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