1 /*
   2  * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "classfile/classLoaderData.inline.hpp"
  27 #include "classfile/classLoaderDataGraph.inline.hpp"
  28 #include "classfile/dictionary.hpp"
  29 #include "classfile/javaClasses.hpp"
  30 #include "classfile/moduleEntry.hpp"
  31 #include "classfile/systemDictionary.hpp"
  32 #include "classfile/vmSymbols.hpp"
  33 #include "gc/shared/collectedHeap.inline.hpp"
  34 #include "logging/log.hpp"
  35 #include "memory/heapInspection.hpp"
  36 #include "memory/heapShared.hpp"
  37 #include "memory/metadataFactory.hpp"
  38 #include "memory/metaspaceClosure.hpp"
  39 #include "memory/metaspaceShared.hpp"
  40 #include "memory/oopFactory.hpp"
  41 #include "memory/resourceArea.hpp"
  42 #include "oops/compressedOops.inline.hpp"
  43 #include "oops/instanceKlass.hpp"
  44 #include "oops/klass.inline.hpp"
  45 #include "oops/oop.inline.hpp"
  46 #include "oops/oopHandle.inline.hpp"
  47 #include "runtime/atomic.hpp"
  48 #include "runtime/handles.inline.hpp"
  49 #include "runtime/orderAccess.hpp"
  50 #include "utilities/macros.hpp"
  51 #include "utilities/stack.inline.hpp"
  52 
  53 void Klass::set_java_mirror(Handle m) {
  54   assert(!m.is_null(), "New mirror should never be null.");
  55   assert(_java_mirror.resolve() == NULL, "should only be used to initialize mirror");
  56   _java_mirror = class_loader_data()->add_handle(m);
  57 }
  58 
  59 oop Klass::java_mirror() const {
  60   return _java_mirror.resolve();
  61 }
  62 
  63 oop Klass::java_mirror_no_keepalive() const {
  64   return _java_mirror.peek();
  65 }
  66 
  67 bool Klass::is_cloneable() const {
  68   return _access_flags.is_cloneable_fast() ||
  69          is_subtype_of(SystemDictionary::Cloneable_klass());
  70 }
  71 
  72 void Klass::set_is_cloneable() {
  73   if (name() == vmSymbols::java_lang_invoke_MemberName()) {
  74     assert(is_final(), "no subclasses allowed");
  75     // MemberName cloning should not be intrinsified and always happen in JVM_Clone.
  76   } else if (is_instance_klass() && InstanceKlass::cast(this)->reference_type() != REF_NONE) {
  77     // Reference cloning should not be intrinsified and always happen in JVM_Clone.
  78   } else {
  79     _access_flags.set_is_cloneable_fast();
  80   }
  81 }
  82 
  83 void Klass::set_name(Symbol* n) {
  84   _name = n;
  85   if (_name != NULL) _name->increment_refcount();
  86 }
  87 
  88 bool Klass::is_subclass_of(const Klass* k) const {
  89   // Run up the super chain and check
  90   if (this == k) return true;
  91 
  92   Klass* t = const_cast<Klass*>(this)->super();
  93 
  94   while (t != NULL) {
  95     if (t == k) return true;
  96     t = t->super();
  97   }
  98   return false;
  99 }
 100 
 101 bool Klass::search_secondary_supers(Klass* k) const {
 102   // Put some extra logic here out-of-line, before the search proper.
 103   // This cuts down the size of the inline method.
 104 
 105   // This is necessary, since I am never in my own secondary_super list.
 106   if (this == k)
 107     return true;
 108   // Scan the array-of-objects for a match
 109   int cnt = secondary_supers()->length();
 110   for (int i = 0; i < cnt; i++) {
 111     if (secondary_supers()->at(i) == k) {
 112       ((Klass*)this)->set_secondary_super_cache(k);
 113       return true;
 114     }
 115   }
 116   return false;
 117 }
 118 
 119 // Return self, except for abstract classes with exactly 1
 120 // implementor.  Then return the 1 concrete implementation.
 121 Klass *Klass::up_cast_abstract() {
 122   Klass *r = this;
 123   while( r->is_abstract() ) {   // Receiver is abstract?
 124     Klass *s = r->subklass();   // Check for exactly 1 subklass
 125     if (s == NULL || s->next_sibling() != NULL) // Oops; wrong count; give up
 126       return this;              // Return 'this' as a no-progress flag
 127     r = s;                    // Loop till find concrete class
 128   }
 129   return r;                   // Return the 1 concrete class
 130 }
 131 
 132 // Find LCA in class hierarchy
 133 Klass *Klass::LCA( Klass *k2 ) {
 134   Klass *k1 = this;
 135   while( 1 ) {
 136     if( k1->is_subtype_of(k2) ) return k2;
 137     if( k2->is_subtype_of(k1) ) return k1;
 138     k1 = k1->super();
 139     k2 = k2->super();
 140   }
 141 }
 142 
 143 
 144 void Klass::check_valid_for_instantiation(bool throwError, TRAPS) {
 145   ResourceMark rm(THREAD);
 146   THROW_MSG(throwError ? vmSymbols::java_lang_InstantiationError()
 147             : vmSymbols::java_lang_InstantiationException(), external_name());
 148 }
 149 
 150 
 151 void Klass::copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS) {
 152   ResourceMark rm(THREAD);
 153   assert(s != NULL, "Throw NPE!");
 154   THROW_MSG(vmSymbols::java_lang_ArrayStoreException(),
 155             err_msg("arraycopy: source type %s is not an array", s->klass()->external_name()));
 156 }
 157 
 158 
 159 void Klass::initialize(TRAPS) {
 160   ShouldNotReachHere();
 161 }
 162 
 163 Klass* Klass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
 164 #ifdef ASSERT
 165   tty->print_cr("Error: find_field called on a klass oop."
 166                 " Likely error: reflection method does not correctly"
 167                 " wrap return value in a mirror object.");
 168 #endif
 169   ShouldNotReachHere();
 170   return NULL;
 171 }
 172 
 173 Method* Klass::uncached_lookup_method(const Symbol* name, const Symbol* signature,
 174                                       OverpassLookupMode overpass_mode,
 175                                       PrivateLookupMode private_mode) const {
 176 #ifdef ASSERT
 177   tty->print_cr("Error: uncached_lookup_method called on a klass oop."
 178                 " Likely error: reflection method does not correctly"
 179                 " wrap return value in a mirror object.");
 180 #endif
 181   ShouldNotReachHere();
 182   return NULL;
 183 }
 184 
 185 void* Klass::operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, TRAPS) throw() {
 186   return Metaspace::allocate(loader_data, word_size, MetaspaceObj::ClassType, THREAD);
 187 }
 188 
 189 // "Normal" instantiation is preceeded by a MetaspaceObj allocation
 190 // which zeros out memory - calloc equivalent.
 191 // The constructor is also used from CppVtableCloner,
 192 // which doesn't zero out the memory before calling the constructor.
 193 // Need to set the _java_mirror field explicitly to not hit an assert that the field
 194 // should be NULL before setting it.
 195 Klass::Klass(KlassID id) : _id(id),
 196                            _java_mirror(NULL),
 197                            _prototype_header(markOopDesc::prototype()),
 198                            _shared_class_path_index(-1) {
 199   CDS_ONLY(_shared_class_flags = 0;)
 200   CDS_JAVA_HEAP_ONLY(_archived_mirror = 0;)
 201   _primary_supers[0] = this;
 202   set_super_check_offset(in_bytes(primary_supers_offset()));
 203 }
 204 
 205 jint Klass::array_layout_helper(BasicType etype) {
 206   assert(etype >= T_BOOLEAN && etype <= T_OBJECT, "valid etype");
 207   // Note that T_ARRAY is not allowed here.
 208   int  hsize = arrayOopDesc::base_offset_in_bytes(etype);
 209   int  esize = type2aelembytes(etype);
 210   bool isobj = (etype == T_OBJECT);
 211   int  tag   =  isobj ? _lh_array_tag_obj_value : _lh_array_tag_type_value;
 212   int lh = array_layout_helper(tag, hsize, etype, exact_log2(esize));
 213 
 214   assert(lh < (int)_lh_neutral_value, "must look like an array layout");
 215   assert(layout_helper_is_array(lh), "correct kind");
 216   assert(layout_helper_is_objArray(lh) == isobj, "correct kind");
 217   assert(layout_helper_is_typeArray(lh) == !isobj, "correct kind");
 218   assert(layout_helper_header_size(lh) == hsize, "correct decode");
 219   assert(layout_helper_element_type(lh) == etype, "correct decode");
 220   assert(1 << layout_helper_log2_element_size(lh) == esize, "correct decode");
 221 
 222   return lh;
 223 }
 224 
 225 bool Klass::can_be_primary_super_slow() const {
 226   if (super() == NULL)
 227     return true;
 228   else if (super()->super_depth() >= primary_super_limit()-1)
 229     return false;
 230   else
 231     return true;
 232 }
 233 
 234 void Klass::initialize_supers(Klass* k, Array<InstanceKlass*>* transitive_interfaces, TRAPS) {
 235   if (k == NULL) {
 236     set_super(NULL);
 237     _primary_supers[0] = this;
 238     assert(super_depth() == 0, "Object must already be initialized properly");
 239   } else if (k != super() || k == SystemDictionary::Object_klass()) {
 240     assert(super() == NULL || super() == SystemDictionary::Object_klass(),
 241            "initialize this only once to a non-trivial value");
 242     set_super(k);
 243     Klass* sup = k;
 244     int sup_depth = sup->super_depth();
 245     juint my_depth  = MIN2(sup_depth + 1, (int)primary_super_limit());
 246     if (!can_be_primary_super_slow())
 247       my_depth = primary_super_limit();
 248     for (juint i = 0; i < my_depth; i++) {
 249       _primary_supers[i] = sup->_primary_supers[i];
 250     }
 251     Klass* *super_check_cell;
 252     if (my_depth < primary_super_limit()) {
 253       _primary_supers[my_depth] = this;
 254       super_check_cell = &_primary_supers[my_depth];
 255     } else {
 256       // Overflow of the primary_supers array forces me to be secondary.
 257       super_check_cell = &_secondary_super_cache;
 258     }
 259     set_super_check_offset((address)super_check_cell - (address) this);
 260 
 261 #ifdef ASSERT
 262     {
 263       juint j = super_depth();
 264       assert(j == my_depth, "computed accessor gets right answer");
 265       Klass* t = this;
 266       while (!t->can_be_primary_super()) {
 267         t = t->super();
 268         j = t->super_depth();
 269       }
 270       for (juint j1 = j+1; j1 < primary_super_limit(); j1++) {
 271         assert(primary_super_of_depth(j1) == NULL, "super list padding");
 272       }
 273       while (t != NULL) {
 274         assert(primary_super_of_depth(j) == t, "super list initialization");
 275         t = t->super();
 276         --j;
 277       }
 278       assert(j == (juint)-1, "correct depth count");
 279     }
 280 #endif
 281   }
 282 
 283   if (secondary_supers() == NULL) {
 284 
 285     // Now compute the list of secondary supertypes.
 286     // Secondaries can occasionally be on the super chain,
 287     // if the inline "_primary_supers" array overflows.
 288     int extras = 0;
 289     Klass* p;
 290     for (p = super(); !(p == NULL || p->can_be_primary_super()); p = p->super()) {
 291       ++extras;
 292     }
 293 
 294     ResourceMark rm(THREAD);  // need to reclaim GrowableArrays allocated below
 295 
 296     // Compute the "real" non-extra secondaries.
 297     GrowableArray<Klass*>* secondaries = compute_secondary_supers(extras, transitive_interfaces);
 298     if (secondaries == NULL) {
 299       // secondary_supers set by compute_secondary_supers
 300       return;
 301     }
 302 
 303     GrowableArray<Klass*>* primaries = new GrowableArray<Klass*>(extras);
 304 
 305     for (p = super(); !(p == NULL || p->can_be_primary_super()); p = p->super()) {
 306       int i;                    // Scan for overflow primaries being duplicates of 2nd'arys
 307 
 308       // This happens frequently for very deeply nested arrays: the
 309       // primary superclass chain overflows into the secondary.  The
 310       // secondary list contains the element_klass's secondaries with
 311       // an extra array dimension added.  If the element_klass's
 312       // secondary list already contains some primary overflows, they
 313       // (with the extra level of array-ness) will collide with the
 314       // normal primary superclass overflows.
 315       for( i = 0; i < secondaries->length(); i++ ) {
 316         if( secondaries->at(i) == p )
 317           break;
 318       }
 319       if( i < secondaries->length() )
 320         continue;               // It's a dup, don't put it in
 321       primaries->push(p);
 322     }
 323     // Combine the two arrays into a metadata object to pack the array.
 324     // The primaries are added in the reverse order, then the secondaries.
 325     int new_length = primaries->length() + secondaries->length();
 326     Array<Klass*>* s2 = MetadataFactory::new_array<Klass*>(
 327                                        class_loader_data(), new_length, CHECK);
 328     int fill_p = primaries->length();
 329     for (int j = 0; j < fill_p; j++) {
 330       s2->at_put(j, primaries->pop());  // add primaries in reverse order.
 331     }
 332     for( int j = 0; j < secondaries->length(); j++ ) {
 333       s2->at_put(j+fill_p, secondaries->at(j));  // add secondaries on the end.
 334     }
 335 
 336   #ifdef ASSERT
 337       // We must not copy any NULL placeholders left over from bootstrap.
 338     for (int j = 0; j < s2->length(); j++) {
 339       assert(s2->at(j) != NULL, "correct bootstrapping order");
 340     }
 341   #endif
 342 
 343     set_secondary_supers(s2);
 344   }
 345 }
 346 
 347 GrowableArray<Klass*>* Klass::compute_secondary_supers(int num_extra_slots,
 348                                                        Array<InstanceKlass*>* transitive_interfaces) {
 349   assert(num_extra_slots == 0, "override for complex klasses");
 350   assert(transitive_interfaces == NULL, "sanity");
 351   set_secondary_supers(Universe::the_empty_klass_array());
 352   return NULL;
 353 }
 354 
 355 
 356 // superklass links
 357 InstanceKlass* Klass::superklass() const {
 358   assert(super() == NULL || super()->is_instance_klass(), "must be instance klass");
 359   return _super == NULL ? NULL : InstanceKlass::cast(_super);
 360 }
 361 
 362 // subklass links.  Used by the compiler (and vtable initialization)
 363 // May be cleaned concurrently, so must use the Compile_lock.
 364 // The log parameter is for clean_weak_klass_links to report unlinked classes.
 365 Klass* Klass::subklass(bool log) const {
 366   // Need load_acquire on the _subklass, because it races with inserts that
 367   // publishes freshly initialized data.
 368   for (Klass* chain = OrderAccess::load_acquire(&_subklass);
 369        chain != NULL;
 370        // Do not need load_acquire on _next_sibling, because inserts never
 371        // create _next_sibling edges to dead data.
 372        chain = Atomic::load(&chain->_next_sibling))
 373   {
 374     if (chain->is_loader_alive()) {
 375       return chain;
 376     } else if (log) {
 377       if (log_is_enabled(Trace, class, unload)) {
 378         ResourceMark rm;
 379         log_trace(class, unload)("unlinking class (subclass): %s", chain->external_name());
 380       }
 381     }
 382   }
 383   return NULL;
 384 }
 385 
 386 Klass* Klass::next_sibling(bool log) const {
 387   // Do not need load_acquire on _next_sibling, because inserts never
 388   // create _next_sibling edges to dead data.
 389   for (Klass* chain = Atomic::load(&_next_sibling);
 390        chain != NULL;
 391        chain = Atomic::load(&chain->_next_sibling)) {
 392     // Only return alive klass, there may be stale klass
 393     // in this chain if cleaned concurrently.
 394     if (chain->is_loader_alive()) {
 395       return chain;
 396     } else if (log) {
 397       if (log_is_enabled(Trace, class, unload)) {
 398         ResourceMark rm;
 399         log_trace(class, unload)("unlinking class (sibling): %s", chain->external_name());
 400       }
 401     }
 402   }
 403   return NULL;
 404 }
 405 
 406 void Klass::set_subklass(Klass* s) {
 407   assert(s != this, "sanity check");
 408   OrderAccess::release_store(&_subklass, s);
 409 }
 410 
 411 void Klass::set_next_sibling(Klass* s) {
 412   assert(s != this, "sanity check");
 413   // Does not need release semantics. If used by cleanup, it will link to
 414   // already safely published data, and if used by inserts, will be published
 415   // safely using cmpxchg.
 416   Atomic::store(s, &_next_sibling);
 417 }
 418 
 419 void Klass::append_to_sibling_list() {
 420   assert_locked_or_safepoint(Compile_lock);
 421   debug_only(verify();)
 422   // add ourselves to superklass' subklass list
 423   InstanceKlass* super = superklass();
 424   if (super == NULL) return;        // special case: class Object
 425   assert((!super->is_interface()    // interfaces cannot be supers
 426           && (super->superklass() == NULL || !is_interface())),
 427          "an interface can only be a subklass of Object");
 428 
 429   // Make sure there is no stale subklass head
 430   super->clean_subklass();
 431 
 432   for (;;) {
 433     Klass* prev_first_subklass = OrderAccess::load_acquire(&_super->_subklass);
 434     if (prev_first_subklass != NULL) {
 435       // set our sibling to be the superklass' previous first subklass
 436       assert(prev_first_subklass->is_loader_alive(), "May not attach not alive klasses");
 437       set_next_sibling(prev_first_subklass);
 438     }
 439     // Note that the prev_first_subklass is always alive, meaning no sibling_next links
 440     // are ever created to not alive klasses. This is an important invariant of the lock-free
 441     // cleaning protocol, that allows us to safely unlink dead klasses from the sibling list.
 442     if (Atomic::cmpxchg(this, &super->_subklass, prev_first_subklass) == prev_first_subklass) {
 443       return;
 444     }
 445   }
 446   debug_only(verify();)
 447 }
 448 
 449 void Klass::clean_subklass() {
 450   for (;;) {
 451     // Need load_acquire, due to contending with concurrent inserts
 452     Klass* subklass = OrderAccess::load_acquire(&_subklass);
 453     if (subklass == NULL || subklass->is_loader_alive()) {
 454       return;
 455     }
 456     // Try to fix _subklass until it points at something not dead.
 457     Atomic::cmpxchg(subklass->next_sibling(), &_subklass, subklass);
 458   }
 459 }
 460 
 461 void Klass::clean_weak_klass_links(bool unloading_occurred, bool clean_alive_klasses) {
 462   if (!ClassUnloading || !unloading_occurred) {
 463     return;
 464   }
 465 
 466   Klass* root = SystemDictionary::Object_klass();
 467   Stack<Klass*, mtGC> stack;
 468 
 469   stack.push(root);
 470   while (!stack.is_empty()) {
 471     Klass* current = stack.pop();
 472 
 473     assert(current->is_loader_alive(), "just checking, this should be live");
 474 
 475     // Find and set the first alive subklass
 476     Klass* sub = current->subklass(true);
 477     current->clean_subklass();
 478     if (sub != NULL) {
 479       stack.push(sub);
 480     }
 481 
 482     // Find and set the first alive sibling
 483     Klass* sibling = current->next_sibling(true);
 484     current->set_next_sibling(sibling);
 485     if (sibling != NULL) {
 486       stack.push(sibling);
 487     }
 488 
 489     // Clean the implementors list and method data.
 490     if (clean_alive_klasses && current->is_instance_klass()) {
 491       InstanceKlass* ik = InstanceKlass::cast(current);
 492       ik->clean_weak_instanceklass_links();
 493 
 494       // JVMTI RedefineClasses creates previous versions that are not in
 495       // the class hierarchy, so process them here.
 496       while ((ik = ik->previous_versions()) != NULL) {
 497         ik->clean_weak_instanceklass_links();
 498       }
 499     }
 500   }
 501 }
 502 
 503 void Klass::metaspace_pointers_do(MetaspaceClosure* it) {
 504   if (log_is_enabled(Trace, cds)) {
 505     ResourceMark rm;
 506     log_trace(cds)("Iter(Klass): %p (%s)", this, external_name());
 507   }
 508 
 509   it->push(&_name);
 510   it->push(&_secondary_super_cache);
 511   it->push(&_secondary_supers);
 512   for (int i = 0; i < _primary_super_limit; i++) {
 513     it->push(&_primary_supers[i]);
 514   }
 515   it->push(&_super);
 516   it->push((Klass**)&_subklass);
 517   it->push((Klass**)&_next_sibling);
 518   it->push(&_next_link);
 519 
 520   vtableEntry* vt = start_of_vtable();
 521   for (int i=0; i<vtable_length(); i++) {
 522     it->push(vt[i].method_addr());
 523   }
 524 }
 525 
 526 void Klass::remove_unshareable_info() {
 527   assert (DumpSharedSpaces, "only called for DumpSharedSpaces");
 528   JFR_ONLY(REMOVE_ID(this);)
 529   if (log_is_enabled(Trace, cds, unshareable)) {
 530     ResourceMark rm;
 531     log_trace(cds, unshareable)("remove: %s", external_name());
 532   }
 533 
 534   set_subklass(NULL);
 535   set_next_sibling(NULL);
 536   set_next_link(NULL);
 537 
 538   // Null out class_loader_data because we don't share that yet.
 539   set_class_loader_data(NULL);
 540   set_is_shared();
 541 }
 542 
 543 void Klass::remove_java_mirror() {
 544   assert (DumpSharedSpaces, "only called for DumpSharedSpaces");
 545   if (log_is_enabled(Trace, cds, unshareable)) {
 546     ResourceMark rm;
 547     log_trace(cds, unshareable)("remove java_mirror: %s", external_name());
 548   }
 549   // Just null out the mirror.  The class_loader_data() no longer exists.
 550   _java_mirror = NULL;
 551 }
 552 
 553 void Klass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) {
 554   assert(is_klass(), "ensure C++ vtable is restored");
 555   assert(is_shared(), "must be set");
 556   JFR_ONLY(RESTORE_ID(this);)
 557   if (log_is_enabled(Trace, cds, unshareable)) {
 558     ResourceMark rm;
 559     log_trace(cds, unshareable)("restore: %s", external_name());
 560   }
 561 
 562   // If an exception happened during CDS restore, some of these fields may already be
 563   // set.  We leave the class on the CLD list, even if incomplete so that we don't
 564   // modify the CLD list outside a safepoint.
 565   if (class_loader_data() == NULL) {
 566     // Restore class_loader_data to the null class loader data
 567     set_class_loader_data(loader_data);
 568 
 569     // Add to null class loader list first before creating the mirror
 570     // (same order as class file parsing)
 571     loader_data->add_class(this);
 572   }
 573 
 574   Handle loader(THREAD, loader_data->class_loader());
 575   ModuleEntry* module_entry = NULL;
 576   Klass* k = this;
 577   if (k->is_objArray_klass()) {
 578     k = ObjArrayKlass::cast(k)->bottom_klass();
 579   }
 580   // Obtain klass' module.
 581   if (k->is_instance_klass()) {
 582     InstanceKlass* ik = (InstanceKlass*) k;
 583     module_entry = ik->module();
 584   } else {
 585     module_entry = ModuleEntryTable::javabase_moduleEntry();
 586   }
 587   // Obtain java.lang.Module, if available
 588   Handle module_handle(THREAD, ((module_entry != NULL) ? module_entry->module() : (oop)NULL));
 589 
 590   if (this->has_raw_archived_mirror()) {
 591     ResourceMark rm;
 592     log_debug(cds, mirror)("%s has raw archived mirror", external_name());
 593     if (HeapShared::open_archive_heap_region_mapped()) {
 594       bool present = java_lang_Class::restore_archived_mirror(this, loader, module_handle,
 595                                                               protection_domain,
 596                                                               CHECK);
 597       if (present) {
 598         return;
 599       }
 600     }
 601 
 602     // No archived mirror data
 603     log_debug(cds, mirror)("No archived mirror data for %s", external_name());
 604     _java_mirror = NULL;
 605     this->clear_has_raw_archived_mirror();
 606   }
 607 
 608   // Only recreate it if not present.  A previous attempt to restore may have
 609   // gotten an OOM later but keep the mirror if it was created.
 610   if (java_mirror() == NULL) {
 611     log_trace(cds, mirror)("Recreate mirror for %s", external_name());
 612     java_lang_Class::create_mirror(this, loader, module_handle, protection_domain, Handle(), CHECK);
 613   }
 614 }
 615 
 616 #if INCLUDE_CDS_JAVA_HEAP
 617 // Used at CDS dump time to access the archived mirror. No GC barrier.
 618 oop Klass::archived_java_mirror_raw() {
 619   assert(has_raw_archived_mirror(), "must have raw archived mirror");
 620   return CompressedOops::decode(_archived_mirror);
 621 }
 622 
 623 narrowOop Klass::archived_java_mirror_raw_narrow() {
 624   assert(has_raw_archived_mirror(), "must have raw archived mirror");
 625   return _archived_mirror;
 626 }
 627 
 628 // No GC barrier
 629 void Klass::set_archived_java_mirror_raw(oop m) {
 630   assert(DumpSharedSpaces, "called only during runtime");
 631   _archived_mirror = CompressedOops::encode(m);
 632 }
 633 #endif // INCLUDE_CDS_JAVA_HEAP
 634 
 635 Klass* Klass::array_klass_or_null(int rank) {
 636   EXCEPTION_MARK;
 637   // No exception can be thrown by array_klass_impl when called with or_null == true.
 638   // (In anycase, the execption mark will fail if it do so)
 639   return array_klass_impl(true, rank, THREAD);
 640 }
 641 
 642 
 643 Klass* Klass::array_klass_or_null() {
 644   EXCEPTION_MARK;
 645   // No exception can be thrown by array_klass_impl when called with or_null == true.
 646   // (In anycase, the execption mark will fail if it do so)
 647   return array_klass_impl(true, THREAD);
 648 }
 649 
 650 
 651 Klass* Klass::array_klass_impl(bool or_null, int rank, TRAPS) {
 652   fatal("array_klass should be dispatched to InstanceKlass, ObjArrayKlass or TypeArrayKlass");
 653   return NULL;
 654 }
 655 
 656 
 657 Klass* Klass::array_klass_impl(bool or_null, TRAPS) {
 658   fatal("array_klass should be dispatched to InstanceKlass, ObjArrayKlass or TypeArrayKlass");
 659   return NULL;
 660 }
 661 
 662 void Klass::check_array_allocation_length(int length, int max_length, TRAPS) {
 663   if (length > max_length) {
 664     if (!THREAD->in_retryable_allocation()) {
 665       report_java_out_of_memory("Requested array size exceeds VM limit");
 666       JvmtiExport::post_array_size_exhausted();
 667       THROW_OOP(Universe::out_of_memory_error_array_size());
 668     } else {
 669       THROW_OOP(Universe::out_of_memory_error_retry());
 670     }
 671   } else if (length < 0) {
 672     THROW_MSG(vmSymbols::java_lang_NegativeArraySizeException(), err_msg("%d", length));
 673   }
 674 }
 675 
 676 oop Klass::class_loader() const { return class_loader_data()->class_loader(); }
 677 
 678 // In product mode, this function doesn't have virtual function calls so
 679 // there might be some performance advantage to handling InstanceKlass here.
 680 const char* Klass::external_name() const {
 681   if (is_instance_klass()) {
 682     const InstanceKlass* ik = static_cast<const InstanceKlass*>(this);
 683     if (ik->is_unsafe_anonymous()) {
 684       char addr_buf[20];
 685       jio_snprintf(addr_buf, 20, "/" INTPTR_FORMAT, p2i(ik));
 686       size_t addr_len = strlen(addr_buf);
 687       size_t name_len = name()->utf8_length();
 688       char*  result   = NEW_RESOURCE_ARRAY(char, name_len + addr_len + 1);
 689       name()->as_klass_external_name(result, (int) name_len + 1);
 690       assert(strlen(result) == name_len, "");
 691       strcpy(result + name_len, addr_buf);
 692       assert(strlen(result) == name_len + addr_len, "");
 693       return result;
 694     }
 695   }
 696   if (name() == NULL)  return "<unknown>";
 697   return name()->as_klass_external_name();
 698 }
 699 
 700 const char* Klass::signature_name() const {
 701   if (name() == NULL)  return "<unknown>";
 702   return name()->as_C_string();
 703 }
 704 
 705 const char* Klass::external_kind() const {
 706   if (is_interface()) return "interface";
 707   if (is_abstract()) return "abstract class";
 708   return "class";
 709 }
 710 
 711 // Unless overridden, modifier_flags is 0.
 712 jint Klass::compute_modifier_flags(TRAPS) const {
 713   return 0;
 714 }
 715 
 716 int Klass::atomic_incr_biased_lock_revocation_count() {
 717   return (int) Atomic::add(1, &_biased_lock_revocation_count);
 718 }
 719 
 720 // Unless overridden, jvmti_class_status has no flags set.
 721 jint Klass::jvmti_class_status() const {
 722   return 0;
 723 }
 724 
 725 
 726 // Printing
 727 
 728 void Klass::print_on(outputStream* st) const {
 729   ResourceMark rm;
 730   // print title
 731   st->print("%s", internal_name());
 732   print_address_on(st);
 733   st->cr();
 734 }
 735 
 736 void Klass::oop_print_on(oop obj, outputStream* st) {
 737   ResourceMark rm;
 738   // print title
 739   st->print_cr("%s ", internal_name());
 740   obj->print_address_on(st);
 741 
 742   if (WizardMode) {
 743      // print header
 744      obj->mark()->print_on(st);
 745   }
 746 
 747   // print class
 748   st->print(" - klass: ");
 749   obj->klass()->print_value_on(st);
 750   st->cr();
 751 }
 752 
 753 void Klass::oop_print_value_on(oop obj, outputStream* st) {
 754   // print title
 755   ResourceMark rm;              // Cannot print in debug mode without this
 756   st->print("%s", internal_name());
 757   obj->print_address_on(st);
 758 }
 759 
 760 #if INCLUDE_SERVICES
 761 // Size Statistics
 762 void Klass::collect_statistics(KlassSizeStats *sz) const {
 763   sz->_klass_bytes = sz->count(this);
 764   sz->_mirror_bytes = sz->count(java_mirror());
 765   sz->_secondary_supers_bytes = sz->count_array(secondary_supers());
 766 
 767   sz->_ro_bytes += sz->_secondary_supers_bytes;
 768   sz->_rw_bytes += sz->_klass_bytes + sz->_mirror_bytes;
 769 }
 770 #endif // INCLUDE_SERVICES
 771 
 772 // Verification
 773 
 774 void Klass::verify_on(outputStream* st) {
 775 
 776   // This can be expensive, but it is worth checking that this klass is actually
 777   // in the CLD graph but not in production.
 778   assert(Metaspace::contains((address)this), "Should be");
 779 
 780   guarantee(this->is_klass(),"should be klass");
 781 
 782   if (super() != NULL) {
 783     guarantee(super()->is_klass(), "should be klass");
 784   }
 785   if (secondary_super_cache() != NULL) {
 786     Klass* ko = secondary_super_cache();
 787     guarantee(ko->is_klass(), "should be klass");
 788   }
 789   for ( uint i = 0; i < primary_super_limit(); i++ ) {
 790     Klass* ko = _primary_supers[i];
 791     if (ko != NULL) {
 792       guarantee(ko->is_klass(), "should be klass");
 793     }
 794   }
 795 
 796   if (java_mirror_no_keepalive() != NULL) {
 797     guarantee(oopDesc::is_oop(java_mirror_no_keepalive()), "should be instance");
 798   }
 799 }
 800 
 801 void Klass::oop_verify_on(oop obj, outputStream* st) {
 802   guarantee(oopDesc::is_oop(obj),  "should be oop");
 803   guarantee(obj->klass()->is_klass(), "klass field is not a klass");
 804 }
 805 
 806 Klass* Klass::decode_klass_raw(narrowKlass narrow_klass) {
 807   return (Klass*)(void*)( (uintptr_t)Universe::narrow_klass_base() +
 808                          ((uintptr_t)narrow_klass << Universe::narrow_klass_shift()));
 809 }
 810 
 811 bool Klass::is_valid(Klass* k) {
 812   if (!is_aligned(k, sizeof(MetaWord))) return false;
 813   if ((size_t)k < os::min_page_size()) return false;
 814 
 815   if (!os::is_readable_range(k, k + 1)) return false;
 816   if (!MetaspaceUtils::is_range_in_committed(k, k + 1)) return false;
 817 
 818   if (!Symbol::is_valid(k->name())) return false;
 819   return ClassLoaderDataGraph::is_valid(k->class_loader_data());
 820 }
 821 
 822 klassVtable Klass::vtable() const {
 823   return klassVtable(const_cast<Klass*>(this), start_of_vtable(), vtable_length() / vtableEntry::size());
 824 }
 825 
 826 vtableEntry* Klass::start_of_vtable() const {
 827   return (vtableEntry*) ((address)this + in_bytes(vtable_start_offset()));
 828 }
 829 
 830 Method* Klass::method_at_vtable(int index)  {
 831 #ifndef PRODUCT
 832   assert(index >= 0, "valid vtable index");
 833   if (DebugVtables) {
 834     verify_vtable_index(index);
 835   }
 836 #endif
 837   return start_of_vtable()[index].method();
 838 }
 839 
 840 ByteSize Klass::vtable_start_offset() {
 841   return in_ByteSize(InstanceKlass::header_size() * wordSize);
 842 }
 843 
 844 #ifndef PRODUCT
 845 
 846 bool Klass::verify_vtable_index(int i) {
 847   int limit = vtable_length()/vtableEntry::size();
 848   assert(i >= 0 && i < limit, "index %d out of bounds %d", i, limit);
 849   return true;
 850 }
 851 
 852 #endif // PRODUCT
 853 
 854 // Caller needs ResourceMark
 855 // joint_in_module_of_loader provides an optimization if 2 classes are in
 856 // the same module to succinctly print out relevant information about their
 857 // module name and class loader's name_and_id for error messages.
 858 // Format:
 859 //   <fully-qualified-external-class-name1> and <fully-qualified-external-class-name2>
 860 //                      are in module <module-name>[@<version>]
 861 //                      of loader <loader-name_and_id>[, parent loader <parent-loader-name_and_id>]
 862 const char* Klass::joint_in_module_of_loader(const Klass* class2, bool include_parent_loader) const {
 863   assert(module() == class2->module(), "classes do not have the same module");
 864   const char* class1_name = external_name();
 865   size_t len = strlen(class1_name) + 1;
 866 
 867   const char* class2_description = class2->class_in_module_of_loader(true, include_parent_loader);
 868   len += strlen(class2_description);
 869 
 870   len += strlen(" and ");
 871 
 872   char* joint_description = NEW_RESOURCE_ARRAY_RETURN_NULL(char, len);
 873 
 874   // Just return the FQN if error when allocating string
 875   if (joint_description == NULL) {
 876     return class1_name;
 877   }
 878 
 879   jio_snprintf(joint_description, len, "%s and %s",
 880                class1_name,
 881                class2_description);
 882 
 883   return joint_description;
 884 }
 885 
 886 // Caller needs ResourceMark
 887 // class_in_module_of_loader provides a standard way to include
 888 // relevant information about a class, such as its module name as
 889 // well as its class loader's name_and_id, in error messages and logging.
 890 // Format:
 891 //   <fully-qualified-external-class-name> is in module <module-name>[@<version>]
 892 //                                         of loader <loader-name_and_id>[, parent loader <parent-loader-name_and_id>]
 893 const char* Klass::class_in_module_of_loader(bool use_are, bool include_parent_loader) const {
 894   // 1. fully qualified external name of class
 895   const char* klass_name = external_name();
 896   size_t len = strlen(klass_name) + 1;
 897 
 898   // 2. module name + @version
 899   const char* module_name = "";
 900   const char* version = "";
 901   bool has_version = false;
 902   bool module_is_named = false;
 903   const char* module_name_phrase = "";
 904   const Klass* bottom_klass = is_objArray_klass() ?
 905                                 ObjArrayKlass::cast(this)->bottom_klass() : this;
 906   if (bottom_klass->is_instance_klass()) {
 907     ModuleEntry* module = InstanceKlass::cast(bottom_klass)->module();
 908     if (module->is_named()) {
 909       module_is_named = true;
 910       module_name_phrase = "module ";
 911       module_name = module->name()->as_C_string();
 912       len += strlen(module_name);
 913       // Use version if exists and is not a jdk module
 914       if (module->should_show_version()) {
 915         has_version = true;
 916         version = module->version()->as_C_string();
 917         // Include stlen(version) + 1 for the "@"
 918         len += strlen(version) + 1;
 919       }
 920     } else {
 921       module_name = UNNAMED_MODULE;
 922       len += UNNAMED_MODULE_LEN;
 923     }
 924   } else {
 925     // klass is an array of primitives, module is java.base
 926     module_is_named = true;
 927     module_name_phrase = "module ";
 928     module_name = JAVA_BASE_NAME;
 929     len += JAVA_BASE_NAME_LEN;
 930   }
 931 
 932   // 3. class loader's name_and_id
 933   ClassLoaderData* cld = class_loader_data();
 934   assert(cld != NULL, "class_loader_data should not be null");
 935   const char* loader_name_and_id = cld->loader_name_and_id();
 936   len += strlen(loader_name_and_id);
 937 
 938   // 4. include parent loader information
 939   const char* parent_loader_phrase = "";
 940   const char* parent_loader_name_and_id = "";
 941   if (include_parent_loader &&
 942       !cld->is_builtin_class_loader_data()) {
 943     oop parent_loader = java_lang_ClassLoader::parent(class_loader());
 944     ClassLoaderData *parent_cld = ClassLoaderData::class_loader_data_or_null(parent_loader);
 945     // The parent loader's ClassLoaderData could be null if it is
 946     // a delegating class loader that has never defined a class.
 947     // In this case the loader's name must be obtained via the parent loader's oop.
 948     if (parent_cld == NULL) {
 949       oop cl_name_and_id = java_lang_ClassLoader::nameAndId(parent_loader);
 950       if (cl_name_and_id != NULL) {
 951         parent_loader_name_and_id = java_lang_String::as_utf8_string(cl_name_and_id);
 952       }
 953     } else {
 954       parent_loader_name_and_id = parent_cld->loader_name_and_id();
 955     }
 956     parent_loader_phrase = ", parent loader ";
 957     len += strlen(parent_loader_phrase) + strlen(parent_loader_name_and_id);
 958   }
 959 
 960   // Start to construct final full class description string
 961   len += ((use_are) ? strlen(" are in ") : strlen(" is in "));
 962   len += strlen(module_name_phrase) + strlen(" of loader ");
 963 
 964   char* class_description = NEW_RESOURCE_ARRAY_RETURN_NULL(char, len);
 965 
 966   // Just return the FQN if error when allocating string
 967   if (class_description == NULL) {
 968     return klass_name;
 969   }
 970 
 971   jio_snprintf(class_description, len, "%s %s in %s%s%s%s of loader %s%s%s",
 972                klass_name,
 973                (use_are) ? "are" : "is",
 974                module_name_phrase,
 975                module_name,
 976                (has_version) ? "@" : "",
 977                (has_version) ? version : "",
 978                loader_name_and_id,
 979                parent_loader_phrase,
 980                parent_loader_name_and_id);
 981 
 982   return class_description;
 983 }