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 
  47 void Klass::set_java_mirror(Handle m) {
  48   if (m.is_null()) {
  49     _java_mirror = NULL;
  50   } else {
  51     _java_mirror = class_loader_data()->add_handle(m);
  52   }
  53 }
  54 
  55 oop Klass::java_mirror() const {
  56   return _java_mirror.resolve();
  57 }
  58 
  59 bool Klass::is_cloneable() const {
  60   return _access_flags.is_cloneable_fast() ||
  61          is_subtype_of(SystemDictionary::Cloneable_klass());
  62 }
  63 
  64 void Klass::set_is_cloneable() {
  65   if (name() != vmSymbols::java_lang_invoke_MemberName()) {
  66     _access_flags.set_is_cloneable_fast();
  67   } else {
  68     assert(is_final(), "no subclasses allowed");
  69     // MemberName cloning should not be intrinsified and always happen in JVM_Clone.
  70   }
  71 }
  72 
  73 void Klass::set_name(Symbol* n) {
  74   _name = n;
  75   if (_name != NULL) _name->increment_refcount();
  76 }
  77 
  78 bool Klass::is_subclass_of(const Klass* k) const {
  79   // Run up the super chain and check
  80   if (this == k) return true;
  81 
  82   Klass* t = const_cast<Klass*>(this)->super();
  83 
  84   while (t != NULL) {
  85     if (t == k) return true;
  86     t = t->super();
  87   }
  88   return false;
  89 }
  90 
  91 bool Klass::search_secondary_supers(Klass* k) const {
  92   // Put some extra logic here out-of-line, before the search proper.
  93   // This cuts down the size of the inline method.
  94 
  95   // This is necessary, since I am never in my own secondary_super list.
  96   if (this == k)
  97     return true;
  98   // Scan the array-of-objects for a match
  99   int cnt = secondary_supers()->length();
 100   for (int i = 0; i < cnt; i++) {
 101     if (secondary_supers()->at(i) == k) {
 102       ((Klass*)this)->set_secondary_super_cache(k);
 103       return true;
 104     }
 105   }
 106   return false;
 107 }
 108 
 109 // Return self, except for abstract classes with exactly 1
 110 // implementor.  Then return the 1 concrete implementation.
 111 Klass *Klass::up_cast_abstract() {
 112   Klass *r = this;
 113   while( r->is_abstract() ) {   // Receiver is abstract?
 114     Klass *s = r->subklass();   // Check for exactly 1 subklass
 115     if( !s || s->next_sibling() ) // Oops; wrong count; give up
 116       return this;              // Return 'this' as a no-progress flag
 117     r = s;                    // Loop till find concrete class
 118   }
 119   return r;                   // Return the 1 concrete class
 120 }
 121 
 122 // Find LCA in class hierarchy
 123 Klass *Klass::LCA( Klass *k2 ) {
 124   Klass *k1 = this;
 125   while( 1 ) {
 126     if( k1->is_subtype_of(k2) ) return k2;
 127     if( k2->is_subtype_of(k1) ) return k1;
 128     k1 = k1->super();
 129     k2 = k2->super();
 130   }
 131 }
 132 
 133 
 134 void Klass::check_valid_for_instantiation(bool throwError, TRAPS) {
 135   ResourceMark rm(THREAD);
 136   THROW_MSG(throwError ? vmSymbols::java_lang_InstantiationError()
 137             : vmSymbols::java_lang_InstantiationException(), external_name());
 138 }
 139 
 140 
 141 void Klass::copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS) {
 142   THROW(vmSymbols::java_lang_ArrayStoreException());
 143 }
 144 
 145 
 146 void Klass::initialize(TRAPS) {
 147   ShouldNotReachHere();
 148 }
 149 
 150 bool Klass::compute_is_subtype_of(Klass* k) {
 151   assert(k->is_klass(), "argument must be a class");
 152   return is_subclass_of(k);
 153 }
 154 
 155 Klass* Klass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
 156 #ifdef ASSERT
 157   tty->print_cr("Error: find_field called on a klass oop."
 158                 " Likely error: reflection method does not correctly"
 159                 " wrap return value in a mirror object.");
 160 #endif
 161   ShouldNotReachHere();
 162   return NULL;
 163 }
 164 
 165 Method* Klass::uncached_lookup_method(const Symbol* name, const Symbol* signature, OverpassLookupMode overpass_mode) const {
 166 #ifdef ASSERT
 167   tty->print_cr("Error: uncached_lookup_method called on a klass oop."
 168                 " Likely error: reflection method does not correctly"
 169                 " wrap return value in a mirror object.");
 170 #endif
 171   ShouldNotReachHere();
 172   return NULL;
 173 }
 174 
 175 void* Klass::operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, TRAPS) throw() {
 176   return Metaspace::allocate(loader_data, word_size, MetaspaceObj::ClassType, THREAD);
 177 }
 178 
 179 // "Normal" instantiation is preceeded by a MetaspaceObj allocation
 180 // which zeros out memory - calloc equivalent.
 181 // The constructor is also used from CppVtableCloner,
 182 // which doesn't zero out the memory before calling the constructor.
 183 // Need to set the _java_mirror field explicitly to not hit an assert that the field
 184 // should be NULL before setting it.
 185 Klass::Klass() : _prototype_header(markOopDesc::prototype()),
 186                  _shared_class_path_index(-1),
 187                  _java_mirror(NULL) {
 188 
 189   _primary_supers[0] = this;
 190   set_super_check_offset(in_bytes(primary_supers_offset()));
 191 }
 192 
 193 jint Klass::array_layout_helper(BasicType etype) {
 194   assert(etype >= T_BOOLEAN && etype <= T_OBJECT, "valid etype");
 195   // Note that T_ARRAY is not allowed here.
 196   int  hsize = arrayOopDesc::base_offset_in_bytes(etype);
 197   int  esize = type2aelembytes(etype);
 198   bool isobj = (etype == T_OBJECT);
 199   int  tag   =  isobj ? _lh_array_tag_obj_value : _lh_array_tag_type_value;
 200   int lh = array_layout_helper(tag, hsize, etype, exact_log2(esize));
 201 
 202   assert(lh < (int)_lh_neutral_value, "must look like an array layout");
 203   assert(layout_helper_is_array(lh), "correct kind");
 204   assert(layout_helper_is_objArray(lh) == isobj, "correct kind");
 205   assert(layout_helper_is_typeArray(lh) == !isobj, "correct kind");
 206   assert(layout_helper_header_size(lh) == hsize, "correct decode");
 207   assert(layout_helper_element_type(lh) == etype, "correct decode");
 208   assert(1 << layout_helper_log2_element_size(lh) == esize, "correct decode");
 209 
 210   return lh;
 211 }
 212 
 213 bool Klass::can_be_primary_super_slow() const {
 214   if (super() == NULL)
 215     return true;
 216   else if (super()->super_depth() >= primary_super_limit()-1)
 217     return false;
 218   else
 219     return true;
 220 }
 221 
 222 void Klass::initialize_supers(Klass* k, TRAPS) {
 223   if (FastSuperclassLimit == 0) {
 224     // None of the other machinery matters.
 225     set_super(k);
 226     return;
 227   }
 228   if (k == NULL) {
 229     set_super(NULL);
 230     _primary_supers[0] = this;
 231     assert(super_depth() == 0, "Object must already be initialized properly");
 232   } else if (k != super() || k == SystemDictionary::Object_klass()) {
 233     assert(super() == NULL || super() == SystemDictionary::Object_klass(),
 234            "initialize this only once to a non-trivial value");
 235     set_super(k);
 236     Klass* sup = k;
 237     int sup_depth = sup->super_depth();
 238     juint my_depth  = MIN2(sup_depth + 1, (int)primary_super_limit());
 239     if (!can_be_primary_super_slow())
 240       my_depth = primary_super_limit();
 241     for (juint i = 0; i < my_depth; i++) {
 242       _primary_supers[i] = sup->_primary_supers[i];
 243     }
 244     Klass* *super_check_cell;
 245     if (my_depth < primary_super_limit()) {
 246       _primary_supers[my_depth] = this;
 247       super_check_cell = &_primary_supers[my_depth];
 248     } else {
 249       // Overflow of the primary_supers array forces me to be secondary.
 250       super_check_cell = &_secondary_super_cache;
 251     }
 252     set_super_check_offset((address)super_check_cell - (address) this);
 253 
 254 #ifdef ASSERT
 255     {
 256       juint j = super_depth();
 257       assert(j == my_depth, "computed accessor gets right answer");
 258       Klass* t = this;
 259       while (!t->can_be_primary_super()) {
 260         t = t->super();
 261         j = t->super_depth();
 262       }
 263       for (juint j1 = j+1; j1 < primary_super_limit(); j1++) {
 264         assert(primary_super_of_depth(j1) == NULL, "super list padding");
 265       }
 266       while (t != NULL) {
 267         assert(primary_super_of_depth(j) == t, "super list initialization");
 268         t = t->super();
 269         --j;
 270       }
 271       assert(j == (juint)-1, "correct depth count");
 272     }
 273 #endif
 274   }
 275 
 276   if (secondary_supers() == NULL) {
 277 
 278     // Now compute the list of secondary supertypes.
 279     // Secondaries can occasionally be on the super chain,
 280     // if the inline "_primary_supers" array overflows.
 281     int extras = 0;
 282     Klass* p;
 283     for (p = super(); !(p == NULL || p->can_be_primary_super()); p = p->super()) {
 284       ++extras;
 285     }
 286 
 287     ResourceMark rm(THREAD);  // need to reclaim GrowableArrays allocated below
 288 
 289     // Compute the "real" non-extra secondaries.
 290     GrowableArray<Klass*>* secondaries = compute_secondary_supers(extras);
 291     if (secondaries == NULL) {
 292       // secondary_supers set by compute_secondary_supers
 293       return;
 294     }
 295 
 296     GrowableArray<Klass*>* primaries = new GrowableArray<Klass*>(extras);
 297 
 298     for (p = super(); !(p == NULL || p->can_be_primary_super()); p = p->super()) {
 299       int i;                    // Scan for overflow primaries being duplicates of 2nd'arys
 300 
 301       // This happens frequently for very deeply nested arrays: the
 302       // primary superclass chain overflows into the secondary.  The
 303       // secondary list contains the element_klass's secondaries with
 304       // an extra array dimension added.  If the element_klass's
 305       // secondary list already contains some primary overflows, they
 306       // (with the extra level of array-ness) will collide with the
 307       // normal primary superclass overflows.
 308       for( i = 0; i < secondaries->length(); i++ ) {
 309         if( secondaries->at(i) == p )
 310           break;
 311       }
 312       if( i < secondaries->length() )
 313         continue;               // It's a dup, don't put it in
 314       primaries->push(p);
 315     }
 316     // Combine the two arrays into a metadata object to pack the array.
 317     // The primaries are added in the reverse order, then the secondaries.
 318     int new_length = primaries->length() + secondaries->length();
 319     Array<Klass*>* s2 = MetadataFactory::new_array<Klass*>(
 320                                        class_loader_data(), new_length, CHECK);
 321     int fill_p = primaries->length();
 322     for (int j = 0; j < fill_p; j++) {
 323       s2->at_put(j, primaries->pop());  // add primaries in reverse order.
 324     }
 325     for( int j = 0; j < secondaries->length(); j++ ) {
 326       s2->at_put(j+fill_p, secondaries->at(j));  // add secondaries on the end.
 327     }
 328 
 329   #ifdef ASSERT
 330       // We must not copy any NULL placeholders left over from bootstrap.
 331     for (int j = 0; j < s2->length(); j++) {
 332       assert(s2->at(j) != NULL, "correct bootstrapping order");
 333     }
 334   #endif
 335 
 336     set_secondary_supers(s2);
 337   }
 338 }
 339 
 340 GrowableArray<Klass*>* Klass::compute_secondary_supers(int num_extra_slots) {
 341   assert(num_extra_slots == 0, "override for complex klasses");
 342   set_secondary_supers(Universe::the_empty_klass_array());
 343   return NULL;
 344 }
 345 
 346 
 347 InstanceKlass* Klass::superklass() const {
 348   assert(super() == NULL || super()->is_instance_klass(), "must be instance klass");
 349   return _super == NULL ? NULL : InstanceKlass::cast(_super);
 350 }
 351 
 352 void Klass::set_subklass(Klass* s) {
 353   assert(s != this, "sanity check");
 354   _subklass = s;
 355 }
 356 
 357 void Klass::set_next_sibling(Klass* s) {
 358   assert(s != this, "sanity check");
 359   _next_sibling = s;
 360 }
 361 
 362 void Klass::append_to_sibling_list() {
 363   debug_only(verify();)
 364   // add ourselves to superklass' subklass list
 365   InstanceKlass* super = superklass();
 366   if (super == NULL) return;        // special case: class Object
 367   assert((!super->is_interface()    // interfaces cannot be supers
 368           && (super->superklass() == NULL || !is_interface())),
 369          "an interface can only be a subklass of Object");
 370   Klass* prev_first_subklass = super->subklass();
 371   if (prev_first_subklass != NULL) {
 372     // set our sibling to be the superklass' previous first subklass
 373     set_next_sibling(prev_first_subklass);
 374   }
 375   // make ourselves the superklass' first subklass
 376   super->set_subklass(this);
 377   debug_only(verify();)
 378 }
 379 
 380 bool Klass::is_loader_alive(BoolObjectClosure* is_alive) {
 381 #ifdef ASSERT
 382   // The class is alive iff the class loader is alive.
 383   oop loader = class_loader();
 384   bool loader_alive = (loader == NULL) || is_alive->do_object_b(loader);
 385 #endif // ASSERT
 386 
 387   // The class is alive if it's mirror is alive (which should be marked if the
 388   // loader is alive) unless it's an anoymous class.
 389   bool mirror_alive = is_alive->do_object_b(java_mirror());
 390   assert(!mirror_alive || loader_alive, "loader must be alive if the mirror is"
 391                         " but not the other way around with anonymous classes");
 392   return mirror_alive;
 393 }
 394 
 395 void Klass::clean_weak_klass_links(BoolObjectClosure* is_alive, bool clean_alive_klasses) {
 396   if (!ClassUnloading) {
 397     return;
 398   }
 399 
 400   Klass* root = SystemDictionary::Object_klass();
 401   Stack<Klass*, mtGC> stack;
 402 
 403   stack.push(root);
 404   while (!stack.is_empty()) {
 405     Klass* current = stack.pop();
 406 
 407     assert(current->is_loader_alive(is_alive), "just checking, this should be live");
 408 
 409     // Find and set the first alive subklass
 410     Klass* sub = current->subklass();
 411     while (sub != NULL && !sub->is_loader_alive(is_alive)) {
 412 #ifndef PRODUCT
 413       if (log_is_enabled(Trace, class, unload)) {
 414         ResourceMark rm;
 415         log_trace(class, unload)("unlinking class (subclass): %s", sub->external_name());
 416       }
 417 #endif
 418       sub = sub->next_sibling();
 419     }
 420     current->set_subklass(sub);
 421     if (sub != NULL) {
 422       stack.push(sub);
 423     }
 424 
 425     // Find and set the first alive sibling
 426     Klass* sibling = current->next_sibling();
 427     while (sibling != NULL && !sibling->is_loader_alive(is_alive)) {
 428       if (log_is_enabled(Trace, class, unload)) {
 429         ResourceMark rm;
 430         log_trace(class, unload)("[Unlinking class (sibling) %s]", sibling->external_name());
 431       }
 432       sibling = sibling->next_sibling();
 433     }
 434     current->set_next_sibling(sibling);
 435     if (sibling != NULL) {
 436       stack.push(sibling);
 437     }
 438 
 439     // Clean the implementors list and method data.
 440     if (clean_alive_klasses && current->is_instance_klass()) {
 441       InstanceKlass* ik = InstanceKlass::cast(current);
 442       ik->clean_weak_instanceklass_links(is_alive);
 443 
 444       // JVMTI RedefineClasses creates previous versions that are not in
 445       // the class hierarchy, so process them here.
 446       while ((ik = ik->previous_versions()) != NULL) {
 447         ik->clean_weak_instanceklass_links(is_alive);
 448       }
 449     }
 450   }
 451 }
 452 













































 453 void Klass::metaspace_pointers_do(MetaspaceClosure* it) {
 454   if (log_is_enabled(Trace, cds)) {
 455     ResourceMark rm;
 456     log_trace(cds)("Iter(Klass): %p (%s)", this, external_name());
 457   }
 458 
 459   it->push(&_name);
 460   it->push(&_secondary_super_cache);
 461   it->push(&_secondary_supers);
 462   for (int i = 0; i < _primary_super_limit; i++) {
 463     it->push(&_primary_supers[i]);
 464   }
 465   it->push(&_super);
 466   it->push(&_subklass);
 467   it->push(&_next_sibling);
 468   it->push(&_next_link);
 469 
 470   vtableEntry* vt = start_of_vtable();
 471   for (int i=0; i<vtable_length(); i++) {
 472     it->push(vt[i].method_addr());
 473   }
 474 }
 475 
 476 void Klass::remove_unshareable_info() {
 477   assert (DumpSharedSpaces, "only called for DumpSharedSpaces");
 478   TRACE_REMOVE_ID(this);
 479   if (log_is_enabled(Trace, cds, unshareable)) {
 480     ResourceMark rm;
 481     log_trace(cds, unshareable)("remove: %s", external_name());
 482   }
 483 
 484   set_subklass(NULL);
 485   set_next_sibling(NULL);
 486   set_next_link(NULL);
 487 
 488   // Null out class_loader_data because we don't share that yet.
 489   set_class_loader_data(NULL);
 490   set_is_shared();
 491 }
 492 
 493 void Klass::remove_java_mirror() {
 494   assert (DumpSharedSpaces, "only called for DumpSharedSpaces");
 495   if (log_is_enabled(Trace, cds, unshareable)) {
 496     ResourceMark rm;
 497     log_trace(cds, unshareable)("remove java_mirror: %s", external_name());
 498   }
 499   // Just null out the mirror.  The class_loader_data() no longer exists.
 500   _java_mirror = NULL;
 501 }
 502 
 503 void Klass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) {
 504   assert(is_klass(), "ensure C++ vtable is restored");
 505   assert(is_shared(), "must be set");
 506   TRACE_RESTORE_ID(this);
 507   if (log_is_enabled(Trace, cds, unshareable)) {
 508     ResourceMark rm;
 509     log_trace(cds, unshareable)("restore: %s", external_name());
 510   }
 511 
 512   // If an exception happened during CDS restore, some of these fields may already be
 513   // set.  We leave the class on the CLD list, even if incomplete so that we don't
 514   // modify the CLD list outside a safepoint.
 515   if (class_loader_data() == NULL) {
 516     // Restore class_loader_data to the null class loader data
 517     set_class_loader_data(loader_data);
 518 
 519     // Add to null class loader list first before creating the mirror
 520     // (same order as class file parsing)
 521     loader_data->add_class(this);
 522   }
 523 
 524   // Recreate the class mirror.
 525   // Only recreate it if not present.  A previous attempt to restore may have
 526   // gotten an OOM later but keep the mirror if it was created.
 527   if (java_mirror() == NULL) {
 528     Handle loader(THREAD, loader_data->class_loader());
 529     ModuleEntry* module_entry = NULL;
 530     Klass* k = this;
 531     if (k->is_objArray_klass()) {
 532       k = ObjArrayKlass::cast(k)->bottom_klass();
 533     }
 534     // Obtain klass' module.
 535     if (k->is_instance_klass()) {
 536       InstanceKlass* ik = (InstanceKlass*) k;
 537       module_entry = ik->module();
 538     } else {
 539       module_entry = ModuleEntryTable::javabase_moduleEntry();
 540     }
 541     // Obtain java.lang.Module, if available
 542     Handle module_handle(THREAD, ((module_entry != NULL) ? module_entry->module() : (oop)NULL));
 543     java_lang_Class::create_mirror(this, loader, module_handle, protection_domain, CHECK);
 544   }
 545 }
 546 
 547 Klass* Klass::array_klass_or_null(int rank) {
 548   EXCEPTION_MARK;
 549   // No exception can be thrown by array_klass_impl when called with or_null == true.
 550   // (In anycase, the execption mark will fail if it do so)
 551   return array_klass_impl(true, rank, THREAD);
 552 }
 553 
 554 
 555 Klass* Klass::array_klass_or_null() {
 556   EXCEPTION_MARK;
 557   // No exception can be thrown by array_klass_impl when called with or_null == true.
 558   // (In anycase, the execption mark will fail if it do so)
 559   return array_klass_impl(true, THREAD);
 560 }
 561 
 562 
 563 Klass* Klass::array_klass_impl(bool or_null, int rank, TRAPS) {
 564   fatal("array_klass should be dispatched to InstanceKlass, ObjArrayKlass or TypeArrayKlass");
 565   return NULL;
 566 }
 567 
 568 
 569 Klass* Klass::array_klass_impl(bool or_null, TRAPS) {
 570   fatal("array_klass should be dispatched to InstanceKlass, ObjArrayKlass or TypeArrayKlass");
 571   return NULL;
 572 }
 573 
 574 oop Klass::class_loader() const { return class_loader_data()->class_loader(); }
 575 
 576 // In product mode, this function doesn't have virtual function calls so
 577 // there might be some performance advantage to handling InstanceKlass here.
 578 const char* Klass::external_name() const {
 579   if (is_instance_klass()) {
 580     const InstanceKlass* ik = static_cast<const InstanceKlass*>(this);
 581     if (ik->is_anonymous()) {
 582       intptr_t hash = 0;
 583       if (ik->java_mirror() != NULL) {
 584         // java_mirror might not be created yet, return 0 as hash.
 585         hash = ik->java_mirror()->identity_hash();
 586       }
 587       char     hash_buf[40];
 588       sprintf(hash_buf, "/" UINTX_FORMAT, (uintx)hash);
 589       size_t   hash_len = strlen(hash_buf);
 590 
 591       size_t result_len = name()->utf8_length();
 592       char*  result     = NEW_RESOURCE_ARRAY(char, result_len + hash_len + 1);
 593       name()->as_klass_external_name(result, (int) result_len + 1);
 594       assert(strlen(result) == result_len, "");
 595       strcpy(result + result_len, hash_buf);
 596       assert(strlen(result) == result_len + hash_len, "");
 597       return result;
 598     }
 599   }
 600   if (name() == NULL)  return "<unknown>";
 601   return name()->as_klass_external_name();
 602 }
 603 
 604 
 605 const char* Klass::signature_name() const {
 606   if (name() == NULL)  return "<unknown>";
 607   return name()->as_C_string();
 608 }
 609 
 610 // Unless overridden, modifier_flags is 0.
 611 jint Klass::compute_modifier_flags(TRAPS) const {
 612   return 0;
 613 }
 614 
 615 int Klass::atomic_incr_biased_lock_revocation_count() {
 616   return (int) Atomic::add(1, &_biased_lock_revocation_count);
 617 }
 618 
 619 // Unless overridden, jvmti_class_status has no flags set.
 620 jint Klass::jvmti_class_status() const {
 621   return 0;
 622 }
 623 
 624 
 625 // Printing
 626 
 627 void Klass::print_on(outputStream* st) const {
 628   ResourceMark rm;
 629   // print title
 630   st->print("%s", internal_name());
 631   print_address_on(st);
 632   st->cr();
 633 }
 634 
 635 void Klass::oop_print_on(oop obj, outputStream* st) {
 636   ResourceMark rm;
 637   // print title
 638   st->print_cr("%s ", internal_name());
 639   obj->print_address_on(st);
 640 
 641   if (WizardMode) {
 642      // print header
 643      obj->mark()->print_on(st);
 644   }
 645 
 646   // print class
 647   st->print(" - klass: ");
 648   obj->klass()->print_value_on(st);
 649   st->cr();
 650 }
 651 
 652 void Klass::oop_print_value_on(oop obj, outputStream* st) {
 653   // print title
 654   ResourceMark rm;              // Cannot print in debug mode without this
 655   st->print("%s", internal_name());
 656   obj->print_address_on(st);
 657 }
 658 
 659 #if INCLUDE_SERVICES
 660 // Size Statistics
 661 void Klass::collect_statistics(KlassSizeStats *sz) const {
 662   sz->_klass_bytes = sz->count(this);
 663   sz->_mirror_bytes = sz->count(java_mirror());
 664   sz->_secondary_supers_bytes = sz->count_array(secondary_supers());
 665 
 666   sz->_ro_bytes += sz->_secondary_supers_bytes;
 667   sz->_rw_bytes += sz->_klass_bytes + sz->_mirror_bytes;
 668 }
 669 #endif // INCLUDE_SERVICES
 670 
 671 // Verification
 672 
 673 void Klass::verify_on(outputStream* st) {
 674 
 675   // This can be expensive, but it is worth checking that this klass is actually
 676   // in the CLD graph but not in production.
 677   assert(Metaspace::contains((address)this), "Should be");
 678 
 679   guarantee(this->is_klass(),"should be klass");
 680 
 681   if (super() != NULL) {
 682     guarantee(super()->is_klass(), "should be klass");
 683   }
 684   if (secondary_super_cache() != NULL) {
 685     Klass* ko = secondary_super_cache();
 686     guarantee(ko->is_klass(), "should be klass");
 687   }
 688   for ( uint i = 0; i < primary_super_limit(); i++ ) {
 689     Klass* ko = _primary_supers[i];
 690     if (ko != NULL) {
 691       guarantee(ko->is_klass(), "should be klass");
 692     }
 693   }
 694 
 695   if (java_mirror() != NULL) {
 696     guarantee(oopDesc::is_oop(java_mirror()), "should be instance");
 697   }
 698 }
 699 
 700 void Klass::oop_verify_on(oop obj, outputStream* st) {
 701   guarantee(oopDesc::is_oop(obj),  "should be oop");
 702   guarantee(obj->klass()->is_klass(), "klass field is not a klass");
 703 }
 704 
 705 klassVtable Klass::vtable() const {
 706   return klassVtable(const_cast<Klass*>(this), start_of_vtable(), vtable_length() / vtableEntry::size());
 707 }
 708 
 709 vtableEntry* Klass::start_of_vtable() const {
 710   return (vtableEntry*) ((address)this + in_bytes(vtable_start_offset()));
 711 }
 712 
 713 Method* Klass::method_at_vtable(int index)  {
 714 #ifndef PRODUCT
 715   assert(index >= 0, "valid vtable index");
 716   if (DebugVtables) {
 717     verify_vtable_index(index);
 718   }
 719 #endif
 720   return start_of_vtable()[index].method();
 721 }
 722 
 723 ByteSize Klass::vtable_start_offset() {
 724   return in_ByteSize(InstanceKlass::header_size() * wordSize);
 725 }
 726 
 727 #ifndef PRODUCT
 728 
 729 bool Klass::verify_vtable_index(int i) {
 730   int limit = vtable_length()/vtableEntry::size();
 731   assert(i >= 0 && i < limit, "index %d out of bounds %d", i, limit);
 732   return true;
 733 }
 734 
 735 bool Klass::verify_itable_index(int i) {
 736   assert(is_instance_klass(), "");
 737   int method_count = klassItable::method_count_for_interface(this);
 738   assert(i >= 0 && i < method_count, "index out of bounds");
 739   return true;
 740 }
 741 
 742 #endif
--- EOF ---