1 /*
   2  * Copyright (c) 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 "gc/shared/barrierSet.hpp"
  27 #include "gc/shared/collectedHeap.inline.hpp"
  28 #include "gc/shared/gcLocker.inline.hpp"
  29 #include "interpreter/interpreter.hpp"
  30 #include "logging/log.hpp"
  31 #include "memory/metadataFactory.hpp"
  32 #include "oops/access.hpp"
  33 #include "oops/compressedOops.inline.hpp"
  34 #include "oops/fieldStreams.hpp"
  35 #include "oops/instanceKlass.hpp"
  36 #include "oops/method.hpp"
  37 #include "oops/oop.inline.hpp"
  38 #include "oops/objArrayKlass.hpp"
  39 #include "oops/valueKlass.hpp"
  40 #include "oops/valueArrayKlass.hpp"
  41 #include "runtime/fieldDescriptor.inline.hpp"
  42 #include "runtime/handles.inline.hpp"
  43 #include "runtime/safepointVerifiers.hpp"
  44 #include "runtime/sharedRuntime.hpp"
  45 #include "runtime/signature.hpp"
  46 #include "utilities/copy.hpp"
  47 
  48 int ValueKlass::first_field_offset() const {
  49 #ifdef ASSERT
  50   int first_offset = INT_MAX;
  51   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
  52     if (fs.offset() < first_offset) first_offset= fs.offset();
  53   }
  54 #endif
  55   int base_offset = instanceOopDesc::base_offset_in_bytes();
  56   // The first field of value types is aligned on a long boundary
  57   base_offset = align_up(base_offset, BytesPerLong);
  58   assert(base_offset == first_offset, "inconsistent offsets");
  59   return base_offset;
  60 }
  61 
  62 int ValueKlass::raw_value_byte_size() const {
  63   int heapOopAlignedSize = nonstatic_field_size() << LogBytesPerHeapOop;
  64   // If bigger than 64 bits or needs oop alignment, then use jlong aligned
  65   // which for values should be jlong aligned, asserts in raw_field_copy otherwise
  66   if (heapOopAlignedSize >= longSize || contains_oops()) {
  67     return heapOopAlignedSize;
  68   }
  69   // Small primitives...
  70   // If a few small basic type fields, return the actual size, i.e.
  71   // 1 byte = 1
  72   // 2 byte = 2
  73   // 3 byte = 4, because pow2 needed for element stores
  74   int first_offset = first_field_offset();
  75   int last_offset  = 0; // find the last offset, add basic type size
  76   int last_tsz     = 0;
  77   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
  78     if (fs.access_flags().is_static()) {
  79       continue;
  80     } else if (fs.offset() > last_offset) {
  81       BasicType type = fs.field_descriptor().field_type();
  82       if (is_java_primitive(type)) {
  83         last_tsz = type2aelembytes(type);
  84       } else if (type == T_VALUETYPE) {
  85         // Not just primitives. Layout aligns embedded value, so use jlong aligned it is
  86         return heapOopAlignedSize;
  87       } else {
  88         guarantee(0, "Unknown type %d", type);
  89       }
  90       assert(last_tsz != 0, "Invariant");
  91       last_offset = fs.offset();
  92     }
  93   }
  94   // Assumes VT with no fields are meaningless and illegal
  95   last_offset += last_tsz;
  96   assert(last_offset > first_offset && last_tsz, "Invariant");
  97   return 1 << upper_log2(last_offset - first_offset);
  98 }
  99 
 100 instanceOop ValueKlass::allocate_instance(TRAPS) {
 101   int size = size_helper();  // Query before forming handle.
 102 
 103   instanceOop oop = (instanceOop)Universe::heap()->obj_allocate(this, size, CHECK_NULL);
 104   assert(oop->mark()->is_always_locked(), "Unlocked value type");
 105   return oop;
 106 }
 107 
















 108 bool ValueKlass::is_atomic() {
 109   return (nonstatic_field_size() * heapOopSize) <= longSize;
 110 }
 111 
 112 int ValueKlass::nonstatic_oop_count() {
 113   int oops = 0;
 114   int map_count = nonstatic_oop_map_count();
 115   OopMapBlock* block = start_of_nonstatic_oop_maps();
 116   OopMapBlock* end = block + map_count;
 117   while (block != end) {
 118     oops += block->count();
 119     block++;
 120   }
 121   return oops;
 122 }
 123 
 124 // Arrays of...
 125 
 126 bool ValueKlass::flatten_array() {
 127   if (!ValueArrayFlatten) {
 128     return false;
 129   }
 130 
 131   int elem_bytes = raw_value_byte_size();
 132   // Too big
 133   if ((ValueArrayElemMaxFlatSize >= 0) && (elem_bytes > ValueArrayElemMaxFlatSize)) {
 134     return false;
 135   }
 136   // Too many embedded oops
 137   if ((ValueArrayElemMaxFlatOops >= 0) && (nonstatic_oop_count() > ValueArrayElemMaxFlatOops)) {
 138     return false;
 139   }
 140 
 141   return true;
 142 }
 143 
 144 
 145 Klass* ValueKlass::array_klass_impl(bool or_null, int n, TRAPS) {
 146   if (!flatten_array()) {
 147     return InstanceKlass::array_klass_impl(or_null, n, THREAD);
 148   }
 149 
 150   // Basically the same as instanceKlass, but using "ValueArrayKlass::allocate_klass"
 151   if (array_klasses() == NULL) {
 152     if (or_null) return NULL;
 153 
 154     ResourceMark rm;
 155     JavaThread *jt = (JavaThread *)THREAD;
 156     {
 157       // Atomic creation of array_klasses
 158       MutexLocker mc(Compile_lock, THREAD);   // for vtables
 159       MutexLocker ma(MultiArray_lock, THREAD);
 160 
 161       // Check if update has already taken place
 162       if (array_klasses() == NULL) {
 163         Klass* ak;
 164         if (is_atomic() || (!ValueArrayAtomicAccess)) {
 165           ak = ValueArrayKlass::allocate_klass(this, CHECK_NULL);
 166         } else {
 167           ak = ObjArrayKlass::allocate_objArray_klass(class_loader_data(), 1, this, CHECK_NULL);
 168         }
 169         set_array_klasses(ak);
 170       }
 171     }
 172   }
 173   // _this will always be set at this point
 174   ArrayKlass* ak = ArrayKlass::cast(array_klasses());
 175   if (or_null) {
 176     return ak->array_klass_or_null(n);
 177   }
 178   return ak->array_klass(n, THREAD);
 179 }
 180 
 181 Klass* ValueKlass::array_klass_impl(bool or_null, TRAPS) {
 182   return array_klass_impl(or_null, 1, THREAD);
 183 }
 184 
 185 void ValueKlass::raw_field_copy(void* src, void* dst, size_t raw_byte_size) {
 186   /*
 187    * Try not to shear fields even if not an atomic store...
 188    *
 189    * First 3 cases handle value array store, otherwise works on the same basis
 190    * as JVM_Clone, at this size data is aligned. The order of primitive types
 191    * is largest to smallest, and it not possible for fields to stradle long
 192    * copy boundaries.
 193    *
 194    * If MT without exclusive access, possible to observe partial value store,
 195    * but not partial primitive and reference field values
 196    */
 197   switch (raw_byte_size) {
 198     case 1:
 199       *((jbyte*) dst) = *(jbyte*)src;
 200       break;
 201     case 2:
 202       *((jshort*) dst) = *(jshort*)src;
 203       break;
 204     case 4:
 205       *((jint*) dst) = *(jint*) src;
 206       break;
 207     default:
 208       assert(raw_byte_size % sizeof(jlong) == 0, "Unaligned raw_byte_size");
 209       Copy::conjoint_jlongs_atomic((jlong*)src, (jlong*)dst, raw_byte_size >> LogBytesPerLong);
 210   }
 211 }
 212 
 213 /*
 214  * Store the value of this klass contained with src into dst.
 215  *
 216  * This operation is appropriate for use from vastore, vaload and putfield (for values)
 217  *
 218  * GC barriers currently can lock with no safepoint check and allocate c-heap,
 219  * so raw point is "safe" for now.
 220  *
 221  * Going forward, look to use machine generated (stub gen or bc) version for most used klass layouts
 222  *
 223  */
 224 void ValueKlass::value_store(void* src, void* dst, size_t raw_byte_size, bool dst_heap, bool dst_uninitialized) {
 225   if (contains_oops()) {
 226     if (dst_heap) {
 227       // src/dst aren't oops, need offset to adjust oop map offset
 228       const address dst_oop_addr = ((address) dst) - first_field_offset();
 229 
 230       ModRefBarrierSet* bs = barrier_set_cast<ModRefBarrierSet>(BarrierSet::barrier_set());
 231 
 232       // Pre-barriers...
 233       OopMapBlock* map = start_of_nonstatic_oop_maps();
 234       OopMapBlock* const end = map + nonstatic_oop_map_count();
 235       while (map != end) {
 236         // Shame we can't just use the existing oop iterator...src/dst aren't oop
 237         address doop_address = dst_oop_addr + map->offset();
 238         // TEMP HACK: barrier code need to migrate to => access API (need own versions of value type ops)
 239         if (UseCompressedOops) {
 240           bs->write_ref_array_pre((narrowOop*) doop_address, map->count(), dst_uninitialized);
 241         } else {
 242           bs->write_ref_array_pre((oop*) doop_address, map->count(), dst_uninitialized);
 243         }
 244         map++;
 245       }
 246 
 247       raw_field_copy(src, dst, raw_byte_size);
 248 
 249       // Post-barriers...
 250       map = start_of_nonstatic_oop_maps();
 251       while (map != end) {
 252         address doop_address = dst_oop_addr + map->offset();
 253         bs->write_ref_array((HeapWord*) doop_address, map->count());
 254         map++;
 255       }
 256     } else { // Buffered value case
 257       raw_field_copy(src, dst, raw_byte_size);
 258     }
 259   } else {   // Primitive-only case...
 260     raw_field_copy(src, dst, raw_byte_size);
 261   }
 262 }
 263 
 264 // Value type arguments are not passed by reference, instead each
 265 // field of the value type is passed as an argument. This helper
 266 // function collects the fields of the value types (including embedded
 267 // value type's fields) in a list. Included with the field's type is
 268 // the offset of each field in the value type: i2c and c2i adapters
 269 // need that to load or store fields. Finally, the list of fields is
 270 // sorted in order of increasing offsets: the adapters and the
 271 // compiled code need and agreed upon order of fields.
 272 //
 273 // The list of basic types that is returned starts with a T_VALUETYPE
 274 // and ends with an extra T_VOID. T_VALUETYPE/T_VOID are used as
 275 // delimiters. Every entry between the two is a field of the value
 276 // type. If there's an embedded value type in the list, it also starts
 277 // with a T_VALUETYPE and ends with a T_VOID. This is so we can
 278 // generate a unique fingerprint for the method's adapters and we can
 279 // generate the list of basic types from the interpreter point of view
 280 // (value types passed as reference: iterate on the list until a
 281 // T_VALUETYPE, drop everything until and including the closing
 282 // T_VOID) or the compiler point of view (each field of the value
 283 // types is an argument: drop all T_VALUETYPE/T_VOID from the list).
 284 GrowableArray<SigEntry> ValueKlass::collect_fields(int base_off) const {
 285   GrowableArray<SigEntry> sig_extended;
 286   sig_extended.push(SigEntry(T_VALUETYPE, base_off));
 287   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
 288     if (fs.access_flags().is_static()) continue;
 289     fieldDescriptor& fd = fs.field_descriptor();
 290     BasicType bt = fd.field_type();
 291     int offset = base_off + fd.offset() - (base_off > 0 ? first_field_offset() : 0);
 292     if (bt == T_VALUETYPE) {
 293       if (fd.is_flattened()) {
 294         Symbol* signature = fd.signature();
 295         JavaThread* THREAD = JavaThread::current();
 296         oop loader = class_loader();
 297         oop domain = protection_domain();
 298         ResetNoHandleMark rnhm;
 299         HandleMark hm;
 300         NoSafepointVerifier nsv;
 301         Klass* klass = SystemDictionary::resolve_or_null(signature,
 302                                                          Handle(THREAD, loader), Handle(THREAD, domain),
 303                                                          THREAD);
 304         assert(klass != NULL && !HAS_PENDING_EXCEPTION, "lookup shouldn't fail");
 305         const GrowableArray<SigEntry>& embedded = ValueKlass::cast(klass)->collect_fields(offset);
 306         sig_extended.appendAll(&embedded);
 307       } else {
 308         sig_extended.push(SigEntry(T_VALUETYPEPTR, offset));
 309       }
 310     } else {
 311       sig_extended.push(SigEntry(bt, offset));
 312       if (bt == T_LONG || bt == T_DOUBLE) {
 313         sig_extended.push(SigEntry(T_VOID, offset));
 314       }
 315     }
 316   }
 317   int offset = base_off + size_helper()*HeapWordSize - (base_off > 0 ? first_field_offset() : 0);
 318   sig_extended.push(SigEntry(T_VOID, offset)); // hack: use T_VOID to mark end of value type fields
 319   if (base_off == 0) {
 320     sig_extended.sort(SigEntry::compare);
 321   }
 322   assert(sig_extended.at(0)._bt == T_VALUETYPE && sig_extended.at(sig_extended.length()-1)._bt == T_VOID, "broken structure");
 323   return sig_extended;
 324 }
 325 
 326 void ValueKlass::initialize_calling_convention() {
 327   // Because the pack and unpack handler addresses need to be loadable from generated code,
 328   // they are stored at a fixed offset in the klass metadata. Since value type klasses do
 329   // not have a vtable, the vtable offset is used to store these addresses.
 330   //guarantee(vtable_length() == 0, "vtables are not supported in value klasses");
 331   if (ValueTypeReturnedAsFields || ValueTypePassFieldsAsArgs) {
 332     Thread* THREAD = Thread::current();
 333     assert(!HAS_PENDING_EXCEPTION, "should have no exception");
 334     ResourceMark rm;
 335     const GrowableArray<SigEntry>& sig_vk = collect_fields();
 336     int nb_fields = SigEntry::count_fields(sig_vk)+1;
 337     Array<SigEntry>* extended_sig = MetadataFactory::new_array<SigEntry>(class_loader_data(), sig_vk.length(), CHECK_AND_CLEAR);
 338     *((Array<SigEntry>**)adr_extended_sig()) = extended_sig;
 339     for (int i = 0; i < sig_vk.length(); i++) {
 340       extended_sig->at_put(i, sig_vk.at(i));
 341     }
 342 
 343     if (ValueTypeReturnedAsFields) {
 344       BasicType* sig_bt = NEW_RESOURCE_ARRAY(BasicType, nb_fields);
 345       sig_bt[0] = T_METADATA;
 346       SigEntry::fill_sig_bt(sig_vk, sig_bt+1, nb_fields-1, true);
 347       VMRegPair* regs = NEW_RESOURCE_ARRAY(VMRegPair, nb_fields);
 348       int total = SharedRuntime::java_return_convention(sig_bt, regs, nb_fields);
 349 
 350       if (total > 0) {
 351         Array<VMRegPair>* return_regs = MetadataFactory::new_array<VMRegPair>(class_loader_data(), nb_fields, CHECK_AND_CLEAR);
 352         *((Array<VMRegPair>**)adr_return_regs()) = return_regs;
 353         for (int i = 0; i < nb_fields; i++) {
 354           return_regs->at_put(i, regs[i]);
 355         }
 356 
 357         BufferedValueTypeBlob* buffered_blob = SharedRuntime::generate_buffered_value_type_adapter(this);
 358         *((address*)adr_pack_handler()) = buffered_blob->pack_fields();
 359         *((address*)adr_unpack_handler()) = buffered_blob->unpack_fields();
 360         assert(CodeCache::find_blob(pack_handler()) == buffered_blob, "lost track of blob");
 361       }
 362     }
 363   }
 364 }
 365 
 366 void ValueKlass::deallocate_contents(ClassLoaderData* loader_data) {
 367   if (extended_sig() != NULL) {
 368     MetadataFactory::free_array<SigEntry>(loader_data, extended_sig());
 369   }
 370   if (return_regs() != NULL) {
 371     MetadataFactory::free_array<VMRegPair>(loader_data, return_regs());
 372   }
 373   cleanup_blobs();
 374   InstanceKlass::deallocate_contents(loader_data);
 375 }
 376 
 377 void ValueKlass::cleanup(ValueKlass* ik) {
 378   ik->cleanup_blobs();
 379 }
 380 
 381 void ValueKlass::cleanup_blobs() {
 382   if (pack_handler() != NULL) {
 383     CodeBlob* buffered_blob = CodeCache::find_blob(pack_handler());
 384     assert(buffered_blob->is_buffered_value_type_blob(), "bad blob type");
 385     BufferBlob::free((BufferBlob*)buffered_blob);
 386     *((address*)adr_pack_handler()) = NULL;
 387     *((address*)adr_unpack_handler()) = NULL;
 388   }
 389 }
 390 
 391 // Can this value type be returned as multiple values?
 392 bool ValueKlass::can_be_returned_as_fields() const {
 393   return return_regs() != NULL;
 394 }
 395 
 396 // Create handles for all oop fields returned in registers that are going to be live across a safepoint
 397 void ValueKlass::save_oop_fields(const RegisterMap& reg_map, GrowableArray<Handle>& handles) const {
 398   Thread* thread = Thread::current();
 399   const Array<SigEntry>* sig_vk = extended_sig();
 400   const Array<VMRegPair>* regs = return_regs();
 401   int j = 1;
 402 
 403   for (int i = 0; i < sig_vk->length(); i++) {
 404     BasicType bt = sig_vk->at(i)._bt;
 405     if (bt == T_OBJECT || bt == T_VALUETYPEPTR || bt == T_ARRAY) {
 406       int off = sig_vk->at(i)._offset;
 407       VMRegPair pair = regs->at(j);
 408       address loc = reg_map.location(pair.first());
 409       oop v = *(oop*)loc;
 410       assert(v == NULL || oopDesc::is_oop(v), "not an oop?");
 411       assert(Universe::heap()->is_in_or_null(v), "must be heap pointer");
 412       handles.push(Handle(thread, v));
 413     }
 414     if (bt == T_VALUETYPE) {
 415       continue;
 416     }
 417     if (bt == T_VOID &&
 418         sig_vk->at(i-1)._bt != T_LONG &&
 419         sig_vk->at(i-1)._bt != T_DOUBLE) {
 420       continue;
 421     }
 422     j++;
 423   }
 424   assert(j == regs->length(), "missed a field?");
 425 }
 426 
 427 // Update oop fields in registers from handles after a safepoint
 428 void ValueKlass::restore_oop_results(RegisterMap& reg_map, GrowableArray<Handle>& handles) const {
 429   assert(ValueTypeReturnedAsFields, "inconsistent");
 430   const Array<SigEntry>* sig_vk = extended_sig();
 431   const Array<VMRegPair>* regs = return_regs();
 432   assert(regs != NULL, "inconsistent");
 433 
 434   int j = 1;
 435   for (int i = 0, k = 0; i < sig_vk->length(); i++) {
 436     BasicType bt = sig_vk->at(i)._bt;
 437     if (bt == T_OBJECT || bt == T_ARRAY) {
 438       int off = sig_vk->at(i)._offset;
 439       VMRegPair pair = regs->at(j);
 440       address loc = reg_map.location(pair.first());
 441       *(oop*)loc = handles.at(k++)();
 442     }
 443     if (bt == T_VALUETYPE) {
 444       continue;
 445     }
 446     if (bt == T_VOID &&
 447         sig_vk->at(i-1)._bt != T_LONG &&
 448         sig_vk->at(i-1)._bt != T_DOUBLE) {
 449       continue;
 450     }
 451     j++;
 452   }
 453   assert(j == regs->length(), "missed a field?");
 454 }
 455 
 456 // Fields are in registers. Create an instance of the value type and
 457 // initialize it with the values of the fields.
 458 oop ValueKlass::realloc_result(const RegisterMap& reg_map, const GrowableArray<Handle>& handles, TRAPS) {







 459 
 460   oop new_vt = allocate_instance(CHECK_NULL);
 461   const Array<SigEntry>* sig_vk = extended_sig();
 462   const Array<VMRegPair>* regs = return_regs();
 463 
 464   int j = 1;
 465   int k = 0;
 466   for (int i = 0; i < sig_vk->length(); i++) {
 467     BasicType bt = sig_vk->at(i)._bt;
 468     if (bt == T_VALUETYPE) {
 469       continue;
 470     }
 471     if (bt == T_VOID) {
 472       if (sig_vk->at(i-1)._bt == T_LONG ||
 473           sig_vk->at(i-1)._bt == T_DOUBLE) {
 474         j++;
 475       }
 476       continue;
 477     }
 478     int off = sig_vk->at(i)._offset;
 479     VMRegPair pair = regs->at(j);
 480     address loc = reg_map.location(pair.first());
 481     switch(bt) {
 482     case T_BOOLEAN: {
 483       jboolean v = *(intptr_t*)loc;
 484       *(jboolean*)((address)new_vt + off) = v;
 485       break;
 486     }
 487     case T_CHAR: {
 488       jchar v = *(intptr_t*)loc;
 489       *(jchar*)((address)new_vt + off) = v;
 490       break;
 491     }
 492     case T_BYTE: {
 493       jbyte v = *(intptr_t*)loc;
 494       *(jbyte*)((address)new_vt + off) = v;
 495       break;
 496     }
 497     case T_SHORT: {
 498       jshort v = *(intptr_t*)loc;
 499       *(jshort*)((address)new_vt + off) = v;
 500       break;
 501     }
 502     case T_INT: {
 503       jint v = *(intptr_t*)loc;
 504       *(jint*)((address)new_vt + off) = v;
 505       break;
 506     }
 507     case T_LONG: {
 508 #ifdef _LP64
 509       jlong v = *(intptr_t*)loc;
 510       *(jlong*)((address)new_vt + off) = v;
 511 #else
 512       Unimplemented();
 513 #endif
 514       break;
 515     }
 516     case T_OBJECT:
 517     case T_VALUETYPEPTR:
 518     case T_ARRAY: {
 519       Handle handle = handles.at(k++);
 520       HeapAccess<>::oop_store_at(new_vt, off, handle());
 521       break;
 522     }
 523     case T_FLOAT: {
 524       jfloat v = *(jfloat*)loc;
 525       *(jfloat*)((address)new_vt + off) = v;
 526       break;
 527     }
 528     case T_DOUBLE: {
 529       jdouble v = *(jdouble*)loc;
 530       *(jdouble*)((address)new_vt + off) = v;
 531       break;
 532     }
 533     default:
 534       ShouldNotReachHere();
 535     }
 536     *(intptr_t*)loc = 0xDEAD;
 537     j++;
 538   }
 539   assert(j == regs->length(), "missed a field?");
 540   assert(k == handles.length(), "missed an oop?");
 541   return new_vt;
 542 }
 543 
 544 // Check the return register for a ValueKlass oop
 545 ValueKlass* ValueKlass::returned_value_klass(const RegisterMap& map) {
 546   BasicType bt = T_METADATA;
 547   VMRegPair pair;
 548   int nb = SharedRuntime::java_return_convention(&bt, &pair, 1);
 549   assert(nb == 1, "broken");
 550 
 551   address loc = map.location(pair.first());
 552   intptr_t ptr = *(intptr_t*)loc;
 553   if (is_set_nth_bit(ptr, 0)) {
 554     // Oop is tagged, must be a ValueKlass oop
 555     clear_nth_bit(ptr, 0);
 556     assert(Metaspace::contains((void*)ptr), "should be klass");
 557     ValueKlass* vk = (ValueKlass*)ptr;
 558     assert(vk->can_be_returned_as_fields(), "must be able to return as fields");
 559     return vk;
 560   }
 561 #ifdef ASSERT
 562   // Oop is not tagged, must be a valid oop
 563   if (VerifyOops) {
 564     oopDesc::verify(oop((HeapWord*)ptr));
 565   }
 566 #endif
 567   return NULL;
 568 }
 569 
 570 void ValueKlass::iterate_over_inside_oops(OopClosure* f, oop value) {
 571   assert(!Universe::heap()->is_in_reserved(value), "This method is used on buffered values");
 572 
 573   oop* addr_mirror = (oop*)(value)->mark_addr_raw();
 574   f->do_oop_no_buffering(addr_mirror);
 575 
 576   if (!contains_oops()) return;
 577 
 578   OopMapBlock* map = start_of_nonstatic_oop_maps();
 579   OopMapBlock* const end_map = map + nonstatic_oop_map_count();
 580 
 581   if (!UseCompressedOops) {
 582     for (; map < end_map; map++) {
 583       oop* p = (oop*) (((char*)(oopDesc*)value) + map->offset());
 584       oop* const end = p + map->count();
 585       for (; p < end; ++p) {
 586         assert(oopDesc::is_oop_or_null(*p), "Sanity check");
 587         f->do_oop(p);
 588       }
 589     }
 590   } else {
 591     for (; map < end_map; map++) {
 592       narrowOop* p = (narrowOop*) (((char*)(oopDesc*)value) + map->offset());
 593       narrowOop* const end = p + map->count();
 594       for (; p < end; ++p) {
 595         oop o = CompressedOops::decode(*p);
 596         assert(Universe::heap()->is_in_reserved_or_null(o), "Sanity check");
 597         assert(oopDesc::is_oop_or_null(o), "Sanity check");
 598         f->do_oop(p);
 599       }
 600     }
 601   }
 602 }
 603 
 604 void ValueKlass::verify_on(outputStream* st) {
 605   InstanceKlass::verify_on(st);
 606   guarantee(prototype_header()->is_always_locked(), "Prototype header is not always locked");
 607 }
 608 
 609 void ValueKlass::oop_verify_on(oop obj, outputStream* st) {
 610   InstanceKlass::oop_verify_on(obj, st);
 611   guarantee(obj->mark()->is_always_locked(), "Header is not always locked");
 612 }
--- EOF ---