1 /*
2 * Copyright (c) 1997, 2022, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "cds/archiveHeapLoader.hpp"
27 #include "cds/heapShared.hpp"
28 #include "classfile/classLoaderData.inline.hpp"
29 #include "classfile/classLoaderDataGraph.inline.hpp"
30 #include "classfile/javaClasses.inline.hpp"
31 #include "classfile/moduleEntry.hpp"
32 #include "classfile/systemDictionary.hpp"
33 #include "classfile/systemDictionaryShared.hpp"
34 #include "classfile/vmClasses.hpp"
35 #include "classfile/vmSymbols.hpp"
36 #include "gc/shared/collectedHeap.inline.hpp"
37 #include "jvm_io.h"
38 #include "logging/log.hpp"
39 #include "memory/metadataFactory.hpp"
40 #include "memory/metaspaceClosure.hpp"
41 #include "memory/oopFactory.hpp"
42 #include "memory/resourceArea.hpp"
43 #include "memory/universe.hpp"
44 #include "oops/compressedOops.inline.hpp"
45 #include "oops/instanceKlass.hpp"
46 #include "oops/klass.inline.hpp"
47 #include "oops/objArrayKlass.hpp"
48 #include "oops/oop.inline.hpp"
49 #include "oops/oopHandle.inline.hpp"
50 #include "prims/jvmtiExport.hpp"
51 #include "runtime/arguments.hpp"
52 #include "runtime/atomic.hpp"
53 #include "runtime/handles.inline.hpp"
54 #include "utilities/macros.hpp"
55 #include "utilities/powerOfTwo.hpp"
56 #include "utilities/stack.inline.hpp"
57
58 void Klass::set_java_mirror(Handle m) {
59 assert(!m.is_null(), "New mirror should never be null.");
60 assert(_java_mirror.is_empty(), "should only be used to initialize mirror");
61 _java_mirror = class_loader_data()->add_handle(m);
62 }
63
64 oop Klass::java_mirror_no_keepalive() const {
65 return _java_mirror.peek();
66 }
67
68 bool Klass::is_cloneable() const {
69 return _access_flags.is_cloneable_fast() ||
70 is_subtype_of(vmClasses::Cloneable_klass());
71 }
72
73 void Klass::set_is_cloneable() {
74 if (name() == vmSymbols::java_lang_invoke_MemberName()) {
75 assert(is_final(), "no subclasses allowed");
76 // MemberName cloning should not be intrinsified and always happen in JVM_Clone.
77 } else if (is_instance_klass() && InstanceKlass::cast(this)->reference_type() != REF_NONE) {
78 // Reference cloning should not be intrinsified and always happen in JVM_Clone.
79 } else {
80 _access_flags.set_is_cloneable_fast();
81 }
82 }
83
84 void Klass::set_name(Symbol* n) {
85 _name = n;
86 if (_name != NULL) _name->increment_refcount();
87
88 if (Arguments::is_dumping_archive() && is_instance_klass()) {
89 SystemDictionaryShared::init_dumptime_info(InstanceKlass::cast(this));
90 }
91 }
92
93 bool Klass::is_subclass_of(const Klass* k) const {
94 // Run up the super chain and check
95 if (this == k) return true;
96
97 Klass* t = const_cast<Klass*>(this)->super();
98
99 while (t != NULL) {
100 if (t == k) return true;
101 t = t->super();
102 }
103 return false;
104 }
105
106 void Klass::release_C_heap_structures(bool release_constant_pool) {
107 if (_name != NULL) _name->decrement_refcount();
108 }
109
110 bool Klass::search_secondary_supers(Klass* k) const {
111 // Put some extra logic here out-of-line, before the search proper.
112 // This cuts down the size of the inline method.
113
114 // This is necessary, since I am never in my own secondary_super list.
115 if (this == k)
116 return true;
117 // Scan the array-of-objects for a match
118 int cnt = secondary_supers()->length();
119 for (int i = 0; i < cnt; i++) {
120 if (secondary_supers()->at(i) == k) {
121 ((Klass*)this)->set_secondary_super_cache(k);
122 return true;
123 }
124 }
125 return false;
126 }
127
128 // Return self, except for abstract classes with exactly 1
129 // implementor. Then return the 1 concrete implementation.
130 Klass *Klass::up_cast_abstract() {
131 Klass *r = this;
132 while( r->is_abstract() ) { // Receiver is abstract?
133 Klass *s = r->subklass(); // Check for exactly 1 subklass
134 if (s == NULL || s->next_sibling() != NULL) // Oops; wrong count; give up
135 return this; // Return 'this' as a no-progress flag
136 r = s; // Loop till find concrete class
137 }
138 return r; // Return the 1 concrete class
139 }
140
141 // Find LCA in class hierarchy
142 Klass *Klass::LCA( Klass *k2 ) {
143 Klass *k1 = this;
144 while( 1 ) {
145 if( k1->is_subtype_of(k2) ) return k2;
146 if( k2->is_subtype_of(k1) ) return k1;
147 k1 = k1->super();
148 k2 = k2->super();
149 }
150 }
151
152
153 void Klass::check_valid_for_instantiation(bool throwError, TRAPS) {
154 ResourceMark rm(THREAD);
155 THROW_MSG(throwError ? vmSymbols::java_lang_InstantiationError()
156 : vmSymbols::java_lang_InstantiationException(), external_name());
157 }
158
159
160 void Klass::copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS) {
161 ResourceMark rm(THREAD);
162 assert(s != NULL, "Throw NPE!");
163 THROW_MSG(vmSymbols::java_lang_ArrayStoreException(),
164 err_msg("arraycopy: source type %s is not an array", s->klass()->external_name()));
165 }
166
167
168 void Klass::initialize(TRAPS) {
169 ShouldNotReachHere();
170 }
171
172 Klass* Klass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
173 #ifdef ASSERT
174 tty->print_cr("Error: find_field called on a klass oop."
175 " Likely error: reflection method does not correctly"
176 " wrap return value in a mirror object.");
177 #endif
178 ShouldNotReachHere();
179 return NULL;
180 }
181
182 Method* Klass::uncached_lookup_method(const Symbol* name, const Symbol* signature,
183 OverpassLookupMode overpass_mode,
184 PrivateLookupMode private_mode) const {
185 #ifdef ASSERT
186 tty->print_cr("Error: uncached_lookup_method called on a klass oop."
187 " Likely error: reflection method does not correctly"
188 " wrap return value in a mirror object.");
189 #endif
190 ShouldNotReachHere();
191 return NULL;
192 }
193
194 void* Klass::operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, TRAPS) throw() {
195 return Metaspace::allocate(loader_data, word_size, MetaspaceObj::ClassType, THREAD);
196 }
197
198 // "Normal" instantiation is preceded by a MetaspaceObj allocation
199 // which zeros out memory - calloc equivalent.
200 // The constructor is also used from CppVtableCloner,
201 // which doesn't zero out the memory before calling the constructor.
202 Klass::Klass(KlassKind kind) : _kind(kind),
203 _prototype_header(markWord::prototype()),
204 _shared_class_path_index(-1) {
205 CDS_ONLY(_shared_class_flags = 0;)
206 CDS_JAVA_HEAP_ONLY(_archived_mirror_index = -1;)
207 _primary_supers[0] = this;
208 set_super_check_offset(in_bytes(primary_supers_offset()));
209 }
210
211 jint Klass::array_layout_helper(BasicType etype) {
212 assert(etype >= T_BOOLEAN && etype <= T_OBJECT, "valid etype");
213 // Note that T_ARRAY is not allowed here.
214 int hsize = arrayOopDesc::base_offset_in_bytes(etype);
215 int esize = type2aelembytes(etype);
216 bool isobj = (etype == T_OBJECT);
217 int tag = isobj ? _lh_array_tag_obj_value : _lh_array_tag_type_value;
218 int lh = array_layout_helper(tag, false, hsize, etype, exact_log2(esize));
219
220 assert(lh < (int)_lh_neutral_value, "must look like an array layout");
221 assert(layout_helper_is_array(lh), "correct kind");
222 assert(layout_helper_is_objArray(lh) == isobj, "correct kind");
223 assert(layout_helper_is_typeArray(lh) == !isobj, "correct kind");
224 assert(layout_helper_header_size(lh) == hsize, "correct decode");
225 assert(layout_helper_element_type(lh) == etype, "correct decode");
226 assert(1 << layout_helper_log2_element_size(lh) == esize, "correct decode");
227
228 return lh;
229 }
230
231 bool Klass::can_be_primary_super_slow() const {
232 if (super() == NULL)
233 return true;
234 else if (super()->super_depth() >= primary_super_limit()-1)
235 return false;
236 else
237 return true;
238 }
239
240 void Klass::initialize_supers(Klass* k, Array<InstanceKlass*>* transitive_interfaces, TRAPS) {
241 if (k == NULL) {
242 set_super(NULL);
243 _primary_supers[0] = this;
244 assert(super_depth() == 0, "Object must already be initialized properly");
245 } else if (k != super() || k == vmClasses::Object_klass()) {
246 assert(super() == NULL || super() == vmClasses::Object_klass(),
247 "initialize this only once to a non-trivial value");
248 set_super(k);
249 Klass* sup = k;
250 int sup_depth = sup->super_depth();
251 juint my_depth = MIN2(sup_depth + 1, (int)primary_super_limit());
252 if (!can_be_primary_super_slow())
253 my_depth = primary_super_limit();
254 for (juint i = 0; i < my_depth; i++) {
255 _primary_supers[i] = sup->_primary_supers[i];
256 }
257 Klass* *super_check_cell;
258 if (my_depth < primary_super_limit()) {
259 _primary_supers[my_depth] = this;
260 super_check_cell = &_primary_supers[my_depth];
261 } else {
262 // Overflow of the primary_supers array forces me to be secondary.
263 super_check_cell = &_secondary_super_cache;
264 }
265 set_super_check_offset((address)super_check_cell - (address) this);
266
267 #ifdef ASSERT
268 {
269 juint j = super_depth();
270 assert(j == my_depth, "computed accessor gets right answer");
271 Klass* t = this;
272 while (!t->can_be_primary_super()) {
273 t = t->super();
274 j = t->super_depth();
275 }
276 for (juint j1 = j+1; j1 < primary_super_limit(); j1++) {
277 assert(primary_super_of_depth(j1) == NULL, "super list padding");
278 }
279 while (t != NULL) {
280 assert(primary_super_of_depth(j) == t, "super list initialization");
281 t = t->super();
282 --j;
283 }
284 assert(j == (juint)-1, "correct depth count");
285 }
286 #endif
287 }
288
289 if (secondary_supers() == NULL) {
290
291 // Now compute the list of secondary supertypes.
292 // Secondaries can occasionally be on the super chain,
293 // if the inline "_primary_supers" array overflows.
294 int extras = 0;
295 Klass* p;
296 for (p = super(); !(p == NULL || p->can_be_primary_super()); p = p->super()) {
297 ++extras;
298 }
299
300 ResourceMark rm(THREAD); // need to reclaim GrowableArrays allocated below
301
302 // Compute the "real" non-extra secondaries.
303 GrowableArray<Klass*>* secondaries = compute_secondary_supers(extras, transitive_interfaces);
304 if (secondaries == NULL) {
305 // secondary_supers set by compute_secondary_supers
306 return;
307 }
308
309 GrowableArray<Klass*>* primaries = new GrowableArray<Klass*>(extras);
310
311 for (p = super(); !(p == NULL || p->can_be_primary_super()); p = p->super()) {
312 int i; // Scan for overflow primaries being duplicates of 2nd'arys
313
314 // This happens frequently for very deeply nested arrays: the
315 // primary superclass chain overflows into the secondary. The
316 // secondary list contains the element_klass's secondaries with
317 // an extra array dimension added. If the element_klass's
318 // secondary list already contains some primary overflows, they
319 // (with the extra level of array-ness) will collide with the
320 // normal primary superclass overflows.
321 for( i = 0; i < secondaries->length(); i++ ) {
322 if( secondaries->at(i) == p )
323 break;
324 }
325 if( i < secondaries->length() )
326 continue; // It's a dup, don't put it in
327 primaries->push(p);
328 }
329 // Combine the two arrays into a metadata object to pack the array.
330 // The primaries are added in the reverse order, then the secondaries.
331 int new_length = primaries->length() + secondaries->length();
332 Array<Klass*>* s2 = MetadataFactory::new_array<Klass*>(
333 class_loader_data(), new_length, CHECK);
334 int fill_p = primaries->length();
335 for (int j = 0; j < fill_p; j++) {
336 s2->at_put(j, primaries->pop()); // add primaries in reverse order.
337 }
338 for( int j = 0; j < secondaries->length(); j++ ) {
339 s2->at_put(j+fill_p, secondaries->at(j)); // add secondaries on the end.
340 }
341
342 #ifdef ASSERT
343 // We must not copy any NULL placeholders left over from bootstrap.
344 for (int j = 0; j < s2->length(); j++) {
345 assert(s2->at(j) != NULL, "correct bootstrapping order");
346 }
347 #endif
348
349 set_secondary_supers(s2);
350 }
351 }
352
353 GrowableArray<Klass*>* Klass::compute_secondary_supers(int num_extra_slots,
354 Array<InstanceKlass*>* transitive_interfaces) {
355 assert(num_extra_slots == 0, "override for complex klasses");
356 assert(transitive_interfaces == NULL, "sanity");
357 set_secondary_supers(Universe::the_empty_klass_array());
358 return NULL;
359 }
360
361
362 // superklass links
363 InstanceKlass* Klass::superklass() const {
364 assert(super() == NULL || super()->is_instance_klass(), "must be instance klass");
365 return _super == NULL ? NULL : InstanceKlass::cast(_super);
366 }
367
368 // subklass links. Used by the compiler (and vtable initialization)
369 // May be cleaned concurrently, so must use the Compile_lock.
370 // The log parameter is for clean_weak_klass_links to report unlinked classes.
371 Klass* Klass::subklass(bool log) const {
372 // Need load_acquire on the _subklass, because it races with inserts that
373 // publishes freshly initialized data.
374 for (Klass* chain = Atomic::load_acquire(&_subklass);
375 chain != NULL;
376 // Do not need load_acquire on _next_sibling, because inserts never
377 // create _next_sibling edges to dead data.
378 chain = Atomic::load(&chain->_next_sibling))
379 {
380 if (chain->is_loader_alive()) {
381 return chain;
382 } else if (log) {
383 if (log_is_enabled(Trace, class, unload)) {
384 ResourceMark rm;
385 log_trace(class, unload)("unlinking class (subclass): %s", chain->external_name());
386 }
387 }
388 }
389 return NULL;
390 }
391
392 Klass* Klass::next_sibling(bool log) const {
393 // Do not need load_acquire on _next_sibling, because inserts never
394 // create _next_sibling edges to dead data.
395 for (Klass* chain = Atomic::load(&_next_sibling);
396 chain != NULL;
397 chain = Atomic::load(&chain->_next_sibling)) {
398 // Only return alive klass, there may be stale klass
399 // in this chain if cleaned concurrently.
400 if (chain->is_loader_alive()) {
401 return chain;
402 } else if (log) {
403 if (log_is_enabled(Trace, class, unload)) {
404 ResourceMark rm;
405 log_trace(class, unload)("unlinking class (sibling): %s", chain->external_name());
406 }
407 }
408 }
409 return NULL;
410 }
411
412 void Klass::set_subklass(Klass* s) {
413 assert(s != this, "sanity check");
414 Atomic::release_store(&_subklass, s);
415 }
416
417 void Klass::set_next_sibling(Klass* s) {
418 assert(s != this, "sanity check");
419 // Does not need release semantics. If used by cleanup, it will link to
420 // already safely published data, and if used by inserts, will be published
421 // safely using cmpxchg.
422 Atomic::store(&_next_sibling, s);
423 }
424
425 void Klass::append_to_sibling_list() {
426 if (Universe::is_fully_initialized()) {
427 assert_locked_or_safepoint(Compile_lock);
428 }
429 debug_only(verify();)
430 // add ourselves to superklass' subklass list
431 InstanceKlass* super = superklass();
432 if (super == NULL) return; // special case: class Object
433 assert((!super->is_interface() // interfaces cannot be supers
434 && (super->superklass() == NULL || !is_interface())),
435 "an interface can only be a subklass of Object");
436
437 // Make sure there is no stale subklass head
438 super->clean_subklass();
439
440 for (;;) {
441 Klass* prev_first_subklass = Atomic::load_acquire(&_super->_subklass);
442 if (prev_first_subklass != NULL) {
443 // set our sibling to be the superklass' previous first subklass
444 assert(prev_first_subklass->is_loader_alive(), "May not attach not alive klasses");
445 set_next_sibling(prev_first_subklass);
446 }
447 // Note that the prev_first_subklass is always alive, meaning no sibling_next links
448 // are ever created to not alive klasses. This is an important invariant of the lock-free
449 // cleaning protocol, that allows us to safely unlink dead klasses from the sibling list.
450 if (Atomic::cmpxchg(&super->_subklass, prev_first_subklass, this) == prev_first_subklass) {
451 return;
452 }
453 }
454 debug_only(verify();)
455 }
456
457 void Klass::clean_subklass() {
458 for (;;) {
459 // Need load_acquire, due to contending with concurrent inserts
460 Klass* subklass = Atomic::load_acquire(&_subklass);
461 if (subklass == NULL || subklass->is_loader_alive()) {
462 return;
463 }
464 // Try to fix _subklass until it points at something not dead.
465 Atomic::cmpxchg(&_subklass, subklass, subklass->next_sibling());
466 }
467 }
468
469 void Klass::clean_weak_klass_links(bool unloading_occurred, bool clean_alive_klasses) {
470 if (!ClassUnloading || !unloading_occurred) {
471 return;
472 }
473
474 Klass* root = vmClasses::Object_klass();
475 Stack<Klass*, mtGC> stack;
476
477 stack.push(root);
478 while (!stack.is_empty()) {
479 Klass* current = stack.pop();
480
481 assert(current->is_loader_alive(), "just checking, this should be live");
482
483 // Find and set the first alive subklass
484 Klass* sub = current->subklass(true);
485 current->clean_subklass();
486 if (sub != NULL) {
487 stack.push(sub);
488 }
489
490 // Find and set the first alive sibling
491 Klass* sibling = current->next_sibling(true);
492 current->set_next_sibling(sibling);
493 if (sibling != NULL) {
494 stack.push(sibling);
495 }
496
497 // Clean the implementors list and method data.
498 if (clean_alive_klasses && current->is_instance_klass()) {
499 InstanceKlass* ik = InstanceKlass::cast(current);
500 ik->clean_weak_instanceklass_links();
501
502 // JVMTI RedefineClasses creates previous versions that are not in
503 // the class hierarchy, so process them here.
504 while ((ik = ik->previous_versions()) != NULL) {
505 ik->clean_weak_instanceklass_links();
506 }
507 }
508 }
509 }
510
511 void Klass::metaspace_pointers_do(MetaspaceClosure* it) {
512 if (log_is_enabled(Trace, cds)) {
513 ResourceMark rm;
514 log_trace(cds)("Iter(Klass): %p (%s)", this, external_name());
515 }
516
517 it->push(&_name);
518 it->push(&_secondary_super_cache);
519 it->push(&_secondary_supers);
520 for (int i = 0; i < _primary_super_limit; i++) {
521 it->push(&_primary_supers[i]);
522 }
523 it->push(&_super);
524 if (!Arguments::is_dumping_archive()) {
525 // If dumping archive, these may point to excluded classes. There's no need
526 // to follow these pointers anyway, as they will be set to NULL in
527 // remove_unshareable_info().
528 it->push((Klass**)&_subklass);
529 it->push((Klass**)&_next_sibling);
530 it->push(&_next_link);
531 }
532
533 vtableEntry* vt = start_of_vtable();
534 for (int i=0; i<vtable_length(); i++) {
535 it->push(vt[i].method_addr());
536 }
537 }
538
539 #if INCLUDE_CDS
540 void Klass::remove_unshareable_info() {
541 assert (Arguments::is_dumping_archive(),
542 "only called during CDS dump time");
543 JFR_ONLY(REMOVE_ID(this);)
544 if (log_is_enabled(Trace, cds, unshareable)) {
545 ResourceMark rm;
546 log_trace(cds, unshareable)("remove: %s", external_name());
547 }
548
549 set_subklass(NULL);
550 set_next_sibling(NULL);
551 set_next_link(NULL);
552
553 // Null out class_loader_data because we don't share that yet.
554 set_class_loader_data(NULL);
555 set_is_shared();
556 }
557
558 void Klass::remove_java_mirror() {
559 Arguments::assert_is_dumping_archive();
560 if (log_is_enabled(Trace, cds, unshareable)) {
561 ResourceMark rm;
562 log_trace(cds, unshareable)("remove java_mirror: %s", external_name());
563 }
564 // Just null out the mirror. The class_loader_data() no longer exists.
565 clear_java_mirror_handle();
566 }
567
568 void Klass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) {
569 assert(is_klass(), "ensure C++ vtable is restored");
570 assert(is_shared(), "must be set");
571 JFR_ONLY(RESTORE_ID(this);)
572 if (log_is_enabled(Trace, cds, unshareable)) {
573 ResourceMark rm(THREAD);
574 log_trace(cds, unshareable)("restore: %s", external_name());
575 }
576
577 // If an exception happened during CDS restore, some of these fields may already be
578 // set. We leave the class on the CLD list, even if incomplete so that we don't
579 // modify the CLD list outside a safepoint.
580 if (class_loader_data() == NULL) {
581 set_class_loader_data(loader_data);
582
583 // Add to class loader list first before creating the mirror
584 // (same order as class file parsing)
585 loader_data->add_class(this);
586 }
587
588 Handle loader(THREAD, loader_data->class_loader());
589 ModuleEntry* module_entry = NULL;
590 Klass* k = this;
591 if (k->is_objArray_klass()) {
592 k = ObjArrayKlass::cast(k)->bottom_klass();
593 }
594 // Obtain klass' module.
595 if (k->is_instance_klass()) {
596 InstanceKlass* ik = (InstanceKlass*) k;
597 module_entry = ik->module();
598 } else {
599 module_entry = ModuleEntryTable::javabase_moduleEntry();
600 }
601 // Obtain java.lang.Module, if available
602 Handle module_handle(THREAD, ((module_entry != NULL) ? module_entry->module() : (oop)NULL));
603
604 if (this->has_archived_mirror_index()) {
605 ResourceMark rm(THREAD);
606 log_debug(cds, mirror)("%s has raw archived mirror", external_name());
607 if (ArchiveHeapLoader::are_archived_mirrors_available()) {
608 bool present = java_lang_Class::restore_archived_mirror(this, loader, module_handle,
609 protection_domain,
610 CHECK);
611 if (present) {
612 return;
613 }
614 }
615
616 // No archived mirror data
617 log_debug(cds, mirror)("No archived mirror data for %s", external_name());
618 clear_java_mirror_handle();
619 this->clear_archived_mirror_index();
620 }
621
622 // Only recreate it if not present. A previous attempt to restore may have
623 // gotten an OOM later but keep the mirror if it was created.
624 if (java_mirror() == NULL) {
625 ResourceMark rm(THREAD);
626 log_trace(cds, mirror)("Recreate mirror for %s", external_name());
627 java_lang_Class::create_mirror(this, loader, module_handle, protection_domain, Handle(), CHECK);
628 }
629 }
630 #endif // INCLUDE_CDS
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(java_lang_Class::is_instance(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 }