1 /*
2 * Copyright (c) 1997, 2022, 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 "jvm_io.h"
27 #include "cds/heapShared.hpp"
28 #include "classfile/classLoaderData.inline.hpp"
29 #include "classfile/classLoaderDataGraph.inline.hpp"
30 #include "classfile/javaClasses.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 "logging/log.hpp"
38 #include "memory/metadataFactory.hpp"
39 #include "memory/metaspaceClosure.hpp"
40 #include "memory/oopFactory.hpp"
41 #include "memory/resourceArea.hpp"
42 #include "memory/universe.hpp"
43 #include "oops/compressedOops.inline.hpp"
44 #include "oops/instanceKlass.hpp"
45 #include "oops/klass.inline.hpp"
46 #include "oops/oop.inline.hpp"
47 #include "oops/oopHandle.inline.hpp"
48 #include "prims/jvmtiExport.hpp"
49 #include "runtime/arguments.hpp"
50 #include "runtime/atomic.hpp"
51 #include "runtime/globals.hpp"
52 #include "runtime/handles.inline.hpp"
53 #include "utilities/align.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 void Klass::replace_java_mirror(oop mirror) {
69 _java_mirror.replace(mirror);
70 }
71
72 bool Klass::is_cloneable() const {
73 return _access_flags.is_cloneable_fast() ||
74 is_subtype_of(vmClasses::Cloneable_klass());
75 }
76
77 void Klass::set_is_cloneable() {
78 if (name() == vmSymbols::java_lang_invoke_MemberName()) {
79 assert(is_final(), "no subclasses allowed");
80 // MemberName cloning should not be intrinsified and always happen in JVM_Clone.
81 } else if (is_instance_klass() && InstanceKlass::cast(this)->reference_type() != REF_NONE) {
82 // Reference cloning should not be intrinsified and always happen in JVM_Clone.
83 } else {
84 _access_flags.set_is_cloneable_fast();
85 }
86 }
87
88 void Klass::set_name(Symbol* n) {
89 _name = n;
90 if (_name != NULL) _name->increment_refcount();
91
92 if (Arguments::is_dumping_archive() && is_instance_klass()) {
93 SystemDictionaryShared::init_dumptime_info(InstanceKlass::cast(this));
94 }
95 }
96
97 bool Klass::is_subclass_of(const Klass* k) const {
98 // Run up the super chain and check
99 if (this == k) return true;
100
101 Klass* t = const_cast<Klass*>(this)->super();
102
103 while (t != NULL) {
104 if (t == k) return true;
105 t = t->super();
106 }
107 return false;
108 }
109
110 void Klass::release_C_heap_structures(bool release_constant_pool) {
111 if (_name != NULL) _name->decrement_refcount();
112 }
113
114 bool Klass::search_secondary_supers(Klass* k) const {
115 // Put some extra logic here out-of-line, before the search proper.
116 // This cuts down the size of the inline method.
117
118 // This is necessary, since I am never in my own secondary_super list.
119 if (this == k)
120 return true;
121 // Scan the array-of-objects for a match
122 int cnt = secondary_supers()->length();
123 for (int i = 0; i < cnt; i++) {
124 if (secondary_supers()->at(i) == k) {
125 ((Klass*)this)->set_secondary_super_cache(k);
126 return true;
127 }
128 }
129 return false;
130 }
131
132 // Return self, except for abstract classes with exactly 1
133 // implementor. Then return the 1 concrete implementation.
134 Klass *Klass::up_cast_abstract() {
135 Klass *r = this;
136 while( r->is_abstract() ) { // Receiver is abstract?
137 Klass *s = r->subklass(); // Check for exactly 1 subklass
138 if (s == NULL || s->next_sibling() != NULL) // Oops; wrong count; give up
139 return this; // Return 'this' as a no-progress flag
140 r = s; // Loop till find concrete class
141 }
142 return r; // Return the 1 concrete class
143 }
144
145 // Find LCA in class hierarchy
146 Klass *Klass::LCA( Klass *k2 ) {
147 Klass *k1 = this;
148 while( 1 ) {
149 if( k1->is_subtype_of(k2) ) return k2;
150 if( k2->is_subtype_of(k1) ) return k1;
151 k1 = k1->super();
152 k2 = k2->super();
153 }
154 }
155
156
157 void Klass::check_valid_for_instantiation(bool throwError, TRAPS) {
158 ResourceMark rm(THREAD);
159 THROW_MSG(throwError ? vmSymbols::java_lang_InstantiationError()
160 : vmSymbols::java_lang_InstantiationException(), external_name());
161 }
162
163
164 void Klass::copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS) {
165 ResourceMark rm(THREAD);
166 assert(s != NULL, "Throw NPE!");
167 THROW_MSG(vmSymbols::java_lang_ArrayStoreException(),
168 err_msg("arraycopy: source type %s is not an array", s->klass()->external_name()));
169 }
170
171
172 void Klass::initialize(TRAPS) {
173 ShouldNotReachHere();
174 }
175
176 Klass* Klass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
177 #ifdef ASSERT
178 tty->print_cr("Error: find_field called on a klass oop."
179 " Likely error: reflection method does not correctly"
180 " wrap return value in a mirror object.");
181 #endif
182 ShouldNotReachHere();
183 return NULL;
184 }
185
186 Method* Klass::uncached_lookup_method(const Symbol* name, const Symbol* signature,
187 OverpassLookupMode overpass_mode,
188 PrivateLookupMode private_mode) const {
189 #ifdef ASSERT
190 tty->print_cr("Error: uncached_lookup_method called on a klass oop."
191 " Likely error: reflection method does not correctly"
192 " wrap return value in a mirror object.");
193 #endif
194 ShouldNotReachHere();
195 return NULL;
196 }
197
198 void* Klass::operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, TRAPS) throw() {
199 MetaWord* p = Metaspace::allocate(loader_data, word_size, MetaspaceObj::ClassType, THREAD);
200 assert(is_aligned(p, KlassAlignmentInBytes), "metaspace returned badly aligned memory.");
201 return p;
202 }
203
204 // "Normal" instantiation is preceded by a MetaspaceObj allocation
205 // which zeros out memory - calloc equivalent.
206 // The constructor is also used from CppVtableCloner,
207 // which doesn't zero out the memory before calling the constructor.
208 Klass::Klass(KlassKind kind) : _kind(kind),
209 _prototype_header(markWord::prototype() LP64_ONLY(.set_klass(this))),
210 _shared_class_path_index(-1) {
211 CDS_ONLY(_shared_class_flags = 0;)
212 CDS_JAVA_HEAP_ONLY(_archived_mirror_index = -1;)
213 _primary_supers[0] = this;
214 set_super_check_offset(in_bytes(primary_supers_offset()));
215 }
216
217 jint Klass::array_layout_helper(BasicType etype) {
218 assert(etype >= T_BOOLEAN && etype <= T_OBJECT, "valid etype");
219 // Note that T_ARRAY is not allowed here.
220 int hsize = arrayOopDesc::base_offset_in_bytes(etype);
221 int esize = type2aelembytes(etype);
222 bool isobj = (etype == T_OBJECT);
223 int tag = isobj ? _lh_array_tag_obj_value : _lh_array_tag_type_value;
224 int lh = array_layout_helper(tag, hsize, etype, exact_log2(esize));
225
226 assert(lh < (int)_lh_neutral_value, "must look like an array layout");
227 assert(layout_helper_is_array(lh), "correct kind");
228 assert(layout_helper_is_objArray(lh) == isobj, "correct kind");
229 assert(layout_helper_is_typeArray(lh) == !isobj, "correct kind");
230 assert(layout_helper_header_size(lh) == hsize, "correct decode");
231 assert(layout_helper_element_type(lh) == etype, "correct decode");
232 assert(1 << layout_helper_log2_element_size(lh) == esize, "correct decode");
233
234 return lh;
235 }
236
237 bool Klass::can_be_primary_super_slow() const {
238 if (super() == NULL)
239 return true;
240 else if (super()->super_depth() >= primary_super_limit()-1)
241 return false;
242 else
243 return true;
244 }
245
246 void Klass::initialize_supers(Klass* k, Array<InstanceKlass*>* transitive_interfaces, TRAPS) {
247 if (k == NULL) {
248 set_super(NULL);
249 _primary_supers[0] = this;
250 assert(super_depth() == 0, "Object must already be initialized properly");
251 } else if (k != super() || k == vmClasses::Object_klass()) {
252 assert(super() == NULL || super() == vmClasses::Object_klass(),
253 "initialize this only once to a non-trivial value");
254 set_super(k);
255 Klass* sup = k;
256 int sup_depth = sup->super_depth();
257 juint my_depth = MIN2(sup_depth + 1, (int)primary_super_limit());
258 if (!can_be_primary_super_slow())
259 my_depth = primary_super_limit();
260 for (juint i = 0; i < my_depth; i++) {
261 _primary_supers[i] = sup->_primary_supers[i];
262 }
263 Klass* *super_check_cell;
264 if (my_depth < primary_super_limit()) {
265 _primary_supers[my_depth] = this;
266 super_check_cell = &_primary_supers[my_depth];
267 } else {
268 // Overflow of the primary_supers array forces me to be secondary.
269 super_check_cell = &_secondary_super_cache;
270 }
271 set_super_check_offset((address)super_check_cell - (address) this);
272
273 #ifdef ASSERT
274 {
275 juint j = super_depth();
276 assert(j == my_depth, "computed accessor gets right answer");
277 Klass* t = this;
278 while (!t->can_be_primary_super()) {
279 t = t->super();
280 j = t->super_depth();
281 }
282 for (juint j1 = j+1; j1 < primary_super_limit(); j1++) {
283 assert(primary_super_of_depth(j1) == NULL, "super list padding");
284 }
285 while (t != NULL) {
286 assert(primary_super_of_depth(j) == t, "super list initialization");
287 t = t->super();
288 --j;
289 }
290 assert(j == (juint)-1, "correct depth count");
291 }
292 #endif
293 }
294
295 if (secondary_supers() == NULL) {
296
297 // Now compute the list of secondary supertypes.
298 // Secondaries can occasionally be on the super chain,
299 // if the inline "_primary_supers" array overflows.
300 int extras = 0;
301 Klass* p;
302 for (p = super(); !(p == NULL || p->can_be_primary_super()); p = p->super()) {
303 ++extras;
304 }
305
306 ResourceMark rm(THREAD); // need to reclaim GrowableArrays allocated below
307
308 // Compute the "real" non-extra secondaries.
309 GrowableArray<Klass*>* secondaries = compute_secondary_supers(extras, transitive_interfaces);
310 if (secondaries == NULL) {
311 // secondary_supers set by compute_secondary_supers
312 return;
313 }
314
315 GrowableArray<Klass*>* primaries = new GrowableArray<Klass*>(extras);
316
317 for (p = super(); !(p == NULL || p->can_be_primary_super()); p = p->super()) {
318 int i; // Scan for overflow primaries being duplicates of 2nd'arys
319
320 // This happens frequently for very deeply nested arrays: the
321 // primary superclass chain overflows into the secondary. The
322 // secondary list contains the element_klass's secondaries with
323 // an extra array dimension added. If the element_klass's
324 // secondary list already contains some primary overflows, they
325 // (with the extra level of array-ness) will collide with the
326 // normal primary superclass overflows.
327 for( i = 0; i < secondaries->length(); i++ ) {
328 if( secondaries->at(i) == p )
329 break;
330 }
331 if( i < secondaries->length() )
332 continue; // It's a dup, don't put it in
333 primaries->push(p);
334 }
335 // Combine the two arrays into a metadata object to pack the array.
336 // The primaries are added in the reverse order, then the secondaries.
337 int new_length = primaries->length() + secondaries->length();
338 Array<Klass*>* s2 = MetadataFactory::new_array<Klass*>(
339 class_loader_data(), new_length, CHECK);
340 int fill_p = primaries->length();
341 for (int j = 0; j < fill_p; j++) {
342 s2->at_put(j, primaries->pop()); // add primaries in reverse order.
343 }
344 for( int j = 0; j < secondaries->length(); j++ ) {
345 s2->at_put(j+fill_p, secondaries->at(j)); // add secondaries on the end.
346 }
347
348 #ifdef ASSERT
349 // We must not copy any NULL placeholders left over from bootstrap.
350 for (int j = 0; j < s2->length(); j++) {
351 assert(s2->at(j) != NULL, "correct bootstrapping order");
352 }
353 #endif
354
355 set_secondary_supers(s2);
356 }
357 }
358
359 GrowableArray<Klass*>* Klass::compute_secondary_supers(int num_extra_slots,
360 Array<InstanceKlass*>* transitive_interfaces) {
361 assert(num_extra_slots == 0, "override for complex klasses");
362 assert(transitive_interfaces == NULL, "sanity");
363 set_secondary_supers(Universe::the_empty_klass_array());
364 return NULL;
365 }
366
367
368 // superklass links
369 InstanceKlass* Klass::superklass() const {
370 assert(super() == NULL || super()->is_instance_klass(), "must be instance klass");
371 return _super == NULL ? NULL : InstanceKlass::cast(_super);
372 }
373
374 // subklass links. Used by the compiler (and vtable initialization)
375 // May be cleaned concurrently, so must use the Compile_lock.
376 // The log parameter is for clean_weak_klass_links to report unlinked classes.
377 Klass* Klass::subklass(bool log) const {
378 // Need load_acquire on the _subklass, because it races with inserts that
379 // publishes freshly initialized data.
380 for (Klass* chain = Atomic::load_acquire(&_subklass);
381 chain != NULL;
382 // Do not need load_acquire on _next_sibling, because inserts never
383 // create _next_sibling edges to dead data.
384 chain = Atomic::load(&chain->_next_sibling))
385 {
386 if (chain->is_loader_alive()) {
387 return chain;
388 } else if (log) {
389 if (log_is_enabled(Trace, class, unload)) {
390 ResourceMark rm;
391 log_trace(class, unload)("unlinking class (subclass): %s", chain->external_name());
392 }
393 }
394 }
395 return NULL;
396 }
397
398 Klass* Klass::next_sibling(bool log) const {
399 // Do not need load_acquire on _next_sibling, because inserts never
400 // create _next_sibling edges to dead data.
401 for (Klass* chain = Atomic::load(&_next_sibling);
402 chain != NULL;
403 chain = Atomic::load(&chain->_next_sibling)) {
404 // Only return alive klass, there may be stale klass
405 // in this chain if cleaned concurrently.
406 if (chain->is_loader_alive()) {
407 return chain;
408 } else if (log) {
409 if (log_is_enabled(Trace, class, unload)) {
410 ResourceMark rm;
411 log_trace(class, unload)("unlinking class (sibling): %s", chain->external_name());
412 }
413 }
414 }
415 return NULL;
416 }
417
418 void Klass::set_subklass(Klass* s) {
419 assert(s != this, "sanity check");
420 Atomic::release_store(&_subklass, s);
421 }
422
423 void Klass::set_next_sibling(Klass* s) {
424 assert(s != this, "sanity check");
425 // Does not need release semantics. If used by cleanup, it will link to
426 // already safely published data, and if used by inserts, will be published
427 // safely using cmpxchg.
428 Atomic::store(&_next_sibling, s);
429 }
430
431 void Klass::append_to_sibling_list() {
432 if (Universe::is_fully_initialized()) {
433 assert_locked_or_safepoint(Compile_lock);
434 }
435 debug_only(verify();)
436 // add ourselves to superklass' subklass list
437 InstanceKlass* super = superklass();
438 if (super == NULL) return; // special case: class Object
439 assert((!super->is_interface() // interfaces cannot be supers
440 && (super->superklass() == NULL || !is_interface())),
441 "an interface can only be a subklass of Object");
442
443 // Make sure there is no stale subklass head
444 super->clean_subklass();
445
446 for (;;) {
447 Klass* prev_first_subklass = Atomic::load_acquire(&_super->_subklass);
448 if (prev_first_subklass != NULL) {
449 // set our sibling to be the superklass' previous first subklass
450 assert(prev_first_subklass->is_loader_alive(), "May not attach not alive klasses");
451 set_next_sibling(prev_first_subklass);
452 }
453 // Note that the prev_first_subklass is always alive, meaning no sibling_next links
454 // are ever created to not alive klasses. This is an important invariant of the lock-free
455 // cleaning protocol, that allows us to safely unlink dead klasses from the sibling list.
456 if (Atomic::cmpxchg(&super->_subklass, prev_first_subklass, this) == prev_first_subklass) {
457 return;
458 }
459 }
460 debug_only(verify();)
461 }
462
463 void Klass::clean_subklass() {
464 for (;;) {
465 // Need load_acquire, due to contending with concurrent inserts
466 Klass* subklass = Atomic::load_acquire(&_subklass);
467 if (subklass == NULL || subklass->is_loader_alive()) {
468 return;
469 }
470 // Try to fix _subklass until it points at something not dead.
471 Atomic::cmpxchg(&_subklass, subklass, subklass->next_sibling());
472 }
473 }
474
475 void Klass::clean_weak_klass_links(bool unloading_occurred, bool clean_alive_klasses) {
476 if (!ClassUnloading || !unloading_occurred) {
477 return;
478 }
479
480 Klass* root = vmClasses::Object_klass();
481 Stack<Klass*, mtGC> stack;
482
483 stack.push(root);
484 while (!stack.is_empty()) {
485 Klass* current = stack.pop();
486
487 assert(current->is_loader_alive(), "just checking, this should be live");
488
489 // Find and set the first alive subklass
490 Klass* sub = current->subklass(true);
491 current->clean_subklass();
492 if (sub != NULL) {
493 stack.push(sub);
494 }
495
496 // Find and set the first alive sibling
497 Klass* sibling = current->next_sibling(true);
498 current->set_next_sibling(sibling);
499 if (sibling != NULL) {
500 stack.push(sibling);
501 }
502
503 // Clean the implementors list and method data.
504 if (clean_alive_klasses && current->is_instance_klass()) {
505 InstanceKlass* ik = InstanceKlass::cast(current);
506 ik->clean_weak_instanceklass_links();
507
508 // JVMTI RedefineClasses creates previous versions that are not in
509 // the class hierarchy, so process them here.
510 while ((ik = ik->previous_versions()) != NULL) {
511 ik->clean_weak_instanceklass_links();
512 }
513 }
514 }
515 }
516
517 void Klass::metaspace_pointers_do(MetaspaceClosure* it) {
518 if (log_is_enabled(Trace, cds)) {
519 ResourceMark rm;
520 log_trace(cds)("Iter(Klass): %p (%s)", this, external_name());
521 }
522
523 it->push(&_name);
524 it->push(&_secondary_super_cache);
525 it->push(&_secondary_supers);
526 for (int i = 0; i < _primary_super_limit; i++) {
527 it->push(&_primary_supers[i]);
528 }
529 it->push(&_super);
530 if (!Arguments::is_dumping_archive()) {
531 // If dumping archive, these may point to excluded classes. There's no need
532 // to follow these pointers anyway, as they will be set to NULL in
533 // remove_unshareable_info().
534 it->push((Klass**)&_subklass);
535 it->push((Klass**)&_next_sibling);
536 it->push(&_next_link);
537 }
538
539 vtableEntry* vt = start_of_vtable();
540 for (int i=0; i<vtable_length(); i++) {
541 it->push(vt[i].method_addr());
542 }
543 }
544
545 void Klass::remove_unshareable_info() {
546 assert (Arguments::is_dumping_archive(),
547 "only called during CDS dump time");
548 JFR_ONLY(REMOVE_ID(this);)
549 if (log_is_enabled(Trace, cds, unshareable)) {
550 ResourceMark rm;
551 log_trace(cds, unshareable)("remove: %s", external_name());
552 }
553
554 set_subklass(NULL);
555 set_next_sibling(NULL);
556 set_next_link(NULL);
557
558 // Null out class_loader_data because we don't share that yet.
559 set_class_loader_data(NULL);
560 set_is_shared();
561 }
562
563 void Klass::remove_java_mirror() {
564 Arguments::assert_is_dumping_archive();
565 if (log_is_enabled(Trace, cds, unshareable)) {
566 ResourceMark rm;
567 log_trace(cds, unshareable)("remove java_mirror: %s", external_name());
568 }
569 // Just null out the mirror. The class_loader_data() no longer exists.
570 clear_java_mirror_handle();
571 }
572
573 void Klass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) {
574 assert(is_klass(), "ensure C++ vtable is restored");
575 assert(is_shared(), "must be set");
576 JFR_ONLY(RESTORE_ID(this);)
577 if (log_is_enabled(Trace, cds, unshareable)) {
578 ResourceMark rm(THREAD);
579 log_trace(cds, unshareable)("restore: %s", external_name());
580 }
581
582 // If an exception happened during CDS restore, some of these fields may already be
583 // set. We leave the class on the CLD list, even if incomplete so that we don't
584 // modify the CLD list outside a safepoint.
585 if (class_loader_data() == NULL) {
586 set_class_loader_data(loader_data);
587
588 // Add to class loader list first before creating the mirror
589 // (same order as class file parsing)
590 loader_data->add_class(this);
591 }
592
593 Handle loader(THREAD, loader_data->class_loader());
594 ModuleEntry* module_entry = NULL;
595 Klass* k = this;
596 if (k->is_objArray_klass()) {
597 k = ObjArrayKlass::cast(k)->bottom_klass();
598 }
599 // Obtain klass' module.
600 if (k->is_instance_klass()) {
601 InstanceKlass* ik = (InstanceKlass*) k;
602 module_entry = ik->module();
603 } else {
604 module_entry = ModuleEntryTable::javabase_moduleEntry();
605 }
606 // Obtain java.lang.Module, if available
607 Handle module_handle(THREAD, ((module_entry != NULL) ? module_entry->module() : (oop)NULL));
608
609 if (this->has_archived_mirror_index()) {
610 ResourceMark rm(THREAD);
611 log_debug(cds, mirror)("%s has raw archived mirror", external_name());
612 if (HeapShared::are_archived_mirrors_available()) {
613 bool present = java_lang_Class::restore_archived_mirror(this, loader, module_handle,
614 protection_domain,
615 CHECK);
616 if (present) {
617 return;
618 }
619 }
620
621 // No archived mirror data
622 log_debug(cds, mirror)("No archived mirror data for %s", external_name());
623 clear_java_mirror_handle();
624 this->clear_archived_mirror_index();
625 }
626
627 // Only recreate it if not present. A previous attempt to restore may have
628 // gotten an OOM later but keep the mirror if it was created.
629 if (java_mirror() == NULL) {
630 ResourceMark rm(THREAD);
631 log_trace(cds, mirror)("Recreate mirror for %s", external_name());
632 java_lang_Class::create_mirror(this, loader, module_handle, protection_domain, Handle(), CHECK);
633 }
634 }
635
636 #if INCLUDE_CDS_JAVA_HEAP
637 oop Klass::archived_java_mirror() {
638 assert(has_archived_mirror_index(), "must have archived mirror");
639 return HeapShared::get_root(_archived_mirror_index);
640 }
641
642 void Klass::clear_archived_mirror_index() {
643 if (_archived_mirror_index >= 0) {
644 HeapShared::clear_root(_archived_mirror_index);
645 }
646 _archived_mirror_index = -1;
647 }
648
649 // No GC barrier
650 void Klass::set_archived_java_mirror(oop m) {
651 assert(DumpSharedSpaces, "called only during runtime");
652 _archived_mirror_index = HeapShared::append_root(m);
653 }
654 #endif // INCLUDE_CDS_JAVA_HEAP
655
656 void Klass::check_array_allocation_length(int length, int max_length, TRAPS) {
657 if (length > max_length) {
658 if (!THREAD->in_retryable_allocation()) {
659 report_java_out_of_memory("Requested array size exceeds VM limit");
660 JvmtiExport::post_array_size_exhausted();
661 THROW_OOP(Universe::out_of_memory_error_array_size());
662 } else {
663 THROW_OOP(Universe::out_of_memory_error_retry());
664 }
665 } else if (length < 0) {
666 THROW_MSG(vmSymbols::java_lang_NegativeArraySizeException(), err_msg("%d", length));
667 }
668 }
669
670 // Replace the last '+' char with '/'.
671 static char* convert_hidden_name_to_java(Symbol* name) {
672 size_t name_len = name->utf8_length();
673 char* result = NEW_RESOURCE_ARRAY(char, name_len + 1);
674 name->as_klass_external_name(result, (int)name_len + 1);
675 for (int index = (int)name_len; index > 0; index--) {
676 if (result[index] == '+') {
677 result[index] = JVM_SIGNATURE_SLASH;
678 break;
679 }
680 }
681 return result;
682 }
683
684 // In product mode, this function doesn't have virtual function calls so
685 // there might be some performance advantage to handling InstanceKlass here.
686 const char* Klass::external_name() const {
687 if (is_instance_klass()) {
688 const InstanceKlass* ik = static_cast<const InstanceKlass*>(this);
689 if (ik->is_hidden()) {
690 char* result = convert_hidden_name_to_java(name());
691 return result;
692 }
693 } else if (is_objArray_klass() && ObjArrayKlass::cast(this)->bottom_klass()->is_hidden()) {
694 char* result = convert_hidden_name_to_java(name());
695 return result;
696 }
697 if (name() == NULL) return "<unknown>";
698 return name()->as_klass_external_name();
699 }
700
701 const char* Klass::signature_name() const {
702 if (name() == NULL) return "<unknown>";
703 if (is_objArray_klass() && ObjArrayKlass::cast(this)->bottom_klass()->is_hidden()) {
704 size_t name_len = name()->utf8_length();
705 char* result = NEW_RESOURCE_ARRAY(char, name_len + 1);
706 name()->as_C_string(result, (int)name_len + 1);
707 for (int index = (int)name_len; index > 0; index--) {
708 if (result[index] == '+') {
709 result[index] = JVM_SIGNATURE_DOT;
710 break;
711 }
712 }
713 return result;
714 }
715 return name()->as_C_string();
716 }
717
718 const char* Klass::external_kind() const {
719 if (is_interface()) return "interface";
720 if (is_abstract()) return "abstract class";
721 return "class";
722 }
723
724 // Unless overridden, jvmti_class_status has no flags set.
725 jint Klass::jvmti_class_status() const {
726 return 0;
727 }
728
729
730 // Printing
731
732 void Klass::print_on(outputStream* st) const {
733 ResourceMark rm;
734 // print title
735 st->print("%s", internal_name());
736 print_address_on(st);
737 st->cr();
738 }
739
740 #define BULLET " - "
741
742 // Caller needs ResourceMark
743 void Klass::oop_print_on(oop obj, outputStream* st) {
744 // print title
745 st->print_cr("%s ", internal_name());
746 obj->print_address_on(st);
747
748 if (WizardMode) {
749 // print header
750 obj->mark().print_on(st);
751 st->cr();
752 st->print(BULLET"prototype_header: " INTPTR_FORMAT, _prototype_header.value());
753 st->cr();
754 }
755
756 // print class
757 st->print(BULLET"klass: ");
758 obj->klass()->print_value_on(st);
759 st->cr();
760 }
761
762 void Klass::oop_print_value_on(oop obj, outputStream* st) {
763 // print title
764 ResourceMark rm; // Cannot print in debug mode without this
765 st->print("%s", internal_name());
766 obj->print_address_on(st);
767 }
768
769 // Verification
770
771 void Klass::verify_on(outputStream* st) {
772
773 // This can be expensive, but it is worth checking that this klass is actually
774 // in the CLD graph but not in production.
775 assert(Metaspace::contains((address)this), "Should be");
776
777 if (UseCompressedClassPointers) {
778 assert(is_aligned(this, KlassAlignmentInBytes), "misaligned Klass structure");
779 }
780
781 guarantee(this->is_klass(),"should be klass");
782
783 if (super() != NULL) {
784 guarantee(super()->is_klass(), "should be klass");
785 }
786 if (secondary_super_cache() != NULL) {
787 Klass* ko = secondary_super_cache();
788 guarantee(ko->is_klass(), "should be klass");
789 }
790 for ( uint i = 0; i < primary_super_limit(); i++ ) {
791 Klass* ko = _primary_supers[i];
792 if (ko != NULL) {
793 guarantee(ko->is_klass(), "should be klass");
794 }
795 }
796
797 if (java_mirror_no_keepalive() != NULL) {
798 guarantee(oopDesc::is_oop(java_mirror_no_keepalive()), "should be instance");
799 }
800 }
801
802 void Klass::oop_verify_on(oop obj, outputStream* st) {
803 guarantee(oopDesc::is_oop(obj), "should be oop");
804 guarantee(obj->klass()->is_klass(), "klass field is not a klass");
805 }
806
807 bool Klass::is_valid(Klass* k) {
808 if (!is_aligned(k, sizeof(MetaWord))) return false;
809 if ((size_t)k < os::min_page_size()) return false;
810
811 if (!os::is_readable_range(k, k + 1)) return false;
812 if (!Metaspace::contains(k)) return false;
813
814 if (!Symbol::is_valid(k->name())) return false;
815 return ClassLoaderDataGraph::is_valid(k->class_loader_data());
816 }
817
818 Method* Klass::method_at_vtable(int index) {
819 #ifndef PRODUCT
820 assert(index >= 0, "valid vtable index");
821 if (DebugVtables) {
822 verify_vtable_index(index);
823 }
824 #endif
825 return start_of_vtable()[index].method();
826 }
827
828
829 #ifndef PRODUCT
830
831 bool Klass::verify_vtable_index(int i) {
832 int limit = vtable_length()/vtableEntry::size();
833 assert(i >= 0 && i < limit, "index %d out of bounds %d", i, limit);
834 return true;
835 }
836
837 #endif // PRODUCT
838
839 // Caller needs ResourceMark
840 // joint_in_module_of_loader provides an optimization if 2 classes are in
841 // the same module to succinctly print out relevant information about their
842 // module name and class loader's name_and_id for error messages.
843 // Format:
844 // <fully-qualified-external-class-name1> and <fully-qualified-external-class-name2>
845 // are in module <module-name>[@<version>]
846 // of loader <loader-name_and_id>[, parent loader <parent-loader-name_and_id>]
847 const char* Klass::joint_in_module_of_loader(const Klass* class2, bool include_parent_loader) const {
848 assert(module() == class2->module(), "classes do not have the same module");
849 const char* class1_name = external_name();
850 size_t len = strlen(class1_name) + 1;
851
852 const char* class2_description = class2->class_in_module_of_loader(true, include_parent_loader);
853 len += strlen(class2_description);
854
855 len += strlen(" and ");
856
857 char* joint_description = NEW_RESOURCE_ARRAY_RETURN_NULL(char, len);
858
859 // Just return the FQN if error when allocating string
860 if (joint_description == NULL) {
861 return class1_name;
862 }
863
864 jio_snprintf(joint_description, len, "%s and %s",
865 class1_name,
866 class2_description);
867
868 return joint_description;
869 }
870
871 // Caller needs ResourceMark
872 // class_in_module_of_loader provides a standard way to include
873 // relevant information about a class, such as its module name as
874 // well as its class loader's name_and_id, in error messages and logging.
875 // Format:
876 // <fully-qualified-external-class-name> is in module <module-name>[@<version>]
877 // of loader <loader-name_and_id>[, parent loader <parent-loader-name_and_id>]
878 const char* Klass::class_in_module_of_loader(bool use_are, bool include_parent_loader) const {
879 // 1. fully qualified external name of class
880 const char* klass_name = external_name();
881 size_t len = strlen(klass_name) + 1;
882
883 // 2. module name + @version
884 const char* module_name = "";
885 const char* version = "";
886 bool has_version = false;
887 bool module_is_named = false;
888 const char* module_name_phrase = "";
889 const Klass* bottom_klass = is_objArray_klass() ?
890 ObjArrayKlass::cast(this)->bottom_klass() : this;
891 if (bottom_klass->is_instance_klass()) {
892 ModuleEntry* module = InstanceKlass::cast(bottom_klass)->module();
893 if (module->is_named()) {
894 module_is_named = true;
895 module_name_phrase = "module ";
896 module_name = module->name()->as_C_string();
897 len += strlen(module_name);
898 // Use version if exists and is not a jdk module
899 if (module->should_show_version()) {
900 has_version = true;
901 version = module->version()->as_C_string();
902 // Include stlen(version) + 1 for the "@"
903 len += strlen(version) + 1;
904 }
905 } else {
906 module_name = UNNAMED_MODULE;
907 len += UNNAMED_MODULE_LEN;
908 }
909 } else {
910 // klass is an array of primitives, module is java.base
911 module_is_named = true;
912 module_name_phrase = "module ";
913 module_name = JAVA_BASE_NAME;
914 len += JAVA_BASE_NAME_LEN;
915 }
916
917 // 3. class loader's name_and_id
918 ClassLoaderData* cld = class_loader_data();
919 assert(cld != NULL, "class_loader_data should not be null");
920 const char* loader_name_and_id = cld->loader_name_and_id();
921 len += strlen(loader_name_and_id);
922
923 // 4. include parent loader information
924 const char* parent_loader_phrase = "";
925 const char* parent_loader_name_and_id = "";
926 if (include_parent_loader &&
927 !cld->is_builtin_class_loader_data()) {
928 oop parent_loader = java_lang_ClassLoader::parent(class_loader());
929 ClassLoaderData *parent_cld = ClassLoaderData::class_loader_data_or_null(parent_loader);
930 // The parent loader's ClassLoaderData could be null if it is
931 // a delegating class loader that has never defined a class.
932 // In this case the loader's name must be obtained via the parent loader's oop.
933 if (parent_cld == NULL) {
934 oop cl_name_and_id = java_lang_ClassLoader::nameAndId(parent_loader);
935 if (cl_name_and_id != NULL) {
936 parent_loader_name_and_id = java_lang_String::as_utf8_string(cl_name_and_id);
937 }
938 } else {
939 parent_loader_name_and_id = parent_cld->loader_name_and_id();
940 }
941 parent_loader_phrase = ", parent loader ";
942 len += strlen(parent_loader_phrase) + strlen(parent_loader_name_and_id);
943 }
944
945 // Start to construct final full class description string
946 len += ((use_are) ? strlen(" are in ") : strlen(" is in "));
947 len += strlen(module_name_phrase) + strlen(" of loader ");
948
949 char* class_description = NEW_RESOURCE_ARRAY_RETURN_NULL(char, len);
950
951 // Just return the FQN if error when allocating string
952 if (class_description == NULL) {
953 return klass_name;
954 }
955
956 jio_snprintf(class_description, len, "%s %s in %s%s%s%s of loader %s%s%s",
957 klass_name,
958 (use_are) ? "are" : "is",
959 module_name_phrase,
960 module_name,
961 (has_version) ? "@" : "",
962 (has_version) ? version : "",
963 loader_name_and_id,
964 parent_loader_phrase,
965 parent_loader_name_and_id);
966
967 return class_description;
968 }