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.inline.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 "runtime/thread.inline.hpp"
  47 #include "utilities/copy.hpp"
  48 
  49 int ValueKlass::first_field_offset() const {



  50 #ifdef ASSERT
  51   int first_offset = INT_MAX;
  52   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
  53     if (fs.offset() < first_offset) first_offset= fs.offset();
  54   }
  55 #endif
  56   int base_offset = instanceOopDesc::base_offset_in_bytes();
  57   // The first field of value types is aligned on a long boundary
  58   base_offset = align_up(base_offset, BytesPerLong);
  59   assert(base_offset == first_offset, "inconsistent offsets");
  60   return base_offset;
  61 }
  62 
  63 int ValueKlass::raw_value_byte_size() const {
  64   int heapOopAlignedSize = nonstatic_field_size() << LogBytesPerHeapOop;
  65   // If bigger than 64 bits or needs oop alignment, then use jlong aligned
  66   // which for values should be jlong aligned, asserts in raw_field_copy otherwise
  67   if (heapOopAlignedSize >= longSize || contains_oops()) {
  68     return heapOopAlignedSize;
  69   }
  70   // Small primitives...
  71   // If a few small basic type fields, return the actual size, i.e.
  72   // 1 byte = 1
  73   // 2 byte = 2
  74   // 3 byte = 4, because pow2 needed for element stores
  75   int first_offset = first_field_offset();
  76   int last_offset  = 0; // find the last offset, add basic type size
  77   int last_tsz     = 0;
  78   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
  79     if (fs.access_flags().is_static()) {
  80       continue;
  81     } else if (fs.offset() > last_offset) {
  82       BasicType type = fs.field_descriptor().field_type();
  83       if (is_java_primitive(type)) {
  84         last_tsz = type2aelembytes(type);
  85       } else if (type == T_VALUETYPE) {
  86         // Not just primitives. Layout aligns embedded value, so use jlong aligned it is
  87         return heapOopAlignedSize;
  88       } else {
  89         guarantee(0, "Unknown type %d", type);
  90       }
  91       assert(last_tsz != 0, "Invariant");
  92       last_offset = fs.offset();
  93     }
  94   }
  95   // Assumes VT with no fields are meaningless and illegal
  96   last_offset += last_tsz;
  97   assert(last_offset > first_offset && last_tsz, "Invariant");
  98   return 1 << upper_log2(last_offset - first_offset);
  99 }
 100 
 101 instanceOop ValueKlass::allocate_instance(TRAPS) {
 102   int size = size_helper();  // Query before forming handle.
 103 
 104   instanceOop oop = (instanceOop)Universe::heap()->obj_allocate(this, size, CHECK_NULL);
 105   assert(oop->mark()->is_always_locked(), "Unlocked value type");
 106   return oop;
 107 }
 108 
 109 bool ValueKlass::is_atomic() {
 110   return (nonstatic_field_size() * heapOopSize) <= longSize;
 111 }
 112 
 113 int ValueKlass::nonstatic_oop_count() {
 114   int oops = 0;
 115   int map_count = nonstatic_oop_map_count();
 116   OopMapBlock* block = start_of_nonstatic_oop_maps();
 117   OopMapBlock* end = block + map_count;
 118   while (block != end) {
 119     oops += block->count();
 120     block++;
 121   }
 122   return oops;
 123 }
 124 
 125 // Arrays of...
 126 
 127 bool ValueKlass::flatten_array() {
 128   if (!ValueArrayFlatten) {
 129     return false;
 130   }
 131 
 132   int elem_bytes = raw_value_byte_size();
 133   // Too big
 134   if ((ValueArrayElemMaxFlatSize >= 0) && (elem_bytes > ValueArrayElemMaxFlatSize)) {
 135     return false;
 136   }
 137   // Too many embedded oops
 138   if ((ValueArrayElemMaxFlatOops >= 0) && (nonstatic_oop_count() > ValueArrayElemMaxFlatOops)) {
 139     return false;
 140   }
 141 
 142   return true;
 143 }
 144 
 145 
 146 Klass* ValueKlass::array_klass_impl(ArrayStorageProperties storage_props, bool or_null, int n, TRAPS) {
 147   if (storage_props.is_null_free()) {
 148     return value_array_klass(storage_props, or_null, n, THREAD);
 149   } else {
 150     return InstanceKlass::array_klass_impl(storage_props, or_null, n, THREAD);
 151   }
 152 }
 153 
 154 Klass* ValueKlass::array_klass_impl(ArrayStorageProperties storage_props, bool or_null, TRAPS) {
 155   return array_klass_impl(storage_props, or_null, 1, THREAD);
 156 }
 157 
 158 Klass* ValueKlass::value_array_klass(ArrayStorageProperties storage_props, bool or_null, int rank, TRAPS) {
 159   Klass* vak = acquire_value_array_klass();
 160   if (vak == NULL) {
 161     if (or_null) return NULL;
 162     ResourceMark rm;
 163     {
 164       // Atomic creation of array_klasses
 165       MutexLocker ma(MultiArray_lock, THREAD);
 166       if (get_value_array_klass() == NULL) {
 167         vak = allocate_value_array_klass(CHECK_NULL);
 168         OrderAccess::release_store((Klass**)adr_value_array_klass(), vak);
 169       }
 170     }
 171   }
 172   if (!vak->is_valueArray_klass()) {
 173     storage_props.clear_flattened();
 174   }
 175   if (or_null) {
 176     return vak->array_klass_or_null(storage_props, rank);
 177   }
 178   return vak->array_klass(storage_props, rank, THREAD);
 179 }
 180 
 181 Klass* ValueKlass::allocate_value_array_klass(TRAPS) {
 182   if (flatten_array() && (is_atomic() || (!ValueArrayAtomicAccess))) {
 183     return ValueArrayKlass::allocate_klass(ArrayStorageProperties::flattened_and_null_free, this, THREAD);
 184   }
 185   return ObjArrayKlass::allocate_objArray_klass(ArrayStorageProperties::null_free, 1, this, THREAD);
 186 }
 187 
 188 void ValueKlass::array_klasses_do(void f(Klass* k)) {
 189   InstanceKlass::array_klasses_do(f);
 190   if (get_value_array_klass() != NULL)
 191     ArrayKlass::cast(get_value_array_klass())->array_klasses_do(f);
 192 }
 193 
 194 void ValueKlass::raw_field_copy(void* src, void* dst, size_t raw_byte_size) {

 195   /*
 196    * Try not to shear fields even if not an atomic store...
 197    *
 198    * First 3 cases handle value array store, otherwise works on the same basis
 199    * as JVM_Clone, at this size data is aligned. The order of primitive types
 200    * is largest to smallest, and it not possible for fields to stradle long
 201    * copy boundaries.
 202    *
 203    * If MT without exclusive access, possible to observe partial value store,
 204    * but not partial primitive and reference field values
 205    */
 206   switch (raw_byte_size) {
 207     case 1:
 208       *((jbyte*) dst) = *(jbyte*)src;
 209       break;
 210     case 2:
 211       *((jshort*) dst) = *(jshort*)src;
 212       break;
 213     case 4:
 214       *((jint*) dst) = *(jint*) src;
 215       break;
 216     default:
 217       assert(raw_byte_size % sizeof(jlong) == 0, "Unaligned raw_byte_size");
 218       Copy::conjoint_jlongs_atomic((jlong*)src, (jlong*)dst, raw_byte_size >> LogBytesPerLong);
 219   }






































 220 }
 221 
 222 /*
 223  * Store the value of this klass contained with src into dst.
 224  *
 225  * This operation is appropriate for use from vastore, vaload and putfield (for values)
 226  *
 227  * GC barriers currently can lock with no safepoint check and allocate c-heap,
 228  * so raw point is "safe" for now.
 229  *
 230  * Going forward, look to use machine generated (stub gen or bc) version for most used klass layouts
 231  *
 232  */
 233 void ValueKlass::value_store(void* src, void* dst, size_t raw_byte_size, bool dst_heap, bool dst_uninitialized) {
 234   if (contains_oops()) {
 235     if (dst_heap) {
 236       // src/dst aren't oops, need offset to adjust oop map offset
 237       const address dst_oop_addr = ((address) dst) - first_field_offset();
 238 
 239       ModRefBarrierSet* bs = barrier_set_cast<ModRefBarrierSet>(BarrierSet::barrier_set());
 240 
 241       // Pre-barriers...
 242       OopMapBlock* map = start_of_nonstatic_oop_maps();
 243       OopMapBlock* const end = map + nonstatic_oop_map_count();
 244       while (map != end) {
 245         // Shame we can't just use the existing oop iterator...src/dst aren't oop
 246         address doop_address = dst_oop_addr + map->offset();
 247         // TEMP HACK: barrier code need to migrate to => access API (need own versions of value type ops)
 248         if (UseCompressedOops) {
 249           bs->write_ref_array_pre((narrowOop*) doop_address, map->count(), dst_uninitialized);
 250         } else {
 251           bs->write_ref_array_pre((oop*) doop_address, map->count(), dst_uninitialized);
 252         }
 253         map++;
 254       }
 255 
 256       raw_field_copy(src, dst, raw_byte_size);
 257 
 258       // Post-barriers...
 259       map = start_of_nonstatic_oop_maps();
 260       while (map != end) {
 261         address doop_address = dst_oop_addr + map->offset();
 262         bs->write_ref_array((HeapWord*) doop_address, map->count());
 263         map++;
 264       }
 265     } else { // Buffered value case
 266       raw_field_copy(src, dst, raw_byte_size);
 267     }
 268   } else {   // Primitive-only case...
 269     raw_field_copy(src, dst, raw_byte_size);
 270   }
 271 }
 272 
 273 // Value type arguments are not passed by reference, instead each
 274 // field of the value type is passed as an argument. This helper
 275 // function collects the fields of the value types (including embedded
 276 // value type's fields) in a list. Included with the field's type is
 277 // the offset of each field in the value type: i2c and c2i adapters
 278 // need that to load or store fields. Finally, the list of fields is
 279 // sorted in order of increasing offsets: the adapters and the
 280 // compiled code need to agree upon the order of fields.
 281 //
 282 // The list of basic types that is returned starts with a T_VALUETYPE
 283 // and ends with an extra T_VOID. T_VALUETYPE/T_VOID pairs are used as
 284 // delimiters. Every entry between the two is a field of the value
 285 // type. If there's an embedded value type in the list, it also starts
 286 // with a T_VALUETYPE and ends with a T_VOID. This is so we can
 287 // generate a unique fingerprint for the method's adapters and we can
 288 // generate the list of basic types from the interpreter point of view
 289 // (value types passed as reference: iterate on the list until a
 290 // T_VALUETYPE, drop everything until and including the closing
 291 // T_VOID) or the compiler point of view (each field of the value
 292 // types is an argument: drop all T_VALUETYPE/T_VOID from the list).
 293 int ValueKlass::collect_fields(GrowableArray<SigEntry>* sig, int base_off) const {
 294   int count = 0;
 295   SigEntry::add_entry(sig, T_VALUETYPE, base_off);
 296   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
 297     if (fs.access_flags().is_static()) continue;
 298     int offset = base_off + fs.offset() - (base_off > 0 ? first_field_offset() : 0);
 299     if (fs.is_flattened()) {
 300       // Resolve klass of flattened value type field and recursively collect fields
 301       Klass* vk = get_value_field_klass(fs.index());
 302       count += ValueKlass::cast(vk)->collect_fields(sig, offset);
 303     } else {
 304       BasicType bt = FieldType::basic_type(fs.signature());
 305       if (bt == T_VALUETYPE) {
 306         bt = T_OBJECT;
 307       }
 308       SigEntry::add_entry(sig, bt, offset);
 309       count += type2size[bt];
 310     }
 311   }
 312   int offset = base_off + size_helper()*HeapWordSize - (base_off > 0 ? first_field_offset() : 0);
 313   SigEntry::add_entry(sig, T_VOID, offset);
 314   if (base_off == 0) {
 315     sig->sort(SigEntry::compare);
 316   }
 317   assert(sig->at(0)._bt == T_VALUETYPE && sig->at(sig->length()-1)._bt == T_VOID, "broken structure");
 318   return count;
 319 }
 320 
 321 void ValueKlass::initialize_calling_convention(TRAPS) {
 322   // Because the pack and unpack handler addresses need to be loadable from generated code,
 323   // they are stored at a fixed offset in the klass metadata. Since value type klasses do
 324   // not have a vtable, the vtable offset is used to store these addresses.
 325   if (is_scalarizable() && (ValueTypeReturnedAsFields || ValueTypePassFieldsAsArgs)) {
 326     ResourceMark rm;
 327     GrowableArray<SigEntry> sig_vk;
 328     int nb_fields = collect_fields(&sig_vk);
 329     Array<SigEntry>* extended_sig = MetadataFactory::new_array<SigEntry>(class_loader_data(), sig_vk.length(), CHECK);
 330     *((Array<SigEntry>**)adr_extended_sig()) = extended_sig;
 331     for (int i = 0; i < sig_vk.length(); i++) {
 332       extended_sig->at_put(i, sig_vk.at(i));
 333     }
 334 
 335     if (ValueTypeReturnedAsFields) {
 336       nb_fields++;
 337       BasicType* sig_bt = NEW_RESOURCE_ARRAY(BasicType, nb_fields);
 338       sig_bt[0] = T_METADATA;
 339       SigEntry::fill_sig_bt(&sig_vk, sig_bt+1);
 340       VMRegPair* regs = NEW_RESOURCE_ARRAY(VMRegPair, nb_fields);
 341       int total = SharedRuntime::java_return_convention(sig_bt, regs, nb_fields);
 342 
 343       if (total > 0) {
 344         Array<VMRegPair>* return_regs = MetadataFactory::new_array<VMRegPair>(class_loader_data(), nb_fields, CHECK);
 345         *((Array<VMRegPair>**)adr_return_regs()) = return_regs;
 346         for (int i = 0; i < nb_fields; i++) {
 347           return_regs->at_put(i, regs[i]);
 348         }
 349 
 350         BufferedValueTypeBlob* buffered_blob = SharedRuntime::generate_buffered_value_type_adapter(this);
 351         *((address*)adr_pack_handler()) = buffered_blob->pack_fields();
 352         *((address*)adr_unpack_handler()) = buffered_blob->unpack_fields();
 353         assert(CodeCache::find_blob(pack_handler()) == buffered_blob, "lost track of blob");
 354       }
 355     }
 356   }
 357 }
 358 
 359 void ValueKlass::deallocate_contents(ClassLoaderData* loader_data) {
 360   if (extended_sig() != NULL) {
 361     MetadataFactory::free_array<SigEntry>(loader_data, extended_sig());
 362   }
 363   if (return_regs() != NULL) {
 364     MetadataFactory::free_array<VMRegPair>(loader_data, return_regs());
 365   }
 366   cleanup_blobs();
 367   InstanceKlass::deallocate_contents(loader_data);
 368 }
 369 
 370 void ValueKlass::cleanup(ValueKlass* ik) {
 371   ik->cleanup_blobs();
 372 }
 373 
 374 void ValueKlass::cleanup_blobs() {
 375   if (pack_handler() != NULL) {
 376     CodeBlob* buffered_blob = CodeCache::find_blob(pack_handler());
 377     assert(buffered_blob->is_buffered_value_type_blob(), "bad blob type");
 378     BufferBlob::free((BufferBlob*)buffered_blob);
 379     *((address*)adr_pack_handler()) = NULL;
 380     *((address*)adr_unpack_handler()) = NULL;
 381   }
 382 }
 383 
 384 // Can this value type be scalarized?
 385 bool ValueKlass::is_scalarizable() const {
 386   return ScalarizeValueTypes;
 387 }
 388 
 389 // Can this value type be returned as multiple values?
 390 bool ValueKlass::can_be_returned_as_fields() const {
 391   return return_regs() != NULL;
 392 }
 393 
 394 // Create handles for all oop fields returned in registers that are going to be live across a safepoint
 395 void ValueKlass::save_oop_fields(const RegisterMap& reg_map, GrowableArray<Handle>& handles) const {
 396   Thread* thread = Thread::current();
 397   const Array<SigEntry>* sig_vk = extended_sig();
 398   const Array<VMRegPair>* regs = return_regs();
 399   int j = 1;
 400 
 401   for (int i = 0; i < sig_vk->length(); i++) {
 402     BasicType bt = sig_vk->at(i)._bt;
 403     if (bt == T_OBJECT || bt == T_ARRAY) {
 404       VMRegPair pair = regs->at(j);
 405       address loc = reg_map.location(pair.first());
 406       oop v = *(oop*)loc;
 407       assert(v == NULL || oopDesc::is_oop(v), "not an oop?");
 408       assert(Universe::heap()->is_in_or_null(v), "must be heap pointer");
 409       handles.push(Handle(thread, v));
 410     }
 411     if (bt == T_VALUETYPE) {
 412       continue;
 413     }
 414     if (bt == T_VOID &&
 415         sig_vk->at(i-1)._bt != T_LONG &&
 416         sig_vk->at(i-1)._bt != T_DOUBLE) {
 417       continue;
 418     }
 419     j++;
 420   }
 421   assert(j == regs->length(), "missed a field?");
 422 }
 423 
 424 // Update oop fields in registers from handles after a safepoint
 425 void ValueKlass::restore_oop_results(RegisterMap& reg_map, GrowableArray<Handle>& handles) const {
 426   assert(ValueTypeReturnedAsFields, "inconsistent");
 427   const Array<SigEntry>* sig_vk = extended_sig();
 428   const Array<VMRegPair>* regs = return_regs();
 429   assert(regs != NULL, "inconsistent");
 430 
 431   int j = 1;
 432   for (int i = 0, k = 0; i < sig_vk->length(); i++) {
 433     BasicType bt = sig_vk->at(i)._bt;
 434     if (bt == T_OBJECT || bt == T_ARRAY) {
 435       VMRegPair pair = regs->at(j);
 436       address loc = reg_map.location(pair.first());
 437       *(oop*)loc = handles.at(k++)();
 438     }
 439     if (bt == T_VALUETYPE) {
 440       continue;
 441     }
 442     if (bt == T_VOID &&
 443         sig_vk->at(i-1)._bt != T_LONG &&
 444         sig_vk->at(i-1)._bt != T_DOUBLE) {
 445       continue;
 446     }
 447     j++;
 448   }
 449   assert(j == regs->length(), "missed a field?");
 450 }
 451 
 452 // Fields are in registers. Create an instance of the value type and
 453 // initialize it with the values of the fields.
 454 oop ValueKlass::realloc_result(const RegisterMap& reg_map, const GrowableArray<Handle>& handles, TRAPS) {
 455   oop new_vt = allocate_instance(CHECK_NULL);
 456   const Array<SigEntry>* sig_vk = extended_sig();
 457   const Array<VMRegPair>* regs = return_regs();
 458 
 459   int j = 1;
 460   int k = 0;
 461   for (int i = 0; i < sig_vk->length(); i++) {
 462     BasicType bt = sig_vk->at(i)._bt;
 463     if (bt == T_VALUETYPE) {
 464       continue;
 465     }
 466     if (bt == T_VOID) {
 467       if (sig_vk->at(i-1)._bt == T_LONG ||
 468           sig_vk->at(i-1)._bt == T_DOUBLE) {
 469         j++;
 470       }
 471       continue;
 472     }
 473     int off = sig_vk->at(i)._offset;
 474     assert(off > 0, "offset in object should be positive");
 475     VMRegPair pair = regs->at(j);
 476     address loc = reg_map.location(pair.first());
 477     switch(bt) {
 478     case T_BOOLEAN: {
 479       new_vt->bool_field_put(off, *(jboolean*)loc);
 480       break;
 481     }
 482     case T_CHAR: {
 483       new_vt->char_field_put(off, *(jchar*)loc);
 484       break;
 485     }
 486     case T_BYTE: {
 487       new_vt->byte_field_put(off, *(jbyte*)loc);
 488       break;
 489     }
 490     case T_SHORT: {
 491       new_vt->short_field_put(off, *(jshort*)loc);
 492       break;
 493     }
 494     case T_INT: {
 495       new_vt->int_field_put(off, *(jint*)loc);
 496       break;
 497     }
 498     case T_LONG: {
 499 #ifdef _LP64
 500       new_vt->double_field_put(off,  *(jdouble*)loc);
 501 #else
 502       Unimplemented();
 503 #endif
 504       break;
 505     }
 506     case T_OBJECT:
 507     case T_ARRAY: {
 508       Handle handle = handles.at(k++);
 509       new_vt->obj_field_put(off, handle());
 510       break;
 511     }
 512     case T_FLOAT: {
 513       new_vt->float_field_put(off,  *(jfloat*)loc);
 514       break;
 515     }
 516     case T_DOUBLE: {
 517       new_vt->double_field_put(off, *(jdouble*)loc);
 518       break;
 519     }
 520     default:
 521       ShouldNotReachHere();
 522     }
 523     *(intptr_t*)loc = 0xDEAD;
 524     j++;
 525   }
 526   assert(j == regs->length(), "missed a field?");
 527   assert(k == handles.length(), "missed an oop?");
 528   return new_vt;
 529 }
 530 
 531 // Check the return register for a ValueKlass oop
 532 ValueKlass* ValueKlass::returned_value_klass(const RegisterMap& map) {
 533   BasicType bt = T_METADATA;
 534   VMRegPair pair;
 535   int nb = SharedRuntime::java_return_convention(&bt, &pair, 1);
 536   assert(nb == 1, "broken");
 537 
 538   address loc = map.location(pair.first());
 539   intptr_t ptr = *(intptr_t*)loc;
 540   if (is_set_nth_bit(ptr, 0)) {
 541     // Oop is tagged, must be a ValueKlass oop
 542     clear_nth_bit(ptr, 0);
 543     assert(Metaspace::contains((void*)ptr), "should be klass");
 544     ValueKlass* vk = (ValueKlass*)ptr;
 545     assert(vk->can_be_returned_as_fields(), "must be able to return as fields");
 546     return vk;
 547   }
 548 #ifdef ASSERT
 549   // Oop is not tagged, must be a valid oop
 550   if (VerifyOops) {
 551     oopDesc::verify(oop((HeapWord*)ptr));
 552   }
 553 #endif
 554   return NULL;
 555 }
 556 
 557 void ValueKlass::verify_on(outputStream* st) {
 558   InstanceKlass::verify_on(st);
 559   guarantee(prototype_header()->is_always_locked(), "Prototype header is not always locked");
 560 }
 561 
 562 void ValueKlass::oop_verify_on(oop obj, outputStream* st) {
 563   InstanceKlass::oop_verify_on(obj, st);
 564   guarantee(obj->mark()->is_always_locked(), "Header is not always locked");
 565 }
--- EOF ---