1 /*
2 * Copyright (c) 1997, 2020, 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 "classfile/classLoaderData.inline.hpp"
27 #include "classfile/classLoaderDataGraph.inline.hpp"
28 #include "classfile/dictionary.hpp"
29 #include "classfile/javaClasses.hpp"
30 #include "classfile/moduleEntry.hpp"
31 #include "classfile/systemDictionary.hpp"
32 #include "classfile/vmSymbols.hpp"
33 #include "gc/shared/collectedHeap.inline.hpp"
34 #include "logging/log.hpp"
35 #include "memory/heapShared.hpp"
36 #include "memory/metadataFactory.hpp"
37 #include "memory/metaspaceClosure.hpp"
38 #include "memory/metaspaceShared.hpp"
39 #include "memory/oopFactory.hpp"
40 #include "memory/resourceArea.hpp"
41 #include "memory/universe.hpp"
42 #include "oops/compressedOops.inline.hpp"
43 #include "oops/instanceKlass.hpp"
44 #include "oops/klass.inline.hpp"
45 #include "oops/oop.inline.hpp"
46 #include "oops/oopHandle.inline.hpp"
47 #include "runtime/atomic.hpp"
48 #include "runtime/handles.inline.hpp"
49 #include "utilities/macros.hpp"
50 #include "utilities/powerOfTwo.hpp"
51 #include "utilities/stack.inline.hpp"
52
53 void Klass::set_java_mirror(Handle m) {
54 assert(!m.is_null(), "New mirror should never be null.");
55 assert(_java_mirror.resolve() == NULL, "should only be used to initialize mirror");
56 _java_mirror = class_loader_data()->add_handle(m);
57 }
58
59 oop Klass::java_mirror_no_keepalive() const {
60 return _java_mirror.peek();
61 }
62
63 bool Klass::is_cloneable() const {
64 return _access_flags.is_cloneable_fast() ||
65 is_subtype_of(SystemDictionary::Cloneable_klass());
66 }
67
68 void Klass::set_is_cloneable() {
69 if (name() == vmSymbols::java_lang_invoke_MemberName()) {
70 assert(is_final(), "no subclasses allowed");
71 // MemberName cloning should not be intrinsified and always happen in JVM_Clone.
72 } else if (is_instance_klass() && InstanceKlass::cast(this)->reference_type() != REF_NONE) {
73 // Reference cloning should not be intrinsified and always happen in JVM_Clone.
74 } else {
75 _access_flags.set_is_cloneable_fast();
76 }
77 }
78
79 void Klass::set_name(Symbol* n) {
80 _name = n;
81 if (_name != NULL) _name->increment_refcount();
82 }
83
84 bool Klass::is_subclass_of(const Klass* k) const {
85 // Run up the super chain and check
86 if (this == k) return true;
87
88 Klass* t = const_cast<Klass*>(this)->super();
89
90 while (t != NULL) {
91 if (t == k) return true;
92 t = t->super();
93 }
94 return false;
95 }
96
97 void Klass::release_C_heap_structures() {
98 if (_name != NULL) _name->decrement_refcount();
99 }
100
101 bool Klass::search_secondary_supers(Klass* k) const {
102 // Put some extra logic here out-of-line, before the search proper.
103 // This cuts down the size of the inline method.
104
105 // This is necessary, since I am never in my own secondary_super list.
106 if (this == k)
107 return true;
108 // Scan the array-of-objects for a match
109 int cnt = secondary_supers()->length();
110 for (int i = 0; i < cnt; i++) {
111 if (secondary_supers()->at(i) == k) {
112 ((Klass*)this)->set_secondary_super_cache(k);
113 return true;
114 }
115 }
116 return false;
117 }
118
119 // Return self, except for abstract classes with exactly 1
120 // implementor. Then return the 1 concrete implementation.
121 Klass *Klass::up_cast_abstract() {
122 Klass *r = this;
123 while( r->is_abstract() ) { // Receiver is abstract?
124 Klass *s = r->subklass(); // Check for exactly 1 subklass
125 if (s == NULL || s->next_sibling() != NULL) // Oops; wrong count; give up
126 return this; // Return 'this' as a no-progress flag
127 r = s; // Loop till find concrete class
128 }
129 return r; // Return the 1 concrete class
130 }
131
132 // Find LCA in class hierarchy
133 Klass *Klass::LCA( Klass *k2 ) {
134 Klass *k1 = this;
135 while( 1 ) {
136 if( k1->is_subtype_of(k2) ) return k2;
137 if( k2->is_subtype_of(k1) ) return k1;
138 k1 = k1->super();
139 k2 = k2->super();
140 }
141 }
142
143
144 void Klass::check_valid_for_instantiation(bool throwError, TRAPS) {
145 ResourceMark rm(THREAD);
146 THROW_MSG(throwError ? vmSymbols::java_lang_InstantiationError()
147 : vmSymbols::java_lang_InstantiationException(), external_name());
148 }
149
150
151 void Klass::copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS) {
152 ResourceMark rm(THREAD);
153 assert(s != NULL, "Throw NPE!");
154 THROW_MSG(vmSymbols::java_lang_ArrayStoreException(),
155 err_msg("arraycopy: source type %s is not an array", s->klass()->external_name()));
156 }
157
158
159 void Klass::initialize(TRAPS) {
160 ShouldNotReachHere();
161 }
162
163 Klass* Klass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
164 #ifdef ASSERT
165 tty->print_cr("Error: find_field called on a klass oop."
166 " Likely error: reflection method does not correctly"
167 " wrap return value in a mirror object.");
168 #endif
169 ShouldNotReachHere();
170 return NULL;
171 }
172
173 Method* Klass::uncached_lookup_method(const Symbol* name, const Symbol* signature,
174 OverpassLookupMode overpass_mode,
175 PrivateLookupMode private_mode) const {
176 #ifdef ASSERT
177 tty->print_cr("Error: uncached_lookup_method called on a klass oop."
178 " Likely error: reflection method does not correctly"
179 " wrap return value in a mirror object.");
180 #endif
181 ShouldNotReachHere();
182 return NULL;
183 }
184
185 void* Klass::operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, TRAPS) throw() {
186 return Metaspace::allocate(loader_data, word_size, MetaspaceObj::ClassType, THREAD);
187 }
188
189 // "Normal" instantiation is preceeded by a MetaspaceObj allocation
190 // which zeros out memory - calloc equivalent.
191 // The constructor is also used from CppVtableCloner,
192 // which doesn't zero out the memory before calling the constructor.
193 // Need to set the _java_mirror field explicitly to not hit an assert that the field
194 // should be NULL before setting it.
195 Klass::Klass(KlassID id) : _id(id),
196 _java_mirror(NULL),
197 _prototype_header(markWord::prototype()),
198 _shared_class_path_index(-1) {
199 CDS_ONLY(_shared_class_flags = 0;)
200 CDS_JAVA_HEAP_ONLY(_archived_mirror = 0;)
201 _primary_supers[0] = this;
202 set_super_check_offset(in_bytes(primary_supers_offset()));
203 }
204
205 jint Klass::array_layout_helper(BasicType etype) {
206 assert(etype >= T_BOOLEAN && etype <= T_OBJECT, "valid etype");
207 // Note that T_ARRAY is not allowed here.
208 int hsize = arrayOopDesc::base_offset_in_bytes(etype);
209 int esize = type2aelembytes(etype);
210 bool isobj = (etype == T_OBJECT);
211 int tag = isobj ? _lh_array_tag_obj_value : _lh_array_tag_type_value;
212 int lh = array_layout_helper(tag, hsize, etype, exact_log2(esize));
213
214 assert(lh < (int)_lh_neutral_value, "must look like an array layout");
215 assert(layout_helper_is_array(lh), "correct kind");
216 assert(layout_helper_is_objArray(lh) == isobj, "correct kind");
217 assert(layout_helper_is_typeArray(lh) == !isobj, "correct kind");
218 assert(layout_helper_header_size(lh) == hsize, "correct decode");
219 assert(layout_helper_element_type(lh) == etype, "correct decode");
220 assert(1 << layout_helper_log2_element_size(lh) == esize, "correct decode");
221
222 return lh;
223 }
224
225 bool Klass::can_be_primary_super_slow() const {
226 if (super() == NULL)
227 return true;
228 else if (super()->super_depth() >= primary_super_limit()-1)
229 return false;
230 else
231 return true;
232 }
233
234 void Klass::initialize_supers(Klass* k, Array<InstanceKlass*>* transitive_interfaces, TRAPS) {
235 if (k == NULL) {
236 set_super(NULL);
237 _primary_supers[0] = this;
238 assert(super_depth() == 0, "Object must already be initialized properly");
239 } else if (k != super() || k == SystemDictionary::Object_klass()) {
240 assert(super() == NULL || super() == SystemDictionary::Object_klass(),
241 "initialize this only once to a non-trivial value");
242 set_super(k);
243 Klass* sup = k;
244 int sup_depth = sup->super_depth();
245 juint my_depth = MIN2(sup_depth + 1, (int)primary_super_limit());
246 if (!can_be_primary_super_slow())
247 my_depth = primary_super_limit();
248 for (juint i = 0; i < my_depth; i++) {
249 _primary_supers[i] = sup->_primary_supers[i];
250 }
251 Klass* *super_check_cell;
252 if (my_depth < primary_super_limit()) {
253 _primary_supers[my_depth] = this;
254 super_check_cell = &_primary_supers[my_depth];
255 } else {
256 // Overflow of the primary_supers array forces me to be secondary.
257 super_check_cell = &_secondary_super_cache;
258 }
259 set_super_check_offset((address)super_check_cell - (address) this);
260
261 #ifdef ASSERT
262 {
263 juint j = super_depth();
264 assert(j == my_depth, "computed accessor gets right answer");
265 Klass* t = this;
266 while (!t->can_be_primary_super()) {
267 t = t->super();
268 j = t->super_depth();
269 }
270 for (juint j1 = j+1; j1 < primary_super_limit(); j1++) {
271 assert(primary_super_of_depth(j1) == NULL, "super list padding");
272 }
273 while (t != NULL) {
274 assert(primary_super_of_depth(j) == t, "super list initialization");
275 t = t->super();
276 --j;
277 }
278 assert(j == (juint)-1, "correct depth count");
279 }
280 #endif
281 }
282
283 if (secondary_supers() == NULL) {
284
285 // Now compute the list of secondary supertypes.
286 // Secondaries can occasionally be on the super chain,
287 // if the inline "_primary_supers" array overflows.
288 int extras = 0;
289 Klass* p;
290 for (p = super(); !(p == NULL || p->can_be_primary_super()); p = p->super()) {
291 ++extras;
292 }
293
294 ResourceMark rm(THREAD); // need to reclaim GrowableArrays allocated below
295
296 // Compute the "real" non-extra secondaries.
297 GrowableArray<Klass*>* secondaries = compute_secondary_supers(extras, transitive_interfaces);
298 if (secondaries == NULL) {
299 // secondary_supers set by compute_secondary_supers
300 return;
301 }
302
303 GrowableArray<Klass*>* primaries = new GrowableArray<Klass*>(extras);
304
305 for (p = super(); !(p == NULL || p->can_be_primary_super()); p = p->super()) {
306 int i; // Scan for overflow primaries being duplicates of 2nd'arys
307
308 // This happens frequently for very deeply nested arrays: the
309 // primary superclass chain overflows into the secondary. The
310 // secondary list contains the element_klass's secondaries with
311 // an extra array dimension added. If the element_klass's
312 // secondary list already contains some primary overflows, they
313 // (with the extra level of array-ness) will collide with the
314 // normal primary superclass overflows.
315 for( i = 0; i < secondaries->length(); i++ ) {
316 if( secondaries->at(i) == p )
317 break;
318 }
319 if( i < secondaries->length() )
320 continue; // It's a dup, don't put it in
321 primaries->push(p);
322 }
323 // Combine the two arrays into a metadata object to pack the array.
324 // The primaries are added in the reverse order, then the secondaries.
325 int new_length = primaries->length() + secondaries->length();
326 Array<Klass*>* s2 = MetadataFactory::new_array<Klass*>(
327 class_loader_data(), new_length, CHECK);
328 int fill_p = primaries->length();
329 for (int j = 0; j < fill_p; j++) {
330 s2->at_put(j, primaries->pop()); // add primaries in reverse order.
331 }
332 for( int j = 0; j < secondaries->length(); j++ ) {
333 s2->at_put(j+fill_p, secondaries->at(j)); // add secondaries on the end.
334 }
335
336 #ifdef ASSERT
337 // We must not copy any NULL placeholders left over from bootstrap.
338 for (int j = 0; j < s2->length(); j++) {
339 assert(s2->at(j) != NULL, "correct bootstrapping order");
340 }
341 #endif
342
343 set_secondary_supers(s2);
344 }
345 }
346
347 GrowableArray<Klass*>* Klass::compute_secondary_supers(int num_extra_slots,
348 Array<InstanceKlass*>* transitive_interfaces) {
349 assert(num_extra_slots == 0, "override for complex klasses");
350 assert(transitive_interfaces == NULL, "sanity");
351 set_secondary_supers(Universe::the_empty_klass_array());
352 return NULL;
353 }
354
355
356 // superklass links
357 InstanceKlass* Klass::superklass() const {
358 assert(super() == NULL || super()->is_instance_klass(), "must be instance klass");
359 return _super == NULL ? NULL : InstanceKlass::cast(_super);
360 }
361
362 // subklass links. Used by the compiler (and vtable initialization)
363 // May be cleaned concurrently, so must use the Compile_lock.
364 // The log parameter is for clean_weak_klass_links to report unlinked classes.
365 Klass* Klass::subklass(bool log) const {
366 // Need load_acquire on the _subklass, because it races with inserts that
367 // publishes freshly initialized data.
368 for (Klass* chain = Atomic::load_acquire(&_subklass);
369 chain != NULL;
370 // Do not need load_acquire on _next_sibling, because inserts never
371 // create _next_sibling edges to dead data.
372 chain = Atomic::load(&chain->_next_sibling))
373 {
374 if (chain->is_loader_alive()) {
375 return chain;
376 } else if (log) {
377 if (log_is_enabled(Trace, class, unload)) {
378 ResourceMark rm;
379 log_trace(class, unload)("unlinking class (subclass): %s", chain->external_name());
380 }
381 }
382 }
383 return NULL;
384 }
385
386 Klass* Klass::next_sibling(bool log) const {
387 // Do not need load_acquire on _next_sibling, because inserts never
388 // create _next_sibling edges to dead data.
389 for (Klass* chain = Atomic::load(&_next_sibling);
390 chain != NULL;
391 chain = Atomic::load(&chain->_next_sibling)) {
392 // Only return alive klass, there may be stale klass
393 // in this chain if cleaned concurrently.
394 if (chain->is_loader_alive()) {
395 return chain;
396 } else if (log) {
397 if (log_is_enabled(Trace, class, unload)) {
398 ResourceMark rm;
399 log_trace(class, unload)("unlinking class (sibling): %s", chain->external_name());
400 }
401 }
402 }
403 return NULL;
404 }
405
406 void Klass::set_subklass(Klass* s) {
407 assert(s != this, "sanity check");
408 Atomic::release_store(&_subklass, s);
409 }
410
411 void Klass::set_next_sibling(Klass* s) {
412 assert(s != this, "sanity check");
413 // Does not need release semantics. If used by cleanup, it will link to
414 // already safely published data, and if used by inserts, will be published
415 // safely using cmpxchg.
416 Atomic::store(&_next_sibling, s);
417 }
418
419 void Klass::append_to_sibling_list() {
420 if (Universe::is_fully_initialized()) {
421 assert_locked_or_safepoint(Compile_lock);
422 }
423 debug_only(verify();)
424 // add ourselves to superklass' subklass list
425 InstanceKlass* super = superklass();
426 if (super == NULL) return; // special case: class Object
427 assert((!super->is_interface() // interfaces cannot be supers
428 && (super->superklass() == NULL || !is_interface())),
429 "an interface can only be a subklass of Object");
430
431 // Make sure there is no stale subklass head
432 super->clean_subklass();
433
434 for (;;) {
435 Klass* prev_first_subklass = Atomic::load_acquire(&_super->_subklass);
436 if (prev_first_subklass != NULL) {
437 // set our sibling to be the superklass' previous first subklass
438 assert(prev_first_subklass->is_loader_alive(), "May not attach not alive klasses");
439 set_next_sibling(prev_first_subklass);
440 }
441 // Note that the prev_first_subklass is always alive, meaning no sibling_next links
442 // are ever created to not alive klasses. This is an important invariant of the lock-free
443 // cleaning protocol, that allows us to safely unlink dead klasses from the sibling list.
444 if (Atomic::cmpxchg(&super->_subklass, prev_first_subklass, this) == prev_first_subklass) {
445 return;
446 }
447 }
448 debug_only(verify();)
449 }
450
451 void Klass::clean_subklass() {
452 for (;;) {
453 // Need load_acquire, due to contending with concurrent inserts
454 Klass* subklass = Atomic::load_acquire(&_subklass);
455 if (subklass == NULL || subklass->is_loader_alive()) {
456 return;
457 }
458 // Try to fix _subklass until it points at something not dead.
459 Atomic::cmpxchg(&_subklass, subklass, subklass->next_sibling());
460 }
461 }
462
463 void Klass::clean_weak_klass_links(bool unloading_occurred, bool clean_alive_klasses) {
464 if (!ClassUnloading || !unloading_occurred) {
465 return;
466 }
467
468 Klass* root = SystemDictionary::Object_klass();
469 Stack<Klass*, mtGC> stack;
470
471 stack.push(root);
472 while (!stack.is_empty()) {
473 Klass* current = stack.pop();
474
475 assert(current->is_loader_alive(), "just checking, this should be live");
476
477 // Find and set the first alive subklass
478 Klass* sub = current->subklass(true);
479 current->clean_subklass();
480 if (sub != NULL) {
481 stack.push(sub);
482 }
483
484 // Find and set the first alive sibling
485 Klass* sibling = current->next_sibling(true);
486 current->set_next_sibling(sibling);
487 if (sibling != NULL) {
488 stack.push(sibling);
489 }
490
491 // Clean the implementors list and method data.
492 if (clean_alive_klasses && current->is_instance_klass()) {
493 InstanceKlass* ik = InstanceKlass::cast(current);
494 ik->clean_weak_instanceklass_links();
495
496 // JVMTI RedefineClasses creates previous versions that are not in
497 // the class hierarchy, so process them here.
498 while ((ik = ik->previous_versions()) != NULL) {
499 ik->clean_weak_instanceklass_links();
500 }
501 }
502 }
503 }
504
505 void Klass::metaspace_pointers_do(MetaspaceClosure* it) {
506 if (log_is_enabled(Trace, cds)) {
507 ResourceMark rm;
508 log_trace(cds)("Iter(Klass): %p (%s)", this, external_name());
509 }
510
511 it->push(&_name);
512 it->push(&_secondary_super_cache);
513 it->push(&_secondary_supers);
514 for (int i = 0; i < _primary_super_limit; i++) {
515 it->push(&_primary_supers[i]);
516 }
517 it->push(&_super);
518 it->push((Klass**)&_subklass);
519 it->push((Klass**)&_next_sibling);
520 it->push(&_next_link);
521
522 vtableEntry* vt = start_of_vtable();
523 for (int i=0; i<vtable_length(); i++) {
524 it->push(vt[i].method_addr());
525 }
526 }
527
528 void Klass::remove_unshareable_info() {
529 assert (Arguments::is_dumping_archive(),
530 "only called during CDS dump time");
531 JFR_ONLY(REMOVE_ID(this);)
532 if (log_is_enabled(Trace, cds, unshareable)) {
533 ResourceMark rm;
534 log_trace(cds, unshareable)("remove: %s", external_name());
535 }
536
537 set_subklass(NULL);
538 set_next_sibling(NULL);
539 set_next_link(NULL);
540
541 // Null out class_loader_data because we don't share that yet.
542 set_class_loader_data(NULL);
543 set_is_shared();
544 }
545
546 void Klass::remove_java_mirror() {
547 Arguments::assert_is_dumping_archive();
548 if (log_is_enabled(Trace, cds, unshareable)) {
549 ResourceMark rm;
550 log_trace(cds, unshareable)("remove java_mirror: %s", external_name());
551 }
552 // Just null out the mirror. The class_loader_data() no longer exists.
553 _java_mirror = NULL;
554 }
555
556 void Klass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) {
557 assert(is_klass(), "ensure C++ vtable is restored");
558 assert(is_shared(), "must be set");
559 JFR_ONLY(RESTORE_ID(this);)
560 if (log_is_enabled(Trace, cds, unshareable)) {
561 ResourceMark rm(THREAD);
562 log_trace(cds, unshareable)("restore: %s", external_name());
563 }
564
565 // If an exception happened during CDS restore, some of these fields may already be
566 // set. We leave the class on the CLD list, even if incomplete so that we don't
567 // modify the CLD list outside a safepoint.
568 if (class_loader_data() == NULL) {
569 // Restore class_loader_data to the null class loader data
570 set_class_loader_data(loader_data);
571
572 // Add to null class loader list first before creating the mirror
573 // (same order as class file parsing)
574 loader_data->add_class(this);
575 }
576
577 Handle loader(THREAD, loader_data->class_loader());
578 ModuleEntry* module_entry = NULL;
579 Klass* k = this;
580 if (k->is_objArray_klass()) {
581 k = ObjArrayKlass::cast(k)->bottom_klass();
582 }
583 // Obtain klass' module.
584 if (k->is_instance_klass()) {
585 InstanceKlass* ik = (InstanceKlass*) k;
586 module_entry = ik->module();
587 } else {
588 module_entry = ModuleEntryTable::javabase_moduleEntry();
589 }
590 // Obtain java.lang.Module, if available
591 Handle module_handle(THREAD, ((module_entry != NULL) ? module_entry->module() : (oop)NULL));
592
593 if (this->has_raw_archived_mirror()) {
594 ResourceMark rm(THREAD);
595 log_debug(cds, mirror)("%s has raw archived mirror", external_name());
596 if (HeapShared::open_archive_heap_region_mapped()) {
597 bool present = java_lang_Class::restore_archived_mirror(this, loader, module_handle,
598 protection_domain,
599 CHECK);
600 if (present) {
601 return;
602 }
603 }
604
605 // No archived mirror data
606 log_debug(cds, mirror)("No archived mirror data for %s", external_name());
607 _java_mirror = NULL;
608 this->clear_has_raw_archived_mirror();
609 }
610
611 // Only recreate it if not present. A previous attempt to restore may have
612 // gotten an OOM later but keep the mirror if it was created.
613 if (java_mirror() == NULL) {
614 log_trace(cds, mirror)("Recreate mirror for %s", external_name());
615 java_lang_Class::create_mirror(this, loader, module_handle, protection_domain, Handle(), CHECK);
616 }
617 }
618
619 #if INCLUDE_CDS_JAVA_HEAP
620 // Used at CDS dump time to access the archived mirror. No GC barrier.
621 oop Klass::archived_java_mirror_raw() {
622 assert(has_raw_archived_mirror(), "must have raw archived mirror");
623 return CompressedOops::decode(_archived_mirror);
624 }
625
626 narrowOop Klass::archived_java_mirror_raw_narrow() {
627 assert(has_raw_archived_mirror(), "must have raw archived mirror");
628 return _archived_mirror;
629 }
630
631 // No GC barrier
632 void Klass::set_archived_java_mirror_raw(oop m) {
633 assert(DumpSharedSpaces, "called only during runtime");
634 _archived_mirror = CompressedOops::encode(m);
635 }
636 #endif // INCLUDE_CDS_JAVA_HEAP
637
638 Klass* Klass::array_klass_or_null(int rank) {
639 EXCEPTION_MARK;
640 // No exception can be thrown by array_klass_impl when called with or_null == true.
641 // (In anycase, the execption mark will fail if it do so)
642 return array_klass_impl(true, rank, THREAD);
643 }
644
645
646 Klass* Klass::array_klass_or_null() {
647 EXCEPTION_MARK;
648 // No exception can be thrown by array_klass_impl when called with or_null == true.
649 // (In anycase, the execption mark will fail if it do so)
650 return array_klass_impl(true, THREAD);
651 }
652
653
654 Klass* Klass::array_klass_impl(bool or_null, int rank, TRAPS) {
655 fatal("array_klass should be dispatched to InstanceKlass, ObjArrayKlass or TypeArrayKlass");
656 return NULL;
657 }
658
659
660 Klass* Klass::array_klass_impl(bool or_null, TRAPS) {
661 fatal("array_klass should be dispatched to InstanceKlass, ObjArrayKlass or TypeArrayKlass");
662 return NULL;
663 }
664
665 void Klass::check_array_allocation_length(int length, int max_length, TRAPS) {
666 if (length > max_length) {
667 if (!THREAD->in_retryable_allocation()) {
668 report_java_out_of_memory("Requested array size exceeds VM limit");
669 JvmtiExport::post_array_size_exhausted();
670 THROW_OOP(Universe::out_of_memory_error_array_size());
671 } else {
672 THROW_OOP(Universe::out_of_memory_error_retry());
673 }
674 } else if (length < 0) {
675 THROW_MSG(vmSymbols::java_lang_NegativeArraySizeException(), err_msg("%d", length));
676 }
677 }
678
679 // Replace the last '+' char with '/'.
680 static char* convert_hidden_name_to_java(Symbol* name) {
681 size_t name_len = name->utf8_length();
682 char* result = NEW_RESOURCE_ARRAY(char, name_len + 1);
683 name->as_klass_external_name(result, (int)name_len + 1);
684 for (int index = (int)name_len; index > 0; index--) {
685 if (result[index] == '+') {
686 result[index] = JVM_SIGNATURE_SLASH;
687 break;
688 }
689 }
690 return result;
691 }
692
693 // In product mode, this function doesn't have virtual function calls so
694 // there might be some performance advantage to handling InstanceKlass here.
695 const char* Klass::external_name() const {
696 if (is_instance_klass()) {
697 const InstanceKlass* ik = static_cast<const InstanceKlass*>(this);
698 if (ik->is_unsafe_anonymous()) {
699 char addr_buf[20];
700 jio_snprintf(addr_buf, 20, "/" INTPTR_FORMAT, p2i(ik));
701 size_t addr_len = strlen(addr_buf);
702 size_t name_len = name()->utf8_length();
703 char* result = NEW_RESOURCE_ARRAY(char, name_len + addr_len + 1);
704 name()->as_klass_external_name(result, (int) name_len + 1);
705 assert(strlen(result) == name_len, "");
706 strcpy(result + name_len, addr_buf);
707 assert(strlen(result) == name_len + addr_len, "");
708 return result;
709
710 } else if (ik->is_hidden()) {
711 char* result = convert_hidden_name_to_java(name());
712 return result;
713 }
714 } else if (is_objArray_klass() && ObjArrayKlass::cast(this)->bottom_klass()->is_hidden()) {
715 char* result = convert_hidden_name_to_java(name());
716 return result;
717 }
718 if (name() == NULL) return "<unknown>";
719 return name()->as_klass_external_name();
720 }
721
722 const char* Klass::signature_name() const {
723 if (name() == NULL) return "<unknown>";
724 if (is_objArray_klass() && ObjArrayKlass::cast(this)->bottom_klass()->is_hidden()) {
725 size_t name_len = name()->utf8_length();
726 char* result = NEW_RESOURCE_ARRAY(char, name_len + 1);
727 name()->as_C_string(result, (int)name_len + 1);
728 for (int index = (int)name_len; index > 0; index--) {
729 if (result[index] == '+') {
730 result[index] = JVM_SIGNATURE_DOT;
731 break;
732 }
733 }
734 return result;
735 }
736 return name()->as_C_string();
737 }
738
739 const char* Klass::external_kind() const {
740 if (is_interface()) return "interface";
741 if (is_abstract()) return "abstract class";
742 return "class";
743 }
744
745 // Unless overridden, modifier_flags is 0.
746 jint Klass::compute_modifier_flags(TRAPS) const {
747 return 0;
748 }
749
750 int Klass::atomic_incr_biased_lock_revocation_count() {
751 return (int) Atomic::add(&_biased_lock_revocation_count, 1);
752 }
753
754 // Unless overridden, jvmti_class_status has no flags set.
755 jint Klass::jvmti_class_status() const {
756 return 0;
757 }
758
759
760 // Printing
761
762 void Klass::print_on(outputStream* st) const {
763 ResourceMark rm;
764 // print title
765 st->print("%s", internal_name());
766 print_address_on(st);
767 st->cr();
768 }
769
770 #define BULLET " - "
771
772 void Klass::oop_print_on(oop obj, outputStream* st) {
773 // print title
774 st->print_cr("%s ", internal_name());
775 obj->print_address_on(st);
776
777 if (WizardMode) {
778 // print header
779 obj->mark().print_on(st);
780 st->cr();
781 st->print(BULLET"prototype_header: " INTPTR_FORMAT, _prototype_header.value());
782 st->cr();
783 }
784
785 // print class
786 st->print(BULLET"klass: ");
787 obj->klass()->print_value_on(st);
788 st->cr();
789 }
790
791 void Klass::oop_print_value_on(oop obj, outputStream* st) {
792 // print title
793 ResourceMark rm; // Cannot print in debug mode without this
794 st->print("%s", internal_name());
795 obj->print_address_on(st);
796 }
797
798 // Verification
799
800 void Klass::verify_on(outputStream* st) {
801
802 // This can be expensive, but it is worth checking that this klass is actually
803 // in the CLD graph but not in production.
804 assert(Metaspace::contains((address)this), "Should be");
805
806 guarantee(this->is_klass(),"should be klass");
807
808 if (super() != NULL) {
809 guarantee(super()->is_klass(), "should be klass");
810 }
811 if (secondary_super_cache() != NULL) {
812 Klass* ko = secondary_super_cache();
813 guarantee(ko->is_klass(), "should be klass");
814 }
815 for ( uint i = 0; i < primary_super_limit(); i++ ) {
816 Klass* ko = _primary_supers[i];
817 if (ko != NULL) {
818 guarantee(ko->is_klass(), "should be klass");
819 }
820 }
821
822 if (java_mirror_no_keepalive() != NULL) {
823 guarantee(oopDesc::is_oop(java_mirror_no_keepalive()), "should be instance");
824 }
825 }
826
827 void Klass::oop_verify_on(oop obj, outputStream* st) {
828 guarantee(oopDesc::is_oop(obj), "should be oop");
829 guarantee(obj->klass()->is_klass(), "klass field is not a klass");
830 }
831
832 bool Klass::is_valid(Klass* k) {
833 if (!is_aligned(k, sizeof(MetaWord))) return false;
834 if ((size_t)k < os::min_page_size()) return false;
835
836 if (!os::is_readable_range(k, k + 1)) return false;
837 if (!Metaspace::contains(k)) return false;
838
839 if (!Symbol::is_valid(k->name())) return false;
840 return ClassLoaderDataGraph::is_valid(k->class_loader_data());
841 }
842
843 Method* Klass::method_at_vtable(int index) {
844 #ifndef PRODUCT
845 assert(index >= 0, "valid vtable index");
846 if (DebugVtables) {
847 verify_vtable_index(index);
848 }
849 #endif
850 return start_of_vtable()[index].method();
851 }
852
853
854 #ifndef PRODUCT
855
856 bool Klass::verify_vtable_index(int i) {
857 int limit = vtable_length()/vtableEntry::size();
858 assert(i >= 0 && i < limit, "index %d out of bounds %d", i, limit);
859 return true;
860 }
861
862 #endif // PRODUCT
863
864 // Caller needs ResourceMark
865 // joint_in_module_of_loader provides an optimization if 2 classes are in
866 // the same module to succinctly print out relevant information about their
867 // module name and class loader's name_and_id for error messages.
868 // Format:
869 // <fully-qualified-external-class-name1> and <fully-qualified-external-class-name2>
870 // are in module <module-name>[@<version>]
871 // of loader <loader-name_and_id>[, parent loader <parent-loader-name_and_id>]
872 const char* Klass::joint_in_module_of_loader(const Klass* class2, bool include_parent_loader) const {
873 assert(module() == class2->module(), "classes do not have the same module");
874 const char* class1_name = external_name();
875 size_t len = strlen(class1_name) + 1;
876
877 const char* class2_description = class2->class_in_module_of_loader(true, include_parent_loader);
878 len += strlen(class2_description);
879
880 len += strlen(" and ");
881
882 char* joint_description = NEW_RESOURCE_ARRAY_RETURN_NULL(char, len);
883
884 // Just return the FQN if error when allocating string
885 if (joint_description == NULL) {
886 return class1_name;
887 }
888
889 jio_snprintf(joint_description, len, "%s and %s",
890 class1_name,
891 class2_description);
892
893 return joint_description;
894 }
895
896 // Caller needs ResourceMark
897 // class_in_module_of_loader provides a standard way to include
898 // relevant information about a class, such as its module name as
899 // well as its class loader's name_and_id, in error messages and logging.
900 // Format:
901 // <fully-qualified-external-class-name> is in module <module-name>[@<version>]
902 // of loader <loader-name_and_id>[, parent loader <parent-loader-name_and_id>]
903 const char* Klass::class_in_module_of_loader(bool use_are, bool include_parent_loader) const {
904 // 1. fully qualified external name of class
905 const char* klass_name = external_name();
906 size_t len = strlen(klass_name) + 1;
907
908 // 2. module name + @version
909 const char* module_name = "";
910 const char* version = "";
911 bool has_version = false;
912 bool module_is_named = false;
913 const char* module_name_phrase = "";
914 const Klass* bottom_klass = is_objArray_klass() ?
915 ObjArrayKlass::cast(this)->bottom_klass() : this;
916 if (bottom_klass->is_instance_klass()) {
917 ModuleEntry* module = InstanceKlass::cast(bottom_klass)->module();
918 if (module->is_named()) {
919 module_is_named = true;
920 module_name_phrase = "module ";
921 module_name = module->name()->as_C_string();
922 len += strlen(module_name);
923 // Use version if exists and is not a jdk module
924 if (module->should_show_version()) {
925 has_version = true;
926 version = module->version()->as_C_string();
927 // Include stlen(version) + 1 for the "@"
928 len += strlen(version) + 1;
929 }
930 } else {
931 module_name = UNNAMED_MODULE;
932 len += UNNAMED_MODULE_LEN;
933 }
934 } else {
935 // klass is an array of primitives, module is java.base
936 module_is_named = true;
937 module_name_phrase = "module ";
938 module_name = JAVA_BASE_NAME;
939 len += JAVA_BASE_NAME_LEN;
940 }
941
942 // 3. class loader's name_and_id
943 ClassLoaderData* cld = class_loader_data();
944 assert(cld != NULL, "class_loader_data should not be null");
945 const char* loader_name_and_id = cld->loader_name_and_id();
946 len += strlen(loader_name_and_id);
947
948 // 4. include parent loader information
949 const char* parent_loader_phrase = "";
950 const char* parent_loader_name_and_id = "";
951 if (include_parent_loader &&
952 !cld->is_builtin_class_loader_data()) {
953 oop parent_loader = java_lang_ClassLoader::parent(class_loader());
954 ClassLoaderData *parent_cld = ClassLoaderData::class_loader_data_or_null(parent_loader);
955 // The parent loader's ClassLoaderData could be null if it is
956 // a delegating class loader that has never defined a class.
957 // In this case the loader's name must be obtained via the parent loader's oop.
958 if (parent_cld == NULL) {
959 oop cl_name_and_id = java_lang_ClassLoader::nameAndId(parent_loader);
960 if (cl_name_and_id != NULL) {
961 parent_loader_name_and_id = java_lang_String::as_utf8_string(cl_name_and_id);
962 }
963 } else {
964 parent_loader_name_and_id = parent_cld->loader_name_and_id();
965 }
966 parent_loader_phrase = ", parent loader ";
967 len += strlen(parent_loader_phrase) + strlen(parent_loader_name_and_id);
968 }
969
970 // Start to construct final full class description string
971 len += ((use_are) ? strlen(" are in ") : strlen(" is in "));
972 len += strlen(module_name_phrase) + strlen(" of loader ");
973
974 char* class_description = NEW_RESOURCE_ARRAY_RETURN_NULL(char, len);
975
976 // Just return the FQN if error when allocating string
977 if (class_description == NULL) {
978 return klass_name;
979 }
980
981 jio_snprintf(class_description, len, "%s %s in %s%s%s%s of loader %s%s%s",
982 klass_name,
983 (use_are) ? "are" : "is",
984 module_name_phrase,
985 module_name,
986 (has_version) ? "@" : "",
987 (has_version) ? version : "",
988 loader_name_and_id,
989 parent_loader_phrase,
990 parent_loader_name_and_id);
991
992 return class_description;
993 }