%s ", internal_name());
741 obj->print_address_on(st);
742
743 if (WizardMode) {
744 // print header
745 obj->mark().print_on(st);
746 st->cr();
747 }
748
749 // print class
750 st->print(BULLET"klass: ");
751 obj->klass()->print_value_on(st);
752 st->cr();
753 }
754
755 void Klass::oop_print_value_on(oop obj, outputStream* st) {
756 // print title
757 ResourceMark rm; // Cannot print in debug mode without this
758 st->print("%s", internal_name());
759 obj->print_address_on(st);
760 }
761
762 // Verification
763
764 void Klass::verify_on(outputStream* st) {
765
766 // This can be expensive, but it is worth checking that this klass is actually
767 // in the CLD graph but not in production.
768 assert(Metaspace::contains((address)this), "Should be");
769
770 guarantee(this->is_klass(),"should be klass");
771
772 if (super() != nullptr) {
773 guarantee(super()->is_klass(), "should be klass");
774 }
775 if (secondary_super_cache() != nullptr) {
776 Klass* ko = secondary_super_cache();
777 guarantee(ko->is_klass(), "should be klass");
778 }
779 for ( uint i = 0; i < primary_super_limit(); i++ ) {
780 Klass* ko = _primary_supers[i];
781 if (ko != nullptr) {
782 guarantee(ko->is_klass(), "should be klass");
783 }
784 }
785
786 if (java_mirror_no_keepalive() != nullptr) {
787 guarantee(java_lang_Class::is_instance(java_mirror_no_keepalive()), "should be instance");
788 }
789 }
790
791 void Klass::oop_verify_on(oop obj, outputStream* st) {
792 guarantee(oopDesc::is_oop(obj), "should be oop");
793 guarantee(obj->klass()->is_klass(), "klass field is not a klass");
794 }
795
796 bool Klass::is_valid(Klass* k) {
797 if (!is_aligned(k, sizeof(MetaWord))) return false;
798 if ((size_t)k < os::min_page_size()) return false;
799
800 if (!os::is_readable_range(k, k + 1)) return false;
801 if (!Metaspace::contains(k)) return false;
802
803 if (!Symbol::is_valid(k->name())) return false;
804 return ClassLoaderDataGraph::is_valid(k->class_loader_data());
805 }
806
807 Method* Klass::method_at_vtable(int index) {
808 #ifndef PRODUCT
809 assert(index >= 0, "valid vtable index");
810 if (DebugVtables) {
811 verify_vtable_index(index);
812 }
813 #endif
814 return start_of_vtable()[index].method();
815 }
816
817
818 #ifndef PRODUCT
819
820 bool Klass::verify_vtable_index(int i) {
821 int limit = vtable_length()/vtableEntry::size();
822 assert(i >= 0 && i < limit, "index %d out of bounds %d", i, limit);
823 return true;
824 }
825
826 #endif // PRODUCT
827
828 // Caller needs ResourceMark
829 // joint_in_module_of_loader provides an optimization if 2 classes are in
830 // the same module to succinctly print out relevant information about their
831 // module name and class loader's name_and_id for error messages.
832 // Format:
833 // <fully-qualified-external-class-name1> and <fully-qualified-external-class-name2>
834 // are in module <module-name>[@<version>]
835 // of loader <loader-name_and_id>[, parent loader <parent-loader-name_and_id>]
836 const char* Klass::joint_in_module_of_loader(const Klass* class2, bool include_parent_loader) const {
837 assert(module() == class2->module(), "classes do not have the same module");
838 const char* class1_name = external_name();
839 size_t len = strlen(class1_name) + 1;
840
841 const char* class2_description = class2->class_in_module_of_loader(true, include_parent_loader);
842 len += strlen(class2_description);
843
844 len += strlen(" and ");
845
846 char* joint_description = NEW_RESOURCE_ARRAY_RETURN_NULL(char, len);
847
848 // Just return the FQN if error when allocating string
849 if (joint_description == nullptr) {
850 return class1_name;
851 }
852
853 jio_snprintf(joint_description, len, "%s and %s",
854 class1_name,
855 class2_description);
856
857 return joint_description;
858 }
859
860 // Caller needs ResourceMark
861 // class_in_module_of_loader provides a standard way to include
862 // relevant information about a class, such as its module name as
863 // well as its class loader's name_and_id, in error messages and logging.
864 // Format:
865 // <fully-qualified-external-class-name> is in module <module-name>[@<version>]
866 // of loader <loader-name_and_id>[, parent loader <parent-loader-name_and_id>]
867 const char* Klass::class_in_module_of_loader(bool use_are, bool include_parent_loader) const {
868 // 1. fully qualified external name of class
869 const char* klass_name = external_name();
870 size_t len = strlen(klass_name) + 1;
871
872 // 2. module name + @version
873 const char* module_name = "";
874 const char* version = "";
875 bool has_version = false;
876 bool module_is_named = false;
877 const char* module_name_phrase = "";
878 const Klass* bottom_klass = is_objArray_klass() ?
879 ObjArrayKlass::cast(this)->bottom_klass() : this;
880 if (bottom_klass->is_instance_klass()) {
881 ModuleEntry* module = InstanceKlass::cast(bottom_klass)->module();
882 if (module->is_named()) {
883 module_is_named = true;
884 module_name_phrase = "module ";
885 module_name = module->name()->as_C_string();
886 len += strlen(module_name);
887 // Use version if exists and is not a jdk module
888 if (module->should_show_version()) {
889 has_version = true;
890 version = module->version()->as_C_string();
891 // Include stlen(version) + 1 for the "@"
892 len += strlen(version) + 1;
893 }
894 } else {
895 module_name = UNNAMED_MODULE;
896 len += UNNAMED_MODULE_LEN;
897 }
898 } else {
899 // klass is an array of primitives, module is java.base
900 module_is_named = true;
901 module_name_phrase = "module ";
902 module_name = JAVA_BASE_NAME;
903 len += JAVA_BASE_NAME_LEN;
904 }
905
906 // 3. class loader's name_and_id
907 ClassLoaderData* cld = class_loader_data();
908 assert(cld != nullptr, "class_loader_data should not be null");
909 const char* loader_name_and_id = cld->loader_name_and_id();
910 len += strlen(loader_name_and_id);
911
912 // 4. include parent loader information
913 const char* parent_loader_phrase = "";
914 const char* parent_loader_name_and_id = "";
915 if (include_parent_loader &&
916 !cld->is_builtin_class_loader_data()) {
917 oop parent_loader = java_lang_ClassLoader::parent(class_loader());
918 ClassLoaderData *parent_cld = ClassLoaderData::class_loader_data_or_null(parent_loader);
919 // The parent loader's ClassLoaderData could be null if it is
920 // a delegating class loader that has never defined a class.
921 // In this case the loader's name must be obtained via the parent loader's oop.
922 if (parent_cld == nullptr) {
923 oop cl_name_and_id = java_lang_ClassLoader::nameAndId(parent_loader);
924 if (cl_name_and_id != nullptr) {
925 parent_loader_name_and_id = java_lang_String::as_utf8_string(cl_name_and_id);
926 }
927 } else {
928 parent_loader_name_and_id = parent_cld->loader_name_and_id();
929 }
930 parent_loader_phrase = ", parent loader ";
931 len += strlen(parent_loader_phrase) + strlen(parent_loader_name_and_id);
932 }
933
934 // Start to construct final full class description string
935 len += ((use_are) ? strlen(" are in ") : strlen(" is in "));
936 len += strlen(module_name_phrase) + strlen(" of loader ");
937
938 char* class_description = NEW_RESOURCE_ARRAY_RETURN_NULL(char, len);
939
940 // Just return the FQN if error when allocating string
941 if (class_description == nullptr) {
942 return klass_name;
943 }
944
945 jio_snprintf(class_description, len, "%s %s in %s%s%s%s of loader %s%s%s",
946 klass_name,
947 (use_are) ? "are" : "is",
948 module_name_phrase,
949 module_name,
950 (has_version) ? "@" : "",
951 (has_version) ? version : "",
952 loader_name_and_id,
953 parent_loader_phrase,
954 parent_loader_name_and_id);
955
956 return class_description;
957 }