1 /* 2 * Copyright (c) 1997, 2023, 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/heapShared.hpp" 28 #include "classfile/classLoaderData.inline.hpp" 29 #include "classfile/classLoaderDataGraph.inline.hpp" 30 #include "classfile/javaClasses.inline.hpp" 31 #include "classfile/moduleEntry.hpp" 32 #include "classfile/systemDictionary.hpp" 33 #include "classfile/systemDictionaryShared.hpp" 34 #include "classfile/vmClasses.hpp" 35 #include "classfile/vmSymbols.hpp" 36 #include "gc/shared/collectedHeap.inline.hpp" 37 #include "jvm_io.h" 38 #include "logging/log.hpp" 39 #include "memory/metadataFactory.hpp" 40 #include "memory/metaspaceClosure.hpp" 41 #include "memory/oopFactory.hpp" 42 #include "memory/resourceArea.hpp" 43 #include "memory/universe.hpp" 44 #include "oops/compressedOops.inline.hpp" 45 #include "oops/instanceKlass.hpp" 46 #include "oops/klass.inline.hpp" 47 #include "oops/objArrayKlass.hpp" 48 #include "oops/oop.inline.hpp" 49 #include "oops/oopHandle.inline.hpp" 50 #include "prims/jvmtiExport.hpp" 51 #include "runtime/arguments.hpp" 52 #include "runtime/atomic.hpp" 53 #include "runtime/handles.inline.hpp" 54 #include "utilities/macros.hpp" 55 #include "utilities/powerOfTwo.hpp" 56 #include "utilities/stack.inline.hpp" 57 58 void Klass::set_java_mirror(Handle m) { 59 assert(!m.is_null(), "New mirror should never be null."); 60 assert(_java_mirror.is_empty(), "should only be used to initialize mirror"); 61 _java_mirror = class_loader_data()->add_handle(m); 62 } 63 64 oop Klass::java_mirror_no_keepalive() const { 65 return _java_mirror.peek(); 66 } 67 68 bool Klass::is_cloneable() const { 69 return _access_flags.is_cloneable_fast() || 70 is_subtype_of(vmClasses::Cloneable_klass()); 71 } 72 73 void Klass::set_is_cloneable() { 74 if (name() == vmSymbols::java_lang_invoke_MemberName()) { 75 assert(is_final(), "no subclasses allowed"); 76 // MemberName cloning should not be intrinsified and always happen in JVM_Clone. 77 } else if (is_instance_klass() && InstanceKlass::cast(this)->reference_type() != REF_NONE) { 78 // Reference cloning should not be intrinsified and always happen in JVM_Clone. 79 } else { 80 _access_flags.set_is_cloneable_fast(); 81 } 82 } 83 84 void Klass::set_name(Symbol* n) { 85 _name = n; 86 if (_name != nullptr) _name->increment_refcount(); 87 88 if (Arguments::is_dumping_archive() && is_instance_klass()) { 89 SystemDictionaryShared::init_dumptime_info(InstanceKlass::cast(this)); 90 } 91 } 92 93 bool Klass::is_subclass_of(const Klass* k) const { 94 // Run up the super chain and check 95 if (this == k) return true; 96 97 Klass* t = const_cast<Klass*>(this)->super(); 98 99 while (t != nullptr) { 100 if (t == k) return true; 101 t = t->super(); 102 } 103 return false; 104 } 105 106 void Klass::release_C_heap_structures(bool release_constant_pool) { 107 if (_name != nullptr) _name->decrement_refcount(); 108 } 109 110 bool Klass::search_secondary_supers(Klass* k) const { 111 // Put some extra logic here out-of-line, before the search proper. 112 // This cuts down the size of the inline method. 113 114 // This is necessary, since I am never in my own secondary_super list. 115 if (this == k) 116 return true; 117 // Scan the array-of-objects for a match 118 int cnt = secondary_supers()->length(); 119 for (int i = 0; i < cnt; i++) { 120 if (secondary_supers()->at(i) == k) { 121 ((Klass*)this)->set_secondary_super_cache(k); 122 return true; 123 } 124 } 125 return false; 126 } 127 128 // Return self, except for abstract classes with exactly 1 129 // implementor. Then return the 1 concrete implementation. 130 Klass *Klass::up_cast_abstract() { 131 Klass *r = this; 132 while( r->is_abstract() ) { // Receiver is abstract? 133 Klass *s = r->subklass(); // Check for exactly 1 subklass 134 if (s == nullptr || s->next_sibling() != nullptr) // Oops; wrong count; give up 135 return this; // Return 'this' as a no-progress flag 136 r = s; // Loop till find concrete class 137 } 138 return r; // Return the 1 concrete class 139 } 140 141 // Find LCA in class hierarchy 142 Klass *Klass::LCA( Klass *k2 ) { 143 Klass *k1 = this; 144 while( 1 ) { 145 if( k1->is_subtype_of(k2) ) return k2; 146 if( k2->is_subtype_of(k1) ) return k1; 147 k1 = k1->super(); 148 k2 = k2->super(); 149 } 150 } 151 152 153 void Klass::check_valid_for_instantiation(bool throwError, TRAPS) { 154 ResourceMark rm(THREAD); 155 THROW_MSG(throwError ? vmSymbols::java_lang_InstantiationError() 156 : vmSymbols::java_lang_InstantiationException(), external_name()); 157 } 158 159 160 void Klass::copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS) { 161 ResourceMark rm(THREAD); 162 assert(s != nullptr, "Throw NPE!"); 163 THROW_MSG(vmSymbols::java_lang_ArrayStoreException(), 164 err_msg("arraycopy: source type %s is not an array", s->klass()->external_name())); 165 } 166 167 168 void Klass::initialize(TRAPS) { 169 ShouldNotReachHere(); 170 } 171 172 Klass* Klass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const { 173 #ifdef ASSERT 174 tty->print_cr("Error: find_field called on a klass oop." 175 " Likely error: reflection method does not correctly" 176 " wrap return value in a mirror object."); 177 #endif 178 ShouldNotReachHere(); 179 return nullptr; 180 } 181 182 Method* Klass::uncached_lookup_method(const Symbol* name, const Symbol* signature, 183 OverpassLookupMode overpass_mode, 184 PrivateLookupMode private_mode) const { 185 #ifdef ASSERT 186 tty->print_cr("Error: uncached_lookup_method called on a klass oop." 187 " Likely error: reflection method does not correctly" 188 " wrap return value in a mirror object."); 189 #endif 190 ShouldNotReachHere(); 191 return nullptr; 192 } 193 194 void* Klass::operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, TRAPS) throw() { 195 return Metaspace::allocate(loader_data, word_size, MetaspaceObj::ClassType, THREAD); 196 } 197 198 // "Normal" instantiation is preceded by a MetaspaceObj allocation 199 // which zeros out memory - calloc equivalent. 200 // The constructor is also used from CppVtableCloner, 201 // which doesn't zero out the memory before calling the constructor. 202 Klass::Klass(KlassKind kind) : _kind(kind), 203 _prototype_header(markWord::prototype()), 204 _shared_class_path_index(-1) { 205 CDS_ONLY(_shared_class_flags = 0;) 206 CDS_JAVA_HEAP_ONLY(_archived_mirror_index = -1;) 207 _primary_supers[0] = this; 208 set_super_check_offset(in_bytes(primary_supers_offset())); 209 } 210 211 jint Klass::array_layout_helper(BasicType etype) { 212 assert(etype >= T_BOOLEAN && etype <= T_OBJECT, "valid etype"); 213 // Note that T_ARRAY is not allowed here. 214 int hsize = arrayOopDesc::base_offset_in_bytes(etype); 215 int esize = type2aelembytes(etype); 216 bool isobj = (etype == T_OBJECT); 217 int tag = isobj ? _lh_array_tag_obj_value : _lh_array_tag_type_value; 218 int lh = array_layout_helper(tag, false, hsize, etype, exact_log2(esize)); 219 220 assert(lh < (int)_lh_neutral_value, "must look like an array layout"); 221 assert(layout_helper_is_array(lh), "correct kind"); 222 assert(layout_helper_is_objArray(lh) == isobj, "correct kind"); 223 assert(layout_helper_is_typeArray(lh) == !isobj, "correct kind"); 224 assert(layout_helper_header_size(lh) == hsize, "correct decode"); 225 assert(layout_helper_element_type(lh) == etype, "correct decode"); 226 assert(1 << layout_helper_log2_element_size(lh) == esize, "correct decode"); 227 228 return lh; 229 } 230 231 bool Klass::can_be_primary_super_slow() const { 232 if (super() == nullptr) 233 return true; 234 else if (super()->super_depth() >= primary_super_limit()-1) 235 return false; 236 else 237 return true; 238 } 239 240 void Klass::initialize_supers(Klass* k, Array<InstanceKlass*>* transitive_interfaces, TRAPS) { 241 if (k == nullptr) { 242 set_super(nullptr); 243 _primary_supers[0] = this; 244 assert(super_depth() == 0, "Object must already be initialized properly"); 245 } else if (k != super() || k == vmClasses::Object_klass()) { 246 assert(super() == nullptr || super() == vmClasses::Object_klass(), 247 "initialize this only once to a non-trivial value"); 248 set_super(k); 249 Klass* sup = k; 250 int sup_depth = sup->super_depth(); 251 juint my_depth = MIN2(sup_depth + 1, (int)primary_super_limit()); 252 if (!can_be_primary_super_slow()) 253 my_depth = primary_super_limit(); 254 for (juint i = 0; i < my_depth; i++) { 255 _primary_supers[i] = sup->_primary_supers[i]; 256 } 257 Klass* *super_check_cell; 258 if (my_depth < primary_super_limit()) { 259 _primary_supers[my_depth] = this; 260 super_check_cell = &_primary_supers[my_depth]; 261 } else { 262 // Overflow of the primary_supers array forces me to be secondary. 263 super_check_cell = &_secondary_super_cache; 264 } 265 set_super_check_offset(u4((address)super_check_cell - (address) this)); 266 267 #ifdef ASSERT 268 { 269 juint j = super_depth(); 270 assert(j == my_depth, "computed accessor gets right answer"); 271 Klass* t = this; 272 while (!t->can_be_primary_super()) { 273 t = t->super(); 274 j = t->super_depth(); 275 } 276 for (juint j1 = j+1; j1 < primary_super_limit(); j1++) { 277 assert(primary_super_of_depth(j1) == nullptr, "super list padding"); 278 } 279 while (t != nullptr) { 280 assert(primary_super_of_depth(j) == t, "super list initialization"); 281 t = t->super(); 282 --j; 283 } 284 assert(j == (juint)-1, "correct depth count"); 285 } 286 #endif 287 } 288 289 if (secondary_supers() == nullptr) { 290 291 // Now compute the list of secondary supertypes. 292 // Secondaries can occasionally be on the super chain, 293 // if the inline "_primary_supers" array overflows. 294 int extras = 0; 295 Klass* p; 296 for (p = super(); !(p == nullptr || p->can_be_primary_super()); p = p->super()) { 297 ++extras; 298 } 299 300 ResourceMark rm(THREAD); // need to reclaim GrowableArrays allocated below 301 302 // Compute the "real" non-extra secondaries. 303 GrowableArray<Klass*>* secondaries = compute_secondary_supers(extras, transitive_interfaces); 304 if (secondaries == nullptr) { 305 // secondary_supers set by compute_secondary_supers 306 return; 307 } 308 309 GrowableArray<Klass*>* primaries = new GrowableArray<Klass*>(extras); 310 311 for (p = super(); !(p == nullptr || p->can_be_primary_super()); p = p->super()) { 312 int i; // Scan for overflow primaries being duplicates of 2nd'arys 313 314 // This happens frequently for very deeply nested arrays: the 315 // primary superclass chain overflows into the secondary. The 316 // secondary list contains the element_klass's secondaries with 317 // an extra array dimension added. If the element_klass's 318 // secondary list already contains some primary overflows, they 319 // (with the extra level of array-ness) will collide with the 320 // normal primary superclass overflows. 321 for( i = 0; i < secondaries->length(); i++ ) { 322 if( secondaries->at(i) == p ) 323 break; 324 } 325 if( i < secondaries->length() ) 326 continue; // It's a dup, don't put it in 327 primaries->push(p); 328 } 329 // Combine the two arrays into a metadata object to pack the array. 330 // The primaries are added in the reverse order, then the secondaries. 331 int new_length = primaries->length() + secondaries->length(); 332 Array<Klass*>* s2 = MetadataFactory::new_array<Klass*>( 333 class_loader_data(), new_length, CHECK); 334 int fill_p = primaries->length(); 335 for (int j = 0; j < fill_p; j++) { 336 s2->at_put(j, primaries->pop()); // add primaries in reverse order. 337 } 338 for( int j = 0; j < secondaries->length(); j++ ) { 339 s2->at_put(j+fill_p, secondaries->at(j)); // add secondaries on the end. 340 } 341 342 #ifdef ASSERT 343 // We must not copy any null placeholders left over from bootstrap. 344 for (int j = 0; j < s2->length(); j++) { 345 assert(s2->at(j) != nullptr, "correct bootstrapping order"); 346 } 347 #endif 348 349 set_secondary_supers(s2); 350 } 351 } 352 353 GrowableArray<Klass*>* Klass::compute_secondary_supers(int num_extra_slots, 354 Array<InstanceKlass*>* transitive_interfaces) { 355 assert(num_extra_slots == 0, "override for complex klasses"); 356 assert(transitive_interfaces == nullptr, "sanity"); 357 set_secondary_supers(Universe::the_empty_klass_array()); 358 return nullptr; 359 } 360 361 362 // superklass links 363 InstanceKlass* Klass::superklass() const { 364 assert(super() == nullptr || super()->is_instance_klass(), "must be instance klass"); 365 return _super == nullptr ? nullptr : InstanceKlass::cast(_super); 366 } 367 368 // subklass links. Used by the compiler (and vtable initialization) 369 // May be cleaned concurrently, so must use the Compile_lock. 370 // The log parameter is for clean_weak_klass_links to report unlinked classes. 371 Klass* Klass::subklass(bool log) const { 372 // Need load_acquire on the _subklass, because it races with inserts that 373 // publishes freshly initialized data. 374 for (Klass* chain = Atomic::load_acquire(&_subklass); 375 chain != nullptr; 376 // Do not need load_acquire on _next_sibling, because inserts never 377 // create _next_sibling edges to dead data. 378 chain = Atomic::load(&chain->_next_sibling)) 379 { 380 if (chain->is_loader_alive()) { 381 return chain; 382 } else if (log) { 383 if (log_is_enabled(Trace, class, unload)) { 384 ResourceMark rm; 385 log_trace(class, unload)("unlinking class (subclass): %s", chain->external_name()); 386 } 387 } 388 } 389 return nullptr; 390 } 391 392 Klass* Klass::next_sibling(bool log) const { 393 // Do not need load_acquire on _next_sibling, because inserts never 394 // create _next_sibling edges to dead data. 395 for (Klass* chain = Atomic::load(&_next_sibling); 396 chain != nullptr; 397 chain = Atomic::load(&chain->_next_sibling)) { 398 // Only return alive klass, there may be stale klass 399 // in this chain if cleaned concurrently. 400 if (chain->is_loader_alive()) { 401 return chain; 402 } else if (log) { 403 if (log_is_enabled(Trace, class, unload)) { 404 ResourceMark rm; 405 log_trace(class, unload)("unlinking class (sibling): %s", chain->external_name()); 406 } 407 } 408 } 409 return nullptr; 410 } 411 412 void Klass::set_subklass(Klass* s) { 413 assert(s != this, "sanity check"); 414 Atomic::release_store(&_subklass, s); 415 } 416 417 void Klass::set_next_sibling(Klass* s) { 418 assert(s != this, "sanity check"); 419 // Does not need release semantics. If used by cleanup, it will link to 420 // already safely published data, and if used by inserts, will be published 421 // safely using cmpxchg. 422 Atomic::store(&_next_sibling, s); 423 } 424 425 void Klass::append_to_sibling_list() { 426 if (Universe::is_fully_initialized()) { 427 assert_locked_or_safepoint(Compile_lock); 428 } 429 debug_only(verify();) 430 // add ourselves to superklass' subklass list 431 InstanceKlass* super = superklass(); 432 if (super == nullptr) return; // special case: class Object 433 assert((!super->is_interface() // interfaces cannot be supers 434 && (super->superklass() == nullptr || !is_interface())), 435 "an interface can only be a subklass of Object"); 436 437 // Make sure there is no stale subklass head 438 super->clean_subklass(); 439 440 for (;;) { 441 Klass* prev_first_subklass = Atomic::load_acquire(&_super->_subklass); 442 if (prev_first_subklass != nullptr) { 443 // set our sibling to be the superklass' previous first subklass 444 assert(prev_first_subklass->is_loader_alive(), "May not attach not alive klasses"); 445 set_next_sibling(prev_first_subklass); 446 } 447 // Note that the prev_first_subklass is always alive, meaning no sibling_next links 448 // are ever created to not alive klasses. This is an important invariant of the lock-free 449 // cleaning protocol, that allows us to safely unlink dead klasses from the sibling list. 450 if (Atomic::cmpxchg(&super->_subklass, prev_first_subklass, this) == prev_first_subklass) { 451 return; 452 } 453 } 454 debug_only(verify();) 455 } 456 457 void Klass::clean_subklass() { 458 for (;;) { 459 // Need load_acquire, due to contending with concurrent inserts 460 Klass* subklass = Atomic::load_acquire(&_subklass); 461 if (subklass == nullptr || subklass->is_loader_alive()) { 462 return; 463 } 464 // Try to fix _subklass until it points at something not dead. 465 Atomic::cmpxchg(&_subklass, subklass, subklass->next_sibling()); 466 } 467 } 468 469 void Klass::clean_weak_klass_links(bool unloading_occurred, bool clean_alive_klasses) { 470 if (!ClassUnloading || !unloading_occurred) { 471 return; 472 } 473 474 Klass* root = vmClasses::Object_klass(); 475 Stack<Klass*, mtGC> stack; 476 477 stack.push(root); 478 while (!stack.is_empty()) { 479 Klass* current = stack.pop(); 480 481 assert(current->is_loader_alive(), "just checking, this should be live"); 482 483 // Find and set the first alive subklass 484 Klass* sub = current->subklass(true); 485 current->clean_subklass(); 486 if (sub != nullptr) { 487 stack.push(sub); 488 } 489 490 // Find and set the first alive sibling 491 Klass* sibling = current->next_sibling(true); 492 current->set_next_sibling(sibling); 493 if (sibling != nullptr) { 494 stack.push(sibling); 495 } 496 497 // Clean the implementors list and method data. 498 if (clean_alive_klasses && current->is_instance_klass()) { 499 InstanceKlass* ik = InstanceKlass::cast(current); 500 ik->clean_weak_instanceklass_links(); 501 502 // JVMTI RedefineClasses creates previous versions that are not in 503 // the class hierarchy, so process them here. 504 while ((ik = ik->previous_versions()) != nullptr) { 505 ik->clean_weak_instanceklass_links(); 506 } 507 } 508 } 509 } 510 511 void Klass::metaspace_pointers_do(MetaspaceClosure* it) { 512 if (log_is_enabled(Trace, cds)) { 513 ResourceMark rm; 514 log_trace(cds)("Iter(Klass): %p (%s)", this, external_name()); 515 } 516 517 it->push(&_name); 518 it->push(&_secondary_super_cache); 519 it->push(&_secondary_supers); 520 for (int i = 0; i < _primary_super_limit; i++) { 521 it->push(&_primary_supers[i]); 522 } 523 it->push(&_super); 524 if (!Arguments::is_dumping_archive()) { 525 // If dumping archive, these may point to excluded classes. There's no need 526 // to follow these pointers anyway, as they will be set to null in 527 // remove_unshareable_info(). 528 it->push((Klass**)&_subklass); 529 it->push((Klass**)&_next_sibling); 530 it->push(&_next_link); 531 } 532 533 vtableEntry* vt = start_of_vtable(); 534 for (int i=0; i<vtable_length(); i++) { 535 it->push(vt[i].method_addr()); 536 } 537 } 538 539 #if INCLUDE_CDS 540 void Klass::remove_unshareable_info() { 541 assert (Arguments::is_dumping_archive(), 542 "only called during CDS dump time"); 543 JFR_ONLY(REMOVE_ID(this);) 544 if (log_is_enabled(Trace, cds, unshareable)) { 545 ResourceMark rm; 546 log_trace(cds, unshareable)("remove: %s", external_name()); 547 } 548 549 set_subklass(nullptr); 550 set_next_sibling(nullptr); 551 set_next_link(nullptr); 552 553 // Null out class_loader_data because we don't share that yet. 554 set_class_loader_data(nullptr); 555 set_is_shared(); 556 } 557 558 void Klass::remove_java_mirror() { 559 Arguments::assert_is_dumping_archive(); 560 if (log_is_enabled(Trace, cds, unshareable)) { 561 ResourceMark rm; 562 log_trace(cds, unshareable)("remove java_mirror: %s", external_name()); 563 } 564 // Just null out the mirror. The class_loader_data() no longer exists. 565 clear_java_mirror_handle(); 566 } 567 568 void Klass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) { 569 assert(is_klass(), "ensure C++ vtable is restored"); 570 assert(is_shared(), "must be set"); 571 JFR_ONLY(RESTORE_ID(this);) 572 if (log_is_enabled(Trace, cds, unshareable)) { 573 ResourceMark rm(THREAD); 574 oop class_loader = loader_data->class_loader(); 575 log_trace(cds, unshareable)("restore: %s with class loader: %s", external_name(), 576 class_loader != nullptr ? class_loader->klass()->external_name() : "boot"); 577 } 578 579 // If an exception happened during CDS restore, some of these fields may already be 580 // set. We leave the class on the CLD list, even if incomplete so that we don't 581 // modify the CLD list outside a safepoint. 582 if (class_loader_data() == nullptr) { 583 set_class_loader_data(loader_data); 584 585 // Add to class loader list first before creating the mirror 586 // (same order as class file parsing) 587 loader_data->add_class(this); 588 } 589 590 Handle loader(THREAD, loader_data->class_loader()); 591 ModuleEntry* module_entry = nullptr; 592 Klass* k = this; 593 if (k->is_objArray_klass()) { 594 k = ObjArrayKlass::cast(k)->bottom_klass(); 595 } 596 // Obtain klass' module. 597 if (k->is_instance_klass()) { 598 InstanceKlass* ik = (InstanceKlass*) k; 599 module_entry = ik->module(); 600 } else { 601 module_entry = ModuleEntryTable::javabase_moduleEntry(); 602 } 603 // Obtain java.lang.Module, if available 604 Handle module_handle(THREAD, ((module_entry != nullptr) ? module_entry->module() : (oop)nullptr)); 605 606 if (this->has_archived_mirror_index()) { 607 ResourceMark rm(THREAD); 608 log_debug(cds, mirror)("%s has raw archived mirror", external_name()); 609 if (ArchiveHeapLoader::is_in_use()) { 610 bool present = java_lang_Class::restore_archived_mirror(this, loader, module_handle, 611 protection_domain, 612 CHECK); 613 if (present) { 614 return; 615 } 616 } 617 618 // No archived mirror data 619 log_debug(cds, mirror)("No archived mirror data for %s", external_name()); 620 clear_java_mirror_handle(); 621 this->clear_archived_mirror_index(); 622 } 623 624 // Only recreate it if not present. A previous attempt to restore may have 625 // gotten an OOM later but keep the mirror if it was created. 626 if (java_mirror() == nullptr) { 627 ResourceMark rm(THREAD); 628 log_trace(cds, mirror)("Recreate mirror for %s", external_name()); 629 java_lang_Class::create_mirror(this, loader, module_handle, protection_domain, Handle(), CHECK); 630 } 631 } 632 #endif // INCLUDE_CDS 633 634 #if INCLUDE_CDS_JAVA_HEAP 635 oop Klass::archived_java_mirror() { 636 assert(has_archived_mirror_index(), "must have archived mirror"); 637 return HeapShared::get_root(_archived_mirror_index); 638 } 639 640 void Klass::clear_archived_mirror_index() { 641 if (_archived_mirror_index >= 0) { 642 HeapShared::clear_root(_archived_mirror_index); 643 } 644 _archived_mirror_index = -1; 645 } 646 647 // No GC barrier 648 void Klass::set_archived_java_mirror(int mirror_index) { 649 assert(DumpSharedSpaces, "called only during dumptime"); 650 _archived_mirror_index = mirror_index; 651 } 652 #endif // INCLUDE_CDS_JAVA_HEAP 653 654 void Klass::check_array_allocation_length(int length, int max_length, TRAPS) { 655 if (length > max_length) { 656 if (!THREAD->in_retryable_allocation()) { 657 report_java_out_of_memory("Requested array size exceeds VM limit"); 658 JvmtiExport::post_array_size_exhausted(); 659 THROW_OOP(Universe::out_of_memory_error_array_size()); 660 } else { 661 THROW_OOP(Universe::out_of_memory_error_retry()); 662 } 663 } else if (length < 0) { 664 THROW_MSG(vmSymbols::java_lang_NegativeArraySizeException(), err_msg("%d", length)); 665 } 666 } 667 668 // Replace the last '+' char with '/'. 669 static char* convert_hidden_name_to_java(Symbol* name) { 670 size_t name_len = name->utf8_length(); 671 char* result = NEW_RESOURCE_ARRAY(char, name_len + 1); 672 name->as_klass_external_name(result, (int)name_len + 1); 673 for (int index = (int)name_len; index > 0; index--) { 674 if (result[index] == '+') { 675 result[index] = JVM_SIGNATURE_SLASH; 676 break; 677 } 678 } 679 return result; 680 } 681 682 // In product mode, this function doesn't have virtual function calls so 683 // there might be some performance advantage to handling InstanceKlass here. 684 const char* Klass::external_name() const { 685 if (is_instance_klass()) { 686 const InstanceKlass* ik = static_cast<const InstanceKlass*>(this); 687 if (ik->is_hidden()) { 688 char* result = convert_hidden_name_to_java(name()); 689 return result; 690 } 691 } else if (is_objArray_klass() && ObjArrayKlass::cast(this)->bottom_klass()->is_hidden()) { 692 char* result = convert_hidden_name_to_java(name()); 693 return result; 694 } 695 if (name() == nullptr) return "<unknown>"; 696 return name()->as_klass_external_name(); 697 } 698 699 const char* Klass::signature_name() const { 700 if (name() == nullptr) return "<unknown>"; 701 if (is_objArray_klass() && ObjArrayKlass::cast(this)->bottom_klass()->is_hidden()) { 702 size_t name_len = name()->utf8_length(); 703 char* result = NEW_RESOURCE_ARRAY(char, name_len + 1); 704 name()->as_C_string(result, (int)name_len + 1); 705 for (int index = (int)name_len; index > 0; index--) { 706 if (result[index] == '+') { 707 result[index] = JVM_SIGNATURE_DOT; 708 break; 709 } 710 } 711 return result; 712 } 713 return name()->as_C_string(); 714 } 715 716 const char* Klass::external_kind() const { 717 if (is_interface()) return "interface"; 718 if (is_abstract()) return "abstract class"; 719 return "class"; 720 } 721 722 // Unless overridden, jvmti_class_status has no flags set. 723 jint Klass::jvmti_class_status() const { 724 return 0; 725 } 726 727 728 // Printing 729 730 void Klass::print_on(outputStream* st) const { 731 ResourceMark rm; 732 // print title 733 st->print("%s", internal_name()); 734 print_address_on(st); 735 st->cr(); 736 } 737 738 #define BULLET " - " 739 740 // Caller needs ResourceMark 741 void Klass::oop_print_on(oop obj, outputStream* st) { 742 // print title 743 st->print_cr("%s ", internal_name()); 744 obj->print_address_on(st); 745 746 if (WizardMode) { 747 // print header 748 obj->mark().print_on(st); 749 st->cr(); 750 st->print(BULLET"prototype_header: " INTPTR_FORMAT, _prototype_header.value()); 751 st->cr(); 752 } 753 754 // print class 755 st->print(BULLET"klass: "); 756 obj->klass()->print_value_on(st); 757 st->cr(); 758 } 759 760 void Klass::oop_print_value_on(oop obj, outputStream* st) { 761 // print title 762 ResourceMark rm; // Cannot print in debug mode without this 763 st->print("%s", internal_name()); 764 obj->print_address_on(st); 765 } 766 767 // Verification 768 769 void Klass::verify_on(outputStream* st) { 770 771 // This can be expensive, but it is worth checking that this klass is actually 772 // in the CLD graph but not in production. 773 assert(Metaspace::contains((address)this), "Should be"); 774 775 guarantee(this->is_klass(),"should be klass"); 776 777 if (super() != nullptr) { 778 guarantee(super()->is_klass(), "should be klass"); 779 } 780 if (secondary_super_cache() != nullptr) { 781 Klass* ko = secondary_super_cache(); 782 guarantee(ko->is_klass(), "should be klass"); 783 } 784 for ( uint i = 0; i < primary_super_limit(); i++ ) { 785 Klass* ko = _primary_supers[i]; 786 if (ko != nullptr) { 787 guarantee(ko->is_klass(), "should be klass"); 788 } 789 } 790 791 if (java_mirror_no_keepalive() != nullptr) { 792 guarantee(java_lang_Class::is_instance(java_mirror_no_keepalive()), "should be instance"); 793 } 794 } 795 796 void Klass::oop_verify_on(oop obj, outputStream* st) { 797 guarantee(oopDesc::is_oop(obj), "should be oop"); 798 guarantee(obj->klass()->is_klass(), "klass field is not a klass"); 799 } 800 801 bool Klass::is_valid(Klass* k) { 802 if (!is_aligned(k, sizeof(MetaWord))) return false; 803 if ((size_t)k < os::min_page_size()) return false; 804 805 if (!os::is_readable_range(k, k + 1)) return false; 806 if (!Metaspace::contains(k)) return false; 807 808 if (!Symbol::is_valid(k->name())) return false; 809 return ClassLoaderDataGraph::is_valid(k->class_loader_data()); 810 } 811 812 Method* Klass::method_at_vtable(int index) { 813 #ifndef PRODUCT 814 assert(index >= 0, "valid vtable index"); 815 if (DebugVtables) { 816 verify_vtable_index(index); 817 } 818 #endif 819 return start_of_vtable()[index].method(); 820 } 821 822 823 #ifndef PRODUCT 824 825 bool Klass::verify_vtable_index(int i) { 826 int limit = vtable_length()/vtableEntry::size(); 827 assert(i >= 0 && i < limit, "index %d out of bounds %d", i, limit); 828 return true; 829 } 830 831 #endif // PRODUCT 832 833 // Caller needs ResourceMark 834 // joint_in_module_of_loader provides an optimization if 2 classes are in 835 // the same module to succinctly print out relevant information about their 836 // module name and class loader's name_and_id for error messages. 837 // Format: 838 // <fully-qualified-external-class-name1> and <fully-qualified-external-class-name2> 839 // are in module <module-name>[@<version>] 840 // of loader <loader-name_and_id>[, parent loader <parent-loader-name_and_id>] 841 const char* Klass::joint_in_module_of_loader(const Klass* class2, bool include_parent_loader) const { 842 assert(module() == class2->module(), "classes do not have the same module"); 843 const char* class1_name = external_name(); 844 size_t len = strlen(class1_name) + 1; 845 846 const char* class2_description = class2->class_in_module_of_loader(true, include_parent_loader); 847 len += strlen(class2_description); 848 849 len += strlen(" and "); 850 851 char* joint_description = NEW_RESOURCE_ARRAY_RETURN_NULL(char, len); 852 853 // Just return the FQN if error when allocating string 854 if (joint_description == nullptr) { 855 return class1_name; 856 } 857 858 jio_snprintf(joint_description, len, "%s and %s", 859 class1_name, 860 class2_description); 861 862 return joint_description; 863 } 864 865 // Caller needs ResourceMark 866 // class_in_module_of_loader provides a standard way to include 867 // relevant information about a class, such as its module name as 868 // well as its class loader's name_and_id, in error messages and logging. 869 // Format: 870 // <fully-qualified-external-class-name> is in module <module-name>[@<version>] 871 // of loader <loader-name_and_id>[, parent loader <parent-loader-name_and_id>] 872 const char* Klass::class_in_module_of_loader(bool use_are, bool include_parent_loader) const { 873 // 1. fully qualified external name of class 874 const char* klass_name = external_name(); 875 size_t len = strlen(klass_name) + 1; 876 877 // 2. module name + @version 878 const char* module_name = ""; 879 const char* version = ""; 880 bool has_version = false; 881 bool module_is_named = false; 882 const char* module_name_phrase = ""; 883 const Klass* bottom_klass = is_objArray_klass() ? 884 ObjArrayKlass::cast(this)->bottom_klass() : this; 885 if (bottom_klass->is_instance_klass()) { 886 ModuleEntry* module = InstanceKlass::cast(bottom_klass)->module(); 887 if (module->is_named()) { 888 module_is_named = true; 889 module_name_phrase = "module "; 890 module_name = module->name()->as_C_string(); 891 len += strlen(module_name); 892 // Use version if exists and is not a jdk module 893 if (module->should_show_version()) { 894 has_version = true; 895 version = module->version()->as_C_string(); 896 // Include stlen(version) + 1 for the "@" 897 len += strlen(version) + 1; 898 } 899 } else { 900 module_name = UNNAMED_MODULE; 901 len += UNNAMED_MODULE_LEN; 902 } 903 } else { 904 // klass is an array of primitives, module is java.base 905 module_is_named = true; 906 module_name_phrase = "module "; 907 module_name = JAVA_BASE_NAME; 908 len += JAVA_BASE_NAME_LEN; 909 } 910 911 // 3. class loader's name_and_id 912 ClassLoaderData* cld = class_loader_data(); 913 assert(cld != nullptr, "class_loader_data should not be null"); 914 const char* loader_name_and_id = cld->loader_name_and_id(); 915 len += strlen(loader_name_and_id); 916 917 // 4. include parent loader information 918 const char* parent_loader_phrase = ""; 919 const char* parent_loader_name_and_id = ""; 920 if (include_parent_loader && 921 !cld->is_builtin_class_loader_data()) { 922 oop parent_loader = java_lang_ClassLoader::parent(class_loader()); 923 ClassLoaderData *parent_cld = ClassLoaderData::class_loader_data_or_null(parent_loader); 924 // The parent loader's ClassLoaderData could be null if it is 925 // a delegating class loader that has never defined a class. 926 // In this case the loader's name must be obtained via the parent loader's oop. 927 if (parent_cld == nullptr) { 928 oop cl_name_and_id = java_lang_ClassLoader::nameAndId(parent_loader); 929 if (cl_name_and_id != nullptr) { 930 parent_loader_name_and_id = java_lang_String::as_utf8_string(cl_name_and_id); 931 } 932 } else { 933 parent_loader_name_and_id = parent_cld->loader_name_and_id(); 934 } 935 parent_loader_phrase = ", parent loader "; 936 len += strlen(parent_loader_phrase) + strlen(parent_loader_name_and_id); 937 } 938 939 // Start to construct final full class description string 940 len += ((use_are) ? strlen(" are in ") : strlen(" is in ")); 941 len += strlen(module_name_phrase) + strlen(" of loader "); 942 943 char* class_description = NEW_RESOURCE_ARRAY_RETURN_NULL(char, len); 944 945 // Just return the FQN if error when allocating string 946 if (class_description == nullptr) { 947 return klass_name; 948 } 949 950 jio_snprintf(class_description, len, "%s %s in %s%s%s%s of loader %s%s%s", 951 klass_name, 952 (use_are) ? "are" : "is", 953 module_name_phrase, 954 module_name, 955 (has_version) ? "@" : "", 956 (has_version) ? version : "", 957 loader_name_and_id, 958 parent_loader_phrase, 959 parent_loader_name_and_id); 960 961 return class_description; 962 }