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