1 /*
2 * Copyright (c) 1997, 2019, 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/heapInspection.hpp"
36 #include "memory/heapShared.hpp"
37 #include "memory/metadataFactory.hpp"
38 #include "memory/metaspaceClosure.hpp"
39 #include "memory/metaspaceShared.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 "runtime/atomic.hpp"
49 #include "runtime/handles.inline.hpp"
50 #include "runtime/orderAccess.hpp"
51 #include "utilities/macros.hpp"
52 #include "utilities/stack.inline.hpp"
53
54 void Klass::set_java_mirror(Handle m) {
55 assert(!m.is_null(), "New mirror should never be null.");
56 assert(_java_mirror.resolve() == NULL, "should only be used to initialize mirror");
57 _java_mirror = class_loader_data()->add_handle(m);
58 }
59
60 oop Klass::java_mirror() const {
61 return _java_mirror.resolve();
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(SystemDictionary::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
89 bool Klass::is_subclass_of(const Klass* k) const {
90 // Run up the super chain and check
91 if (this == k) return true;
92
93 Klass* t = const_cast<Klass*>(this)->super();
94
95 while (t != NULL) {
96 if (t == k) return true;
97 t = t->super();
98 }
99 return false;
100 }
101
102 bool Klass::search_secondary_supers(Klass* k) const {
103 // Put some extra logic here out-of-line, before the search proper.
104 // This cuts down the size of the inline method.
105
106 // This is necessary, since I am never in my own secondary_super list.
107 if (this == k)
108 return true;
109 // Scan the array-of-objects for a match
110 int cnt = secondary_supers()->length();
111 for (int i = 0; i < cnt; i++) {
112 if (secondary_supers()->at(i) == k) {
113 ((Klass*)this)->set_secondary_super_cache(k);
114 return true;
115 }
116 }
117 return false;
118 }
119
120 // Return self, except for abstract classes with exactly 1
121 // implementor. Then return the 1 concrete implementation.
122 Klass *Klass::up_cast_abstract() {
123 Klass *r = this;
124 while( r->is_abstract() ) { // Receiver is abstract?
125 Klass *s = r->subklass(); // Check for exactly 1 subklass
126 if (s == NULL || s->next_sibling() != NULL) // Oops; wrong count; give up
127 return this; // Return 'this' as a no-progress flag
128 r = s; // Loop till find concrete class
129 }
130 return r; // Return the 1 concrete class
131 }
132
133 // Find LCA in class hierarchy
134 Klass *Klass::LCA( Klass *k2 ) {
135 Klass *k1 = this;
136 while( 1 ) {
137 if( k1->is_subtype_of(k2) ) return k2;
138 if( k2->is_subtype_of(k1) ) return k1;
139 k1 = k1->super();
140 k2 = k2->super();
141 }
142 }
143
144
145 void Klass::check_valid_for_instantiation(bool throwError, TRAPS) {
146 ResourceMark rm(THREAD);
147 THROW_MSG(throwError ? vmSymbols::java_lang_InstantiationError()
148 : vmSymbols::java_lang_InstantiationException(), external_name());
149 }
150
151
152 void Klass::copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS) {
153 ResourceMark rm(THREAD);
154 assert(s != NULL, "Throw NPE!");
155 THROW_MSG(vmSymbols::java_lang_ArrayStoreException(),
156 err_msg("arraycopy: source type %s is not an array", s->klass()->external_name()));
157 }
158
159
160 void Klass::initialize(TRAPS) {
161 ShouldNotReachHere();
162 }
163
164 Klass* Klass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
165 #ifdef ASSERT
166 tty->print_cr("Error: find_field called on a klass oop."
167 " Likely error: reflection method does not correctly"
168 " wrap return value in a mirror object.");
169 #endif
170 ShouldNotReachHere();
171 return NULL;
172 }
173
174 Method* Klass::uncached_lookup_method(const Symbol* name, const Symbol* signature,
175 OverpassLookupMode overpass_mode,
176 PrivateLookupMode private_mode) const {
177 #ifdef ASSERT
178 tty->print_cr("Error: uncached_lookup_method called on a klass oop."
179 " Likely error: reflection method does not correctly"
180 " wrap return value in a mirror object.");
181 #endif
182 ShouldNotReachHere();
183 return NULL;
184 }
185
186 void* Klass::operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, TRAPS) throw() {
187 return Metaspace::allocate(loader_data, word_size, MetaspaceObj::ClassType, THREAD);
188 }
189
190 // "Normal" instantiation is preceeded by a MetaspaceObj allocation
191 // which zeros out memory - calloc equivalent.
192 // The constructor is also used from CppVtableCloner,
193 // which doesn't zero out the memory before calling the constructor.
194 // Need to set the _java_mirror field explicitly to not hit an assert that the field
195 // should be NULL before setting it.
196 Klass::Klass(KlassID id) : _id(id),
197 _java_mirror(NULL),
198 _prototype_header(markWord::prototype()),
199 _shared_class_path_index(-1) {
200 CDS_ONLY(_shared_class_flags = 0;)
201 CDS_JAVA_HEAP_ONLY(_archived_mirror = 0;)
202 _primary_supers[0] = this;
203 set_super_check_offset(in_bytes(primary_supers_offset()));
204 }
205
206 jint Klass::array_layout_helper(BasicType etype) {
207 assert(etype >= T_BOOLEAN && etype <= T_OBJECT, "valid etype");
208 // Note that T_ARRAY is not allowed here.
209 int hsize = arrayOopDesc::base_offset_in_bytes(etype);
210 int esize = type2aelembytes(etype);
211 bool isobj = (etype == T_OBJECT);
212 int tag = isobj ? _lh_array_tag_obj_value : _lh_array_tag_type_value;
213 int lh = array_layout_helper(tag, hsize, etype, exact_log2(esize));
214
215 assert(lh < (int)_lh_neutral_value, "must look like an array layout");
216 assert(layout_helper_is_array(lh), "correct kind");
217 assert(layout_helper_is_objArray(lh) == isobj, "correct kind");
218 assert(layout_helper_is_typeArray(lh) == !isobj, "correct kind");
219 assert(layout_helper_header_size(lh) == hsize, "correct decode");
220 assert(layout_helper_element_type(lh) == etype, "correct decode");
221 assert(1 << layout_helper_log2_element_size(lh) == esize, "correct decode");
222
223 return lh;
224 }
225
226 bool Klass::can_be_primary_super_slow() const {
227 if (super() == NULL)
228 return true;
229 else if (super()->super_depth() >= primary_super_limit()-1)
230 return false;
231 else
232 return true;
233 }
234
235 void Klass::initialize_supers(Klass* k, Array<InstanceKlass*>* transitive_interfaces, TRAPS) {
236 if (k == NULL) {
237 set_super(NULL);
238 _primary_supers[0] = this;
239 assert(super_depth() == 0, "Object must already be initialized properly");
240 } else if (k != super() || k == SystemDictionary::Object_klass()) {
241 assert(super() == NULL || super() == SystemDictionary::Object_klass(),
242 "initialize this only once to a non-trivial value");
243 set_super(k);
244 Klass* sup = k;
245 int sup_depth = sup->super_depth();
246 juint my_depth = MIN2(sup_depth + 1, (int)primary_super_limit());
247 if (!can_be_primary_super_slow())
248 my_depth = primary_super_limit();
249 for (juint i = 0; i < my_depth; i++) {
250 _primary_supers[i] = sup->_primary_supers[i];
251 }
252 Klass* *super_check_cell;
253 if (my_depth < primary_super_limit()) {
254 _primary_supers[my_depth] = this;
255 super_check_cell = &_primary_supers[my_depth];
256 } else {
257 // Overflow of the primary_supers array forces me to be secondary.
258 super_check_cell = &_secondary_super_cache;
259 }
260 set_super_check_offset((address)super_check_cell - (address) this);
261
262 #ifdef ASSERT
263 {
264 juint j = super_depth();
265 assert(j == my_depth, "computed accessor gets right answer");
266 Klass* t = this;
267 while (!t->can_be_primary_super()) {
268 t = t->super();
269 j = t->super_depth();
270 }
271 for (juint j1 = j+1; j1 < primary_super_limit(); j1++) {
272 assert(primary_super_of_depth(j1) == NULL, "super list padding");
273 }
274 while (t != NULL) {
275 assert(primary_super_of_depth(j) == t, "super list initialization");
276 t = t->super();
277 --j;
278 }
279 assert(j == (juint)-1, "correct depth count");
280 }
281 #endif
282 }
283
284 if (secondary_supers() == NULL) {
285
286 // Now compute the list of secondary supertypes.
287 // Secondaries can occasionally be on the super chain,
288 // if the inline "_primary_supers" array overflows.
289 int extras = 0;
290 Klass* p;
291 for (p = super(); !(p == NULL || p->can_be_primary_super()); p = p->super()) {
292 ++extras;
293 }
294
295 ResourceMark rm(THREAD); // need to reclaim GrowableArrays allocated below
296
297 // Compute the "real" non-extra secondaries.
298 GrowableArray<Klass*>* secondaries = compute_secondary_supers(extras, transitive_interfaces);
299 if (secondaries == NULL) {
300 // secondary_supers set by compute_secondary_supers
301 return;
302 }
303
304 GrowableArray<Klass*>* primaries = new GrowableArray<Klass*>(extras);
305
306 for (p = super(); !(p == NULL || p->can_be_primary_super()); p = p->super()) {
307 int i; // Scan for overflow primaries being duplicates of 2nd'arys
308
309 // This happens frequently for very deeply nested arrays: the
310 // primary superclass chain overflows into the secondary. The
311 // secondary list contains the element_klass's secondaries with
312 // an extra array dimension added. If the element_klass's
313 // secondary list already contains some primary overflows, they
314 // (with the extra level of array-ness) will collide with the
315 // normal primary superclass overflows.
316 for( i = 0; i < secondaries->length(); i++ ) {
317 if( secondaries->at(i) == p )
318 break;
319 }
320 if( i < secondaries->length() )
321 continue; // It's a dup, don't put it in
322 primaries->push(p);
323 }
324 // Combine the two arrays into a metadata object to pack the array.
325 // The primaries are added in the reverse order, then the secondaries.
326 int new_length = primaries->length() + secondaries->length();
327 Array<Klass*>* s2 = MetadataFactory::new_array<Klass*>(
328 class_loader_data(), new_length, CHECK);
329 int fill_p = primaries->length();
330 for (int j = 0; j < fill_p; j++) {
331 s2->at_put(j, primaries->pop()); // add primaries in reverse order.
332 }
333 for( int j = 0; j < secondaries->length(); j++ ) {
334 s2->at_put(j+fill_p, secondaries->at(j)); // add secondaries on the end.
335 }
336
337 #ifdef ASSERT
338 // We must not copy any NULL placeholders left over from bootstrap.
339 for (int j = 0; j < s2->length(); j++) {
340 assert(s2->at(j) != NULL, "correct bootstrapping order");
341 }
342 #endif
343
344 set_secondary_supers(s2);
345 }
346 }
347
348 GrowableArray<Klass*>* Klass::compute_secondary_supers(int num_extra_slots,
349 Array<InstanceKlass*>* transitive_interfaces) {
350 assert(num_extra_slots == 0, "override for complex klasses");
351 assert(transitive_interfaces == NULL, "sanity");
352 set_secondary_supers(Universe::the_empty_klass_array());
353 return NULL;
354 }
355
356
357 // superklass links
358 InstanceKlass* Klass::superklass() const {
359 assert(super() == NULL || super()->is_instance_klass(), "must be instance klass");
360 return _super == NULL ? NULL : InstanceKlass::cast(_super);
361 }
362
363 // subklass links. Used by the compiler (and vtable initialization)
364 // May be cleaned concurrently, so must use the Compile_lock.
365 // The log parameter is for clean_weak_klass_links to report unlinked classes.
366 Klass* Klass::subklass(bool log) const {
367 // Need load_acquire on the _subklass, because it races with inserts that
368 // publishes freshly initialized data.
369 for (Klass* chain = OrderAccess::load_acquire(&_subklass);
370 chain != NULL;
371 // Do not need load_acquire on _next_sibling, because inserts never
372 // create _next_sibling edges to dead data.
373 chain = Atomic::load(&chain->_next_sibling))
374 {
375 if (chain->is_loader_alive()) {
376 return chain;
377 } else if (log) {
378 if (log_is_enabled(Trace, class, unload)) {
379 ResourceMark rm;
380 log_trace(class, unload)("unlinking class (subclass): %s", chain->external_name());
381 }
382 }
383 }
384 return NULL;
385 }
386
387 Klass* Klass::next_sibling(bool log) const {
388 // Do not need load_acquire on _next_sibling, because inserts never
389 // create _next_sibling edges to dead data.
390 for (Klass* chain = Atomic::load(&_next_sibling);
391 chain != NULL;
392 chain = Atomic::load(&chain->_next_sibling)) {
393 // Only return alive klass, there may be stale klass
394 // in this chain if cleaned concurrently.
395 if (chain->is_loader_alive()) {
396 return chain;
397 } else if (log) {
398 if (log_is_enabled(Trace, class, unload)) {
399 ResourceMark rm;
400 log_trace(class, unload)("unlinking class (sibling): %s", chain->external_name());
401 }
402 }
403 }
404 return NULL;
405 }
406
407 void Klass::set_subklass(Klass* s) {
408 assert(s != this, "sanity check");
409 OrderAccess::release_store(&_subklass, s);
410 }
411
412 void Klass::set_next_sibling(Klass* s) {
413 assert(s != this, "sanity check");
414 // Does not need release semantics. If used by cleanup, it will link to
415 // already safely published data, and if used by inserts, will be published
416 // safely using cmpxchg.
417 Atomic::store(s, &_next_sibling);
418 }
419
420 void Klass::append_to_sibling_list() {
421 assert_locked_or_safepoint(Compile_lock);
422 debug_only(verify();)
423 // add ourselves to superklass' subklass list
424 InstanceKlass* super = superklass();
425 if (super == NULL) return; // special case: class Object
426 assert((!super->is_interface() // interfaces cannot be supers
427 && (super->superklass() == NULL || !is_interface())),
428 "an interface can only be a subklass of Object");
429
430 // Make sure there is no stale subklass head
431 super->clean_subklass();
432
433 for (;;) {
434 Klass* prev_first_subklass = OrderAccess::load_acquire(&_super->_subklass);
435 if (prev_first_subklass != NULL) {
436 // set our sibling to be the superklass' previous first subklass
437 assert(prev_first_subklass->is_loader_alive(), "May not attach not alive klasses");
438 set_next_sibling(prev_first_subklass);
439 }
440 // Note that the prev_first_subklass is always alive, meaning no sibling_next links
441 // are ever created to not alive klasses. This is an important invariant of the lock-free
442 // cleaning protocol, that allows us to safely unlink dead klasses from the sibling list.
443 if (Atomic::cmpxchg(this, &super->_subklass, prev_first_subklass) == prev_first_subklass) {
444 return;
445 }
446 }
447 debug_only(verify();)
448 }
449
450 void Klass::clean_subklass() {
451 for (;;) {
452 // Need load_acquire, due to contending with concurrent inserts
453 Klass* subklass = OrderAccess::load_acquire(&_subklass);
454 if (subklass == NULL || subklass->is_loader_alive()) {
455 return;
456 }
457 // Try to fix _subklass until it points at something not dead.
458 Atomic::cmpxchg(subklass->next_sibling(), &_subklass, subklass);
459 }
460 }
461
462 void Klass::clean_weak_klass_links(bool unloading_occurred, bool clean_alive_klasses) {
463 if (!ClassUnloading || !unloading_occurred) {
464 return;
465 }
466
467 Klass* root = SystemDictionary::Object_klass();
468 Stack<Klass*, mtGC> stack;
469
470 stack.push(root);
471 while (!stack.is_empty()) {
472 Klass* current = stack.pop();
473
474 assert(current->is_loader_alive(), "just checking, this should be live");
475
476 // Find and set the first alive subklass
477 Klass* sub = current->subklass(true);
478 current->clean_subklass();
479 if (sub != NULL) {
480 stack.push(sub);
481 }
482
483 // Find and set the first alive sibling
484 Klass* sibling = current->next_sibling(true);
485 current->set_next_sibling(sibling);
486 if (sibling != NULL) {
487 stack.push(sibling);
488 }
489
490 // Clean the implementors list and method data.
491 if (clean_alive_klasses && current->is_instance_klass()) {
492 InstanceKlass* ik = InstanceKlass::cast(current);
493 ik->clean_weak_instanceklass_links();
494
495 // JVMTI RedefineClasses creates previous versions that are not in
496 // the class hierarchy, so process them here.
497 while ((ik = ik->previous_versions()) != NULL) {
498 ik->clean_weak_instanceklass_links();
499 }
500 }
501 }
502 }
503
504 void Klass::metaspace_pointers_do(MetaspaceClosure* it) {
505 if (log_is_enabled(Trace, cds)) {
506 ResourceMark rm;
507 log_trace(cds)("Iter(Klass): %p (%s)", this, external_name());
508 }
509
510 it->push(&_name);
511 it->push(&_secondary_super_cache);
512 it->push(&_secondary_supers);
513 for (int i = 0; i < _primary_super_limit; i++) {
514 it->push(&_primary_supers[i]);
515 }
516 it->push(&_super);
517 it->push((Klass**)&_subklass);
518 it->push((Klass**)&_next_sibling);
519 it->push(&_next_link);
520
521 vtableEntry* vt = start_of_vtable();
522 for (int i=0; i<vtable_length(); i++) {
523 it->push(vt[i].method_addr());
524 }
525 }
526
527 void Klass::remove_unshareable_info() {
528 assert (DumpSharedSpaces || DynamicDumpSharedSpaces,
529 "only called during CDS dump time");
530 JFR_ONLY(REMOVE_ID(this);)
531 if (log_is_enabled(Trace, cds, unshareable)) {
532 ResourceMark rm;
533 log_trace(cds, unshareable)("remove: %s", external_name());
534 }
535
536 set_subklass(NULL);
537 set_next_sibling(NULL);
538 set_next_link(NULL);
539
540 // Null out class_loader_data because we don't share that yet.
541 set_class_loader_data(NULL);
542 set_is_shared();
543 }
544
545 void Klass::remove_java_mirror() {
546 assert(DumpSharedSpaces || DynamicDumpSharedSpaces, "only called during CDS dump time");
547 if (log_is_enabled(Trace, cds, unshareable)) {
548 ResourceMark rm;
549 log_trace(cds, unshareable)("remove java_mirror: %s", external_name());
550 }
551 // Just null out the mirror. The class_loader_data() no longer exists.
552 _java_mirror = NULL;
553 }
554
555 void Klass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) {
556 assert(is_klass(), "ensure C++ vtable is restored");
557 assert(is_shared(), "must be set");
558 JFR_ONLY(RESTORE_ID(this);)
559 if (log_is_enabled(Trace, cds, unshareable)) {
560 ResourceMark rm;
561 log_trace(cds, unshareable)("restore: %s", external_name());
562 }
563
564 // If an exception happened during CDS restore, some of these fields may already be
565 // set. We leave the class on the CLD list, even if incomplete so that we don't
566 // modify the CLD list outside a safepoint.
567 if (class_loader_data() == NULL) {
568 // Restore class_loader_data to the null class loader data
569 set_class_loader_data(loader_data);
570
571 // Workaround for suspected bug. Make sure other threads see this assignment.
572 // This shouldn't be necessary but the compiler thread seems to be behind
573 // the times, even though this thread takes MethodCompileQueue_lock and the thread
574 // that doesn't see this value also takes that lock.
575 OrderAccess::fence();
576
577 // Add to null class loader list first before creating the mirror
578 // (same order as class file parsing)
579 loader_data->add_class(this);
580 }
581
582 Handle loader(THREAD, loader_data->class_loader());
583 ModuleEntry* module_entry = NULL;
584 Klass* k = this;
585 if (k->is_objArray_klass()) {
586 k = ObjArrayKlass::cast(k)->bottom_klass();
587 }
588 // Obtain klass' module.
589 if (k->is_instance_klass()) {
590 InstanceKlass* ik = (InstanceKlass*) k;
591 module_entry = ik->module();
592 } else {
593 module_entry = ModuleEntryTable::javabase_moduleEntry();
594 }
595 // Obtain java.lang.Module, if available
596 Handle module_handle(THREAD, ((module_entry != NULL) ? module_entry->module() : (oop)NULL));
597
598 if (this->has_raw_archived_mirror()) {
599 ResourceMark rm;
600 log_debug(cds, mirror)("%s has raw archived mirror", external_name());
601 if (HeapShared::open_archive_heap_region_mapped()) {
602 bool present = java_lang_Class::restore_archived_mirror(this, loader, module_handle,
603 protection_domain,
604 CHECK);
605 if (present) {
606 return;
607 }
608 }
609
610 // No archived mirror data
611 log_debug(cds, mirror)("No archived mirror data for %s", external_name());
612 _java_mirror = NULL;
613 this->clear_has_raw_archived_mirror();
614 }
615
616 // Only recreate it if not present. A previous attempt to restore may have
617 // gotten an OOM later but keep the mirror if it was created.
618 if (java_mirror() == NULL) {
619 log_trace(cds, mirror)("Recreate mirror for %s", external_name());
620 java_lang_Class::create_mirror(this, loader, module_handle, protection_domain, CHECK);
621 }
622 }
623
624 #if INCLUDE_CDS_JAVA_HEAP
625 // Used at CDS dump time to access the archived mirror. No GC barrier.
626 oop Klass::archived_java_mirror_raw() {
627 assert(has_raw_archived_mirror(), "must have raw archived mirror");
628 return CompressedOops::decode(_archived_mirror);
629 }
630
631 narrowOop Klass::archived_java_mirror_raw_narrow() {
632 assert(has_raw_archived_mirror(), "must have raw archived mirror");
633 return _archived_mirror;
634 }
635
636 // No GC barrier
637 void Klass::set_archived_java_mirror_raw(oop m) {
638 assert(DumpSharedSpaces, "called only during runtime");
639 _archived_mirror = CompressedOops::encode(m);
640 }
641 #endif // INCLUDE_CDS_JAVA_HEAP
642
643 Klass* Klass::array_klass_or_null(int rank) {
644 EXCEPTION_MARK;
645 // No exception can be thrown by array_klass_impl when called with or_null == true.
646 // (In anycase, the execption mark will fail if it do so)
647 return array_klass_impl(true, rank, THREAD);
648 }
649
650
651 Klass* Klass::array_klass_or_null() {
652 EXCEPTION_MARK;
653 // No exception can be thrown by array_klass_impl when called with or_null == true.
654 // (In anycase, the execption mark will fail if it do so)
655 return array_klass_impl(true, THREAD);
656 }
657
658
659 Klass* Klass::array_klass_impl(bool or_null, int rank, TRAPS) {
660 fatal("array_klass should be dispatched to InstanceKlass, ObjArrayKlass or TypeArrayKlass");
661 return NULL;
662 }
663
664
665 Klass* Klass::array_klass_impl(bool or_null, TRAPS) {
666 fatal("array_klass should be dispatched to InstanceKlass, ObjArrayKlass or TypeArrayKlass");
667 return NULL;
668 }
669
670 void Klass::check_array_allocation_length(int length, int max_length, TRAPS) {
671 if (length > max_length) {
672 if (!THREAD->in_retryable_allocation()) {
673 report_java_out_of_memory("Requested array size exceeds VM limit");
674 JvmtiExport::post_array_size_exhausted();
675 THROW_OOP(Universe::out_of_memory_error_array_size());
676 } else {
677 THROW_OOP(Universe::out_of_memory_error_retry());
678 }
679 } else if (length < 0) {
680 THROW_MSG(vmSymbols::java_lang_NegativeArraySizeException(), err_msg("%d", length));
681 }
682 }
683
684 oop Klass::class_loader() const { return class_loader_data()->class_loader(); }
685
686 // In product mode, this function doesn't have virtual function calls so
687 // there might be some performance advantage to handling InstanceKlass here.
688 const char* Klass::external_name() const {
689 if (is_instance_klass()) {
690 const InstanceKlass* ik = static_cast<const InstanceKlass*>(this);
691 if (ik->is_unsafe_anonymous()) {
692 char addr_buf[20];
693 jio_snprintf(addr_buf, 20, "/" INTPTR_FORMAT, p2i(ik));
694 size_t addr_len = strlen(addr_buf);
695 size_t name_len = name()->utf8_length();
696 char* result = NEW_RESOURCE_ARRAY(char, name_len + addr_len + 1);
697 name()->as_klass_external_name(result, (int) name_len + 1);
698 assert(strlen(result) == name_len, "");
699 strcpy(result + name_len, addr_buf);
700 assert(strlen(result) == name_len + addr_len, "");
701 return result;
702 }
703 }
704 if (name() == NULL) return "<unknown>";
705 return name()->as_klass_external_name();
706 }
707
708 const char* Klass::signature_name() const {
709 if (name() == NULL) return "<unknown>";
710 return name()->as_C_string();
711 }
712
713 const char* Klass::external_kind() const {
714 if (is_interface()) return "interface";
715 if (is_abstract()) return "abstract class";
716 return "class";
717 }
718
719 // Unless overridden, modifier_flags is 0.
720 jint Klass::compute_modifier_flags(TRAPS) const {
721 return 0;
722 }
723
724 int Klass::atomic_incr_biased_lock_revocation_count() {
725 return (int) Atomic::add(1, &_biased_lock_revocation_count);
726 }
727
728 // Unless overridden, jvmti_class_status has no flags set.
729 jint Klass::jvmti_class_status() const {
730 return 0;
731 }
732
733
734 // Printing
735
736 void Klass::print_on(outputStream* st) const {
737 ResourceMark rm;
738 // print title
739 st->print("%s", internal_name());
740 print_address_on(st);
741 st->cr();
742 }
743
744 #define BULLET " - "
745
746 void Klass::oop_print_on(oop obj, outputStream* st) {
747 // print title
748 st->print_cr("%s ", internal_name());
749 obj->print_address_on(st);
750
751 if (WizardMode) {
752 // print header
753 obj->mark().print_on(st);
754 st->cr();
755 st->print(BULLET"prototype_header: " INTPTR_FORMAT, _prototype_header.value());
756 st->cr();
757 }
758
759 // print class
760 st->print(BULLET"klass: ");
761 obj->klass()->print_value_on(st);
762 st->cr();
763 }
764
765 void Klass::oop_print_value_on(oop obj, outputStream* st) {
766 // print title
767 ResourceMark rm; // Cannot print in debug mode without this
768 st->print("%s", internal_name());
769 obj->print_address_on(st);
770 }
771
772 #if INCLUDE_SERVICES
773 // Size Statistics
774 void Klass::collect_statistics(KlassSizeStats *sz) const {
775 sz->_klass_bytes = sz->count(this);
776 sz->_mirror_bytes = sz->count(java_mirror_no_keepalive());
777 sz->_secondary_supers_bytes = sz->count_array(secondary_supers());
778
779 sz->_ro_bytes += sz->_secondary_supers_bytes;
780 sz->_rw_bytes += sz->_klass_bytes + sz->_mirror_bytes;
781 }
782 #endif // INCLUDE_SERVICES
783
784 // Verification
785
786 void Klass::verify_on(outputStream* st) {
787
788 // This can be expensive, but it is worth checking that this klass is actually
789 // in the CLD graph but not in production.
790 assert(Metaspace::contains((address)this), "Should be");
791
792 guarantee(this->is_klass(),"should be klass");
793
794 if (super() != NULL) {
795 guarantee(super()->is_klass(), "should be klass");
796 }
797 if (secondary_super_cache() != NULL) {
798 Klass* ko = secondary_super_cache();
799 guarantee(ko->is_klass(), "should be klass");
800 }
801 for ( uint i = 0; i < primary_super_limit(); i++ ) {
802 Klass* ko = _primary_supers[i];
803 if (ko != NULL) {
804 guarantee(ko->is_klass(), "should be klass");
805 }
806 }
807
808 if (java_mirror_no_keepalive() != NULL) {
809 guarantee(oopDesc::is_oop(java_mirror_no_keepalive()), "should be instance");
810 }
811 }
812
813 void Klass::oop_verify_on(oop obj, outputStream* st) {
814 guarantee(oopDesc::is_oop(obj), "should be oop");
815 guarantee(obj->klass()->is_klass(), "klass field is not a klass");
816 }
817
818 bool Klass::is_valid(Klass* k) {
819 if (!is_aligned(k, sizeof(MetaWord))) return false;
820 if ((size_t)k < os::min_page_size()) return false;
821
822 if (!os::is_readable_range(k, k + 1)) return false;
823 if (!Metaspace::contains(k)) return false;
824
825 if (!Symbol::is_valid(k->name())) return false;
826 return ClassLoaderDataGraph::is_valid(k->class_loader_data());
827 }
828
829 klassVtable Klass::vtable() const {
830 return klassVtable(const_cast<Klass*>(this), start_of_vtable(), vtable_length() / vtableEntry::size());
831 }
832
833 vtableEntry* Klass::start_of_vtable() const {
834 return (vtableEntry*) ((address)this + in_bytes(vtable_start_offset()));
835 }
836
837 Method* Klass::method_at_vtable(int index) {
838 #ifndef PRODUCT
839 assert(index >= 0, "valid vtable index");
840 if (DebugVtables) {
841 verify_vtable_index(index);
842 }
843 #endif
844 return start_of_vtable()[index].method();
845 }
846
847 ByteSize Klass::vtable_start_offset() {
848 return in_ByteSize(InstanceKlass::header_size() * wordSize);
849 }
850
851 #ifndef PRODUCT
852
853 bool Klass::verify_vtable_index(int i) {
854 int limit = vtable_length()/vtableEntry::size();
855 assert(i >= 0 && i < limit, "index %d out of bounds %d", i, limit);
856 return true;
857 }
858
859 #endif // PRODUCT
860
861 // Caller needs ResourceMark
862 // joint_in_module_of_loader provides an optimization if 2 classes are in
863 // the same module to succinctly print out relevant information about their
864 // module name and class loader's name_and_id for error messages.
865 // Format:
866 // <fully-qualified-external-class-name1> and <fully-qualified-external-class-name2>
867 // are in module <module-name>[@<version>]
868 // of loader <loader-name_and_id>[, parent loader <parent-loader-name_and_id>]
869 const char* Klass::joint_in_module_of_loader(const Klass* class2, bool include_parent_loader) const {
870 assert(module() == class2->module(), "classes do not have the same module");
871 const char* class1_name = external_name();
872 size_t len = strlen(class1_name) + 1;
873
874 const char* class2_description = class2->class_in_module_of_loader(true, include_parent_loader);
875 len += strlen(class2_description);
876
877 len += strlen(" and ");
878
879 char* joint_description = NEW_RESOURCE_ARRAY_RETURN_NULL(char, len);
880
881 // Just return the FQN if error when allocating string
882 if (joint_description == NULL) {
883 return class1_name;
884 }
885
886 jio_snprintf(joint_description, len, "%s and %s",
887 class1_name,
888 class2_description);
889
890 return joint_description;
891 }
892
893 // Caller needs ResourceMark
894 // class_in_module_of_loader provides a standard way to include
895 // relevant information about a class, such as its module name as
896 // well as its class loader's name_and_id, in error messages and logging.
897 // Format:
898 // <fully-qualified-external-class-name> is in module <module-name>[@<version>]
899 // of loader <loader-name_and_id>[, parent loader <parent-loader-name_and_id>]
900 const char* Klass::class_in_module_of_loader(bool use_are, bool include_parent_loader) const {
901 // 1. fully qualified external name of class
902 const char* klass_name = external_name();
903 size_t len = strlen(klass_name) + 1;
904
905 // 2. module name + @version
906 const char* module_name = "";
907 const char* version = "";
908 bool has_version = false;
909 bool module_is_named = false;
910 const char* module_name_phrase = "";
911 const Klass* bottom_klass = is_objArray_klass() ?
912 ObjArrayKlass::cast(this)->bottom_klass() : this;
913 if (bottom_klass->is_instance_klass()) {
914 ModuleEntry* module = InstanceKlass::cast(bottom_klass)->module();
915 if (module->is_named()) {
916 module_is_named = true;
917 module_name_phrase = "module ";
918 module_name = module->name()->as_C_string();
919 len += strlen(module_name);
920 // Use version if exists and is not a jdk module
921 if (module->should_show_version()) {
922 has_version = true;
923 version = module->version()->as_C_string();
924 // Include stlen(version) + 1 for the "@"
925 len += strlen(version) + 1;
926 }
927 } else {
928 module_name = UNNAMED_MODULE;
929 len += UNNAMED_MODULE_LEN;
930 }
931 } else {
932 // klass is an array of primitives, module is java.base
933 module_is_named = true;
934 module_name_phrase = "module ";
935 module_name = JAVA_BASE_NAME;
936 len += JAVA_BASE_NAME_LEN;
937 }
938
939 // 3. class loader's name_and_id
940 ClassLoaderData* cld = class_loader_data();
941 assert(cld != NULL, "class_loader_data should not be null");
942 const char* loader_name_and_id = cld->loader_name_and_id();
943 len += strlen(loader_name_and_id);
944
945 // 4. include parent loader information
946 const char* parent_loader_phrase = "";
947 const char* parent_loader_name_and_id = "";
948 if (include_parent_loader &&
949 !cld->is_builtin_class_loader_data()) {
950 oop parent_loader = java_lang_ClassLoader::parent(class_loader());
951 ClassLoaderData *parent_cld = ClassLoaderData::class_loader_data_or_null(parent_loader);
952 // The parent loader's ClassLoaderData could be null if it is
953 // a delegating class loader that has never defined a class.
954 // In this case the loader's name must be obtained via the parent loader's oop.
955 if (parent_cld == NULL) {
956 oop cl_name_and_id = java_lang_ClassLoader::nameAndId(parent_loader);
957 if (cl_name_and_id != NULL) {
958 parent_loader_name_and_id = java_lang_String::as_utf8_string(cl_name_and_id);
959 }
960 } else {
961 parent_loader_name_and_id = parent_cld->loader_name_and_id();
962 }
963 parent_loader_phrase = ", parent loader ";
964 len += strlen(parent_loader_phrase) + strlen(parent_loader_name_and_id);
965 }
966
967 // Start to construct final full class description string
968 len += ((use_are) ? strlen(" are in ") : strlen(" is in "));
969 len += strlen(module_name_phrase) + strlen(" of loader ");
970
971 char* class_description = NEW_RESOURCE_ARRAY_RETURN_NULL(char, len);
972
973 // Just return the FQN if error when allocating string
974 if (class_description == NULL) {
975 return klass_name;
976 }
977
978 jio_snprintf(class_description, len, "%s %s in %s%s%s%s of loader %s%s%s",
979 klass_name,
980 (use_are) ? "are" : "is",
981 module_name_phrase,
982 module_name,
983 (has_version) ? "@" : "",
984 (has_version) ? version : "",
985 loader_name_and_id,
986 parent_loader_phrase,
987 parent_loader_name_and_id);
988
989 return class_description;
990 }