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