1 /*
   2  * Copyright (c) 1997, 2017, 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/dictionary.hpp"
  27 #include "classfile/javaClasses.hpp"
  28 #include "classfile/systemDictionary.hpp"
  29 #include "classfile/vmSymbols.hpp"
  30 #include "gc/shared/collectedHeap.inline.hpp"
  31 #include "logging/log.hpp"
  32 #include "memory/heapInspection.hpp"
  33 #include "memory/metadataFactory.hpp"
  34 #include "memory/metaspaceClosure.hpp"
  35 #include "memory/metaspaceShared.hpp"
  36 #include "memory/oopFactory.hpp"
  37 #include "memory/resourceArea.hpp"
  38 #include "oops/instanceKlass.hpp"
  39 #include "oops/klass.inline.hpp"
  40 #include "oops/oop.inline.hpp"
  41 #include "runtime/atomic.hpp"
  42 #include "runtime/orderAccess.inline.hpp"
  43 #include "trace/traceMacros.hpp"
  44 #include "utilities/macros.hpp"
  45 #include "utilities/stack.inline.hpp"
  46 #if INCLUDE_ALL_GCS
  47 #include "gc/g1/g1SATBCardTableModRefBS.hpp"
  48 #endif // INCLUDE_ALL_GCS
  49 
  50 bool Klass::is_cloneable() const {
  51   return _access_flags.is_cloneable_fast() ||
  52          is_subtype_of(SystemDictionary::Cloneable_klass());
  53 }
  54 
  55 void Klass::set_is_cloneable() {
  56   if (name() != vmSymbols::java_lang_invoke_MemberName()) {
  57     _access_flags.set_is_cloneable_fast();
  58   } else {
  59     assert(is_final(), "no subclasses allowed");
  60     // MemberName cloning should not be intrinsified and always happen in JVM_Clone.
  61   }
  62 }
  63 
  64 void Klass::set_name(Symbol* n) {
  65   _name = n;
  66   if (_name != NULL) _name->increment_refcount();
  67 }
  68 
  69 bool Klass::is_subclass_of(const Klass* k) const {
  70   // Run up the super chain and check
  71   if (this == k) return true;
  72 
  73   Klass* t = const_cast<Klass*>(this)->super();
  74 
  75   while (t != NULL) {
  76     if (t == k) return true;
  77     t = t->super();
  78   }
  79   return false;
  80 }
  81 
  82 bool Klass::search_secondary_supers(Klass* k) const {
  83   // Put some extra logic here out-of-line, before the search proper.
  84   // This cuts down the size of the inline method.
  85 
  86   // This is necessary, since I am never in my own secondary_super list.
  87   if (this == k)
  88     return true;
  89   // Scan the array-of-objects for a match
  90   int cnt = secondary_supers()->length();
  91   for (int i = 0; i < cnt; i++) {
  92     if (secondary_supers()->at(i) == k) {
  93       ((Klass*)this)->set_secondary_super_cache(k);
  94       return true;
  95     }
  96   }
  97   return false;
  98 }
  99 
 100 // Return self, except for abstract classes with exactly 1
 101 // implementor.  Then return the 1 concrete implementation.
 102 Klass *Klass::up_cast_abstract() {
 103   Klass *r = this;
 104   while( r->is_abstract() ) {   // Receiver is abstract?
 105     Klass *s = r->subklass();   // Check for exactly 1 subklass
 106     if( !s || s->next_sibling() ) // Oops; wrong count; give up
 107       return this;              // Return 'this' as a no-progress flag
 108     r = s;                    // Loop till find concrete class
 109   }
 110   return r;                   // Return the 1 concrete class
 111 }
 112 
 113 // Find LCA in class hierarchy
 114 Klass *Klass::LCA( Klass *k2 ) {
 115   Klass *k1 = this;
 116   while( 1 ) {
 117     if( k1->is_subtype_of(k2) ) return k2;
 118     if( k2->is_subtype_of(k1) ) return k1;
 119     k1 = k1->super();
 120     k2 = k2->super();
 121   }
 122 }
 123 
 124 
 125 void Klass::check_valid_for_instantiation(bool throwError, TRAPS) {
 126   ResourceMark rm(THREAD);
 127   THROW_MSG(throwError ? vmSymbols::java_lang_InstantiationError()
 128             : vmSymbols::java_lang_InstantiationException(), external_name());
 129 }
 130 
 131 
 132 void Klass::copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS) {
 133   THROW(vmSymbols::java_lang_ArrayStoreException());
 134 }
 135 
 136 
 137 void Klass::initialize(TRAPS) {
 138   ShouldNotReachHere();
 139 }
 140 
 141 bool Klass::compute_is_subtype_of(Klass* k) {
 142   assert(k->is_klass(), "argument must be a class");
 143   return is_subclass_of(k);
 144 }
 145 
 146 Klass* Klass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
 147 #ifdef ASSERT
 148   tty->print_cr("Error: find_field called on a klass oop."
 149                 " Likely error: reflection method does not correctly"
 150                 " wrap return value in a mirror object.");
 151 #endif
 152   ShouldNotReachHere();
 153   return NULL;
 154 }
 155 
 156 Method* Klass::uncached_lookup_method(const Symbol* name, const Symbol* signature, OverpassLookupMode overpass_mode) const {
 157 #ifdef ASSERT
 158   tty->print_cr("Error: uncached_lookup_method called on a klass oop."
 159                 " Likely error: reflection method does not correctly"
 160                 " wrap return value in a mirror object.");
 161 #endif
 162   ShouldNotReachHere();
 163   return NULL;
 164 }
 165 
 166 void* Klass::operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, TRAPS) throw() {
 167   return Metaspace::allocate(loader_data, word_size, MetaspaceObj::ClassType, THREAD);
 168 }
 169 
 170 // "Normal" instantiation is preceeded by a MetaspaceObj allocation
 171 // which zeros out memory - calloc equivalent.
 172 // The constructor is also used from CppVtableCloner,
 173 // which doesn't zero out the memory before calling the constructor.
 174 // Need to set the _java_mirror field explicitly to not hit an assert that the field
 175 // should be NULL before setting it.
 176 Klass::Klass() : _prototype_header(markOopDesc::prototype()),
 177                  _shared_class_path_index(-1),
 178                  _java_mirror(NULL) {
 179 
 180   _primary_supers[0] = this;
 181   set_super_check_offset(in_bytes(primary_supers_offset()));
 182 }
 183 
 184 jint Klass::array_layout_helper(BasicType etype) {
 185   assert(etype >= T_BOOLEAN && etype <= T_OBJECT, "valid etype");
 186   // Note that T_ARRAY is not allowed here.
 187   int  hsize = arrayOopDesc::base_offset_in_bytes(etype);
 188   int  esize = type2aelembytes(etype);
 189   bool isobj = (etype == T_OBJECT);
 190   int  tag   =  isobj ? _lh_array_tag_obj_value : _lh_array_tag_type_value;
 191   int lh = array_layout_helper(tag, hsize, etype, exact_log2(esize));
 192 
 193   assert(lh < (int)_lh_neutral_value, "must look like an array layout");
 194   assert(layout_helper_is_array(lh), "correct kind");
 195   assert(layout_helper_is_objArray(lh) == isobj, "correct kind");
 196   assert(layout_helper_is_typeArray(lh) == !isobj, "correct kind");
 197   assert(layout_helper_header_size(lh) == hsize, "correct decode");
 198   assert(layout_helper_element_type(lh) == etype, "correct decode");
 199   assert(1 << layout_helper_log2_element_size(lh) == esize, "correct decode");
 200 
 201   return lh;
 202 }
 203 
 204 bool Klass::can_be_primary_super_slow() const {
 205   if (super() == NULL)
 206     return true;
 207   else if (super()->super_depth() >= primary_super_limit()-1)
 208     return false;
 209   else
 210     return true;
 211 }
 212 
 213 void Klass::initialize_supers(Klass* k, TRAPS) {
 214   if (FastSuperclassLimit == 0) {
 215     // None of the other machinery matters.
 216     set_super(k);
 217     return;
 218   }
 219   if (k == NULL) {
 220     set_super(NULL);
 221     _primary_supers[0] = this;
 222     assert(super_depth() == 0, "Object must already be initialized properly");
 223   } else if (k != super() || k == SystemDictionary::Object_klass()) {
 224     assert(super() == NULL || super() == SystemDictionary::Object_klass(),
 225            "initialize this only once to a non-trivial value");
 226     set_super(k);
 227     Klass* sup = k;
 228     int sup_depth = sup->super_depth();
 229     juint my_depth  = MIN2(sup_depth + 1, (int)primary_super_limit());
 230     if (!can_be_primary_super_slow())
 231       my_depth = primary_super_limit();
 232     for (juint i = 0; i < my_depth; i++) {
 233       _primary_supers[i] = sup->_primary_supers[i];
 234     }
 235     Klass* *super_check_cell;
 236     if (my_depth < primary_super_limit()) {
 237       _primary_supers[my_depth] = this;
 238       super_check_cell = &_primary_supers[my_depth];
 239     } else {
 240       // Overflow of the primary_supers array forces me to be secondary.
 241       super_check_cell = &_secondary_super_cache;
 242     }
 243     set_super_check_offset((address)super_check_cell - (address) this);
 244 
 245 #ifdef ASSERT
 246     {
 247       juint j = super_depth();
 248       assert(j == my_depth, "computed accessor gets right answer");
 249       Klass* t = this;
 250       while (!t->can_be_primary_super()) {
 251         t = t->super();
 252         j = t->super_depth();
 253       }
 254       for (juint j1 = j+1; j1 < primary_super_limit(); j1++) {
 255         assert(primary_super_of_depth(j1) == NULL, "super list padding");
 256       }
 257       while (t != NULL) {
 258         assert(primary_super_of_depth(j) == t, "super list initialization");
 259         t = t->super();
 260         --j;
 261       }
 262       assert(j == (juint)-1, "correct depth count");
 263     }
 264 #endif
 265   }
 266 
 267   if (secondary_supers() == NULL) {
 268 
 269     // Now compute the list of secondary supertypes.
 270     // Secondaries can occasionally be on the super chain,
 271     // if the inline "_primary_supers" array overflows.
 272     int extras = 0;
 273     Klass* p;
 274     for (p = super(); !(p == NULL || p->can_be_primary_super()); p = p->super()) {
 275       ++extras;
 276     }
 277 
 278     ResourceMark rm(THREAD);  // need to reclaim GrowableArrays allocated below
 279 
 280     // Compute the "real" non-extra secondaries.
 281     GrowableArray<Klass*>* secondaries = compute_secondary_supers(extras);
 282     if (secondaries == NULL) {
 283       // secondary_supers set by compute_secondary_supers
 284       return;
 285     }
 286 
 287     GrowableArray<Klass*>* primaries = new GrowableArray<Klass*>(extras);
 288 
 289     for (p = super(); !(p == NULL || p->can_be_primary_super()); p = p->super()) {
 290       int i;                    // Scan for overflow primaries being duplicates of 2nd'arys
 291 
 292       // This happens frequently for very deeply nested arrays: the
 293       // primary superclass chain overflows into the secondary.  The
 294       // secondary list contains the element_klass's secondaries with
 295       // an extra array dimension added.  If the element_klass's
 296       // secondary list already contains some primary overflows, they
 297       // (with the extra level of array-ness) will collide with the
 298       // normal primary superclass overflows.
 299       for( i = 0; i < secondaries->length(); i++ ) {
 300         if( secondaries->at(i) == p )
 301           break;
 302       }
 303       if( i < secondaries->length() )
 304         continue;               // It's a dup, don't put it in
 305       primaries->push(p);
 306     }
 307     // Combine the two arrays into a metadata object to pack the array.
 308     // The primaries are added in the reverse order, then the secondaries.
 309     int new_length = primaries->length() + secondaries->length();
 310     Array<Klass*>* s2 = MetadataFactory::new_array<Klass*>(
 311                                        class_loader_data(), new_length, CHECK);
 312     int fill_p = primaries->length();
 313     for (int j = 0; j < fill_p; j++) {
 314       s2->at_put(j, primaries->pop());  // add primaries in reverse order.
 315     }
 316     for( int j = 0; j < secondaries->length(); j++ ) {
 317       s2->at_put(j+fill_p, secondaries->at(j));  // add secondaries on the end.
 318     }
 319 
 320   #ifdef ASSERT
 321       // We must not copy any NULL placeholders left over from bootstrap.
 322     for (int j = 0; j < s2->length(); j++) {
 323       assert(s2->at(j) != NULL, "correct bootstrapping order");
 324     }
 325   #endif
 326 
 327     set_secondary_supers(s2);
 328   }
 329 }
 330 
 331 GrowableArray<Klass*>* Klass::compute_secondary_supers(int num_extra_slots) {
 332   assert(num_extra_slots == 0, "override for complex klasses");
 333   set_secondary_supers(Universe::the_empty_klass_array());
 334   return NULL;
 335 }
 336 
 337 
 338 InstanceKlass* Klass::superklass() const {
 339   assert(super() == NULL || super()->is_instance_klass(), "must be instance klass");
 340   return _super == NULL ? NULL : InstanceKlass::cast(_super);
 341 }
 342 
 343 void Klass::set_subklass(Klass* s) {
 344   assert(s != this, "sanity check");
 345   _subklass = s;
 346 }
 347 
 348 void Klass::set_next_sibling(Klass* s) {
 349   assert(s != this, "sanity check");
 350   _next_sibling = s;
 351 }
 352 
 353 void Klass::append_to_sibling_list() {
 354   debug_only(verify();)
 355   // add ourselves to superklass' subklass list
 356   InstanceKlass* super = superklass();
 357   if (super == NULL) return;        // special case: class Object
 358   assert((!super->is_interface()    // interfaces cannot be supers
 359           && (super->superklass() == NULL || !is_interface())),
 360          "an interface can only be a subklass of Object");
 361   Klass* prev_first_subklass = super->subklass();
 362   if (prev_first_subklass != NULL) {
 363     // set our sibling to be the superklass' previous first subklass
 364     set_next_sibling(prev_first_subklass);
 365   }
 366   // make ourselves the superklass' first subklass
 367   super->set_subklass(this);
 368   debug_only(verify();)
 369 }
 370 
 371 bool Klass::is_loader_alive(BoolObjectClosure* is_alive) {
 372 #ifdef ASSERT
 373   // The class is alive iff the class loader is alive.
 374   oop loader = class_loader();
 375   bool loader_alive = (loader == NULL) || is_alive->do_object_b(loader);
 376 #endif // ASSERT
 377 
 378   // The class is alive if it's mirror is alive (which should be marked if the
 379   // loader is alive) unless it's an anoymous class.
 380   bool mirror_alive = is_alive->do_object_b(java_mirror());
 381   assert(!mirror_alive || loader_alive, "loader must be alive if the mirror is"
 382                         " but not the other way around with anonymous classes");
 383   return mirror_alive;
 384 }
 385 
 386 void Klass::clean_weak_klass_links(BoolObjectClosure* is_alive, bool clean_alive_klasses) {
 387   if (!ClassUnloading) {
 388     return;
 389   }
 390 
 391   Klass* root = SystemDictionary::Object_klass();
 392   Stack<Klass*, mtGC> stack;
 393 
 394   stack.push(root);
 395   while (!stack.is_empty()) {
 396     Klass* current = stack.pop();
 397 
 398     assert(current->is_loader_alive(is_alive), "just checking, this should be live");
 399 
 400     // Find and set the first alive subklass
 401     Klass* sub = current->subklass();
 402     while (sub != NULL && !sub->is_loader_alive(is_alive)) {
 403 #ifndef PRODUCT
 404       if (log_is_enabled(Trace, class, unload)) {
 405         ResourceMark rm;
 406         log_trace(class, unload)("unlinking class (subclass): %s", sub->external_name());
 407       }
 408 #endif
 409       sub = sub->next_sibling();
 410     }
 411     current->set_subklass(sub);
 412     if (sub != NULL) {
 413       stack.push(sub);
 414     }
 415 
 416     // Find and set the first alive sibling
 417     Klass* sibling = current->next_sibling();
 418     while (sibling != NULL && !sibling->is_loader_alive(is_alive)) {
 419       if (log_is_enabled(Trace, class, unload)) {
 420         ResourceMark rm;
 421         log_trace(class, unload)("[Unlinking class (sibling) %s]", sibling->external_name());
 422       }
 423       sibling = sibling->next_sibling();
 424     }
 425     current->set_next_sibling(sibling);
 426     if (sibling != NULL) {
 427       stack.push(sibling);
 428     }
 429 
 430     // Clean the implementors list and method data.
 431     if (clean_alive_klasses && current->is_instance_klass()) {
 432       InstanceKlass* ik = InstanceKlass::cast(current);
 433       ik->clean_weak_instanceklass_links(is_alive);
 434 
 435       // JVMTI RedefineClasses creates previous versions that are not in
 436       // the class hierarchy, so process them here.
 437       while ((ik = ik->previous_versions()) != NULL) {
 438         ik->clean_weak_instanceklass_links(is_alive);
 439       }
 440     }
 441   }
 442 }
 443 
 444 void Klass::klass_update_barrier_set(oop v) {
 445   record_modified_oops();
 446 }
 447 
 448 // This barrier is used by G1 to remember the old oop values, so
 449 // that we don't forget any objects that were live at the snapshot at
 450 // the beginning. This function is only used when we write oops into Klasses.
 451 void Klass::klass_update_barrier_set_pre(oop* p, oop v) {
 452 #if INCLUDE_ALL_GCS
 453   if (UseG1GC) {
 454     oop obj = *p;
 455     if (obj != NULL) {
 456       G1SATBCardTableModRefBS::enqueue(obj);
 457     }
 458   }
 459 #endif
 460 }
 461 
 462 void Klass::klass_oop_store(oop* p, oop v) {
 463   assert(!Universe::heap()->is_in_reserved((void*)p), "Should store pointer into metadata");
 464   assert(v == NULL || Universe::heap()->is_in_reserved((void*)v), "Should store pointer to an object");
 465 
 466   // do the store
 467   if (always_do_update_barrier) {
 468     klass_oop_store((volatile oop*)p, v);
 469   } else {
 470     klass_update_barrier_set_pre(p, v);
 471     *p = v;
 472     klass_update_barrier_set(v);
 473   }
 474 }
 475 
 476 void Klass::klass_oop_store(volatile oop* p, oop v) {
 477   assert(!Universe::heap()->is_in_reserved((void*)p), "Should store pointer into metadata");
 478   assert(v == NULL || Universe::heap()->is_in_reserved((void*)v), "Should store pointer to an object");
 479 
 480   klass_update_barrier_set_pre((oop*)p, v); // Cast away volatile.
 481   OrderAccess::release_store_ptr(p, v);
 482   klass_update_barrier_set(v);
 483 }
 484 
 485 void Klass::oops_do(OopClosure* cl) {
 486   cl->do_oop(&_java_mirror);
 487 }
 488 
 489 void Klass::metaspace_pointers_do(MetaspaceClosure* it) {
 490   if (log_is_enabled(Trace, cds)) {
 491     ResourceMark rm;
 492     log_trace(cds)("Iter(Klass): %p (%s)", this, external_name());
 493   }
 494 
 495   it->push(&_name);
 496   it->push(&_secondary_super_cache);
 497   it->push(&_secondary_supers);
 498   for (int i = 0; i < _primary_super_limit; i++) {
 499     it->push(&_primary_supers[i]);
 500   }
 501   it->push(&_super);
 502   it->push(&_subklass);
 503   it->push(&_next_sibling);
 504   it->push(&_next_link);
 505 
 506   vtableEntry* vt = start_of_vtable();
 507   for (int i=0; i<vtable_length(); i++) {
 508     it->push(vt[i].method_addr());
 509   }
 510 }
 511 
 512 void Klass::remove_unshareable_info() {
 513   assert (DumpSharedSpaces, "only called for DumpSharedSpaces");
 514   TRACE_REMOVE_ID(this);
 515 
 516   set_subklass(NULL);
 517   set_next_sibling(NULL);
 518   // Clear the java mirror
 519   set_java_mirror(NULL);
 520   set_next_link(NULL);
 521 
 522   // Null out class_loader_data because we don't share that yet.
 523   set_class_loader_data(NULL);
 524   set_is_shared();
 525 }
 526 
 527 void Klass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) {
 528   assert(is_klass(), "ensure C++ vtable is restored");
 529   assert(is_shared(), "must be set");
 530   TRACE_RESTORE_ID(this);
 531 
 532   // If an exception happened during CDS restore, some of these fields may already be
 533   // set.  We leave the class on the CLD list, even if incomplete so that we don't
 534   // modify the CLD list outside a safepoint.
 535   if (class_loader_data() == NULL) {
 536     // Restore class_loader_data to the null class loader data
 537     set_class_loader_data(loader_data);
 538 
 539     // Add to null class loader list first before creating the mirror
 540     // (same order as class file parsing)
 541     loader_data->add_class(this);
 542   }
 543 
 544   // Recreate the class mirror.
 545   // Only recreate it if not present.  A previous attempt to restore may have
 546   // gotten an OOM later but keep the mirror if it was created.
 547   if (java_mirror() == NULL) {
 548     Handle loader(THREAD, loader_data->class_loader());
 549     ModuleEntry* module_entry = NULL;
 550     Klass* k = this;
 551     if (k->is_objArray_klass()) {
 552       k = ObjArrayKlass::cast(k)->bottom_klass();
 553     }
 554     // Obtain klass' module.
 555     if (k->is_instance_klass()) {
 556       InstanceKlass* ik = (InstanceKlass*) k;
 557       module_entry = ik->module();
 558     } else {
 559       module_entry = ModuleEntryTable::javabase_moduleEntry();
 560     }
 561     // Obtain java.lang.Module, if available
 562     Handle module_handle(THREAD, ((module_entry != NULL) ? module_entry->module() : (oop)NULL));
 563     java_lang_Class::create_mirror(this, loader, module_handle, protection_domain, CHECK);
 564   }
 565 }
 566 
 567 Klass* Klass::array_klass_or_null(int rank) {
 568   EXCEPTION_MARK;
 569   // No exception can be thrown by array_klass_impl when called with or_null == true.
 570   // (In anycase, the execption mark will fail if it do so)
 571   return array_klass_impl(true, rank, THREAD);
 572 }
 573 
 574 
 575 Klass* Klass::array_klass_or_null() {
 576   EXCEPTION_MARK;
 577   // No exception can be thrown by array_klass_impl when called with or_null == true.
 578   // (In anycase, the execption mark will fail if it do so)
 579   return array_klass_impl(true, THREAD);
 580 }
 581 
 582 
 583 Klass* Klass::array_klass_impl(bool or_null, int rank, TRAPS) {
 584   fatal("array_klass should be dispatched to InstanceKlass, ObjArrayKlass or TypeArrayKlass");
 585   return NULL;
 586 }
 587 
 588 
 589 Klass* Klass::array_klass_impl(bool or_null, TRAPS) {
 590   fatal("array_klass should be dispatched to InstanceKlass, ObjArrayKlass or TypeArrayKlass");
 591   return NULL;
 592 }
 593 
 594 oop Klass::class_loader() const { return class_loader_data()->class_loader(); }
 595 
 596 // In product mode, this function doesn't have virtual function calls so
 597 // there might be some performance advantage to handling InstanceKlass here.
 598 const char* Klass::external_name() const {
 599   if (is_instance_klass()) {
 600     const InstanceKlass* ik = static_cast<const InstanceKlass*>(this);
 601     if (ik->is_anonymous()) {
 602       intptr_t hash = 0;
 603       if (ik->java_mirror() != NULL) {
 604         // java_mirror might not be created yet, return 0 as hash.
 605         hash = ik->java_mirror()->identity_hash();
 606       }
 607       char     hash_buf[40];
 608       sprintf(hash_buf, "/" UINTX_FORMAT, (uintx)hash);
 609       size_t   hash_len = strlen(hash_buf);
 610 
 611       size_t result_len = name()->utf8_length();
 612       char*  result     = NEW_RESOURCE_ARRAY(char, result_len + hash_len + 1);
 613       name()->as_klass_external_name(result, (int) result_len + 1);
 614       assert(strlen(result) == result_len, "");
 615       strcpy(result + result_len, hash_buf);
 616       assert(strlen(result) == result_len + hash_len, "");
 617       return result;
 618     }
 619   }
 620   if (name() == NULL)  return "<unknown>";
 621   return name()->as_klass_external_name();
 622 }
 623 
 624 
 625 const char* Klass::signature_name() const {
 626   if (name() == NULL)  return "<unknown>";
 627   return name()->as_C_string();
 628 }
 629 
 630 // Unless overridden, modifier_flags is 0.
 631 jint Klass::compute_modifier_flags(TRAPS) const {
 632   return 0;
 633 }
 634 
 635 int Klass::atomic_incr_biased_lock_revocation_count() {
 636   return (int) Atomic::add(1, &_biased_lock_revocation_count);
 637 }
 638 
 639 // Unless overridden, jvmti_class_status has no flags set.
 640 jint Klass::jvmti_class_status() const {
 641   return 0;
 642 }
 643 
 644 
 645 // Printing
 646 
 647 void Klass::print_on(outputStream* st) const {
 648   ResourceMark rm;
 649   // print title
 650   st->print("%s", internal_name());
 651   print_address_on(st);
 652   st->cr();
 653 }
 654 
 655 void Klass::oop_print_on(oop obj, outputStream* st) {
 656   ResourceMark rm;
 657   // print title
 658   st->print_cr("%s ", internal_name());
 659   obj->print_address_on(st);
 660 
 661   if (WizardMode) {
 662      // print header
 663      obj->mark()->print_on(st);
 664   }
 665 
 666   // print class
 667   st->print(" - klass: ");
 668   obj->klass()->print_value_on(st);
 669   st->cr();
 670 }
 671 
 672 void Klass::oop_print_value_on(oop obj, outputStream* st) {
 673   // print title
 674   ResourceMark rm;              // Cannot print in debug mode without this
 675   st->print("%s", internal_name());
 676   obj->print_address_on(st);
 677 }
 678 
 679 #if INCLUDE_SERVICES
 680 // Size Statistics
 681 void Klass::collect_statistics(KlassSizeStats *sz) const {
 682   sz->_klass_bytes = sz->count(this);
 683   sz->_mirror_bytes = sz->count(java_mirror());
 684   sz->_secondary_supers_bytes = sz->count_array(secondary_supers());
 685 
 686   sz->_ro_bytes += sz->_secondary_supers_bytes;
 687   sz->_rw_bytes += sz->_klass_bytes + sz->_mirror_bytes;
 688 }
 689 #endif // INCLUDE_SERVICES
 690 
 691 // Verification
 692 
 693 void Klass::verify_on(outputStream* st) {
 694 
 695   // This can be expensive, but it is worth checking that this klass is actually
 696   // in the CLD graph but not in production.
 697   assert(Metaspace::contains((address)this), "Should be");
 698 
 699   guarantee(this->is_klass(),"should be klass");
 700 
 701   if (super() != NULL) {
 702     guarantee(super()->is_klass(), "should be klass");
 703   }
 704   if (secondary_super_cache() != NULL) {
 705     Klass* ko = secondary_super_cache();
 706     guarantee(ko->is_klass(), "should be klass");
 707   }
 708   for ( uint i = 0; i < primary_super_limit(); i++ ) {
 709     Klass* ko = _primary_supers[i];
 710     if (ko != NULL) {
 711       guarantee(ko->is_klass(), "should be klass");
 712     }
 713   }
 714 
 715   if (java_mirror() != NULL) {
 716     guarantee(java_mirror()->is_oop(), "should be instance");
 717   }
 718 }
 719 
 720 void Klass::oop_verify_on(oop obj, outputStream* st) {
 721   guarantee(obj->is_oop(),  "should be oop");
 722   guarantee(obj->klass()->is_klass(), "klass field is not a klass");
 723 }
 724 
 725 klassVtable Klass::vtable() const {
 726   return klassVtable(const_cast<Klass*>(this), start_of_vtable(), vtable_length() / vtableEntry::size());
 727 }
 728 
 729 vtableEntry* Klass::start_of_vtable() const {
 730   return (vtableEntry*) ((address)this + in_bytes(vtable_start_offset()));
 731 }
 732 
 733 Method* Klass::method_at_vtable(int index)  {
 734 #ifndef PRODUCT
 735   assert(index >= 0, "valid vtable index");
 736   if (DebugVtables) {
 737     verify_vtable_index(index);
 738   }
 739 #endif
 740   return start_of_vtable()[index].method();
 741 }
 742 
 743 ByteSize Klass::vtable_start_offset() {
 744   return in_ByteSize(InstanceKlass::header_size() * wordSize);
 745 }
 746 
 747 #ifndef PRODUCT
 748 
 749 bool Klass::verify_vtable_index(int i) {
 750   int limit = vtable_length()/vtableEntry::size();
 751   assert(i >= 0 && i < limit, "index %d out of bounds %d", i, limit);
 752   return true;
 753 }
 754 
 755 bool Klass::verify_itable_index(int i) {
 756   assert(is_instance_klass(), "");
 757   int method_count = klassItable::method_count_for_interface(this);
 758   assert(i >= 0 && i < method_count, "index out of bounds");
 759   return true;
 760 }
 761 
 762 #endif