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 }