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/javaClasses.hpp"
  27 #include "classfile/dictionary.hpp"
  28 #include "classfile/systemDictionary.hpp"
  29 #include "classfile/vmSymbols.hpp"
  30 #include "gc_implementation/shared/markSweep.inline.hpp"
  31 #include "gc_interface/collectedHeap.inline.hpp"
  32 #include "memory/heapInspection.hpp"
  33 #include "memory/metadataFactory.hpp"
  34 #include "memory/oopFactory.hpp"
  35 #include "memory/resourceArea.hpp"
  36 #include "oops/instanceKlass.hpp"
  37 #include "oops/klass.inline.hpp"
  38 #include "oops/oop.inline2.hpp"
  39 #include "runtime/atomic.inline.hpp"
  40 #include "runtime/orderAccess.inline.hpp"
  41 #include "trace/traceMacros.hpp"
  42 #include "utilities/stack.hpp"
  43 #include "utilities/macros.hpp"
  44 #if INCLUDE_ALL_GCS
  45 #include "gc_implementation/g1/g1SATBCardTableModRefBS.hpp"
  46 #include "gc_implementation/parallelScavenge/psParallelCompact.hpp"
  47 #include "gc_implementation/parallelScavenge/psPromotionManager.hpp"
  48 #include "gc_implementation/parallelScavenge/psScavenge.hpp"
  49 #endif // INCLUDE_ALL_GCS
  50 
  51 bool Klass::is_cloneable() const {
  52   return _access_flags.is_cloneable() ||
  53          is_subtype_of(SystemDictionary::Cloneable_klass());
  54 }
  55 
  56 void Klass::set_is_cloneable() {
  57   if (oop_is_instance() && InstanceKlass::cast(this)->reference_type() != REF_NONE) {
  58     // Reference cloning should not be intrinsified and always happen in JVM_Clone.
  59   } else {
  60     _access_flags.set_is_cloneable();
  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(Symbol* name, 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, /*read_only*/false,
 168                              MetaspaceObj::ClassType, THREAD);
 169 }
 170 
 171 Klass::Klass() {
 172   Klass* k = this;
 173 
 174   // Preinitialize supertype information.
 175   // A later call to initialize_supers() may update these settings:
 176   set_super(NULL);
 177   for (juint i = 0; i < Klass::primary_super_limit(); i++) {
 178     _primary_supers[i] = NULL;
 179   }
 180   set_secondary_supers(NULL);
 181   set_secondary_super_cache(NULL);
 182   _primary_supers[0] = k;
 183   set_super_check_offset(in_bytes(primary_supers_offset()));
 184 
 185   // The constructor is used from init_self_patching_vtbl_list,
 186   // which doesn't zero out the memory before calling the constructor.
 187   // Need to set the field explicitly to not hit an assert that the field
 188   // should be NULL before setting it.
 189   _java_mirror = NULL;
 190 
 191   set_modifier_flags(0);
 192   set_layout_helper(Klass::_lh_neutral_value);
 193   set_name(NULL);
 194   AccessFlags af;
 195   af.set_flags(0);
 196   set_access_flags(af);
 197   set_subklass(NULL);
 198   set_next_sibling(NULL);
 199   set_next_link(NULL);
 200   TRACE_INIT_ID(this);
 201 
 202   set_prototype_header(markOopDesc::prototype());
 203   set_biased_lock_revocation_count(0);
 204   set_last_biased_lock_bulk_revocation_time(0);
 205 
 206   // The klass doesn't have any references at this point.
 207   clear_modified_oops();
 208   clear_accumulated_modified_oops();
 209   _shared_class_path_index = -1;
 210 }
 211 
 212 jint Klass::array_layout_helper(BasicType etype) {
 213   assert(etype >= T_BOOLEAN && etype <= T_OBJECT, "valid etype");
 214   // Note that T_ARRAY is not allowed here.
 215   int  hsize = arrayOopDesc::base_offset_in_bytes(etype);
 216   int  esize = type2aelembytes(etype);
 217   bool isobj = (etype == T_OBJECT);
 218   int  tag   =  isobj ? _lh_array_tag_obj_value : _lh_array_tag_type_value;
 219   int lh = array_layout_helper(tag, hsize, etype, exact_log2(esize));
 220 
 221   assert(lh < (int)_lh_neutral_value, "must look like an array layout");
 222   assert(layout_helper_is_array(lh), "correct kind");
 223   assert(layout_helper_is_objArray(lh) == isobj, "correct kind");
 224   assert(layout_helper_is_typeArray(lh) == !isobj, "correct kind");
 225   assert(layout_helper_header_size(lh) == hsize, "correct decode");
 226   assert(layout_helper_element_type(lh) == etype, "correct decode");
 227   assert(1 << layout_helper_log2_element_size(lh) == esize, "correct decode");
 228 
 229   return lh;
 230 }
 231 
 232 bool Klass::can_be_primary_super_slow() const {
 233   if (super() == NULL)
 234     return true;
 235   else if (super()->super_depth() >= primary_super_limit()-1)
 236     return false;
 237   else
 238     return true;
 239 }
 240 
 241 void Klass::initialize_supers(Klass* k, TRAPS) {
 242   if (FastSuperclassLimit == 0) {
 243     // None of the other machinery matters.
 244     set_super(k);
 245     return;
 246   }
 247   if (k == NULL) {
 248     set_super(NULL);
 249     _primary_supers[0] = this;
 250     assert(super_depth() == 0, "Object must already be initialized properly");
 251   } else if (k != super() || k == SystemDictionary::Object_klass()) {
 252     assert(super() == NULL || super() == SystemDictionary::Object_klass(),
 253            "initialize this only once to a non-trivial value");
 254     set_super(k);
 255     Klass* sup = k;
 256     int sup_depth = sup->super_depth();
 257     juint my_depth  = MIN2(sup_depth + 1, (int)primary_super_limit());
 258     if (!can_be_primary_super_slow())
 259       my_depth = primary_super_limit();
 260     for (juint i = 0; i < my_depth; i++) {
 261       _primary_supers[i] = sup->_primary_supers[i];
 262     }
 263     Klass* *super_check_cell;
 264     if (my_depth < primary_super_limit()) {
 265       _primary_supers[my_depth] = this;
 266       super_check_cell = &_primary_supers[my_depth];
 267     } else {
 268       // Overflow of the primary_supers array forces me to be secondary.
 269       super_check_cell = &_secondary_super_cache;
 270     }
 271     set_super_check_offset((address)super_check_cell - (address) this);
 272 
 273 #ifdef ASSERT
 274     {
 275       juint j = super_depth();
 276       assert(j == my_depth, "computed accessor gets right answer");
 277       Klass* t = this;
 278       while (!t->can_be_primary_super()) {
 279         t = t->super();
 280         j = t->super_depth();
 281       }
 282       for (juint j1 = j+1; j1 < primary_super_limit(); j1++) {
 283         assert(primary_super_of_depth(j1) == NULL, "super list padding");
 284       }
 285       while (t != NULL) {
 286         assert(primary_super_of_depth(j) == t, "super list initialization");
 287         t = t->super();
 288         --j;
 289       }
 290       assert(j == (juint)-1, "correct depth count");
 291     }
 292 #endif
 293   }
 294 
 295   if (secondary_supers() == NULL) {
 296     KlassHandle this_kh (THREAD, this);
 297 
 298     // Now compute the list of secondary supertypes.
 299     // Secondaries can occasionally be on the super chain,
 300     // if the inline "_primary_supers" array overflows.
 301     int extras = 0;
 302     Klass* p;
 303     for (p = super(); !(p == NULL || p->can_be_primary_super()); p = p->super()) {
 304       ++extras;
 305     }
 306 
 307     ResourceMark rm(THREAD);  // need to reclaim GrowableArrays allocated below
 308 
 309     // Compute the "real" non-extra secondaries.
 310     GrowableArray<Klass*>* secondaries = compute_secondary_supers(extras);
 311     if (secondaries == NULL) {
 312       // secondary_supers set by compute_secondary_supers
 313       return;
 314     }
 315 
 316     GrowableArray<Klass*>* primaries = new GrowableArray<Klass*>(extras);
 317 
 318     for (p = this_kh->super(); !(p == NULL || p->can_be_primary_super()); p = p->super()) {
 319       int i;                    // Scan for overflow primaries being duplicates of 2nd'arys
 320 
 321       // This happens frequently for very deeply nested arrays: the
 322       // primary superclass chain overflows into the secondary.  The
 323       // secondary list contains the element_klass's secondaries with
 324       // an extra array dimension added.  If the element_klass's
 325       // secondary list already contains some primary overflows, they
 326       // (with the extra level of array-ness) will collide with the
 327       // normal primary superclass overflows.
 328       for( i = 0; i < secondaries->length(); i++ ) {
 329         if( secondaries->at(i) == p )
 330           break;
 331       }
 332       if( i < secondaries->length() )
 333         continue;               // It's a dup, don't put it in
 334       primaries->push(p);
 335     }
 336     // Combine the two arrays into a metadata object to pack the array.
 337     // The primaries are added in the reverse order, then the secondaries.
 338     int new_length = primaries->length() + secondaries->length();
 339     Array<Klass*>* s2 = MetadataFactory::new_array<Klass*>(
 340                                        class_loader_data(), new_length, CHECK);
 341     int fill_p = primaries->length();
 342     for (int j = 0; j < fill_p; j++) {
 343       s2->at_put(j, primaries->pop());  // add primaries in reverse order.
 344     }
 345     for( int j = 0; j < secondaries->length(); j++ ) {
 346       s2->at_put(j+fill_p, secondaries->at(j));  // add secondaries on the end.
 347     }
 348 
 349   #ifdef ASSERT
 350       // We must not copy any NULL placeholders left over from bootstrap.
 351     for (int j = 0; j < s2->length(); j++) {
 352       assert(s2->at(j) != NULL, "correct bootstrapping order");
 353     }
 354   #endif
 355 
 356     this_kh->set_secondary_supers(s2);
 357   }
 358 }
 359 
 360 GrowableArray<Klass*>* Klass::compute_secondary_supers(int num_extra_slots) {
 361   assert(num_extra_slots == 0, "override for complex klasses");
 362   set_secondary_supers(Universe::the_empty_klass_array());
 363   return NULL;
 364 }
 365 
 366 
 367 Klass* Klass::subklass() const {
 368   return _subklass == NULL ? NULL : _subklass;
 369 }
 370 
 371 InstanceKlass* Klass::superklass() const {
 372   assert(super() == NULL || super()->oop_is_instance(), "must be instance klass");
 373   return _super == NULL ? NULL : InstanceKlass::cast(_super);
 374 }
 375 
 376 Klass* Klass::next_sibling() const {
 377   return _next_sibling == NULL ? NULL : _next_sibling;
 378 }
 379 
 380 void Klass::set_subklass(Klass* s) {
 381   assert(s != this, "sanity check");
 382   _subklass = s;
 383 }
 384 
 385 void Klass::set_next_sibling(Klass* s) {
 386   assert(s != this, "sanity check");
 387   _next_sibling = s;
 388 }
 389 
 390 void Klass::append_to_sibling_list() {
 391   debug_only(verify();)
 392   // add ourselves to superklass' subklass list
 393   InstanceKlass* super = superklass();
 394   if (super == NULL) return;        // special case: class Object
 395   assert((!super->is_interface()    // interfaces cannot be supers
 396           && (super->superklass() == NULL || !is_interface())),
 397          "an interface can only be a subklass of Object");
 398   Klass* prev_first_subklass = super->subklass_oop();
 399   if (prev_first_subklass != NULL) {
 400     // set our sibling to be the superklass' previous first subklass
 401     set_next_sibling(prev_first_subklass);
 402   }
 403   // make ourselves the superklass' first subklass
 404   super->set_subklass(this);
 405   debug_only(verify();)
 406 }
 407 
 408 bool Klass::is_loader_alive(BoolObjectClosure* is_alive) {
 409 #ifdef ASSERT
 410   // The class is alive iff the class loader is alive.
 411   oop loader = class_loader();
 412   bool loader_alive = (loader == NULL) || is_alive->do_object_b(loader);
 413 #endif // ASSERT
 414 
 415   // The class is alive if it's mirror is alive (which should be marked if the
 416   // loader is alive) unless it's an anoymous class.
 417   bool mirror_alive = is_alive->do_object_b(java_mirror());
 418   assert(!mirror_alive || loader_alive, "loader must be alive if the mirror is"
 419                         " but not the other way around with anonymous classes");
 420   return mirror_alive;
 421 }
 422 
 423 void Klass::clean_weak_klass_links(BoolObjectClosure* is_alive, bool clean_alive_klasses) {
 424   if (!ClassUnloading) {
 425     return;
 426   }
 427 
 428   Klass* root = SystemDictionary::Object_klass();
 429   Stack<Klass*, mtGC> stack;
 430 
 431   stack.push(root);
 432   while (!stack.is_empty()) {
 433     Klass* current = stack.pop();
 434 
 435     assert(current->is_loader_alive(is_alive), "just checking, this should be live");
 436 
 437     // Find and set the first alive subklass
 438     Klass* sub = current->subklass_oop();
 439     while (sub != NULL && !sub->is_loader_alive(is_alive)) {
 440 #ifndef PRODUCT
 441       if (TraceClassUnloading && WizardMode) {
 442         ResourceMark rm;
 443         tty->print_cr("[Unlinking class (subclass) %s]", sub->external_name());
 444       }
 445 #endif
 446       sub = sub->next_sibling_oop();
 447     }
 448     current->set_subklass(sub);
 449     if (sub != NULL) {
 450       stack.push(sub);
 451     }
 452 
 453     // Find and set the first alive sibling
 454     Klass* sibling = current->next_sibling_oop();
 455     while (sibling != NULL && !sibling->is_loader_alive(is_alive)) {
 456       if (TraceClassUnloading && WizardMode) {
 457         ResourceMark rm;
 458         tty->print_cr("[Unlinking class (sibling) %s]", sibling->external_name());
 459       }
 460       sibling = sibling->next_sibling_oop();
 461     }
 462     current->set_next_sibling(sibling);
 463     if (sibling != NULL) {
 464       stack.push(sibling);
 465     }
 466 
 467     // Clean the implementors list and method data.
 468     if (clean_alive_klasses && current->oop_is_instance()) {
 469       InstanceKlass* ik = InstanceKlass::cast(current);
 470       ik->clean_weak_instanceklass_links(is_alive);
 471 
 472       // JVMTI RedefineClasses creates previous versions that are not in
 473       // the class hierarchy, so process them here.
 474       while ((ik = ik->previous_versions()) != NULL) {
 475         ik->clean_weak_instanceklass_links(is_alive);
 476       }
 477     }
 478   }
 479 }
 480 
 481 void Klass::klass_update_barrier_set(oop v) {
 482   record_modified_oops();
 483 }
 484 
 485 // This barrier is used by G1 to remember the old oop values, so
 486 // that we don't forget any objects that were live at the snapshot at
 487 // the beginning. This function is only used when we write oops into Klasses.
 488 void Klass::klass_update_barrier_set_pre(oop* p, oop v) {
 489 #if INCLUDE_ALL_GCS
 490   if (UseG1GC) {
 491     oop obj = *p;
 492     if (obj != NULL) {
 493       G1SATBCardTableModRefBS::enqueue(obj);
 494     }
 495   }
 496 #endif
 497 }
 498 
 499 void Klass::klass_oop_store(oop* p, oop v) {
 500   assert(!Universe::heap()->is_in_reserved((void*)p), "Should store pointer into metadata");
 501   assert(v == NULL || Universe::heap()->is_in_reserved((void*)v), "Should store pointer to an object");
 502 
 503   // do the store
 504   if (always_do_update_barrier) {
 505     klass_oop_store((volatile oop*)p, v);
 506   } else {
 507     klass_update_barrier_set_pre(p, v);
 508     *p = v;
 509     klass_update_barrier_set(v);
 510   }
 511 }
 512 
 513 void Klass::klass_oop_store(volatile oop* p, oop v) {
 514   assert(!Universe::heap()->is_in_reserved((void*)p), "Should store pointer into metadata");
 515   assert(v == NULL || Universe::heap()->is_in_reserved((void*)v), "Should store pointer to an object");
 516 
 517   klass_update_barrier_set_pre((oop*)p, v); // Cast away volatile.
 518   OrderAccess::release_store_ptr(p, v);
 519   klass_update_barrier_set(v);
 520 }
 521 
 522 void Klass::oops_do(OopClosure* cl) {
 523   cl->do_oop(&_java_mirror);
 524 }
 525 
 526 void Klass::remove_unshareable_info() {
 527   assert (DumpSharedSpaces, "only called for DumpSharedSpaces");
 528 
 529   set_subklass(NULL);
 530   set_next_sibling(NULL);
 531   // Clear the java mirror
 532   set_java_mirror(NULL);
 533   set_next_link(NULL);
 534 
 535   // Null out class_loader_data because we don't share that yet.
 536   set_class_loader_data(NULL);
 537 }
 538 
 539 void Klass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) {
 540   TRACE_INIT_ID(this);
 541   // If an exception happened during CDS restore, some of these fields may already be
 542   // set.  We leave the class on the CLD list, even if incomplete so that we don't
 543   // modify the CLD list outside a safepoint.
 544   if (class_loader_data() == NULL) {
 545     // Restore class_loader_data
 546     set_class_loader_data(loader_data);
 547 
 548     // Add to class loader list first before creating the mirror
 549     // (same order as class file parsing)
 550     loader_data->add_class(this);
 551   }
 552 
 553   // Recreate the class mirror.
 554   // Only recreate it if not present.  A previous attempt to restore may have
 555   // gotten an OOM later but keep the mirror if it was created.
 556   if (java_mirror() == NULL) {
 557     java_lang_Class::create_mirror(this, class_loader(), protection_domain, CHECK);
 558   }
 559 }
 560 
 561 Klass* Klass::array_klass_or_null(int rank) {
 562   EXCEPTION_MARK;
 563   // No exception can be thrown by array_klass_impl when called with or_null == true.
 564   // (In anycase, the execption mark will fail if it do so)
 565   return array_klass_impl(true, rank, THREAD);
 566 }
 567 
 568 
 569 Klass* Klass::array_klass_or_null() {
 570   EXCEPTION_MARK;
 571   // No exception can be thrown by array_klass_impl when called with or_null == true.
 572   // (In anycase, the execption mark will fail if it do so)
 573   return array_klass_impl(true, THREAD);
 574 }
 575 
 576 
 577 Klass* Klass::array_klass_impl(bool or_null, int rank, TRAPS) {
 578   fatal("array_klass should be dispatched to InstanceKlass, ObjArrayKlass or TypeArrayKlass");
 579   return NULL;
 580 }
 581 
 582 
 583 Klass* Klass::array_klass_impl(bool or_null, TRAPS) {
 584   fatal("array_klass should be dispatched to InstanceKlass, ObjArrayKlass or TypeArrayKlass");
 585   return NULL;
 586 }
 587 
 588 oop Klass::class_loader() const { return class_loader_data()->class_loader(); }
 589 
 590 const char* Klass::external_name() const {
 591   if (oop_is_instance()) {
 592     InstanceKlass* ik = (InstanceKlass*) this;
 593     if (ik->is_anonymous()) {
 594       assert(EnableInvokeDynamic, "");
 595       intptr_t hash = 0;
 596       if (ik->java_mirror() != NULL) {
 597         // java_mirror might not be created yet, return 0 as hash.
 598         hash = ik->java_mirror()->identity_hash();
 599       }
 600       char     hash_buf[40];
 601       sprintf(hash_buf, "/" UINTX_FORMAT, (uintx)hash);
 602       size_t   hash_len = strlen(hash_buf);
 603 
 604       size_t result_len = name()->utf8_length();
 605       char*  result     = NEW_RESOURCE_ARRAY(char, result_len + hash_len + 1);
 606       name()->as_klass_external_name(result, (int) result_len + 1);
 607       assert(strlen(result) == result_len, "");
 608       strcpy(result + result_len, hash_buf);
 609       assert(strlen(result) == result_len + hash_len, "");
 610       return result;
 611     }
 612   }
 613   if (name() == NULL)  return "<unknown>";
 614   return name()->as_klass_external_name();
 615 }
 616 
 617 
 618 const char* Klass::signature_name() const {
 619   if (name() == NULL)  return "<unknown>";
 620   return name()->as_C_string();
 621 }
 622 
 623 // Unless overridden, modifier_flags is 0.
 624 jint Klass::compute_modifier_flags(TRAPS) const {
 625   return 0;
 626 }
 627 
 628 int Klass::atomic_incr_biased_lock_revocation_count() {
 629   return (int) Atomic::add(1, &_biased_lock_revocation_count);
 630 }
 631 
 632 // Unless overridden, jvmti_class_status has no flags set.
 633 jint Klass::jvmti_class_status() const {
 634   return 0;
 635 }
 636 
 637 
 638 // Printing
 639 
 640 void Klass::print_on(outputStream* st) const {
 641   ResourceMark rm;
 642   // print title
 643   st->print("%s", internal_name());
 644   print_address_on(st);
 645   st->cr();
 646 }
 647 
 648 void Klass::oop_print_on(oop obj, outputStream* st) {
 649   ResourceMark rm;
 650   // print title
 651   st->print_cr("%s ", internal_name());
 652   obj->print_address_on(st);
 653 
 654   if (WizardMode) {
 655      // print header
 656      obj->mark()->print_on(st);
 657   }
 658 
 659   // print class
 660   st->print(" - klass: ");
 661   obj->klass()->print_value_on(st);
 662   st->cr();
 663 }
 664 
 665 void Klass::oop_print_value_on(oop obj, outputStream* st) {
 666   // print title
 667   ResourceMark rm;              // Cannot print in debug mode without this
 668   st->print("%s", internal_name());
 669   obj->print_address_on(st);
 670 }
 671 
 672 #if INCLUDE_SERVICES
 673 // Size Statistics
 674 void Klass::collect_statistics(KlassSizeStats *sz) const {
 675   sz->_klass_bytes = sz->count(this);
 676   sz->_mirror_bytes = sz->count(java_mirror());
 677   sz->_secondary_supers_bytes = sz->count_array(secondary_supers());
 678 
 679   sz->_ro_bytes += sz->_secondary_supers_bytes;
 680   sz->_rw_bytes += sz->_klass_bytes + sz->_mirror_bytes;
 681 }
 682 #endif // INCLUDE_SERVICES
 683 
 684 // Verification
 685 
 686 void Klass::verify_on(outputStream* st) {
 687 
 688   // This can be expensive, but it is worth checking that this klass is actually
 689   // in the CLD graph but not in production.
 690   assert(Metaspace::contains((address)this), "Should be");
 691 
 692   guarantee(this->is_klass(),"should be klass");
 693 
 694   if (super() != NULL) {
 695     guarantee(super()->is_klass(), "should be klass");
 696   }
 697   if (secondary_super_cache() != NULL) {
 698     Klass* ko = secondary_super_cache();
 699     guarantee(ko->is_klass(), "should be klass");
 700   }
 701   for ( uint i = 0; i < primary_super_limit(); i++ ) {
 702     Klass* ko = _primary_supers[i];
 703     if (ko != NULL) {
 704       guarantee(ko->is_klass(), "should be klass");
 705     }
 706   }
 707 
 708   if (java_mirror() != NULL) {
 709     guarantee(java_mirror()->is_oop(), "should be instance");
 710   }
 711 }
 712 
 713 void Klass::oop_verify_on(oop obj, outputStream* st) {
 714   guarantee(obj->is_oop(),  "should be oop");
 715   guarantee(obj->klass()->is_klass(), "klass field is not a klass");
 716 }
 717 
 718 #ifndef PRODUCT
 719 
 720 bool Klass::verify_vtable_index(int i) {
 721   if (oop_is_instance()) {
 722     int limit = ((InstanceKlass*)this)->vtable_length()/vtableEntry::size();
 723     assert(i >= 0 && i < limit, err_msg("index %d out of bounds %d", i, limit));
 724   } else {
 725     assert(oop_is_array(), "Must be");
 726     int limit = ((ArrayKlass*)this)->vtable_length()/vtableEntry::size();
 727     assert(i >= 0 && i < limit, err_msg("index %d out of bounds %d", i, limit));
 728   }
 729   return true;
 730 }
 731 
 732 bool Klass::verify_itable_index(int i) {
 733   assert(oop_is_instance(), "");
 734   int method_count = klassItable::method_count_for_interface(this);
 735   assert(i >= 0 && i < method_count, "index out of bounds");
 736   return true;
 737 }
 738 
 739 #endif
 740 
 741 /////////////// Unit tests ///////////////
 742 
 743 #ifndef PRODUCT
 744 
 745 class TestKlass {
 746  public:
 747   static void test_oop_is_instanceClassLoader() {
 748     assert(SystemDictionary::ClassLoader_klass()->oop_is_instanceClassLoader(), "assert");
 749     assert(!SystemDictionary::String_klass()->oop_is_instanceClassLoader(), "assert");
 750   }
 751 };
 752 
 753 void TestKlass_test() {
 754   TestKlass::test_oop_is_instanceClassLoader();
 755 }
 756 
 757 #endif