1 /*
2 * Copyright (c) 1997, 2024, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "cds/archiveHeapLoader.hpp"
27 #include "cds/cdsConfig.hpp"
28 #include "cds/heapShared.hpp"
29 #include "classfile/classLoader.hpp"
30 #include "classfile/classLoaderData.inline.hpp"
31 #include "classfile/classLoaderDataGraph.inline.hpp"
32 #include "classfile/javaClasses.inline.hpp"
33 #include "classfile/moduleEntry.hpp"
34 #include "classfile/systemDictionary.hpp"
35 #include "classfile/systemDictionaryShared.hpp"
36 #include "classfile/vmClasses.hpp"
37 #include "classfile/vmSymbols.hpp"
38 #include "gc/shared/collectedHeap.inline.hpp"
39 #include "jvm_io.h"
40 #include "logging/log.hpp"
41 #include "memory/metadataFactory.hpp"
42 #include "memory/metaspaceClosure.hpp"
43 #include "memory/oopFactory.hpp"
44 #include "memory/resourceArea.hpp"
45 #include "memory/universe.hpp"
46 #include "oops/compressedOops.inline.hpp"
47 #include "oops/instanceKlass.hpp"
48 #include "oops/klass.inline.hpp"
49 #include "oops/objArrayKlass.hpp"
50 #include "oops/oop.inline.hpp"
51 #include "oops/oopHandle.inline.hpp"
52 #include "prims/jvmtiExport.hpp"
53 #include "runtime/atomic.hpp"
54 #include "runtime/handles.inline.hpp"
55 #include "runtime/perfData.hpp"
56 #include "utilities/macros.hpp"
57 #include "utilities/powerOfTwo.hpp"
58 #include "utilities/rotate_bits.hpp"
59 #include "utilities/stack.inline.hpp"
60
61 void Klass::set_java_mirror(Handle m) {
62 assert(!m.is_null(), "New mirror should never be null.");
63 assert(_java_mirror.is_empty(), "should only be used to initialize mirror");
64 _java_mirror = class_loader_data()->add_handle(m);
65 }
66
67 bool Klass::is_cloneable() const {
68 return _access_flags.is_cloneable_fast() ||
69 is_subtype_of(vmClasses::Cloneable_klass());
70 }
71
72 void Klass::set_is_cloneable() {
73 if (name() == vmSymbols::java_lang_invoke_MemberName()) {
74 assert(is_final(), "no subclasses allowed");
75 // MemberName cloning should not be intrinsified and always happen in JVM_Clone.
76 } else if (is_instance_klass() && InstanceKlass::cast(this)->reference_type() != REF_NONE) {
77 // Reference cloning should not be intrinsified and always happen in JVM_Clone.
78 } else {
79 _access_flags.set_is_cloneable_fast();
80 }
81 }
82
83 uint8_t Klass::compute_hash_slot(Symbol* n) {
84 uint hash_code;
85 // Special cases for the two superclasses of all Array instances.
86 // Code elsewhere assumes, for all instances of ArrayKlass, that
87 // these two interfaces will be in this order.
88
89 // We ensure there are some empty slots in the hash table between
90 // these two very common interfaces because if they were adjacent
91 // (e.g. Slots 0 and 1), then any other class which hashed to 0 or 1
92 // would result in a probe length of 3.
93 if (n == vmSymbols::java_lang_Cloneable()) {
94 hash_code = 0;
95 } else if (n == vmSymbols::java_io_Serializable()) {
96 hash_code = SECONDARY_SUPERS_TABLE_SIZE / 2;
97 } else {
98 auto s = (const jbyte*) n->bytes();
99 hash_code = java_lang_String::hash_code(s, n->utf8_length());
100 // We use String::hash_code here (rather than e.g.
101 // Symbol::identity_hash()) in order to have a hash code that
102 // does not change from run to run. We want that because the
103 // hash value for a secondary superclass appears in generated
104 // code as a constant.
105
106 // This constant is magic: see Knuth, "Fibonacci Hashing".
107 constexpr uint multiplier
108 = 2654435769; // (uint)(((u8)1 << 32) / ((1 + sqrt(5)) / 2 ))
109 constexpr uint hash_shift = sizeof(hash_code) * 8 - 6;
110 // The leading bits of the least significant half of the product.
111 hash_code = (hash_code * multiplier) >> hash_shift;
112
113 if (StressSecondarySupers) {
114 // Generate many hash collisions in order to stress-test the
115 // linear search fallback.
116 hash_code = hash_code % 3;
117 hash_code = hash_code * (SECONDARY_SUPERS_TABLE_SIZE / 3);
118 }
119 }
120
121 return (hash_code & SECONDARY_SUPERS_TABLE_MASK);
122 }
123
124 void Klass::set_name(Symbol* n) {
125 _name = n;
126
127 if (_name != nullptr) {
128 _name->increment_refcount();
129 }
130
131 if (UseSecondarySupersTable) {
132 elapsedTimer selftime;
133 selftime.start();
134
135 _hash_slot = compute_hash_slot(n);
136 assert(_hash_slot < SECONDARY_SUPERS_TABLE_SIZE, "required");
137
138 selftime.stop();
139 if (UsePerfData) {
140 ClassLoader::perf_secondary_hash_time()->inc(selftime.ticks());
141 }
142 }
143
144 if (CDSConfig::is_dumping_archive() && is_instance_klass()) {
145 SystemDictionaryShared::init_dumptime_info(InstanceKlass::cast(this));
146 }
147 }
148
149 bool Klass::is_subclass_of(const Klass* k) const {
150 // Run up the super chain and check
151 if (this == k) return true;
152
153 Klass* t = const_cast<Klass*>(this)->super();
154
155 while (t != nullptr) {
156 if (t == k) return true;
157 t = t->super();
158 }
159 return false;
160 }
161
162 void Klass::release_C_heap_structures(bool release_constant_pool) {
163 if (_name != nullptr) _name->decrement_refcount();
164 }
165
166 bool Klass::search_secondary_supers(Klass* k) const {
167 // Put some extra logic here out-of-line, before the search proper.
168 // This cuts down the size of the inline method.
169
170 // This is necessary, since I am never in my own secondary_super list.
171 if (this == k)
172 return true;
173 // Scan the array-of-objects for a match
174 int cnt = secondary_supers()->length();
175 for (int i = 0; i < cnt; i++) {
176 if (secondary_supers()->at(i) == k) {
177 ((Klass*)this)->set_secondary_super_cache(k);
178 return true;
179 }
180 }
181 return false;
182 }
183
184 // Return self, except for abstract classes with exactly 1
185 // implementor. Then return the 1 concrete implementation.
186 Klass *Klass::up_cast_abstract() {
187 Klass *r = this;
188 while( r->is_abstract() ) { // Receiver is abstract?
189 Klass *s = r->subklass(); // Check for exactly 1 subklass
190 if (s == nullptr || s->next_sibling() != nullptr) // Oops; wrong count; give up
191 return this; // Return 'this' as a no-progress flag
192 r = s; // Loop till find concrete class
193 }
194 return r; // Return the 1 concrete class
195 }
196
197 // Find LCA in class hierarchy
198 Klass *Klass::LCA( Klass *k2 ) {
199 Klass *k1 = this;
200 while( 1 ) {
201 if( k1->is_subtype_of(k2) ) return k2;
202 if( k2->is_subtype_of(k1) ) return k1;
203 k1 = k1->super();
204 k2 = k2->super();
205 }
206 }
207
208
209 void Klass::check_valid_for_instantiation(bool throwError, TRAPS) {
210 ResourceMark rm(THREAD);
211 THROW_MSG(throwError ? vmSymbols::java_lang_InstantiationError()
212 : vmSymbols::java_lang_InstantiationException(), external_name());
213 }
214
215
216 void Klass::copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS) {
217 ResourceMark rm(THREAD);
218 assert(s != nullptr, "Throw NPE!");
219 THROW_MSG(vmSymbols::java_lang_ArrayStoreException(),
220 err_msg("arraycopy: source type %s is not an array", s->klass()->external_name()));
221 }
222
223
224 void Klass::initialize(TRAPS) {
225 ShouldNotReachHere();
226 }
227
228 Klass* Klass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
229 #ifdef ASSERT
230 tty->print_cr("Error: find_field called on a klass oop."
231 " Likely error: reflection method does not correctly"
232 " wrap return value in a mirror object.");
233 #endif
234 ShouldNotReachHere();
235 return nullptr;
236 }
237
238 Method* Klass::uncached_lookup_method(const Symbol* name, const Symbol* signature,
239 OverpassLookupMode overpass_mode,
240 PrivateLookupMode private_mode) const {
241 #ifdef ASSERT
242 tty->print_cr("Error: uncached_lookup_method called on a klass oop."
243 " Likely error: reflection method does not correctly"
244 " wrap return value in a mirror object.");
245 #endif
246 ShouldNotReachHere();
247 return nullptr;
248 }
249
250 void* Klass::operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, TRAPS) throw() {
251 return Metaspace::allocate(loader_data, word_size, MetaspaceObj::ClassType, THREAD);
252 }
253
254 Klass::Klass() : _kind(UnknownKlassKind) {
255 assert(CDSConfig::is_dumping_static_archive() || CDSConfig::is_using_archive(), "only for cds");
256 }
257
258 // "Normal" instantiation is preceded by a MetaspaceObj allocation
259 // which zeros out memory - calloc equivalent.
260 // The constructor is also used from CppVtableCloner,
261 // which doesn't zero out the memory before calling the constructor.
262 Klass::Klass(KlassKind kind) : _kind(kind),
263 _prototype_header(markWord::prototype()),
264 _shared_class_path_index(-1) {
265 CDS_ONLY(_shared_class_flags = 0;)
266 CDS_JAVA_HEAP_ONLY(_archived_mirror_index = -1;)
267 _primary_supers[0] = this;
268 set_super_check_offset(in_bytes(primary_supers_offset()));
269 }
270
271 jint Klass::array_layout_helper(BasicType etype) {
272 assert(etype >= T_BOOLEAN && etype <= T_OBJECT, "valid etype");
273 // Note that T_ARRAY is not allowed here.
274 int hsize = arrayOopDesc::base_offset_in_bytes(etype);
275 int esize = type2aelembytes(etype);
276 bool isobj = (etype == T_OBJECT);
277 int tag = isobj ? _lh_array_tag_obj_value : _lh_array_tag_type_value;
278 int lh = array_layout_helper(tag, false, hsize, etype, exact_log2(esize));
279
280 assert(lh < (int)_lh_neutral_value, "must look like an array layout");
281 assert(layout_helper_is_array(lh), "correct kind");
282 assert(layout_helper_is_objArray(lh) == isobj, "correct kind");
283 assert(layout_helper_is_typeArray(lh) == !isobj, "correct kind");
284 assert(layout_helper_header_size(lh) == hsize, "correct decode");
285 assert(layout_helper_element_type(lh) == etype, "correct decode");
286 assert(1 << layout_helper_log2_element_size(lh) == esize, "correct decode");
287
288 return lh;
289 }
290
291 bool Klass::can_be_primary_super_slow() const {
292 if (super() == nullptr)
293 return true;
294 else if (super()->super_depth() >= primary_super_limit()-1)
295 return false;
296 else
297 return true;
298 }
299
300 void Klass::set_secondary_supers(Array<Klass*>* secondaries) {
301 assert(!UseSecondarySupersTable || secondaries == nullptr, "");
302 set_secondary_supers(secondaries, SECONDARY_SUPERS_BITMAP_EMPTY);
303 }
304
305 void Klass::set_secondary_supers(Array<Klass*>* secondaries, uintx bitmap) {
306 #ifdef ASSERT
307 if (UseSecondarySupersTable && secondaries != nullptr) {
308 uintx real_bitmap = compute_secondary_supers_bitmap(secondaries);
309 assert(bitmap == real_bitmap, "must be");
310 }
311 #endif
312 _bitmap = bitmap;
313 _secondary_supers = secondaries;
314
315 if (secondaries != nullptr) {
316 LogMessage(class, load) msg;
317 NonInterleavingLogStream log {LogLevel::Debug, msg};
318 if (log.is_enabled()) {
319 ResourceMark rm;
320 log.print_cr("set_secondary_supers: hash_slot: %d; klass: %s", hash_slot(), external_name());
321 print_secondary_supers_on(&log);
322 }
323 }
324 }
325
326 // Hashed secondary superclasses
327 //
328 // We use a compressed 64-entry hash table with linear probing. We
329 // start by creating a hash table in the usual way, followed by a pass
330 // that removes all the null entries. To indicate which entries would
331 // have been null we use a bitmap that contains a 1 in each position
332 // where an entry is present, 0 otherwise. This bitmap also serves as
333 // a kind of Bloom filter, which in many cases allows us quickly to
334 // eliminate the possibility that something is a member of a set of
335 // secondaries.
336 uintx Klass::hash_secondary_supers(Array<Klass*>* secondaries, bool rewrite) {
337 const int length = secondaries->length();
338
339 if (length == 0) {
340 return SECONDARY_SUPERS_BITMAP_EMPTY;
341 }
342
343 if (length == 1) {
344 int hash_slot = secondaries->at(0)->hash_slot();
345 return uintx(1) << hash_slot;
346 }
347
348 // For performance reasons we don't use a hashed table unless there
349 // are at least two empty slots in it. If there were only one empty
350 // slot it'd take a long time to create the table and the resulting
351 // search would be no faster than linear probing.
352 if (length > SECONDARY_SUPERS_TABLE_SIZE - 2) {
353 return SECONDARY_SUPERS_BITMAP_FULL;
354 }
355
356 {
357 PerfTraceTime ptt(ClassLoader::perf_secondary_hash_time());
358
359 ResourceMark rm;
360 uintx bitmap = SECONDARY_SUPERS_BITMAP_EMPTY;
361 auto hashed_secondaries = new GrowableArray<Klass*>(SECONDARY_SUPERS_TABLE_SIZE,
362 SECONDARY_SUPERS_TABLE_SIZE, nullptr);
363
364 for (int j = 0; j < length; j++) {
365 Klass* k = secondaries->at(j);
366 hash_insert(k, hashed_secondaries, bitmap);
367 }
368
369 // Pack the hashed secondaries array by copying it into the
370 // secondaries array, sans nulls, if modification is allowed.
371 // Otherwise, validate the order.
372 int i = 0;
373 for (int slot = 0; slot < SECONDARY_SUPERS_TABLE_SIZE; slot++) {
374 bool has_element = ((bitmap >> slot) & 1) != 0;
375 assert(has_element == (hashed_secondaries->at(slot) != nullptr), "");
376 if (has_element) {
377 Klass* k = hashed_secondaries->at(slot);
378 if (rewrite) {
379 secondaries->at_put(i, k);
380 } else if (secondaries->at(i) != k) {
381 assert(false, "broken secondary supers hash table");
382 return SECONDARY_SUPERS_BITMAP_FULL;
383 }
384 i++;
385 }
386 }
387 assert(i == secondaries->length(), "mismatch");
388
389 return bitmap;
390 }
391 }
392
393 void Klass::hash_insert(Klass* klass, GrowableArray<Klass*>* secondaries, uintx& bitmap) {
394 assert(bitmap != SECONDARY_SUPERS_BITMAP_FULL, "");
395
396 int dist = 0;
397 for (int slot = klass->hash_slot(); true; slot = (slot + 1) & SECONDARY_SUPERS_TABLE_MASK) {
398 Klass* existing = secondaries->at(slot);
399 assert(((bitmap >> slot) & 1) == (existing != nullptr), "mismatch");
400 if (existing == nullptr) { // no conflict
401 secondaries->at_put(slot, klass);
402 bitmap |= uintx(1) << slot;
403 assert(bitmap != SECONDARY_SUPERS_BITMAP_FULL, "");
404 return;
405 } else {
406 // Use Robin Hood hashing to minimize the worst case search.
407 // Also, every permutation of the insertion sequence produces
408 // the same final Robin Hood hash table, provided that a
409 // consistent tie breaker is used.
410 int existing_dist = (slot - existing->hash_slot()) & SECONDARY_SUPERS_TABLE_MASK;
411 if (existing_dist < dist
412 // This tie breaker ensures that the hash order is maintained.
413 || ((existing_dist == dist)
414 && (uintptr_t(existing) < uintptr_t(klass)))) {
415 Klass* tmp = secondaries->at(slot);
416 secondaries->at_put(slot, klass);
417 klass = tmp;
418 dist = existing_dist;
419 }
420 ++dist;
421 }
422 }
423 }
424
425 Array<Klass*>* Klass::pack_secondary_supers(ClassLoaderData* loader_data,
426 GrowableArray<Klass*>* primaries,
427 GrowableArray<Klass*>* secondaries,
428 uintx& bitmap, TRAPS) {
429 int new_length = primaries->length() + secondaries->length();
430 Array<Klass*>* secondary_supers = MetadataFactory::new_array<Klass*>(loader_data, new_length, CHECK_NULL);
431
432 // Combine the two arrays into a metadata object to pack the array.
433 // The primaries are added in the reverse order, then the secondaries.
434 int fill_p = primaries->length();
435 for (int j = 0; j < fill_p; j++) {
436 secondary_supers->at_put(j, primaries->pop()); // add primaries in reverse order.
437 }
438 for( int j = 0; j < secondaries->length(); j++ ) {
439 secondary_supers->at_put(j+fill_p, secondaries->at(j)); // add secondaries on the end.
440 }
441 #ifdef ASSERT
442 // We must not copy any null placeholders left over from bootstrap.
443 for (int j = 0; j < secondary_supers->length(); j++) {
444 assert(secondary_supers->at(j) != nullptr, "correct bootstrapping order");
445 }
446 #endif
447
448 if (UseSecondarySupersTable) {
449 bitmap = hash_secondary_supers(secondary_supers, /*rewrite=*/true); // rewrites freshly allocated array
450 } else {
451 bitmap = SECONDARY_SUPERS_BITMAP_EMPTY;
452 }
453 return secondary_supers;
454 }
455
456 uintx Klass::compute_secondary_supers_bitmap(Array<Klass*>* secondary_supers) {
457 return hash_secondary_supers(secondary_supers, /*rewrite=*/false); // no rewrites allowed
458 }
459
460 uint8_t Klass::compute_home_slot(Klass* k, uintx bitmap) {
461 uint8_t hash = k->hash_slot();
462 if (hash > 0) {
463 return population_count(bitmap << (SECONDARY_SUPERS_TABLE_SIZE - hash));
464 }
465 return 0;
466 }
467
468
469 void Klass::initialize_supers(Klass* k, Array<InstanceKlass*>* transitive_interfaces, TRAPS) {
470 if (k == nullptr) {
471 set_super(nullptr);
472 _primary_supers[0] = this;
473 assert(super_depth() == 0, "Object must already be initialized properly");
474 } else if (k != super() || k == vmClasses::Object_klass()) {
475 assert(super() == nullptr || super() == vmClasses::Object_klass(),
476 "initialize this only once to a non-trivial value");
477 set_super(k);
478 Klass* sup = k;
479 int sup_depth = sup->super_depth();
480 juint my_depth = MIN2(sup_depth + 1, (int)primary_super_limit());
481 if (!can_be_primary_super_slow())
482 my_depth = primary_super_limit();
483 for (juint i = 0; i < my_depth; i++) {
484 _primary_supers[i] = sup->_primary_supers[i];
485 }
486 Klass* *super_check_cell;
487 if (my_depth < primary_super_limit()) {
488 _primary_supers[my_depth] = this;
489 super_check_cell = &_primary_supers[my_depth];
490 } else {
491 // Overflow of the primary_supers array forces me to be secondary.
492 super_check_cell = &_secondary_super_cache;
493 }
494 set_super_check_offset(u4((address)super_check_cell - (address) this));
495
496 #ifdef ASSERT
497 {
498 juint j = super_depth();
499 assert(j == my_depth, "computed accessor gets right answer");
500 Klass* t = this;
501 while (!t->can_be_primary_super()) {
502 t = t->super();
503 j = t->super_depth();
504 }
505 for (juint j1 = j+1; j1 < primary_super_limit(); j1++) {
506 assert(primary_super_of_depth(j1) == nullptr, "super list padding");
507 }
508 while (t != nullptr) {
509 assert(primary_super_of_depth(j) == t, "super list initialization");
510 t = t->super();
511 --j;
512 }
513 assert(j == (juint)-1, "correct depth count");
514 }
515 #endif
516 }
517
518 if (secondary_supers() == nullptr) {
519
520 // Now compute the list of secondary supertypes.
521 // Secondaries can occasionally be on the super chain,
522 // if the inline "_primary_supers" array overflows.
523 int extras = 0;
524 Klass* p;
525 for (p = super(); !(p == nullptr || p->can_be_primary_super()); p = p->super()) {
526 ++extras;
527 }
528
529 ResourceMark rm(THREAD); // need to reclaim GrowableArrays allocated below
530
531 // Compute the "real" non-extra secondaries.
532 GrowableArray<Klass*>* secondaries = compute_secondary_supers(extras, transitive_interfaces);
533 if (secondaries == nullptr) {
534 // secondary_supers set by compute_secondary_supers
535 return;
536 }
537
538 GrowableArray<Klass*>* primaries = new GrowableArray<Klass*>(extras);
539
540 for (p = super(); !(p == nullptr || p->can_be_primary_super()); p = p->super()) {
541 int i; // Scan for overflow primaries being duplicates of 2nd'arys
542
543 // This happens frequently for very deeply nested arrays: the
544 // primary superclass chain overflows into the secondary. The
545 // secondary list contains the element_klass's secondaries with
546 // an extra array dimension added. If the element_klass's
547 // secondary list already contains some primary overflows, they
548 // (with the extra level of array-ness) will collide with the
549 // normal primary superclass overflows.
550 for( i = 0; i < secondaries->length(); i++ ) {
551 if( secondaries->at(i) == p )
552 break;
553 }
554 if( i < secondaries->length() )
555 continue; // It's a dup, don't put it in
556 primaries->push(p);
557 }
558 // Combine the two arrays into a metadata object to pack the array.
559 uintx bitmap = 0;
560 Array<Klass*>* s2 = pack_secondary_supers(class_loader_data(), primaries, secondaries, bitmap, CHECK);
561 set_secondary_supers(s2, bitmap);
562 }
563 }
564
565 GrowableArray<Klass*>* Klass::compute_secondary_supers(int num_extra_slots,
566 Array<InstanceKlass*>* transitive_interfaces) {
567 assert(num_extra_slots == 0, "override for complex klasses");
568 assert(transitive_interfaces == nullptr, "sanity");
569 set_secondary_supers(Universe::the_empty_klass_array(), Universe::the_empty_klass_bitmap());
570 return nullptr;
571 }
572
573
574 // superklass links
575 InstanceKlass* Klass::superklass() const {
576 assert(super() == nullptr || super()->is_instance_klass(), "must be instance klass");
577 return _super == nullptr ? nullptr : InstanceKlass::cast(_super);
578 }
579
580 // subklass links. Used by the compiler (and vtable initialization)
581 // May be cleaned concurrently, so must use the Compile_lock.
582 // The log parameter is for clean_weak_klass_links to report unlinked classes.
583 Klass* Klass::subklass(bool log) const {
584 // Need load_acquire on the _subklass, because it races with inserts that
585 // publishes freshly initialized data.
586 for (Klass* chain = Atomic::load_acquire(&_subklass);
587 chain != nullptr;
588 // Do not need load_acquire on _next_sibling, because inserts never
589 // create _next_sibling edges to dead data.
590 chain = Atomic::load(&chain->_next_sibling))
591 {
592 if (chain->is_loader_alive()) {
593 return chain;
594 } else if (log) {
595 if (log_is_enabled(Trace, class, unload)) {
596 ResourceMark rm;
597 log_trace(class, unload)("unlinking class (subclass): %s", chain->external_name());
598 }
599 }
600 }
601 return nullptr;
602 }
603
604 Klass* Klass::next_sibling(bool log) const {
605 // Do not need load_acquire on _next_sibling, because inserts never
606 // create _next_sibling edges to dead data.
607 for (Klass* chain = Atomic::load(&_next_sibling);
608 chain != nullptr;
609 chain = Atomic::load(&chain->_next_sibling)) {
610 // Only return alive klass, there may be stale klass
611 // in this chain if cleaned concurrently.
612 if (chain->is_loader_alive()) {
613 return chain;
614 } else if (log) {
615 if (log_is_enabled(Trace, class, unload)) {
616 ResourceMark rm;
617 log_trace(class, unload)("unlinking class (sibling): %s", chain->external_name());
618 }
619 }
620 }
621 return nullptr;
622 }
623
624 void Klass::set_subklass(Klass* s) {
625 assert(s != this, "sanity check");
626 Atomic::release_store(&_subklass, s);
627 }
628
629 void Klass::set_next_sibling(Klass* s) {
630 assert(s != this, "sanity check");
631 // Does not need release semantics. If used by cleanup, it will link to
632 // already safely published data, and if used by inserts, will be published
633 // safely using cmpxchg.
634 Atomic::store(&_next_sibling, s);
635 }
636
637 void Klass::append_to_sibling_list() {
638 if (Universe::is_fully_initialized()) {
639 assert_locked_or_safepoint(Compile_lock);
640 }
641 debug_only(verify();)
642 // add ourselves to superklass' subklass list
643 InstanceKlass* super = superklass();
644 if (super == nullptr) return; // special case: class Object
645 assert((!super->is_interface() // interfaces cannot be supers
646 && (super->superklass() == nullptr || !is_interface())),
647 "an interface can only be a subklass of Object");
648
649 // Make sure there is no stale subklass head
650 super->clean_subklass();
651
652 for (;;) {
653 Klass* prev_first_subklass = Atomic::load_acquire(&_super->_subklass);
654 if (prev_first_subklass != nullptr) {
655 // set our sibling to be the superklass' previous first subklass
656 assert(prev_first_subklass->is_loader_alive(), "May not attach not alive klasses");
657 set_next_sibling(prev_first_subklass);
658 }
659 // Note that the prev_first_subklass is always alive, meaning no sibling_next links
660 // are ever created to not alive klasses. This is an important invariant of the lock-free
661 // cleaning protocol, that allows us to safely unlink dead klasses from the sibling list.
662 if (Atomic::cmpxchg(&super->_subklass, prev_first_subklass, this) == prev_first_subklass) {
663 return;
664 }
665 }
666 debug_only(verify();)
667 }
668
669 void Klass::clean_subklass() {
670 for (;;) {
671 // Need load_acquire, due to contending with concurrent inserts
672 Klass* subklass = Atomic::load_acquire(&_subklass);
673 if (subklass == nullptr || subklass->is_loader_alive()) {
674 return;
675 }
676 // Try to fix _subklass until it points at something not dead.
677 Atomic::cmpxchg(&_subklass, subklass, subklass->next_sibling());
678 }
679 }
680
681 void Klass::clean_weak_klass_links(bool unloading_occurred, bool clean_alive_klasses) {
682 if (!ClassUnloading || !unloading_occurred) {
683 return;
684 }
685
686 Klass* root = vmClasses::Object_klass();
687 Stack<Klass*, mtGC> stack;
688
689 stack.push(root);
690 while (!stack.is_empty()) {
691 Klass* current = stack.pop();
692
693 assert(current->is_loader_alive(), "just checking, this should be live");
694
695 // Find and set the first alive subklass
696 Klass* sub = current->subklass(true);
697 current->clean_subklass();
698 if (sub != nullptr) {
699 stack.push(sub);
700 }
701
702 // Find and set the first alive sibling
703 Klass* sibling = current->next_sibling(true);
704 current->set_next_sibling(sibling);
705 if (sibling != nullptr) {
706 stack.push(sibling);
707 }
708
709 // Clean the implementors list and method data.
710 if (clean_alive_klasses && current->is_instance_klass()) {
711 InstanceKlass* ik = InstanceKlass::cast(current);
712 ik->clean_weak_instanceklass_links();
713
714 // JVMTI RedefineClasses creates previous versions that are not in
715 // the class hierarchy, so process them here.
716 while ((ik = ik->previous_versions()) != nullptr) {
717 ik->clean_weak_instanceklass_links();
718 }
719 }
720 }
721 }
722
723 void Klass::metaspace_pointers_do(MetaspaceClosure* it) {
724 if (log_is_enabled(Trace, cds)) {
725 ResourceMark rm;
726 log_trace(cds)("Iter(Klass): %p (%s)", this, external_name());
727 }
728
729 it->push(&_name);
730 it->push(&_secondary_supers);
731 for (int i = 0; i < _primary_super_limit; i++) {
732 it->push(&_primary_supers[i]);
733 }
734 it->push(&_super);
735 if (!CDSConfig::is_dumping_archive()) {
736 // If dumping archive, these may point to excluded classes. There's no need
737 // to follow these pointers anyway, as they will be set to null in
738 // remove_unshareable_info().
739 it->push((Klass**)&_subklass);
740 it->push((Klass**)&_next_sibling);
741 it->push(&_next_link);
742 }
743
744 vtableEntry* vt = start_of_vtable();
745 for (int i=0; i<vtable_length(); i++) {
746 it->push(vt[i].method_addr());
747 }
748 }
749
750 #if INCLUDE_CDS
751 void Klass::remove_unshareable_info() {
752 assert(CDSConfig::is_dumping_archive(),
753 "only called during CDS dump time");
754 JFR_ONLY(REMOVE_ID(this);)
755 if (log_is_enabled(Trace, cds, unshareable)) {
756 ResourceMark rm;
757 log_trace(cds, unshareable)("remove: %s", external_name());
758 }
759
760 // _secondary_super_cache may be updated by an is_subtype_of() call
761 // while ArchiveBuilder is copying metaspace objects. Let's reset it to
762 // null and let it be repopulated at runtime.
763 set_secondary_super_cache(nullptr);
764
765 set_subklass(nullptr);
766 set_next_sibling(nullptr);
767 set_next_link(nullptr);
768
769 // Null out class_loader_data because we don't share that yet.
770 set_class_loader_data(nullptr);
771 set_is_shared();
772
773 // FIXME: validation in Klass::hash_secondary_supers() may fail for shared klasses.
774 // Even though the bitmaps always match, the canonical order of elements in the table
775 // is not guaranteed to stay the same (see tie breaker during Robin Hood hashing in Klass::hash_insert).
776 //assert(compute_secondary_supers_bitmap(secondary_supers()) == _bitmap, "broken table");
777 }
778
779 void Klass::remove_java_mirror() {
780 assert(CDSConfig::is_dumping_archive(), "sanity");
781 if (log_is_enabled(Trace, cds, unshareable)) {
782 ResourceMark rm;
783 log_trace(cds, unshareable)("remove java_mirror: %s", external_name());
784 }
785 // Just null out the mirror. The class_loader_data() no longer exists.
786 clear_java_mirror_handle();
787 }
788
789 void Klass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) {
790 assert(is_klass(), "ensure C++ vtable is restored");
791 assert(is_shared(), "must be set");
792 JFR_ONLY(RESTORE_ID(this);)
793 if (log_is_enabled(Trace, cds, unshareable)) {
794 ResourceMark rm(THREAD);
795 oop class_loader = loader_data->class_loader();
796 log_trace(cds, unshareable)("restore: %s with class loader: %s", external_name(),
797 class_loader != nullptr ? class_loader->klass()->external_name() : "boot");
798 }
799
800 // If an exception happened during CDS restore, some of these fields may already be
801 // set. We leave the class on the CLD list, even if incomplete so that we don't
802 // modify the CLD list outside a safepoint.
803 if (class_loader_data() == nullptr) {
804 set_class_loader_data(loader_data);
805
806 // Add to class loader list first before creating the mirror
807 // (same order as class file parsing)
808 loader_data->add_class(this);
809 }
810
811 Handle loader(THREAD, loader_data->class_loader());
812 ModuleEntry* module_entry = nullptr;
813 Klass* k = this;
814 if (k->is_objArray_klass()) {
815 k = ObjArrayKlass::cast(k)->bottom_klass();
816 }
817 // Obtain klass' module.
818 if (k->is_instance_klass()) {
819 InstanceKlass* ik = (InstanceKlass*) k;
820 module_entry = ik->module();
821 } else {
822 module_entry = ModuleEntryTable::javabase_moduleEntry();
823 }
824 // Obtain java.lang.Module, if available
825 Handle module_handle(THREAD, ((module_entry != nullptr) ? module_entry->module() : (oop)nullptr));
826
827 if (this->has_archived_mirror_index()) {
828 ResourceMark rm(THREAD);
829 log_debug(cds, mirror)("%s has raw archived mirror", external_name());
830 if (ArchiveHeapLoader::is_in_use()) {
831 bool present = java_lang_Class::restore_archived_mirror(this, loader, module_handle,
832 protection_domain,
833 CHECK);
834 if (present) {
835 return;
836 }
837 }
838
839 // No archived mirror data
840 log_debug(cds, mirror)("No archived mirror data for %s", external_name());
841 clear_java_mirror_handle();
842 this->clear_archived_mirror_index();
843 }
844
845 // Only recreate it if not present. A previous attempt to restore may have
846 // gotten an OOM later but keep the mirror if it was created.
847 if (java_mirror() == nullptr) {
848 ResourceMark rm(THREAD);
849 log_trace(cds, mirror)("Recreate mirror for %s", external_name());
850 java_lang_Class::create_mirror(this, loader, module_handle, protection_domain, Handle(), CHECK);
851 }
852 }
853 #endif // INCLUDE_CDS
854
855 #if INCLUDE_CDS_JAVA_HEAP
856 oop Klass::archived_java_mirror() {
857 assert(has_archived_mirror_index(), "must have archived mirror");
858 return HeapShared::get_root(_archived_mirror_index);
859 }
860
861 void Klass::clear_archived_mirror_index() {
862 if (_archived_mirror_index >= 0) {
863 HeapShared::clear_root(_archived_mirror_index);
864 }
865 _archived_mirror_index = -1;
866 }
867
868 // No GC barrier
869 void Klass::set_archived_java_mirror(int mirror_index) {
870 assert(CDSConfig::is_dumping_heap(), "sanity");
871 _archived_mirror_index = mirror_index;
872 }
873 #endif // INCLUDE_CDS_JAVA_HEAP
874
875 void Klass::check_array_allocation_length(int length, int max_length, TRAPS) {
876 if (length > max_length) {
877 if (!THREAD->is_in_internal_oome_mark()) {
878 report_java_out_of_memory("Requested array size exceeds VM limit");
879 JvmtiExport::post_array_size_exhausted();
880 THROW_OOP(Universe::out_of_memory_error_array_size());
881 } else {
882 THROW_OOP(Universe::out_of_memory_error_java_heap_without_backtrace());
883 }
884 } else if (length < 0) {
885 THROW_MSG(vmSymbols::java_lang_NegativeArraySizeException(), err_msg("%d", length));
886 }
887 }
888
889 // Replace the last '+' char with '/'.
890 static char* convert_hidden_name_to_java(Symbol* name) {
891 size_t name_len = name->utf8_length();
892 char* result = NEW_RESOURCE_ARRAY(char, name_len + 1);
893 name->as_klass_external_name(result, (int)name_len + 1);
894 for (int index = (int)name_len; index > 0; index--) {
895 if (result[index] == '+') {
896 result[index] = JVM_SIGNATURE_SLASH;
897 break;
898 }
899 }
900 return result;
901 }
902
903 // In product mode, this function doesn't have virtual function calls so
904 // there might be some performance advantage to handling InstanceKlass here.
905 const char* Klass::external_name() const {
906 if (is_instance_klass()) {
907 const InstanceKlass* ik = static_cast<const InstanceKlass*>(this);
908 if (ik->is_hidden()) {
909 char* result = convert_hidden_name_to_java(name());
910 return result;
911 }
912 } else if (is_objArray_klass() && ObjArrayKlass::cast(this)->bottom_klass()->is_hidden()) {
913 char* result = convert_hidden_name_to_java(name());
914 return result;
915 }
916 if (name() == nullptr) return "<unknown>";
917 return name()->as_klass_external_name();
918 }
919
920 const char* Klass::signature_name() const {
921 if (name() == nullptr) return "<unknown>";
922 if (is_objArray_klass() && ObjArrayKlass::cast(this)->bottom_klass()->is_hidden()) {
923 size_t name_len = name()->utf8_length();
924 char* result = NEW_RESOURCE_ARRAY(char, name_len + 1);
925 name()->as_C_string(result, (int)name_len + 1);
926 for (int index = (int)name_len; index > 0; index--) {
927 if (result[index] == '+') {
928 result[index] = JVM_SIGNATURE_DOT;
929 break;
930 }
931 }
932 return result;
933 }
934 return name()->as_C_string();
935 }
936
937 const char* Klass::external_kind() const {
938 if (is_interface()) return "interface";
939 if (is_abstract()) return "abstract class";
940 return "class";
941 }
942
943 // Unless overridden, jvmti_class_status has no flags set.
944 jint Klass::jvmti_class_status() const {
945 return 0;
946 }
947
948
949 // Printing
950
951 void Klass::print_on(outputStream* st) const {
952 ResourceMark rm;
953 // print title
954 st->print("%s", internal_name());
955 print_address_on(st);
956 st->cr();
957 }
958
959 #define BULLET " - "
960
961 // Caller needs ResourceMark
962 void Klass::oop_print_on(oop obj, outputStream* st) {
963 // print title
964 st->print_cr("%s ", internal_name());
965 obj->print_address_on(st);
966
967 if (WizardMode) {
968 // print header
969 obj->mark().print_on(st);
970 st->cr();
971 st->print(BULLET"prototype_header: " INTPTR_FORMAT, _prototype_header.value());
972 st->cr();
973 }
974
975 // print class
976 st->print(BULLET"klass: ");
977 obj->klass()->print_value_on(st);
978 st->cr();
979 }
980
981 void Klass::oop_print_value_on(oop obj, outputStream* st) {
982 // print title
983 ResourceMark rm; // Cannot print in debug mode without this
984 st->print("%s", internal_name());
985 obj->print_address_on(st);
986 }
987
988 // Verification
989
990 void Klass::verify_on(outputStream* st) {
991
992 // This can be expensive, but it is worth checking that this klass is actually
993 // in the CLD graph but not in production.
994 assert(Metaspace::contains((address)this), "Should be");
995
996 guarantee(this->is_klass(),"should be klass");
997
998 if (super() != nullptr) {
999 guarantee(super()->is_klass(), "should be klass");
1000 }
1001 if (secondary_super_cache() != nullptr) {
1002 Klass* ko = secondary_super_cache();
1003 guarantee(ko->is_klass(), "should be klass");
1004 }
1005 for ( uint i = 0; i < primary_super_limit(); i++ ) {
1006 Klass* ko = _primary_supers[i];
1007 if (ko != nullptr) {
1008 guarantee(ko->is_klass(), "should be klass");
1009 }
1010 }
1011
1012 if (java_mirror_no_keepalive() != nullptr) {
1013 guarantee(java_lang_Class::is_instance(java_mirror_no_keepalive()), "should be instance");
1014 }
1015 }
1016
1017 void Klass::oop_verify_on(oop obj, outputStream* st) {
1018 guarantee(oopDesc::is_oop(obj), "should be oop");
1019 guarantee(obj->klass()->is_klass(), "klass field is not a klass");
1020 }
1021
1022 bool Klass::is_valid(Klass* k) {
1023 if (!is_aligned(k, sizeof(MetaWord))) return false;
1024 if ((size_t)k < os::min_page_size()) return false;
1025
1026 if (!os::is_readable_range(k, k + 1)) return false;
1027 if (!Metaspace::contains(k)) return false;
1028
1029 if (!Symbol::is_valid(k->name())) return false;
1030 return ClassLoaderDataGraph::is_valid(k->class_loader_data());
1031 }
1032
1033 Method* Klass::method_at_vtable(int index) {
1034 #ifndef PRODUCT
1035 assert(index >= 0, "valid vtable index");
1036 if (DebugVtables) {
1037 verify_vtable_index(index);
1038 }
1039 #endif
1040 return start_of_vtable()[index].method();
1041 }
1042
1043
1044 #ifndef PRODUCT
1045
1046 bool Klass::verify_vtable_index(int i) {
1047 int limit = vtable_length()/vtableEntry::size();
1048 assert(i >= 0 && i < limit, "index %d out of bounds %d", i, limit);
1049 return true;
1050 }
1051
1052 #endif // PRODUCT
1053
1054 // Caller needs ResourceMark
1055 // joint_in_module_of_loader provides an optimization if 2 classes are in
1056 // the same module to succinctly print out relevant information about their
1057 // module name and class loader's name_and_id for error messages.
1058 // Format:
1059 // <fully-qualified-external-class-name1> and <fully-qualified-external-class-name2>
1060 // are in module <module-name>[@<version>]
1061 // of loader <loader-name_and_id>[, parent loader <parent-loader-name_and_id>]
1062 const char* Klass::joint_in_module_of_loader(const Klass* class2, bool include_parent_loader) const {
1063 assert(module() == class2->module(), "classes do not have the same module");
1064 const char* class1_name = external_name();
1065 size_t len = strlen(class1_name) + 1;
1066
1067 const char* class2_description = class2->class_in_module_of_loader(true, include_parent_loader);
1068 len += strlen(class2_description);
1069
1070 len += strlen(" and ");
1071
1072 char* joint_description = NEW_RESOURCE_ARRAY_RETURN_NULL(char, len);
1073
1074 // Just return the FQN if error when allocating string
1075 if (joint_description == nullptr) {
1076 return class1_name;
1077 }
1078
1079 jio_snprintf(joint_description, len, "%s and %s",
1080 class1_name,
1081 class2_description);
1082
1083 return joint_description;
1084 }
1085
1086 // Caller needs ResourceMark
1087 // class_in_module_of_loader provides a standard way to include
1088 // relevant information about a class, such as its module name as
1089 // well as its class loader's name_and_id, in error messages and logging.
1090 // Format:
1091 // <fully-qualified-external-class-name> is in module <module-name>[@<version>]
1092 // of loader <loader-name_and_id>[, parent loader <parent-loader-name_and_id>]
1093 const char* Klass::class_in_module_of_loader(bool use_are, bool include_parent_loader) const {
1094 // 1. fully qualified external name of class
1095 const char* klass_name = external_name();
1096 size_t len = strlen(klass_name) + 1;
1097
1098 // 2. module name + @version
1099 const char* module_name = "";
1100 const char* version = "";
1101 bool has_version = false;
1102 bool module_is_named = false;
1103 const char* module_name_phrase = "";
1104 const Klass* bottom_klass = is_objArray_klass() ?
1105 ObjArrayKlass::cast(this)->bottom_klass() : this;
1106 if (bottom_klass->is_instance_klass()) {
1107 ModuleEntry* module = InstanceKlass::cast(bottom_klass)->module();
1108 if (module->is_named()) {
1109 module_is_named = true;
1110 module_name_phrase = "module ";
1111 module_name = module->name()->as_C_string();
1112 len += strlen(module_name);
1113 // Use version if exists and is not a jdk module
1114 if (module->should_show_version()) {
1115 has_version = true;
1116 version = module->version()->as_C_string();
1117 // Include stlen(version) + 1 for the "@"
1118 len += strlen(version) + 1;
1119 }
1120 } else {
1121 module_name = UNNAMED_MODULE;
1122 len += UNNAMED_MODULE_LEN;
1123 }
1124 } else {
1125 // klass is an array of primitives, module is java.base
1126 module_is_named = true;
1127 module_name_phrase = "module ";
1128 module_name = JAVA_BASE_NAME;
1129 len += JAVA_BASE_NAME_LEN;
1130 }
1131
1132 // 3. class loader's name_and_id
1133 ClassLoaderData* cld = class_loader_data();
1134 assert(cld != nullptr, "class_loader_data should not be null");
1135 const char* loader_name_and_id = cld->loader_name_and_id();
1136 len += strlen(loader_name_and_id);
1137
1138 // 4. include parent loader information
1139 const char* parent_loader_phrase = "";
1140 const char* parent_loader_name_and_id = "";
1141 if (include_parent_loader &&
1142 !cld->is_builtin_class_loader_data()) {
1143 oop parent_loader = java_lang_ClassLoader::parent(class_loader());
1144 ClassLoaderData *parent_cld = ClassLoaderData::class_loader_data_or_null(parent_loader);
1145 // The parent loader's ClassLoaderData could be null if it is
1146 // a delegating class loader that has never defined a class.
1147 // In this case the loader's name must be obtained via the parent loader's oop.
1148 if (parent_cld == nullptr) {
1149 oop cl_name_and_id = java_lang_ClassLoader::nameAndId(parent_loader);
1150 if (cl_name_and_id != nullptr) {
1151 parent_loader_name_and_id = java_lang_String::as_utf8_string(cl_name_and_id);
1152 }
1153 } else {
1154 parent_loader_name_and_id = parent_cld->loader_name_and_id();
1155 }
1156 parent_loader_phrase = ", parent loader ";
1157 len += strlen(parent_loader_phrase) + strlen(parent_loader_name_and_id);
1158 }
1159
1160 // Start to construct final full class description string
1161 len += ((use_are) ? strlen(" are in ") : strlen(" is in "));
1162 len += strlen(module_name_phrase) + strlen(" of loader ");
1163
1164 char* class_description = NEW_RESOURCE_ARRAY_RETURN_NULL(char, len);
1165
1166 // Just return the FQN if error when allocating string
1167 if (class_description == nullptr) {
1168 return klass_name;
1169 }
1170
1171 jio_snprintf(class_description, len, "%s %s in %s%s%s%s of loader %s%s%s",
1172 klass_name,
1173 (use_are) ? "are" : "is",
1174 module_name_phrase,
1175 module_name,
1176 (has_version) ? "@" : "",
1177 (has_version) ? version : "",
1178 loader_name_and_id,
1179 parent_loader_phrase,
1180 parent_loader_name_and_id);
1181
1182 return class_description;
1183 }
1184
1185 class LookupStats : StackObj {
1186 private:
1187 uint _no_of_samples;
1188 uint _worst;
1189 uint _worst_count;
1190 uint _average;
1191 uint _best;
1192 uint _best_count;
1193 public:
1194 LookupStats() : _no_of_samples(0), _worst(0), _worst_count(0), _average(0), _best(INT_MAX), _best_count(0) {}
1195
1196 ~LookupStats() {
1197 assert(_best <= _worst || _no_of_samples == 0, "sanity");
1198 }
1199
1200 void sample(uint value) {
1201 ++_no_of_samples;
1202 _average += value;
1203
1204 if (_worst < value) {
1205 _worst = value;
1206 _worst_count = 1;
1207 } else if (_worst == value) {
1208 ++_worst_count;
1209 }
1210
1211 if (_best > value) {
1212 _best = value;
1213 _best_count = 1;
1214 } else if (_best == value) {
1215 ++_best_count;
1216 }
1217 }
1218
1219 void print_on(outputStream* st) const {
1220 st->print("best: %2d (%4.1f%%)", _best, (100.0 * _best_count) / _no_of_samples);
1221 if (_best_count < _no_of_samples) {
1222 st->print("; average: %4.1f; worst: %2d (%4.1f%%)",
1223 (1.0 * _average) / _no_of_samples,
1224 _worst, (100.0 * _worst_count) / _no_of_samples);
1225 }
1226 }
1227 };
1228
1229 static void print_positive_lookup_stats(Array<Klass*>* secondary_supers, uintx bitmap, outputStream* st) {
1230 int num_of_supers = secondary_supers->length();
1231
1232 LookupStats s;
1233 for (int i = 0; i < num_of_supers; i++) {
1234 Klass* secondary_super = secondary_supers->at(i);
1235 int home_slot = Klass::compute_home_slot(secondary_super, bitmap);
1236 uint score = 1 + ((i - home_slot) & Klass::SECONDARY_SUPERS_TABLE_MASK);
1237 s.sample(score);
1238 }
1239 st->print("positive_lookup: "); s.print_on(st);
1240 }
1241
1242 static uint compute_distance_to_nearest_zero(int slot, uintx bitmap) {
1243 assert(~bitmap != 0, "no zeroes");
1244 uintx start = rotate_right(bitmap, slot);
1245 return count_trailing_zeros(~start);
1246 }
1247
1248 static void print_negative_lookup_stats(uintx bitmap, outputStream* st) {
1249 LookupStats s;
1250 for (int slot = 0; slot < Klass::SECONDARY_SUPERS_TABLE_SIZE; slot++) {
1251 uint score = compute_distance_to_nearest_zero(slot, bitmap);
1252 s.sample(score);
1253 }
1254 st->print("negative_lookup: "); s.print_on(st);
1255 }
1256
1257 void Klass::print_secondary_supers_on(outputStream* st) const {
1258 if (secondary_supers() != nullptr) {
1259 if (UseSecondarySupersTable) {
1260 st->print(" - "); st->print("%d elements;", _secondary_supers->length());
1261 st->print_cr(" bitmap: " UINTX_FORMAT_X_0 ";", _bitmap);
1262 if (_bitmap != SECONDARY_SUPERS_BITMAP_EMPTY &&
1263 _bitmap != SECONDARY_SUPERS_BITMAP_FULL) {
1264 st->print(" - "); print_positive_lookup_stats(secondary_supers(), _bitmap, st); st->cr();
1265 st->print(" - "); print_negative_lookup_stats(_bitmap, st); st->cr();
1266 }
1267 }
1268 } else {
1269 st->print("null");
1270 }
1271 }
1272
1273 void Klass::on_secondary_supers_verification_failure(Klass* super, Klass* sub, bool linear_result, bool table_result, const char* msg) {
1274 ResourceMark rm;
1275 super->print();
1276 sub->print();
1277 fatal("%s: %s implements %s: is_subtype_of: %d; linear_search: %d; table_lookup: %d",
1278 msg, sub->external_name(), super->external_name(),
1279 sub->is_subtype_of(super), linear_result, table_result);
1280 }