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