1 /*
2 * Copyright (c) 1997, 2021, 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/handles.inline.hpp"
52 #include "utilities/macros.hpp"
53 #include "utilities/powerOfTwo.hpp"
54 #include "utilities/stack.inline.hpp"
55
56 void Klass::set_java_mirror(Handle m) {
57 assert(!m.is_null(), "New mirror should never be null.");
58 assert(_java_mirror.is_empty(), "should only be used to initialize mirror");
59 _java_mirror = class_loader_data()->add_handle(m);
60 }
61
62 oop Klass::java_mirror_no_keepalive() const {
63 return _java_mirror.peek();
64 }
65
66 void Klass::replace_java_mirror(oop mirror) {
67 _java_mirror.replace(mirror);
68 }
69
70 bool Klass::is_cloneable() const {
71 return _access_flags.is_cloneable_fast() ||
72 is_subtype_of(vmClasses::Cloneable_klass());
73 }
74
75 void Klass::set_is_cloneable() {
76 if (name() == vmSymbols::java_lang_invoke_MemberName()) {
77 assert(is_final(), "no subclasses allowed");
78 // MemberName cloning should not be intrinsified and always happen in JVM_Clone.
79 } else if (is_instance_klass() && InstanceKlass::cast(this)->reference_type() != REF_NONE) {
80 // Reference cloning should not be intrinsified and always happen in JVM_Clone.
81 } else {
82 _access_flags.set_is_cloneable_fast();
83 }
84 }
85
86 void Klass::set_name(Symbol* n) {
87 _name = n;
88 if (_name != NULL) _name->increment_refcount();
89
90 if (Arguments::is_dumping_archive() && is_instance_klass()) {
91 SystemDictionaryShared::init_dumptime_info(InstanceKlass::cast(this));
92 }
93 }
94
95 bool Klass::is_subclass_of(const Klass* k) const {
96 // Run up the super chain and check
97 if (this == k) return true;
98
99 Klass* t = const_cast<Klass*>(this)->super();
100
101 while (t != NULL) {
102 if (t == k) return true;
103 t = t->super();
104 }
105 return false;
106 }
107
108 void Klass::release_C_heap_structures(bool release_constant_pool) {
109 if (_name != NULL) _name->decrement_refcount();
110 }
111
112 bool Klass::search_secondary_supers(Klass* k) const {
113 // Put some extra logic here out-of-line, before the search proper.
114 // This cuts down the size of the inline method.
115
116 // This is necessary, since I am never in my own secondary_super list.
117 if (this == k)
118 return true;
119 // Scan the array-of-objects for a match
120 int cnt = secondary_supers()->length();
121 for (int i = 0; i < cnt; i++) {
122 if (secondary_supers()->at(i) == k) {
123 ((Klass*)this)->set_secondary_super_cache(k);
124 return true;
125 }
126 }
127 return false;
128 }
129
130 // Return self, except for abstract classes with exactly 1
131 // implementor. Then return the 1 concrete implementation.
132 Klass *Klass::up_cast_abstract() {
133 Klass *r = this;
134 while( r->is_abstract() ) { // Receiver is abstract?
135 Klass *s = r->subklass(); // Check for exactly 1 subklass
136 if (s == NULL || s->next_sibling() != NULL) // Oops; wrong count; give up
137 return this; // Return 'this' as a no-progress flag
138 r = s; // Loop till find concrete class
139 }
140 return r; // Return the 1 concrete class
141 }
142
143 // Find LCA in class hierarchy
144 Klass *Klass::LCA( Klass *k2 ) {
145 Klass *k1 = this;
146 while( 1 ) {
147 if( k1->is_subtype_of(k2) ) return k2;
148 if( k2->is_subtype_of(k1) ) return k1;
149 k1 = k1->super();
150 k2 = k2->super();
151 }
152 }
153
154
155 void Klass::check_valid_for_instantiation(bool throwError, TRAPS) {
156 ResourceMark rm(THREAD);
157 THROW_MSG(throwError ? vmSymbols::java_lang_InstantiationError()
158 : vmSymbols::java_lang_InstantiationException(), external_name());
159 }
160
161
162 void Klass::copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS) {
163 ResourceMark rm(THREAD);
164 assert(s != NULL, "Throw NPE!");
165 THROW_MSG(vmSymbols::java_lang_ArrayStoreException(),
166 err_msg("arraycopy: source type %s is not an array", s->klass()->external_name()));
167 }
168
169
170 void Klass::initialize(TRAPS) {
171 ShouldNotReachHere();
172 }
173
174 Klass* Klass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
175 #ifdef ASSERT
176 tty->print_cr("Error: find_field called on a klass oop."
177 " Likely error: reflection method does not correctly"
178 " wrap return value in a mirror object.");
179 #endif
180 ShouldNotReachHere();
181 return NULL;
182 }
183
184 Method* Klass::uncached_lookup_method(const Symbol* name, const Symbol* signature,
185 OverpassLookupMode overpass_mode,
186 PrivateLookupMode private_mode) const {
187 #ifdef ASSERT
188 tty->print_cr("Error: uncached_lookup_method called on a klass oop."
189 " Likely error: reflection method does not correctly"
190 " wrap return value in a mirror object.");
191 #endif
192 ShouldNotReachHere();
193 return NULL;
194 }
195
196 void* Klass::operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, TRAPS) throw() {
197 return Metaspace::allocate(loader_data, word_size, MetaspaceObj::ClassType, THREAD);
198 }
199
200 static markWord make_prototype(Klass* kls) {
201 markWord prototype = markWord::prototype();
202 #ifdef _LP64
203 if (UseCompactObjectHeaders) {
204 prototype = prototype.set_klass(kls);
205 }
206 #endif
207 return prototype;
208 }
209
210 // "Normal" instantiation is preceeded by a MetaspaceObj allocation
211 // which zeros out memory - calloc equivalent.
212 // The constructor is also used from CppVtableCloner,
213 // which doesn't zero out the memory before calling the constructor.
214 Klass::Klass(KlassID id) : _id(id),
215 _prototype_header(make_prototype(this)),
216 _shared_class_path_index(-1) {
217 CDS_ONLY(_shared_class_flags = 0;)
218 CDS_JAVA_HEAP_ONLY(_archived_mirror_index = -1;)
219 _primary_supers[0] = this;
220 set_super_check_offset(in_bytes(primary_supers_offset()));
221 }
222
223 jint Klass::array_layout_helper(BasicType etype) {
224 assert(etype >= T_BOOLEAN && etype <= T_OBJECT, "valid etype");
225 // Note that T_ARRAY is not allowed here.
226 int hsize = arrayOopDesc::base_offset_in_bytes(etype);
227 int esize = type2aelembytes(etype);
228 bool isobj = (etype == T_OBJECT);
229 int tag = isobj ? _lh_array_tag_obj_value : _lh_array_tag_type_value;
230 int lh = array_layout_helper(tag, hsize, etype, exact_log2(esize));
231
232 assert(lh < (int)_lh_neutral_value, "must look like an array layout");
233 assert(layout_helper_is_array(lh), "correct kind");
234 assert(layout_helper_is_objArray(lh) == isobj, "correct kind");
235 assert(layout_helper_is_typeArray(lh) == !isobj, "correct kind");
236 assert(layout_helper_header_size(lh) == hsize, "correct decode");
237 assert(layout_helper_element_type(lh) == etype, "correct decode");
238 assert(1 << layout_helper_log2_element_size(lh) == esize, "correct decode");
239
240 return lh;
241 }
242
243 bool Klass::can_be_primary_super_slow() const {
244 if (super() == NULL)
245 return true;
246 else if (super()->super_depth() >= primary_super_limit()-1)
247 return false;
248 else
249 return true;
250 }
251
252 void Klass::initialize_supers(Klass* k, Array<InstanceKlass*>* transitive_interfaces, TRAPS) {
253 if (k == NULL) {
254 set_super(NULL);
255 _primary_supers[0] = this;
256 assert(super_depth() == 0, "Object must already be initialized properly");
257 } else if (k != super() || k == vmClasses::Object_klass()) {
258 assert(super() == NULL || super() == vmClasses::Object_klass(),
259 "initialize this only once to a non-trivial value");
260 set_super(k);
261 Klass* sup = k;
262 int sup_depth = sup->super_depth();
263 juint my_depth = MIN2(sup_depth + 1, (int)primary_super_limit());
264 if (!can_be_primary_super_slow())
265 my_depth = primary_super_limit();
266 for (juint i = 0; i < my_depth; i++) {
267 _primary_supers[i] = sup->_primary_supers[i];
268 }
269 Klass* *super_check_cell;
270 if (my_depth < primary_super_limit()) {
271 _primary_supers[my_depth] = this;
272 super_check_cell = &_primary_supers[my_depth];
273 } else {
274 // Overflow of the primary_supers array forces me to be secondary.
275 super_check_cell = &_secondary_super_cache;
276 }
277 set_super_check_offset((address)super_check_cell - (address) this);
278
279 #ifdef ASSERT
280 {
281 juint j = super_depth();
282 assert(j == my_depth, "computed accessor gets right answer");
283 Klass* t = this;
284 while (!t->can_be_primary_super()) {
285 t = t->super();
286 j = t->super_depth();
287 }
288 for (juint j1 = j+1; j1 < primary_super_limit(); j1++) {
289 assert(primary_super_of_depth(j1) == NULL, "super list padding");
290 }
291 while (t != NULL) {
292 assert(primary_super_of_depth(j) == t, "super list initialization");
293 t = t->super();
294 --j;
295 }
296 assert(j == (juint)-1, "correct depth count");
297 }
298 #endif
299 }
300
301 if (secondary_supers() == NULL) {
302
303 // Now compute the list of secondary supertypes.
304 // Secondaries can occasionally be on the super chain,
305 // if the inline "_primary_supers" array overflows.
306 int extras = 0;
307 Klass* p;
308 for (p = super(); !(p == NULL || p->can_be_primary_super()); p = p->super()) {
309 ++extras;
310 }
311
312 ResourceMark rm(THREAD); // need to reclaim GrowableArrays allocated below
313
314 // Compute the "real" non-extra secondaries.
315 GrowableArray<Klass*>* secondaries = compute_secondary_supers(extras, transitive_interfaces);
316 if (secondaries == NULL) {
317 // secondary_supers set by compute_secondary_supers
318 return;
319 }
320
321 GrowableArray<Klass*>* primaries = new GrowableArray<Klass*>(extras);
322
323 for (p = super(); !(p == NULL || p->can_be_primary_super()); p = p->super()) {
324 int i; // Scan for overflow primaries being duplicates of 2nd'arys
325
326 // This happens frequently for very deeply nested arrays: the
327 // primary superclass chain overflows into the secondary. The
328 // secondary list contains the element_klass's secondaries with
329 // an extra array dimension added. If the element_klass's
330 // secondary list already contains some primary overflows, they
331 // (with the extra level of array-ness) will collide with the
332 // normal primary superclass overflows.
333 for( i = 0; i < secondaries->length(); i++ ) {
334 if( secondaries->at(i) == p )
335 break;
336 }
337 if( i < secondaries->length() )
338 continue; // It's a dup, don't put it in
339 primaries->push(p);
340 }
341 // Combine the two arrays into a metadata object to pack the array.
342 // The primaries are added in the reverse order, then the secondaries.
343 int new_length = primaries->length() + secondaries->length();
344 Array<Klass*>* s2 = MetadataFactory::new_array<Klass*>(
345 class_loader_data(), new_length, CHECK);
346 int fill_p = primaries->length();
347 for (int j = 0; j < fill_p; j++) {
348 s2->at_put(j, primaries->pop()); // add primaries in reverse order.
349 }
350 for( int j = 0; j < secondaries->length(); j++ ) {
351 s2->at_put(j+fill_p, secondaries->at(j)); // add secondaries on the end.
352 }
353
354 #ifdef ASSERT
355 // We must not copy any NULL placeholders left over from bootstrap.
356 for (int j = 0; j < s2->length(); j++) {
357 assert(s2->at(j) != NULL, "correct bootstrapping order");
358 }
359 #endif
360
361 set_secondary_supers(s2);
362 }
363 }
364
365 GrowableArray<Klass*>* Klass::compute_secondary_supers(int num_extra_slots,
366 Array<InstanceKlass*>* transitive_interfaces) {
367 assert(num_extra_slots == 0, "override for complex klasses");
368 assert(transitive_interfaces == NULL, "sanity");
369 set_secondary_supers(Universe::the_empty_klass_array());
370 return NULL;
371 }
372
373
374 // superklass links
375 InstanceKlass* Klass::superklass() const {
376 assert(super() == NULL || super()->is_instance_klass(), "must be instance klass");
377 return _super == NULL ? NULL : InstanceKlass::cast(_super);
378 }
379
380 // subklass links. Used by the compiler (and vtable initialization)
381 // May be cleaned concurrently, so must use the Compile_lock.
382 // The log parameter is for clean_weak_klass_links to report unlinked classes.
383 Klass* Klass::subklass(bool log) const {
384 // Need load_acquire on the _subklass, because it races with inserts that
385 // publishes freshly initialized data.
386 for (Klass* chain = Atomic::load_acquire(&_subklass);
387 chain != NULL;
388 // Do not need load_acquire on _next_sibling, because inserts never
389 // create _next_sibling edges to dead data.
390 chain = Atomic::load(&chain->_next_sibling))
391 {
392 if (chain->is_loader_alive()) {
393 return chain;
394 } else if (log) {
395 if (log_is_enabled(Trace, class, unload)) {
396 ResourceMark rm;
397 log_trace(class, unload)("unlinking class (subclass): %s", chain->external_name());
398 }
399 }
400 }
401 return NULL;
402 }
403
404 Klass* Klass::next_sibling(bool log) const {
405 // Do not need load_acquire on _next_sibling, because inserts never
406 // create _next_sibling edges to dead data.
407 for (Klass* chain = Atomic::load(&_next_sibling);
408 chain != NULL;
409 chain = Atomic::load(&chain->_next_sibling)) {
410 // Only return alive klass, there may be stale klass
411 // in this chain if cleaned concurrently.
412 if (chain->is_loader_alive()) {
413 return chain;
414 } else if (log) {
415 if (log_is_enabled(Trace, class, unload)) {
416 ResourceMark rm;
417 log_trace(class, unload)("unlinking class (sibling): %s", chain->external_name());
418 }
419 }
420 }
421 return NULL;
422 }
423
424 void Klass::set_subklass(Klass* s) {
425 assert(s != this, "sanity check");
426 Atomic::release_store(&_subklass, s);
427 }
428
429 void Klass::set_next_sibling(Klass* s) {
430 assert(s != this, "sanity check");
431 // Does not need release semantics. If used by cleanup, it will link to
432 // already safely published data, and if used by inserts, will be published
433 // safely using cmpxchg.
434 Atomic::store(&_next_sibling, s);
435 }
436
437 void Klass::append_to_sibling_list() {
438 if (Universe::is_fully_initialized()) {
439 assert_locked_or_safepoint(Compile_lock);
440 }
441 debug_only(verify();)
442 // add ourselves to superklass' subklass list
443 InstanceKlass* super = superklass();
444 if (super == NULL) return; // special case: class Object
445 assert((!super->is_interface() // interfaces cannot be supers
446 && (super->superklass() == NULL || !is_interface())),
447 "an interface can only be a subklass of Object");
448
449 // Make sure there is no stale subklass head
450 super->clean_subklass();
451
452 for (;;) {
453 Klass* prev_first_subklass = Atomic::load_acquire(&_super->_subklass);
454 if (prev_first_subklass != NULL) {
455 // set our sibling to be the superklass' previous first subklass
456 assert(prev_first_subklass->is_loader_alive(), "May not attach not alive klasses");
457 set_next_sibling(prev_first_subklass);
458 }
459 // Note that the prev_first_subklass is always alive, meaning no sibling_next links
460 // are ever created to not alive klasses. This is an important invariant of the lock-free
461 // cleaning protocol, that allows us to safely unlink dead klasses from the sibling list.
462 if (Atomic::cmpxchg(&super->_subklass, prev_first_subklass, this) == prev_first_subklass) {
463 return;
464 }
465 }
466 debug_only(verify();)
467 }
468
469 void Klass::clean_subklass() {
470 for (;;) {
471 // Need load_acquire, due to contending with concurrent inserts
472 Klass* subklass = Atomic::load_acquire(&_subklass);
473 if (subklass == NULL || subklass->is_loader_alive()) {
474 return;
475 }
476 // Try to fix _subklass until it points at something not dead.
477 Atomic::cmpxchg(&_subklass, subklass, subklass->next_sibling());
478 }
479 }
480
481 void Klass::clean_weak_klass_links(bool unloading_occurred, bool clean_alive_klasses) {
482 if (!ClassUnloading || !unloading_occurred) {
483 return;
484 }
485
486 Klass* root = vmClasses::Object_klass();
487 Stack<Klass*, mtGC> stack;
488
489 stack.push(root);
490 while (!stack.is_empty()) {
491 Klass* current = stack.pop();
492
493 assert(current->is_loader_alive(), "just checking, this should be live");
494
495 // Find and set the first alive subklass
496 Klass* sub = current->subklass(true);
497 current->clean_subklass();
498 if (sub != NULL) {
499 stack.push(sub);
500 }
501
502 // Find and set the first alive sibling
503 Klass* sibling = current->next_sibling(true);
504 current->set_next_sibling(sibling);
505 if (sibling != NULL) {
506 stack.push(sibling);
507 }
508
509 // Clean the implementors list and method data.
510 if (clean_alive_klasses && current->is_instance_klass()) {
511 InstanceKlass* ik = InstanceKlass::cast(current);
512 ik->clean_weak_instanceklass_links();
513
514 // JVMTI RedefineClasses creates previous versions that are not in
515 // the class hierarchy, so process them here.
516 while ((ik = ik->previous_versions()) != NULL) {
517 ik->clean_weak_instanceklass_links();
518 }
519 }
520 }
521 }
522
523 void Klass::metaspace_pointers_do(MetaspaceClosure* it) {
524 if (log_is_enabled(Trace, cds)) {
525 ResourceMark rm;
526 log_trace(cds)("Iter(Klass): %p (%s)", this, external_name());
527 }
528
529 it->push(&_name);
530 it->push(&_secondary_super_cache);
531 it->push(&_secondary_supers);
532 for (int i = 0; i < _primary_super_limit; i++) {
533 it->push(&_primary_supers[i]);
534 }
535 it->push(&_super);
536 it->push((Klass**)&_subklass);
537 it->push((Klass**)&_next_sibling);
538 it->push(&_next_link);
539
540 vtableEntry* vt = start_of_vtable();
541 for (int i=0; i<vtable_length(); i++) {
542 it->push(vt[i].method_addr());
543 }
544 }
545
546 void Klass::remove_unshareable_info() {
547 assert (Arguments::is_dumping_archive(),
548 "only called during CDS dump time");
549 JFR_ONLY(REMOVE_ID(this);)
550 if (log_is_enabled(Trace, cds, unshareable)) {
551 ResourceMark rm;
552 log_trace(cds, unshareable)("remove: %s", external_name());
553 }
554
555 set_subklass(NULL);
556 set_next_sibling(NULL);
557 set_next_link(NULL);
558
559 // Null out class_loader_data because we don't share that yet.
560 set_class_loader_data(NULL);
561 set_is_shared();
562 }
563
564 void Klass::remove_java_mirror() {
565 Arguments::assert_is_dumping_archive();
566 if (log_is_enabled(Trace, cds, unshareable)) {
567 ResourceMark rm;
568 log_trace(cds, unshareable)("remove java_mirror: %s", external_name());
569 }
570 // Just null out the mirror. The class_loader_data() no longer exists.
571 clear_java_mirror_handle();
572 }
573
574 void Klass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) {
575 assert(is_klass(), "ensure C++ vtable is restored");
576 assert(is_shared(), "must be set");
577 JFR_ONLY(RESTORE_ID(this);)
578 if (log_is_enabled(Trace, cds, unshareable)) {
579 ResourceMark rm(THREAD);
580 log_trace(cds, unshareable)("restore: %s", external_name());
581 }
582
583 // If an exception happened during CDS restore, some of these fields may already be
584 // set. We leave the class on the CLD list, even if incomplete so that we don't
585 // modify the CLD list outside a safepoint.
586 if (class_loader_data() == NULL) {
587 set_class_loader_data(loader_data);
588
589 // Add to class loader list first before creating the mirror
590 // (same order as class file parsing)
591 loader_data->add_class(this);
592 }
593
594 Handle loader(THREAD, loader_data->class_loader());
595 ModuleEntry* module_entry = NULL;
596 Klass* k = this;
597 if (k->is_objArray_klass()) {
598 k = ObjArrayKlass::cast(k)->bottom_klass();
599 }
600 // Obtain klass' module.
601 if (k->is_instance_klass()) {
602 InstanceKlass* ik = (InstanceKlass*) k;
603 module_entry = ik->module();
604 } else {
605 module_entry = ModuleEntryTable::javabase_moduleEntry();
606 }
607 // Obtain java.lang.Module, if available
608 Handle module_handle(THREAD, ((module_entry != NULL) ? module_entry->module() : (oop)NULL));
609
610 if (this->has_archived_mirror_index()) {
611 ResourceMark rm(THREAD);
612 log_debug(cds, mirror)("%s has raw archived mirror", external_name());
613 if (HeapShared::open_archive_heap_region_mapped()) {
614 bool present = java_lang_Class::restore_archived_mirror(this, loader, module_handle,
615 protection_domain,
616 CHECK);
617 if (present) {
618 return;
619 }
620 }
621
622 // No archived mirror data
623 log_debug(cds, mirror)("No archived mirror data for %s", external_name());
624 clear_java_mirror_handle();
625 this->clear_archived_mirror_index();
626 }
627
628 // Only recreate it if not present. A previous attempt to restore may have
629 // gotten an OOM later but keep the mirror if it was created.
630 if (java_mirror() == NULL) {
631 ResourceMark rm(THREAD);
632 log_trace(cds, mirror)("Recreate mirror for %s", external_name());
633 java_lang_Class::create_mirror(this, loader, module_handle, protection_domain, Handle(), CHECK);
634 }
635 }
636
637 #if INCLUDE_CDS_JAVA_HEAP
638 oop Klass::archived_java_mirror() {
639 assert(has_archived_mirror_index(), "must have archived mirror");
640 return HeapShared::get_root(_archived_mirror_index);
641 }
642
643 void Klass::clear_archived_mirror_index() {
644 if (_archived_mirror_index >= 0) {
645 HeapShared::clear_root(_archived_mirror_index);
646 }
647 _archived_mirror_index = -1;
648 }
649
650 // No GC barrier
651 void Klass::set_archived_java_mirror(oop m) {
652 assert(DumpSharedSpaces, "called only during runtime");
653 _archived_mirror_index = HeapShared::append_root(m);
654 }
655 #endif // INCLUDE_CDS_JAVA_HEAP
656
657 void Klass::check_array_allocation_length(int length, int max_length, TRAPS) {
658 if (length > max_length) {
659 if (!THREAD->in_retryable_allocation()) {
660 report_java_out_of_memory("Requested array size exceeds VM limit");
661 JvmtiExport::post_array_size_exhausted();
662 THROW_OOP(Universe::out_of_memory_error_array_size());
663 } else {
664 THROW_OOP(Universe::out_of_memory_error_retry());
665 }
666 } else if (length < 0) {
667 THROW_MSG(vmSymbols::java_lang_NegativeArraySizeException(), err_msg("%d", length));
668 }
669 }
670
671 // Replace the last '+' char with '/'.
672 static char* convert_hidden_name_to_java(Symbol* name) {
673 size_t name_len = name->utf8_length();
674 char* result = NEW_RESOURCE_ARRAY(char, name_len + 1);
675 name->as_klass_external_name(result, (int)name_len + 1);
676 for (int index = (int)name_len; index > 0; index--) {
677 if (result[index] == '+') {
678 result[index] = JVM_SIGNATURE_SLASH;
679 break;
680 }
681 }
682 return result;
683 }
684
685 // In product mode, this function doesn't have virtual function calls so
686 // there might be some performance advantage to handling InstanceKlass here.
687 const char* Klass::external_name() const {
688 if (is_instance_klass()) {
689 const InstanceKlass* ik = static_cast<const InstanceKlass*>(this);
690 if (ik->is_hidden()) {
691 char* result = convert_hidden_name_to_java(name());
692 return result;
693 }
694 } else if (is_objArray_klass() && ObjArrayKlass::cast(this)->bottom_klass()->is_hidden()) {
695 char* result = convert_hidden_name_to_java(name());
696 return result;
697 }
698 if (name() == NULL) return "<unknown>";
699 return name()->as_klass_external_name();
700 }
701
702 const char* Klass::signature_name() const {
703 if (name() == NULL) return "<unknown>";
704 if (is_objArray_klass() && ObjArrayKlass::cast(this)->bottom_klass()->is_hidden()) {
705 size_t name_len = name()->utf8_length();
706 char* result = NEW_RESOURCE_ARRAY(char, name_len + 1);
707 name()->as_C_string(result, (int)name_len + 1);
708 for (int index = (int)name_len; index > 0; index--) {
709 if (result[index] == '+') {
710 result[index] = JVM_SIGNATURE_DOT;
711 break;
712 }
713 }
714 return result;
715 }
716 return name()->as_C_string();
717 }
718
719 const char* Klass::external_kind() const {
720 if (is_interface()) return "interface";
721 if (is_abstract()) return "abstract class";
722 return "class";
723 }
724
725 int Klass::atomic_incr_biased_lock_revocation_count() {
726 return (int) Atomic::add(&_biased_lock_revocation_count, 1);
727 }
728
729 // Unless overridden, jvmti_class_status has no flags set.
730 jint Klass::jvmti_class_status() const {
731 return 0;
732 }
733
734
735 // Printing
736
737 void Klass::print_on(outputStream* st) const {
738 ResourceMark rm;
739 // print title
740 st->print("%s", internal_name());
741 print_address_on(st);
742 st->cr();
743 }
744
745 #define BULLET " - "
746
747 // Caller needs ResourceMark
748 void Klass::oop_print_on(oop obj, outputStream* st) {
749 // print title
750 st->print_cr("%s ", internal_name());
751 obj->print_address_on(st);
752
753 if (WizardMode) {
754 // print header
755 obj->mark().print_on(st);
756 st->cr();
757 if (UseCompactObjectHeaders) {
758 st->print(BULLET"prototype_header: " INTPTR_FORMAT, _prototype_header.value());
759 st->cr();
760 }
761 }
762
763 // print class
764 st->print(BULLET"klass: ");
765 obj->klass()->print_value_on(st);
766 st->cr();
767 }
768
769 void Klass::oop_print_value_on(oop obj, outputStream* st) {
770 // print title
771 ResourceMark rm; // Cannot print in debug mode without this
772 st->print("%s", internal_name());
773 obj->print_address_on(st);
774 }
775
776 // Verification
777
778 void Klass::verify_on(outputStream* st) {
779
780 // This can be expensive, but it is worth checking that this klass is actually
781 // in the CLD graph but not in production.
782 assert(Metaspace::contains((address)this), "Should be");
783
784 guarantee(this->is_klass(),"should be klass");
785
786 if (super() != NULL) {
787 guarantee(super()->is_klass(), "should be klass");
788 }
789 if (secondary_super_cache() != NULL) {
790 Klass* ko = secondary_super_cache();
791 guarantee(ko->is_klass(), "should be klass");
792 }
793 for ( uint i = 0; i < primary_super_limit(); i++ ) {
794 Klass* ko = _primary_supers[i];
795 if (ko != NULL) {
796 guarantee(ko->is_klass(), "should be klass");
797 }
798 }
799
800 if (java_mirror_no_keepalive() != NULL) {
801 guarantee(oopDesc::is_oop(java_mirror_no_keepalive()), "should be instance");
802 }
803 }
804
805 void Klass::oop_verify_on(oop obj, outputStream* st) {
806 guarantee(oopDesc::is_oop(obj), "should be oop");
807 guarantee(obj->klass()->is_klass(), "klass field is not a klass");
808 }
809
810 bool Klass::is_valid(Klass* k) {
811 if (!is_aligned(k, sizeof(MetaWord))) return false;
812 if ((size_t)k < os::min_page_size()) return false;
813
814 if (!os::is_readable_range(k, k + 1)) return false;
815 if (!Metaspace::contains(k)) return false;
816
817 if (!Symbol::is_valid(k->name())) return false;
818 return ClassLoaderDataGraph::is_valid(k->class_loader_data());
819 }
820
821 Method* Klass::method_at_vtable(int index) {
822 #ifndef PRODUCT
823 assert(index >= 0, "valid vtable index");
824 if (DebugVtables) {
825 verify_vtable_index(index);
826 }
827 #endif
828 return start_of_vtable()[index].method();
829 }
830
831
832 #ifndef PRODUCT
833
834 bool Klass::verify_vtable_index(int i) {
835 int limit = vtable_length()/vtableEntry::size();
836 assert(i >= 0 && i < limit, "index %d out of bounds %d", i, limit);
837 return true;
838 }
839
840 #endif // PRODUCT
841
842 // Caller needs ResourceMark
843 // joint_in_module_of_loader provides an optimization if 2 classes are in
844 // the same module to succinctly print out relevant information about their
845 // module name and class loader's name_and_id for error messages.
846 // Format:
847 // <fully-qualified-external-class-name1> and <fully-qualified-external-class-name2>
848 // are in module <module-name>[@<version>]
849 // of loader <loader-name_and_id>[, parent loader <parent-loader-name_and_id>]
850 const char* Klass::joint_in_module_of_loader(const Klass* class2, bool include_parent_loader) const {
851 assert(module() == class2->module(), "classes do not have the same module");
852 const char* class1_name = external_name();
853 size_t len = strlen(class1_name) + 1;
854
855 const char* class2_description = class2->class_in_module_of_loader(true, include_parent_loader);
856 len += strlen(class2_description);
857
858 len += strlen(" and ");
859
860 char* joint_description = NEW_RESOURCE_ARRAY_RETURN_NULL(char, len);
861
862 // Just return the FQN if error when allocating string
863 if (joint_description == NULL) {
864 return class1_name;
865 }
866
867 jio_snprintf(joint_description, len, "%s and %s",
868 class1_name,
869 class2_description);
870
871 return joint_description;
872 }
873
874 // Caller needs ResourceMark
875 // class_in_module_of_loader provides a standard way to include
876 // relevant information about a class, such as its module name as
877 // well as its class loader's name_and_id, in error messages and logging.
878 // Format:
879 // <fully-qualified-external-class-name> is in module <module-name>[@<version>]
880 // of loader <loader-name_and_id>[, parent loader <parent-loader-name_and_id>]
881 const char* Klass::class_in_module_of_loader(bool use_are, bool include_parent_loader) const {
882 // 1. fully qualified external name of class
883 const char* klass_name = external_name();
884 size_t len = strlen(klass_name) + 1;
885
886 // 2. module name + @version
887 const char* module_name = "";
888 const char* version = "";
889 bool has_version = false;
890 bool module_is_named = false;
891 const char* module_name_phrase = "";
892 const Klass* bottom_klass = is_objArray_klass() ?
893 ObjArrayKlass::cast(this)->bottom_klass() : this;
894 if (bottom_klass->is_instance_klass()) {
895 ModuleEntry* module = InstanceKlass::cast(bottom_klass)->module();
896 if (module->is_named()) {
897 module_is_named = true;
898 module_name_phrase = "module ";
899 module_name = module->name()->as_C_string();
900 len += strlen(module_name);
901 // Use version if exists and is not a jdk module
902 if (module->should_show_version()) {
903 has_version = true;
904 version = module->version()->as_C_string();
905 // Include stlen(version) + 1 for the "@"
906 len += strlen(version) + 1;
907 }
908 } else {
909 module_name = UNNAMED_MODULE;
910 len += UNNAMED_MODULE_LEN;
911 }
912 } else {
913 // klass is an array of primitives, module is java.base
914 module_is_named = true;
915 module_name_phrase = "module ";
916 module_name = JAVA_BASE_NAME;
917 len += JAVA_BASE_NAME_LEN;
918 }
919
920 // 3. class loader's name_and_id
921 ClassLoaderData* cld = class_loader_data();
922 assert(cld != NULL, "class_loader_data should not be null");
923 const char* loader_name_and_id = cld->loader_name_and_id();
924 len += strlen(loader_name_and_id);
925
926 // 4. include parent loader information
927 const char* parent_loader_phrase = "";
928 const char* parent_loader_name_and_id = "";
929 if (include_parent_loader &&
930 !cld->is_builtin_class_loader_data()) {
931 oop parent_loader = java_lang_ClassLoader::parent(class_loader());
932 ClassLoaderData *parent_cld = ClassLoaderData::class_loader_data_or_null(parent_loader);
933 // The parent loader's ClassLoaderData could be null if it is
934 // a delegating class loader that has never defined a class.
935 // In this case the loader's name must be obtained via the parent loader's oop.
936 if (parent_cld == NULL) {
937 oop cl_name_and_id = java_lang_ClassLoader::nameAndId(parent_loader);
938 if (cl_name_and_id != NULL) {
939 parent_loader_name_and_id = java_lang_String::as_utf8_string(cl_name_and_id);
940 }
941 } else {
942 parent_loader_name_and_id = parent_cld->loader_name_and_id();
943 }
944 parent_loader_phrase = ", parent loader ";
945 len += strlen(parent_loader_phrase) + strlen(parent_loader_name_and_id);
946 }
947
948 // Start to construct final full class description string
949 len += ((use_are) ? strlen(" are in ") : strlen(" is in "));
950 len += strlen(module_name_phrase) + strlen(" of loader ");
951
952 char* class_description = NEW_RESOURCE_ARRAY_RETURN_NULL(char, len);
953
954 // Just return the FQN if error when allocating string
955 if (class_description == NULL) {
956 return klass_name;
957 }
958
959 jio_snprintf(class_description, len, "%s %s in %s%s%s%s of loader %s%s%s",
960 klass_name,
961 (use_are) ? "are" : "is",
962 module_name_phrase,
963 module_name,
964 (has_version) ? "@" : "",
965 (has_version) ? version : "",
966 loader_name_and_id,
967 parent_loader_phrase,
968 parent_loader_name_and_id);
969
970 return class_description;
971 }