1 /*
   2  * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "classfile/classLoaderData.inline.hpp"
  27 #include "classfile/classLoaderDataGraph.inline.hpp"
  28 #include "classfile/dictionary.hpp"
  29 #include "classfile/javaClasses.hpp"
  30 #include "classfile/systemDictionary.hpp"
  31 #include "classfile/vmSymbols.hpp"
  32 #include "gc/shared/collectedHeap.inline.hpp"
  33 #include "logging/log.hpp"
  34 #include "memory/heapInspection.hpp"
  35 #include "memory/heapShared.hpp"
  36 #include "memory/metadataFactory.hpp"
  37 #include "memory/metaspaceClosure.hpp"
  38 #include "memory/metaspaceShared.hpp"
  39 #include "memory/oopFactory.hpp"
  40 #include "memory/resourceArea.hpp"
  41 #include "oops/compressedOops.inline.hpp"
  42 #include "oops/instanceKlass.hpp"
  43 #include "oops/klass.inline.hpp"
  44 #include "oops/oop.inline.hpp"
  45 #include "oops/oopHandle.inline.hpp"
  46 #include "runtime/atomic.hpp"
  47 #include "runtime/handles.inline.hpp"
  48 #include "runtime/orderAccess.hpp"
  49 #include "utilities/macros.hpp"
  50 #include "utilities/stack.inline.hpp"
  51 
  52 void Klass::set_java_mirror(Handle m) {
  53   assert(!m.is_null(), "New mirror should never be null.");
  54   assert(_java_mirror.resolve() == NULL, "should only be used to initialize mirror");
  55   _java_mirror = class_loader_data()->add_handle(m);
  56 }
  57 
  58 oop Klass::java_mirror() const {
  59   return _java_mirror.resolve();
  60 }
  61 
  62 bool Klass::is_cloneable() const {
  63   return _access_flags.is_cloneable_fast() ||
  64          is_subtype_of(SystemDictionary::Cloneable_klass());
  65 }
  66 
  67 void Klass::set_is_cloneable() {
  68   if (name() == vmSymbols::java_lang_invoke_MemberName()) {
  69     assert(is_final(), "no subclasses allowed");
  70     // MemberName cloning should not be intrinsified and always happen in JVM_Clone.
  71   } else if (is_instance_klass() && InstanceKlass::cast(this)->reference_type() != REF_NONE) {
  72     // Reference cloning should not be intrinsified and always happen in JVM_Clone.
  73   } else {
  74     _access_flags.set_is_cloneable_fast();
  75   }
  76 }
  77 
  78 void Klass::set_name(Symbol* n) {
  79   _name = n;
  80   if (_name != NULL) _name->increment_refcount();
  81 }
  82 
  83 bool Klass::is_subclass_of(const Klass* k) const {
  84   // Run up the super chain and check
  85   if (this == k) return true;
  86 
  87   Klass* t = const_cast<Klass*>(this)->super();
  88 
  89   while (t != NULL) {
  90     if (t == k) return true;
  91     t = t->super();
  92   }
  93   return false;
  94 }
  95 
  96 bool Klass::search_secondary_supers(Klass* k) const {
  97   // Put some extra logic here out-of-line, before the search proper.
  98   // This cuts down the size of the inline method.
  99 
 100   // This is necessary, since I am never in my own secondary_super list.
 101   if (this == k)
 102     return true;
 103   // Scan the array-of-objects for a match
 104   int cnt = secondary_supers()->length();
 105   for (int i = 0; i < cnt; i++) {
 106     if (secondary_supers()->at(i) == k) {
 107       ((Klass*)this)->set_secondary_super_cache(k);
 108       return true;
 109     }
 110   }
 111   return false;
 112 }
 113 
 114 // Return self, except for abstract classes with exactly 1
 115 // implementor.  Then return the 1 concrete implementation.
 116 Klass *Klass::up_cast_abstract() {
 117   Klass *r = this;
 118   while( r->is_abstract() ) {   // Receiver is abstract?
 119     Klass *s = r->subklass();   // Check for exactly 1 subklass
 120     if( !s || s->next_sibling() ) // Oops; wrong count; give up
 121       return this;              // Return 'this' as a no-progress flag
 122     r = s;                    // Loop till find concrete class
 123   }
 124   return r;                   // Return the 1 concrete class
 125 }
 126 
 127 // Find LCA in class hierarchy
 128 Klass *Klass::LCA( Klass *k2 ) {
 129   Klass *k1 = this;
 130   while( 1 ) {
 131     if( k1->is_subtype_of(k2) ) return k2;
 132     if( k2->is_subtype_of(k1) ) return k1;
 133     k1 = k1->super();
 134     k2 = k2->super();
 135   }
 136 }
 137 
 138 
 139 void Klass::check_valid_for_instantiation(bool throwError, TRAPS) {
 140   ResourceMark rm(THREAD);
 141   THROW_MSG(throwError ? vmSymbols::java_lang_InstantiationError()
 142             : vmSymbols::java_lang_InstantiationException(), external_name());
 143 }
 144 
 145 
 146 void Klass::copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS) {
 147   ResourceMark rm(THREAD);
 148   assert(s != NULL, "Throw NPE!");
 149   THROW_MSG(vmSymbols::java_lang_ArrayStoreException(),
 150             err_msg("arraycopy: source type %s is not an array", s->klass()->external_name()));
 151 }
 152 
 153 
 154 void Klass::initialize(TRAPS) {
 155   ShouldNotReachHere();
 156 }
 157 
 158 bool Klass::compute_is_subtype_of(Klass* k) {
 159   assert(k->is_klass(), "argument must be a class");
 160   return is_subclass_of(k);
 161 }
 162 
 163 Klass* Klass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
 164 #ifdef ASSERT
 165   tty->print_cr("Error: find_field called on a klass oop."
 166                 " Likely error: reflection method does not correctly"
 167                 " wrap return value in a mirror object.");
 168 #endif
 169   ShouldNotReachHere();
 170   return NULL;
 171 }
 172 
 173 Method* Klass::uncached_lookup_method(const Symbol* name, const Symbol* signature,
 174                                       OverpassLookupMode overpass_mode,
 175                                       PrivateLookupMode private_mode) const {
 176 #ifdef ASSERT
 177   tty->print_cr("Error: uncached_lookup_method called on a klass oop."
 178                 " Likely error: reflection method does not correctly"
 179                 " wrap return value in a mirror object.");
 180 #endif
 181   ShouldNotReachHere();
 182   return NULL;
 183 }
 184 
 185 void* Klass::operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, TRAPS) throw() {
 186   return Metaspace::allocate(loader_data, word_size, MetaspaceObj::ClassType, THREAD);
 187 }
 188 
 189 // "Normal" instantiation is preceeded by a MetaspaceObj allocation
 190 // which zeros out memory - calloc equivalent.
 191 // The constructor is also used from CppVtableCloner,
 192 // which doesn't zero out the memory before calling the constructor.
 193 // Need to set the _java_mirror field explicitly to not hit an assert that the field
 194 // should be NULL before setting it.
 195 Klass::Klass(KlassID id) : _id(id),
 196                            _java_mirror(NULL),
 197                            _prototype_header(markOopDesc::prototype()),
 198                            _shared_class_path_index(-1) {
 199   CDS_ONLY(_shared_class_flags = 0;)
 200   CDS_JAVA_HEAP_ONLY(_archived_mirror = 0;)
 201   _primary_supers[0] = this;
 202   set_super_check_offset(in_bytes(primary_supers_offset()));
 203 }
 204 
 205 jint Klass::array_layout_helper(BasicType etype) {
 206   assert(etype >= T_BOOLEAN && etype <= T_OBJECT, "valid etype");
 207   // Note that T_ARRAY is not allowed here.
 208   int  hsize = arrayOopDesc::base_offset_in_bytes(etype);
 209   int  esize = type2aelembytes(etype);
 210   bool isobj = (etype == T_OBJECT);
 211   int  tag   =  isobj ? _lh_array_tag_obj_value : _lh_array_tag_type_value;
 212   int lh = array_layout_helper(tag, hsize, etype, exact_log2(esize));
 213 
 214   assert(lh < (int)_lh_neutral_value, "must look like an array layout");
 215   assert(layout_helper_is_array(lh), "correct kind");
 216   assert(layout_helper_is_objArray(lh) == isobj, "correct kind");
 217   assert(layout_helper_is_typeArray(lh) == !isobj, "correct kind");
 218   assert(layout_helper_header_size(lh) == hsize, "correct decode");
 219   assert(layout_helper_element_type(lh) == etype, "correct decode");
 220   assert(1 << layout_helper_log2_element_size(lh) == esize, "correct decode");
 221 
 222   return lh;
 223 }
 224 
 225 bool Klass::can_be_primary_super_slow() const {
 226   if (super() == NULL)
 227     return true;
 228   else if (super()->super_depth() >= primary_super_limit()-1)
 229     return false;
 230   else
 231     return true;
 232 }
 233 
 234 void Klass::initialize_supers(Klass* k, Array<InstanceKlass*>* transitive_interfaces, TRAPS) {
 235   if (FastSuperclassLimit == 0) {
 236     // None of the other machinery matters.
 237     set_super(k);
 238     return;
 239   }
 240   if (k == NULL) {
 241     set_super(NULL);
 242     _primary_supers[0] = this;
 243     assert(super_depth() == 0, "Object must already be initialized properly");
 244   } else if (k != super() || k == SystemDictionary::Object_klass()) {
 245     assert(super() == NULL || super() == SystemDictionary::Object_klass(),
 246            "initialize this only once to a non-trivial value");
 247     set_super(k);
 248     Klass* sup = k;
 249     int sup_depth = sup->super_depth();
 250     juint my_depth  = MIN2(sup_depth + 1, (int)primary_super_limit());
 251     if (!can_be_primary_super_slow())
 252       my_depth = primary_super_limit();
 253     for (juint i = 0; i < my_depth; i++) {
 254       _primary_supers[i] = sup->_primary_supers[i];
 255     }
 256     Klass* *super_check_cell;
 257     if (my_depth < primary_super_limit()) {
 258       _primary_supers[my_depth] = this;
 259       super_check_cell = &_primary_supers[my_depth];
 260     } else {
 261       // Overflow of the primary_supers array forces me to be secondary.
 262       super_check_cell = &_secondary_super_cache;
 263     }
 264     set_super_check_offset((address)super_check_cell - (address) this);
 265 
 266 #ifdef ASSERT
 267     {
 268       juint j = super_depth();
 269       assert(j == my_depth, "computed accessor gets right answer");
 270       Klass* t = this;
 271       while (!t->can_be_primary_super()) {
 272         t = t->super();
 273         j = t->super_depth();
 274       }
 275       for (juint j1 = j+1; j1 < primary_super_limit(); j1++) {
 276         assert(primary_super_of_depth(j1) == NULL, "super list padding");
 277       }
 278       while (t != NULL) {
 279         assert(primary_super_of_depth(j) == t, "super list initialization");
 280         t = t->super();
 281         --j;
 282       }
 283       assert(j == (juint)-1, "correct depth count");
 284     }
 285 #endif
 286   }
 287 
 288   if (secondary_supers() == NULL) {
 289 
 290     // Now compute the list of secondary supertypes.
 291     // Secondaries can occasionally be on the super chain,
 292     // if the inline "_primary_supers" array overflows.
 293     int extras = 0;
 294     Klass* p;
 295     for (p = super(); !(p == NULL || p->can_be_primary_super()); p = p->super()) {
 296       ++extras;
 297     }
 298 
 299     ResourceMark rm(THREAD);  // need to reclaim GrowableArrays allocated below
 300 
 301     // Compute the "real" non-extra secondaries.
 302     GrowableArray<Klass*>* secondaries = compute_secondary_supers(extras, transitive_interfaces);
 303     if (secondaries == NULL) {
 304       // secondary_supers set by compute_secondary_supers
 305       return;
 306     }
 307 
 308     GrowableArray<Klass*>* primaries = new GrowableArray<Klass*>(extras);
 309 
 310     for (p = super(); !(p == NULL || p->can_be_primary_super()); p = p->super()) {
 311       int i;                    // Scan for overflow primaries being duplicates of 2nd'arys
 312 
 313       // This happens frequently for very deeply nested arrays: the
 314       // primary superclass chain overflows into the secondary.  The
 315       // secondary list contains the element_klass's secondaries with
 316       // an extra array dimension added.  If the element_klass's
 317       // secondary list already contains some primary overflows, they
 318       // (with the extra level of array-ness) will collide with the
 319       // normal primary superclass overflows.
 320       for( i = 0; i < secondaries->length(); i++ ) {
 321         if( secondaries->at(i) == p )
 322           break;
 323       }
 324       if( i < secondaries->length() )
 325         continue;               // It's a dup, don't put it in
 326       primaries->push(p);
 327     }
 328     // Combine the two arrays into a metadata object to pack the array.
 329     // The primaries are added in the reverse order, then the secondaries.
 330     int new_length = primaries->length() + secondaries->length();
 331     Array<Klass*>* s2 = MetadataFactory::new_array<Klass*>(
 332                                        class_loader_data(), new_length, CHECK);
 333     int fill_p = primaries->length();
 334     for (int j = 0; j < fill_p; j++) {
 335       s2->at_put(j, primaries->pop());  // add primaries in reverse order.
 336     }
 337     for( int j = 0; j < secondaries->length(); j++ ) {
 338       s2->at_put(j+fill_p, secondaries->at(j));  // add secondaries on the end.
 339     }
 340 
 341   #ifdef ASSERT
 342       // We must not copy any NULL placeholders left over from bootstrap.
 343     for (int j = 0; j < s2->length(); j++) {
 344       assert(s2->at(j) != NULL, "correct bootstrapping order");
 345     }
 346   #endif
 347 
 348     set_secondary_supers(s2);
 349   }
 350 }
 351 
 352 GrowableArray<Klass*>* Klass::compute_secondary_supers(int num_extra_slots,
 353                                                        Array<InstanceKlass*>* transitive_interfaces) {
 354   assert(num_extra_slots == 0, "override for complex klasses");
 355   assert(transitive_interfaces == NULL, "sanity");
 356   set_secondary_supers(Universe::the_empty_klass_array());
 357   return NULL;
 358 }
 359 
 360 
 361 InstanceKlass* Klass::superklass() const {
 362   assert(super() == NULL || super()->is_instance_klass(), "must be instance klass");
 363   return _super == NULL ? NULL : InstanceKlass::cast(_super);
 364 }
 365 
 366 void Klass::set_subklass(Klass* s) {
 367   assert(s != this, "sanity check");
 368   _subklass = s;
 369 }
 370 
 371 void Klass::set_next_sibling(Klass* s) {
 372   assert(s != this, "sanity check");
 373   _next_sibling = s;
 374 }
 375 
 376 void Klass::append_to_sibling_list() {
 377   debug_only(verify();)
 378   // add ourselves to superklass' subklass list
 379   InstanceKlass* super = superklass();
 380   if (super == NULL) return;        // special case: class Object
 381   assert((!super->is_interface()    // interfaces cannot be supers
 382           && (super->superklass() == NULL || !is_interface())),
 383          "an interface can only be a subklass of Object");
 384   Klass* prev_first_subklass = super->subklass();
 385   if (prev_first_subklass != NULL) {
 386     // set our sibling to be the superklass' previous first subklass
 387     set_next_sibling(prev_first_subklass);
 388   }
 389   // make ourselves the superklass' first subklass
 390   super->set_subklass(this);
 391   debug_only(verify();)
 392 }
 393 
 394 oop Klass::holder_phantom() const {
 395   return class_loader_data()->holder_phantom();
 396 }
 397 
 398 void Klass::clean_weak_klass_links(bool unloading_occurred, bool clean_alive_klasses) {
 399   if (!ClassUnloading || !unloading_occurred) {
 400     return;
 401   }
 402 
 403   Klass* root = SystemDictionary::Object_klass();
 404   Stack<Klass*, mtGC> stack;
 405 
 406   stack.push(root);
 407   while (!stack.is_empty()) {
 408     Klass* current = stack.pop();
 409 
 410     assert(current->is_loader_alive(), "just checking, this should be live");
 411 
 412     // Find and set the first alive subklass
 413     Klass* sub = current->subklass();
 414     while (sub != NULL && !sub->is_loader_alive()) {
 415 #ifndef PRODUCT
 416       if (log_is_enabled(Trace, class, unload)) {
 417         ResourceMark rm;
 418         log_trace(class, unload)("unlinking class (subclass): %s", sub->external_name());
 419       }
 420 #endif
 421       sub = sub->next_sibling();
 422     }
 423     current->set_subklass(sub);
 424     if (sub != NULL) {
 425       stack.push(sub);
 426     }
 427 
 428     // Find and set the first alive sibling
 429     Klass* sibling = current->next_sibling();
 430     while (sibling != NULL && !sibling->is_loader_alive()) {
 431       if (log_is_enabled(Trace, class, unload)) {
 432         ResourceMark rm;
 433         log_trace(class, unload)("[Unlinking class (sibling) %s]", sibling->external_name());
 434       }
 435       sibling = sibling->next_sibling();
 436     }
 437     current->set_next_sibling(sibling);
 438     if (sibling != NULL) {
 439       stack.push(sibling);
 440     }
 441 
 442     // Clean the implementors list and method data.
 443     if (clean_alive_klasses && current->is_instance_klass()) {
 444       InstanceKlass* ik = InstanceKlass::cast(current);
 445       ik->clean_weak_instanceklass_links();
 446 
 447       // JVMTI RedefineClasses creates previous versions that are not in
 448       // the class hierarchy, so process them here.
 449       while ((ik = ik->previous_versions()) != NULL) {
 450         ik->clean_weak_instanceklass_links();
 451       }
 452     }
 453   }
 454 }
 455 
 456 void Klass::metaspace_pointers_do(MetaspaceClosure* it) {
 457   if (log_is_enabled(Trace, cds)) {
 458     ResourceMark rm;
 459     log_trace(cds)("Iter(Klass): %p (%s)", this, external_name());
 460   }
 461 
 462   it->push(&_name);
 463   it->push(&_secondary_super_cache);
 464   it->push(&_secondary_supers);
 465   for (int i = 0; i < _primary_super_limit; i++) {
 466     it->push(&_primary_supers[i]);
 467   }
 468   it->push(&_super);
 469   it->push(&_subklass);
 470   it->push(&_next_sibling);
 471   it->push(&_next_link);
 472 
 473   vtableEntry* vt = start_of_vtable();
 474   for (int i=0; i<vtable_length(); i++) {
 475     it->push(vt[i].method_addr());
 476   }
 477 }
 478 
 479 void Klass::remove_unshareable_info() {
 480   assert (DumpSharedSpaces, "only called for DumpSharedSpaces");
 481   JFR_ONLY(REMOVE_ID(this);)
 482   if (log_is_enabled(Trace, cds, unshareable)) {
 483     ResourceMark rm;
 484     log_trace(cds, unshareable)("remove: %s", external_name());
 485   }
 486 
 487   set_subklass(NULL);
 488   set_next_sibling(NULL);
 489   set_next_link(NULL);
 490 
 491   // Null out class_loader_data because we don't share that yet.
 492   set_class_loader_data(NULL);
 493   set_is_shared();
 494 }
 495 
 496 void Klass::remove_java_mirror() {
 497   assert (DumpSharedSpaces, "only called for DumpSharedSpaces");
 498   if (log_is_enabled(Trace, cds, unshareable)) {
 499     ResourceMark rm;
 500     log_trace(cds, unshareable)("remove java_mirror: %s", external_name());
 501   }
 502   // Just null out the mirror.  The class_loader_data() no longer exists.
 503   _java_mirror = NULL;
 504 }
 505 
 506 void Klass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) {
 507   assert(is_klass(), "ensure C++ vtable is restored");
 508   assert(is_shared(), "must be set");
 509   JFR_ONLY(RESTORE_ID(this);)
 510   if (log_is_enabled(Trace, cds, unshareable)) {
 511     ResourceMark rm;
 512     log_trace(cds, unshareable)("restore: %s", external_name());
 513   }
 514 
 515   // If an exception happened during CDS restore, some of these fields may already be
 516   // set.  We leave the class on the CLD list, even if incomplete so that we don't
 517   // modify the CLD list outside a safepoint.
 518   if (class_loader_data() == NULL) {
 519     // Restore class_loader_data to the null class loader data
 520     set_class_loader_data(loader_data);
 521 
 522     // Add to null class loader list first before creating the mirror
 523     // (same order as class file parsing)
 524     loader_data->add_class(this);
 525   }
 526 
 527   Handle loader(THREAD, loader_data->class_loader());
 528   ModuleEntry* module_entry = NULL;
 529   Klass* k = this;
 530   if (k->is_objArray_klass()) {
 531     k = ObjArrayKlass::cast(k)->bottom_klass();
 532   }
 533   // Obtain klass' module.
 534   if (k->is_instance_klass()) {
 535     InstanceKlass* ik = (InstanceKlass*) k;
 536     module_entry = ik->module();
 537   } else {
 538     module_entry = ModuleEntryTable::javabase_moduleEntry();
 539   }
 540   // Obtain java.lang.Module, if available
 541   Handle module_handle(THREAD, ((module_entry != NULL) ? module_entry->module() : (oop)NULL));
 542 
 543   if (this->has_raw_archived_mirror()) {
 544     ResourceMark rm;
 545     log_debug(cds, mirror)("%s has raw archived mirror", external_name());
 546     if (HeapShared::open_archive_heap_region_mapped()) {
 547       bool present = java_lang_Class::restore_archived_mirror(this, loader, module_handle,
 548                                                               protection_domain,
 549                                                               CHECK);
 550       if (present) {
 551         return;
 552       }
 553     }
 554 
 555     // No archived mirror data
 556     log_debug(cds, mirror)("No archived mirror data for %s", external_name());
 557     _java_mirror = NULL;
 558     this->clear_has_raw_archived_mirror();
 559   }
 560 
 561   // Only recreate it if not present.  A previous attempt to restore may have
 562   // gotten an OOM later but keep the mirror if it was created.
 563   if (java_mirror() == NULL) {
 564     log_trace(cds, mirror)("Recreate mirror for %s", external_name());
 565     java_lang_Class::create_mirror(this, loader, module_handle, protection_domain, CHECK);
 566   }
 567 }
 568 
 569 #if INCLUDE_CDS_JAVA_HEAP
 570 // Used at CDS dump time to access the archived mirror. No GC barrier.
 571 oop Klass::archived_java_mirror_raw() {
 572   assert(has_raw_archived_mirror(), "must have raw archived mirror");
 573   return CompressedOops::decode(_archived_mirror);
 574 }
 575 
 576 narrowOop Klass::archived_java_mirror_raw_narrow() {
 577   assert(has_raw_archived_mirror(), "must have raw archived mirror");
 578   return _archived_mirror;
 579 }
 580 
 581 // No GC barrier
 582 void Klass::set_archived_java_mirror_raw(oop m) {
 583   assert(DumpSharedSpaces, "called only during runtime");
 584   _archived_mirror = CompressedOops::encode(m);
 585 }
 586 #endif // INCLUDE_CDS_JAVA_HEAP
 587 
 588 Klass* Klass::array_klass_or_null(int rank) {
 589   EXCEPTION_MARK;
 590   // No exception can be thrown by array_klass_impl when called with or_null == true.
 591   // (In anycase, the execption mark will fail if it do so)
 592   return array_klass_impl(true, rank, THREAD);
 593 }
 594 
 595 
 596 Klass* Klass::array_klass_or_null() {
 597   EXCEPTION_MARK;
 598   // No exception can be thrown by array_klass_impl when called with or_null == true.
 599   // (In anycase, the execption mark will fail if it do so)
 600   return array_klass_impl(true, THREAD);
 601 }
 602 
 603 
 604 Klass* Klass::array_klass_impl(bool or_null, int rank, TRAPS) {
 605   fatal("array_klass should be dispatched to InstanceKlass, ObjArrayKlass or TypeArrayKlass");
 606   return NULL;
 607 }
 608 
 609 
 610 Klass* Klass::array_klass_impl(bool or_null, TRAPS) {
 611   fatal("array_klass should be dispatched to InstanceKlass, ObjArrayKlass or TypeArrayKlass");
 612   return NULL;
 613 }
 614 
 615 void Klass::check_array_allocation_length(int length, int max_length, TRAPS) {
 616   if (length > max_length) {
 617     if (!THREAD->in_retryable_allocation()) {
 618       report_java_out_of_memory("Requested array size exceeds VM limit");
 619       JvmtiExport::post_array_size_exhausted();
 620       THROW_OOP(Universe::out_of_memory_error_array_size());
 621     } else {
 622       THROW_OOP(Universe::out_of_memory_error_retry());
 623     }
 624   } else if (length < 0) {
 625     THROW_MSG(vmSymbols::java_lang_NegativeArraySizeException(), err_msg("%d", length));
 626   }
 627 }
 628 
 629 oop Klass::class_loader() const { return class_loader_data()->class_loader(); }
 630 
 631 // In product mode, this function doesn't have virtual function calls so
 632 // there might be some performance advantage to handling InstanceKlass here.
 633 const char* Klass::external_name() const {
 634   if (is_instance_klass()) {
 635     const InstanceKlass* ik = static_cast<const InstanceKlass*>(this);
 636     if (ik->is_unsafe_anonymous()) {
 637       char addr_buf[20];
 638       jio_snprintf(addr_buf, 20, "/" INTPTR_FORMAT, p2i(ik));
 639       size_t addr_len = strlen(addr_buf);
 640       size_t name_len = name()->utf8_length();
 641       char*  result   = NEW_RESOURCE_ARRAY(char, name_len + addr_len + 1);
 642       name()->as_klass_external_name(result, (int) name_len + 1);
 643       assert(strlen(result) == name_len, "");
 644       strcpy(result + name_len, addr_buf);
 645       assert(strlen(result) == name_len + addr_len, "");
 646       return result;
 647     }
 648   }
 649   if (name() == NULL)  return "<unknown>";
 650   return name()->as_klass_external_name();
 651 }
 652 
 653 const char* Klass::signature_name() const {
 654   if (name() == NULL)  return "<unknown>";
 655   return name()->as_C_string();
 656 }
 657 
 658 const char* Klass::external_kind() const {
 659   if (is_interface()) return "interface";
 660   if (is_abstract()) return "abstract class";
 661   return "class";
 662 }
 663 
 664 // Unless overridden, modifier_flags is 0.
 665 jint Klass::compute_modifier_flags(TRAPS) const {
 666   return 0;
 667 }
 668 
 669 int Klass::atomic_incr_biased_lock_revocation_count() {
 670   return (int) Atomic::add(1, &_biased_lock_revocation_count);
 671 }
 672 
 673 // Unless overridden, jvmti_class_status has no flags set.
 674 jint Klass::jvmti_class_status() const {
 675   return 0;
 676 }
 677 
 678 
 679 // Printing
 680 
 681 void Klass::print_on(outputStream* st) const {
 682   ResourceMark rm;
 683   // print title
 684   st->print("%s", internal_name());
 685   print_address_on(st);
 686   st->cr();
 687 }
 688 
 689 void Klass::oop_print_on(oop obj, outputStream* st) {
 690   ResourceMark rm;
 691   // print title
 692   st->print_cr("%s ", internal_name());
 693   obj->print_address_on(st);
 694 
 695   if (WizardMode) {
 696      // print header
 697      obj->mark()->print_on(st);
 698   }
 699 
 700   // print class
 701   st->print(" - klass: ");
 702   obj->klass()->print_value_on(st);
 703   st->cr();
 704 }
 705 
 706 void Klass::oop_print_value_on(oop obj, outputStream* st) {
 707   // print title
 708   ResourceMark rm;              // Cannot print in debug mode without this
 709   st->print("%s", internal_name());
 710   obj->print_address_on(st);
 711 }
 712 
 713 #if INCLUDE_SERVICES
 714 // Size Statistics
 715 void Klass::collect_statistics(KlassSizeStats *sz) const {
 716   sz->_klass_bytes = sz->count(this);
 717   sz->_mirror_bytes = sz->count(java_mirror());
 718   sz->_secondary_supers_bytes = sz->count_array(secondary_supers());
 719 
 720   sz->_ro_bytes += sz->_secondary_supers_bytes;
 721   sz->_rw_bytes += sz->_klass_bytes + sz->_mirror_bytes;
 722 }
 723 #endif // INCLUDE_SERVICES
 724 
 725 // Verification
 726 
 727 void Klass::verify_on(outputStream* st) {
 728 
 729   // This can be expensive, but it is worth checking that this klass is actually
 730   // in the CLD graph but not in production.
 731   assert(Metaspace::contains((address)this), "Should be");
 732 
 733   guarantee(this->is_klass(),"should be klass");
 734 
 735   if (super() != NULL) {
 736     guarantee(super()->is_klass(), "should be klass");
 737   }
 738   if (secondary_super_cache() != NULL) {
 739     Klass* ko = secondary_super_cache();
 740     guarantee(ko->is_klass(), "should be klass");
 741   }
 742   for ( uint i = 0; i < primary_super_limit(); i++ ) {
 743     Klass* ko = _primary_supers[i];
 744     if (ko != NULL) {
 745       guarantee(ko->is_klass(), "should be klass");
 746     }
 747   }
 748 
 749   if (java_mirror() != NULL) {
 750     guarantee(oopDesc::is_oop(java_mirror()), "should be instance");
 751   }
 752 }
 753 
 754 void Klass::oop_verify_on(oop obj, outputStream* st) {
 755   guarantee(oopDesc::is_oop(obj),  "should be oop");
 756   guarantee(obj->klass()->is_klass(), "klass field is not a klass");
 757 }
 758 
 759 Klass* Klass::decode_klass_raw(narrowKlass narrow_klass) {
 760   return (Klass*)(void*)( (uintptr_t)Universe::narrow_klass_base() +
 761                          ((uintptr_t)narrow_klass << Universe::narrow_klass_shift()));
 762 }
 763 
 764 bool Klass::is_valid(Klass* k) {
 765   if (!is_aligned(k, sizeof(MetaWord))) return false;
 766   if ((size_t)k < os::min_page_size()) return false;
 767 
 768   if (!os::is_readable_range(k, k + 1)) return false;
 769   if (!MetaspaceUtils::is_range_in_committed(k, k + 1)) return false;
 770 
 771   if (!Symbol::is_valid(k->name())) return false;
 772   return ClassLoaderDataGraph::is_valid(k->class_loader_data());
 773 }
 774 
 775 klassVtable Klass::vtable() const {
 776   return klassVtable(const_cast<Klass*>(this), start_of_vtable(), vtable_length() / vtableEntry::size());
 777 }
 778 
 779 vtableEntry* Klass::start_of_vtable() const {
 780   return (vtableEntry*) ((address)this + in_bytes(vtable_start_offset()));
 781 }
 782 
 783 Method* Klass::method_at_vtable(int index)  {
 784 #ifndef PRODUCT
 785   assert(index >= 0, "valid vtable index");
 786   if (DebugVtables) {
 787     verify_vtable_index(index);
 788   }
 789 #endif
 790   return start_of_vtable()[index].method();
 791 }
 792 
 793 ByteSize Klass::vtable_start_offset() {
 794   return in_ByteSize(InstanceKlass::header_size() * wordSize);
 795 }
 796 
 797 #ifndef PRODUCT
 798 
 799 bool Klass::verify_vtable_index(int i) {
 800   int limit = vtable_length()/vtableEntry::size();
 801   assert(i >= 0 && i < limit, "index %d out of bounds %d", i, limit);
 802   return true;
 803 }
 804 
 805 #endif // PRODUCT
 806 
 807 // Caller needs ResourceMark
 808 // joint_in_module_of_loader provides an optimization if 2 classes are in
 809 // the same module to succinctly print out relevant information about their
 810 // module name and class loader's name_and_id for error messages.
 811 // Format:
 812 //   <fully-qualified-external-class-name1> and <fully-qualified-external-class-name2>
 813 //                      are in module <module-name>[@<version>]
 814 //                      of loader <loader-name_and_id>[, parent loader <parent-loader-name_and_id>]
 815 const char* Klass::joint_in_module_of_loader(const Klass* class2, bool include_parent_loader) const {
 816   assert(module() == class2->module(), "classes do not have the same module");
 817   const char* class1_name = external_name();
 818   size_t len = strlen(class1_name) + 1;
 819 
 820   const char* class2_description = class2->class_in_module_of_loader(true, include_parent_loader);
 821   len += strlen(class2_description);
 822 
 823   len += strlen(" and ");
 824 
 825   char* joint_description = NEW_RESOURCE_ARRAY_RETURN_NULL(char, len);
 826 
 827   // Just return the FQN if error when allocating string
 828   if (joint_description == NULL) {
 829     return class1_name;
 830   }
 831 
 832   jio_snprintf(joint_description, len, "%s and %s",
 833                class1_name,
 834                class2_description);
 835 
 836   return joint_description;
 837 }
 838 
 839 // Caller needs ResourceMark
 840 // class_in_module_of_loader provides a standard way to include
 841 // relevant information about a class, such as its module name as
 842 // well as its class loader's name_and_id, in error messages and logging.
 843 // Format:
 844 //   <fully-qualified-external-class-name> is in module <module-name>[@<version>]
 845 //                                         of loader <loader-name_and_id>[, parent loader <parent-loader-name_and_id>]
 846 const char* Klass::class_in_module_of_loader(bool use_are, bool include_parent_loader) const {
 847   // 1. fully qualified external name of class
 848   const char* klass_name = external_name();
 849   size_t len = strlen(klass_name) + 1;
 850 
 851   // 2. module name + @version
 852   const char* module_name = "";
 853   const char* version = "";
 854   bool has_version = false;
 855   bool module_is_named = false;
 856   const char* module_name_phrase = "";
 857   const Klass* bottom_klass = is_objArray_klass() ?
 858                                 ObjArrayKlass::cast(this)->bottom_klass() : this;
 859   if (bottom_klass->is_instance_klass()) {
 860     ModuleEntry* module = InstanceKlass::cast(bottom_klass)->module();
 861     if (module->is_named()) {
 862       module_is_named = true;
 863       module_name_phrase = "module ";
 864       module_name = module->name()->as_C_string();
 865       len += strlen(module_name);
 866       // Use version if exists and is not a jdk module
 867       if (module->should_show_version()) {
 868         has_version = true;
 869         version = module->version()->as_C_string();
 870         // Include stlen(version) + 1 for the "@"
 871         len += strlen(version) + 1;
 872       }
 873     } else {
 874       module_name = UNNAMED_MODULE;
 875       len += UNNAMED_MODULE_LEN;
 876     }
 877   } else {
 878     // klass is an array of primitives, module is java.base
 879     module_is_named = true;
 880     module_name_phrase = "module ";
 881     module_name = JAVA_BASE_NAME;
 882     len += JAVA_BASE_NAME_LEN;
 883   }
 884 
 885   // 3. class loader's name_and_id
 886   ClassLoaderData* cld = class_loader_data();
 887   assert(cld != NULL, "class_loader_data should not be null");
 888   const char* loader_name_and_id = cld->loader_name_and_id();
 889   len += strlen(loader_name_and_id);
 890 
 891   // 4. include parent loader information
 892   const char* parent_loader_phrase = "";
 893   const char* parent_loader_name_and_id = "";
 894   if (include_parent_loader &&
 895       !cld->is_builtin_class_loader_data()) {
 896     oop parent_loader = java_lang_ClassLoader::parent(class_loader());
 897     ClassLoaderData *parent_cld = SystemDictionary::register_loader(Handle(Thread::current(), parent_loader));
 898     assert(parent_cld != NULL, "parent's class loader data should not be null");
 899     parent_loader_name_and_id = parent_cld->loader_name_and_id();
 900     parent_loader_phrase = ", parent loader ";
 901     len += strlen(parent_loader_phrase) + strlen(parent_loader_name_and_id);
 902   }
 903 
 904   // Start to construct final full class description string
 905   len += ((use_are) ? strlen(" are in ") : strlen(" is in "));
 906   len += strlen(module_name_phrase) + strlen(" of loader ");
 907 
 908   char* class_description = NEW_RESOURCE_ARRAY_RETURN_NULL(char, len);
 909 
 910   // Just return the FQN if error when allocating string
 911   if (class_description == NULL) {
 912     return klass_name;
 913   }
 914 
 915   jio_snprintf(class_description, len, "%s %s in %s%s%s%s of loader %s%s%s",
 916                klass_name,
 917                (use_are) ? "are" : "is",
 918                module_name_phrase,
 919                module_name,
 920                (has_version) ? "@" : "",
 921                (has_version) ? version : "",
 922                loader_name_and_id,
 923                parent_loader_phrase,
 924                parent_loader_name_and_id);
 925 
 926   return class_description;
 927 }
--- EOF ---