1 /* 2 * Copyright (c) 1997, 2018, 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 #ifndef SHARE_VM_OOPS_OOP_INLINE_HPP 26 #define SHARE_VM_OOPS_OOP_INLINE_HPP 27 28 #include "gc/shared/ageTable.hpp" 29 #include "gc/shared/collectedHeap.inline.hpp" 30 #include "gc/shared/genCollectedHeap.hpp" 31 #include "gc/shared/generation.hpp" 32 #include "memory/vtBuffer.hpp" 33 #include "oops/access.inline.hpp" 34 #include "oops/arrayKlass.hpp" 35 #include "oops/arrayOop.hpp" 36 #include "oops/klass.inline.hpp" 37 #include "oops/markOop.inline.hpp" 38 #include "oops/oop.hpp" 39 #include "runtime/atomic.hpp" 40 #include "runtime/orderAccess.inline.hpp" 41 #include "runtime/os.hpp" 42 #include "utilities/align.hpp" 43 #include "utilities/macros.hpp" 44 45 // Implementation of all inlined member functions defined in oop.hpp 46 // We need a separate file to avoid circular references 47 48 void oopDesc::release_set_mark(markOop m) { 49 OrderAccess::release_store(&_mark, m); 50 } 51 52 markOop oopDesc::cas_set_mark(markOop new_mark, markOop old_mark) { 53 return Atomic::cmpxchg(new_mark, &_mark, old_mark); 54 } 55 56 void oopDesc::init_mark() { 57 set_mark(markOopDesc::prototype_for_object(this)); 58 } 59 60 Klass* oopDesc::klass() const { 61 if (UseCompressedClassPointers) { 62 return Klass::decode_klass_not_null(_metadata._compressed_klass); 63 } else { 64 return _metadata._klass; 65 } 66 } 67 68 Klass* oopDesc::klass_or_null() const volatile { 69 if (UseCompressedClassPointers) { 70 return Klass::decode_klass(_metadata._compressed_klass); 71 } else { 72 return _metadata._klass; 73 } 74 } 75 76 Klass* oopDesc::klass_or_null_acquire() const volatile { 77 if (UseCompressedClassPointers) { 78 // Workaround for non-const load_acquire parameter. 79 const volatile narrowKlass* addr = &_metadata._compressed_klass; 80 volatile narrowKlass* xaddr = const_cast<volatile narrowKlass*>(addr); 81 return Klass::decode_klass(OrderAccess::load_acquire(xaddr)); 82 } else { 83 return OrderAccess::load_acquire(&_metadata._klass); 84 } 85 } 86 87 Klass** oopDesc::klass_addr() { 88 // Only used internally and with CMS and will not work with 89 // UseCompressedOops 90 assert(!UseCompressedClassPointers, "only supported with uncompressed klass pointers"); 91 return (Klass**) &_metadata._klass; 92 } 93 94 narrowKlass* oopDesc::compressed_klass_addr() { 95 assert(UseCompressedClassPointers, "only called by compressed klass pointers"); 96 return &_metadata._compressed_klass; 97 } 98 99 // oop only test (does not load klass) 100 bool oopDesc::klass_is_value_type() { 101 if (UseCompressedClassPointers) { 102 return Klass::decode_ptr_is_value_type(_metadata._compressed_klass); 103 } else { 104 return Klass::ptr_is_value_type(_metadata._klass); 105 } 106 } 107 108 109 #define CHECK_SET_KLASS(k) \ 110 do { \ 111 assert(Universe::is_bootstrapping() || k != NULL, "NULL Klass"); \ 112 assert(Universe::is_bootstrapping() || k->is_klass(), "not a Klass"); \ 113 assert(!EnableValhalla || (k->is_value() && Klass::ptr_is_value_type(k)) \ 114 || (!k->is_value() && !Klass::ptr_is_value_type(k)), \ 115 "Klass value encoding"); \ 116 } while (0) 117 118 void oopDesc::set_klass(Klass* k) { 119 CHECK_SET_KLASS(k); 120 if (UseCompressedClassPointers) { 121 *compressed_klass_addr() = Klass::encode_klass_not_null(k); 122 } else { 123 *klass_addr() = k; 124 } 125 } 126 127 void oopDesc::release_set_klass(Klass* k) { 128 CHECK_SET_KLASS(k); 129 if (UseCompressedClassPointers) { 130 OrderAccess::release_store(compressed_klass_addr(), 131 Klass::encode_klass_not_null(k)); 132 } else { 133 OrderAccess::release_store(klass_addr(), k); 134 } 135 } 136 137 #undef CHECK_SET_KLASS 138 139 int oopDesc::klass_gap() const { 140 return *(int*)(((intptr_t)this) + klass_gap_offset_in_bytes()); 141 } 142 143 void oopDesc::set_klass_gap(int v) { 144 if (UseCompressedClassPointers) { 145 *(int*)(((intptr_t)this) + klass_gap_offset_in_bytes()) = v; 146 } 147 } 148 149 void oopDesc::set_klass_to_list_ptr(oop k) { 150 // This is only to be used during GC, for from-space objects, so no 151 // barrier is needed. 152 if (UseCompressedClassPointers) { 153 _metadata._compressed_klass = (narrowKlass)encode_heap_oop(k); // may be null (parnew overflow handling) 154 } else { 155 _metadata._klass = (Klass*)(address)k; 156 } 157 } 158 159 oop oopDesc::list_ptr_from_klass() { 160 // This is only to be used during GC, for from-space objects. 161 if (UseCompressedClassPointers) { 162 return decode_heap_oop((narrowOop)_metadata._compressed_klass); 163 } else { 164 // Special case for GC 165 return (oop)(address)_metadata._klass; 166 } 167 } 168 169 bool oopDesc::is_a(Klass* k) const { 170 return klass()->is_subtype_of(k); 171 } 172 173 int oopDesc::size() { 174 return size_given_klass(klass()); 175 } 176 177 int oopDesc::size_given_klass(Klass* klass) { 178 int lh = klass->layout_helper(); 179 int s; 180 181 // lh is now a value computed at class initialization that may hint 182 // at the size. For instances, this is positive and equal to the 183 // size. For arrays, this is negative and provides log2 of the 184 // array element size. For other oops, it is zero and thus requires 185 // a virtual call. 186 // 187 // We go to all this trouble because the size computation is at the 188 // heart of phase 2 of mark-compaction, and called for every object, 189 // alive or dead. So the speed here is equal in importance to the 190 // speed of allocation. 191 192 if (lh > Klass::_lh_neutral_value) { 193 if (!Klass::layout_helper_needs_slow_path(lh)) { 194 s = lh >> LogHeapWordSize; // deliver size scaled by wordSize 195 } else { 196 s = klass->oop_size(this); 197 } 198 } else if (lh <= Klass::_lh_neutral_value) { 199 // The most common case is instances; fall through if so. 200 if (lh < Klass::_lh_neutral_value) { 201 // Second most common case is arrays. We have to fetch the 202 // length of the array, shift (multiply) it appropriately, 203 // up to wordSize, add the header, and align to object size. 204 size_t size_in_bytes; 205 size_t array_length = (size_t) ((arrayOop)this)->length(); 206 size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh); 207 size_in_bytes += Klass::layout_helper_header_size(lh); 208 209 // This code could be simplified, but by keeping array_header_in_bytes 210 // in units of bytes and doing it this way we can round up just once, 211 // skipping the intermediate round to HeapWordSize. 212 s = (int)(align_up(size_in_bytes, MinObjAlignmentInBytes) / HeapWordSize); 213 214 // ParNew (used by CMS), UseParallelGC and UseG1GC can change the length field 215 // of an "old copy" of an object array in the young gen so it indicates 216 // the grey portion of an already copied array. This will cause the first 217 // disjunct below to fail if the two comparands are computed across such 218 // a concurrent change. 219 // ParNew also runs with promotion labs (which look like int 220 // filler arrays) which are subject to changing their declared size 221 // when finally retiring a PLAB; this also can cause the first disjunct 222 // to fail for another worker thread that is concurrently walking the block 223 // offset table. Both these invariant failures are benign for their 224 // current uses; we relax the assertion checking to cover these two cases below: 225 // is_objArray() && is_forwarded() // covers first scenario above 226 // || is_typeArray() // covers second scenario above 227 // If and when UseParallelGC uses the same obj array oop stealing/chunking 228 // technique, we will need to suitably modify the assertion. 229 assert((s == klass->oop_size(this)) || 230 (Universe::heap()->is_gc_active() && 231 ((is_typeArray() && UseConcMarkSweepGC) || 232 (is_objArray() && is_forwarded() && (UseConcMarkSweepGC || UseParallelGC || UseG1GC)))), 233 "wrong array object size"); 234 } else { 235 // Must be zero, so bite the bullet and take the virtual call. 236 s = klass->oop_size(this); 237 } 238 } 239 240 assert(s > 0, "Oop size must be greater than zero, not %d", s); 241 assert(is_object_aligned(s), "Oop size is not properly aligned: %d", s); 242 return s; 243 } 244 245 bool oopDesc::is_instance() const { return klass()->is_instance_klass(); } 246 bool oopDesc::is_array() const { return klass()->is_array_klass(); } 247 bool oopDesc::is_objArray() const { return klass()->is_objArray_klass(); } 248 bool oopDesc::is_typeArray() const { return klass()->is_typeArray_klass(); } 249 bool oopDesc::is_value() const { return klass()->is_value(); } 250 bool oopDesc::is_valueArray() const { return klass()->is_valueArray_klass(); } 251 252 void* oopDesc::field_addr_raw(int offset) const { return reinterpret_cast<void*>(cast_from_oop<intptr_t>(as_oop()) + offset); } 253 void* oopDesc::field_addr(int offset) const { return Access<>::resolve(as_oop())->field_addr_raw(offset); } 254 255 template <class T> 256 T* oopDesc::obj_field_addr_raw(int offset) const { return (T*) field_addr_raw(offset); } 257 258 // Functions for getting and setting oops within instance objects. 259 // If the oops are compressed, the type passed to these overloaded functions 260 // is narrowOop. All functions are overloaded so they can be called by 261 // template functions without conditionals (the compiler instantiates via 262 // the right type and inlines the appopriate code). 263 264 // Algorithm for encoding and decoding oops from 64 bit pointers to 32 bit 265 // offset from the heap base. Saving the check for null can save instructions 266 // in inner GC loops so these are separated. 267 268 inline bool check_obj_alignment(oop obj) { 269 return (cast_from_oop<intptr_t>(obj) & MinObjAlignmentInBytesMask) == 0; 270 } 271 272 oop oopDesc::decode_heap_oop_not_null(narrowOop v) { 273 assert(!is_null(v), "narrow oop value can never be zero"); 274 address base = Universe::narrow_oop_base(); 275 int shift = Universe::narrow_oop_shift(); 276 oop result = (oop)(void*)((uintptr_t)base + ((uintptr_t)v << shift)); 277 assert(check_obj_alignment(result), "address not aligned: " INTPTR_FORMAT, p2i((void*) result)); 278 return result; 279 } 280 281 oop oopDesc::decode_heap_oop(narrowOop v) { 282 return is_null(v) ? (oop)NULL : decode_heap_oop_not_null(v); 283 } 284 285 narrowOop oopDesc::encode_heap_oop_not_null(oop v) { 286 assert(!is_null(v), "oop value can never be zero"); 287 assert(check_obj_alignment(v), "Address not aligned"); 288 assert(Universe::heap()->is_in_reserved(v), "Address not in heap"); 289 address base = Universe::narrow_oop_base(); 290 int shift = Universe::narrow_oop_shift(); 291 uint64_t pd = (uint64_t)(pointer_delta((void*)v, (void*)base, 1)); 292 assert(OopEncodingHeapMax > pd, "change encoding max if new encoding"); 293 uint64_t result = pd >> shift; 294 assert((result & CONST64(0xffffffff00000000)) == 0, "narrow oop overflow"); 295 assert(decode_heap_oop(result) == v, "reversibility"); 296 return (narrowOop)result; 297 } 298 299 narrowOop oopDesc::encode_heap_oop(oop v) { 300 return (is_null(v)) ? (narrowOop)0 : encode_heap_oop_not_null(v); 301 } 302 303 narrowOop oopDesc::load_heap_oop(narrowOop* p) { return *p; } 304 oop oopDesc::load_heap_oop(oop* p) { return *p; } 305 306 void oopDesc::store_heap_oop(narrowOop* p, narrowOop v) { *p = v; } 307 void oopDesc::store_heap_oop(oop* p, oop v) { *p = v; } 308 309 // Load and decode an oop out of the Java heap into a wide oop. 310 oop oopDesc::load_decode_heap_oop_not_null(narrowOop* p) { 311 return decode_heap_oop_not_null(load_heap_oop(p)); 312 } 313 314 // Load and decode an oop out of the heap accepting null 315 oop oopDesc::load_decode_heap_oop(narrowOop* p) { 316 return decode_heap_oop(load_heap_oop(p)); 317 } 318 319 oop oopDesc::load_decode_heap_oop_not_null(oop* p) { return *p; } 320 oop oopDesc::load_decode_heap_oop(oop* p) { return *p; } 321 322 void oopDesc::encode_store_heap_oop_not_null(oop* p, oop v) { *p = v; } 323 void oopDesc::encode_store_heap_oop(oop* p, oop v) { *p = v; } 324 325 // Encode and store a heap oop. 326 void oopDesc::encode_store_heap_oop_not_null(narrowOop* p, oop v) { 327 *p = encode_heap_oop_not_null(v); 328 } 329 330 // Encode and store a heap oop allowing for null. 331 void oopDesc::encode_store_heap_oop(narrowOop* p, oop v) { 332 *p = encode_heap_oop(v); 333 } 334 335 template <DecoratorSet decorators> 336 inline oop oopDesc::obj_field_access(int offset) const { return HeapAccess<decorators>::oop_load_at(as_oop(), offset); } 337 inline oop oopDesc::obj_field(int offset) const { return HeapAccess<>::oop_load_at(as_oop(), offset); } 338 339 inline void oopDesc::obj_field_put(int offset, oop value) { HeapAccess<>::oop_store_at(as_oop(), offset, value); } 340 341 inline jbyte oopDesc::byte_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); } 342 inline void oopDesc::byte_field_put(int offset, jbyte value) { HeapAccess<>::store_at(as_oop(), offset, value); } 343 344 inline jchar oopDesc::char_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); } 345 inline void oopDesc::char_field_put(int offset, jchar value) { HeapAccess<>::store_at(as_oop(), offset, value); } 346 347 inline jboolean oopDesc::bool_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); } 348 inline void oopDesc::bool_field_put(int offset, jboolean value) { HeapAccess<>::store_at(as_oop(), offset, jboolean(value & 1)); } 349 350 inline jshort oopDesc::short_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); } 351 inline void oopDesc::short_field_put(int offset, jshort value) { HeapAccess<>::store_at(as_oop(), offset, value); } 352 353 inline jint oopDesc::int_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); } 354 inline void oopDesc::int_field_put(int offset, jint value) { HeapAccess<>::store_at(as_oop(), offset, value); } 355 356 inline jlong oopDesc::long_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); } 357 inline void oopDesc::long_field_put(int offset, jlong value) { HeapAccess<>::store_at(as_oop(), offset, value); } 358 359 inline jfloat oopDesc::float_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); } 360 inline void oopDesc::float_field_put(int offset, jfloat value) { HeapAccess<>::store_at(as_oop(), offset, value); } 361 362 inline jdouble oopDesc::double_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); } 363 inline void oopDesc::double_field_put(int offset, jdouble value) { HeapAccess<>::store_at(as_oop(), offset, value); } 364 365 bool oopDesc::is_locked() const { 366 return mark()->is_locked(); 367 } 368 369 bool oopDesc::is_unlocked() const { 370 return mark()->is_unlocked(); 371 } 372 373 bool oopDesc::has_bias_pattern() const { 374 return mark()->has_bias_pattern(); 375 } 376 377 378 // Used only for markSweep, scavenging 379 bool oopDesc::is_gc_marked() const { 380 return mark()->is_marked(); 381 } 382 383 bool oopDesc::is_scavengable() const { 384 return Universe::heap()->is_scavengable(oop(const_cast<oopDesc*>(this))); 385 } 386 387 // Used by scavengers 388 bool oopDesc::is_forwarded() const { 389 // The extra heap check is needed since the obj might be locked, in which case the 390 // mark would point to a stack location and have the sentinel bit cleared 391 return mark()->is_marked(); 392 } 393 394 // Used by scavengers 395 void oopDesc::forward_to(oop p) { 396 assert(check_obj_alignment(p), 397 "forwarding to something not aligned"); 398 assert(Universe::heap()->is_in_reserved(p), 399 "forwarding to something not in heap"); 400 assert(!is_archive_object(oop(this)) && 401 !is_archive_object(p), 402 "forwarding archive object"); 403 markOop m = markOopDesc::encode_pointer_as_mark(p); 404 assert(m->decode_pointer() == p, "encoding must be reversable"); 405 set_mark(m); 406 } 407 408 // Used by parallel scavengers 409 bool oopDesc::cas_forward_to(oop p, markOop compare) { 410 assert(check_obj_alignment(p), 411 "forwarding to something not aligned"); 412 assert(Universe::heap()->is_in_reserved(p), 413 "forwarding to something not in heap"); 414 markOop m = markOopDesc::encode_pointer_as_mark(p); 415 assert(m->decode_pointer() == p, "encoding must be reversable"); 416 return cas_set_mark(m, compare) == compare; 417 } 418 419 #if INCLUDE_ALL_GCS 420 oop oopDesc::forward_to_atomic(oop p) { 421 markOop oldMark = mark(); 422 markOop forwardPtrMark = markOopDesc::encode_pointer_as_mark(p); 423 markOop curMark; 424 425 assert(forwardPtrMark->decode_pointer() == p, "encoding must be reversable"); 426 assert(sizeof(markOop) == sizeof(intptr_t), "CAS below requires this."); 427 428 while (!oldMark->is_marked()) { 429 curMark = Atomic::cmpxchg(forwardPtrMark, &_mark, oldMark); 430 assert(is_forwarded(), "object should have been forwarded"); 431 if (curMark == oldMark) { 432 return NULL; 433 } 434 // If the CAS was unsuccessful then curMark->is_marked() 435 // should return true as another thread has CAS'd in another 436 // forwarding pointer. 437 oldMark = curMark; 438 } 439 return forwardee(); 440 } 441 #endif 442 443 // Note that the forwardee is not the same thing as the displaced_mark. 444 // The forwardee is used when copying during scavenge and mark-sweep. 445 // It does need to clear the low two locking- and GC-related bits. 446 oop oopDesc::forwardee() const { 447 return (oop) mark()->decode_pointer(); 448 } 449 450 // The following method needs to be MT safe. 451 uint oopDesc::age() const { 452 assert(!is_forwarded(), "Attempt to read age from forwarded mark"); 453 if (has_displaced_mark()) { 454 return displaced_mark()->age(); 455 } else { 456 return mark()->age(); 457 } 458 } 459 460 void oopDesc::incr_age() { 461 assert(!is_forwarded(), "Attempt to increment age of forwarded mark"); 462 if (has_displaced_mark()) { 463 set_displaced_mark(displaced_mark()->incr_age()); 464 } else { 465 set_mark(mark()->incr_age()); 466 } 467 } 468 469 #if INCLUDE_ALL_GCS 470 void oopDesc::pc_follow_contents(ParCompactionManager* cm) { 471 klass()->oop_pc_follow_contents(this, cm); 472 } 473 474 void oopDesc::pc_update_contents(ParCompactionManager* cm) { 475 Klass* k = klass(); 476 if (!k->is_typeArray_klass()) { 477 // It might contain oops beyond the header, so take the virtual call. 478 k->oop_pc_update_pointers(this, cm); 479 } 480 // Else skip it. The TypeArrayKlass in the header never needs scavenging. 481 } 482 483 void oopDesc::ps_push_contents(PSPromotionManager* pm) { 484 Klass* k = klass(); 485 if (!k->is_typeArray_klass()) { 486 // It might contain oops beyond the header, so take the virtual call. 487 k->oop_ps_push_contents(this, pm); 488 } 489 // Else skip it. The TypeArrayKlass in the header never needs scavenging. 490 } 491 #endif // INCLUDE_ALL_GCS 492 493 #define OOP_ITERATE_DEFN(OopClosureType, nv_suffix) \ 494 \ 495 void oopDesc::oop_iterate(OopClosureType* blk) { \ 496 klass()->oop_oop_iterate##nv_suffix(this, blk); \ 497 } \ 498 \ 499 void oopDesc::oop_iterate(OopClosureType* blk, MemRegion mr) { \ 500 klass()->oop_oop_iterate_bounded##nv_suffix(this, blk, mr); \ 501 } 502 503 #define OOP_ITERATE_SIZE_DEFN(OopClosureType, nv_suffix) \ 504 \ 505 int oopDesc::oop_iterate_size(OopClosureType* blk) { \ 506 Klass* k = klass(); \ 507 int size = size_given_klass(k); \ 508 k->oop_oop_iterate##nv_suffix(this, blk); \ 509 return size; \ 510 } \ 511 \ 512 int oopDesc::oop_iterate_size(OopClosureType* blk, MemRegion mr) { \ 513 Klass* k = klass(); \ 514 int size = size_given_klass(k); \ 515 k->oop_oop_iterate_bounded##nv_suffix(this, blk, mr); \ 516 return size; \ 517 } 518 519 int oopDesc::oop_iterate_no_header(OopClosure* blk) { 520 // The NoHeaderExtendedOopClosure wraps the OopClosure and proxies all 521 // the do_oop calls, but turns off all other features in ExtendedOopClosure. 522 NoHeaderExtendedOopClosure cl(blk); 523 return oop_iterate_size(&cl); 524 } 525 526 int oopDesc::oop_iterate_no_header(OopClosure* blk, MemRegion mr) { 527 NoHeaderExtendedOopClosure cl(blk); 528 return oop_iterate_size(&cl, mr); 529 } 530 531 #if INCLUDE_ALL_GCS 532 #define OOP_ITERATE_BACKWARDS_DEFN(OopClosureType, nv_suffix) \ 533 \ 534 inline void oopDesc::oop_iterate_backwards(OopClosureType* blk) { \ 535 klass()->oop_oop_iterate_backwards##nv_suffix(this, blk); \ 536 } 537 #else 538 #define OOP_ITERATE_BACKWARDS_DEFN(OopClosureType, nv_suffix) 539 #endif // INCLUDE_ALL_GCS 540 541 #define ALL_OOPDESC_OOP_ITERATE(OopClosureType, nv_suffix) \ 542 OOP_ITERATE_DEFN(OopClosureType, nv_suffix) \ 543 OOP_ITERATE_SIZE_DEFN(OopClosureType, nv_suffix) \ 544 OOP_ITERATE_BACKWARDS_DEFN(OopClosureType, nv_suffix) 545 546 ALL_OOP_OOP_ITERATE_CLOSURES_1(ALL_OOPDESC_OOP_ITERATE) 547 ALL_OOP_OOP_ITERATE_CLOSURES_2(ALL_OOPDESC_OOP_ITERATE) 548 549 intptr_t oopDesc::identity_hash() { 550 // Fast case; if the object is unlocked and the hash value is set, no locking is needed 551 // Note: The mark must be read into local variable to avoid concurrent updates. 552 markOop mrk = mark(); 553 if (mrk->is_unlocked() && !mrk->has_no_hash()) { 554 return mrk->hash(); 555 } else if (mrk->is_marked()) { 556 return mrk->hash(); 557 } else { 558 return slow_identity_hash(); 559 } 560 } 561 562 bool oopDesc::has_displaced_mark() const { 563 return mark()->has_displaced_mark_helper(); 564 } 565 566 markOop oopDesc::displaced_mark() const { 567 return mark()->displaced_mark_helper(); 568 } 569 570 void oopDesc::set_displaced_mark(markOop m) { 571 mark()->set_displaced_mark_helper(m); 572 } 573 574 #endif // SHARE_VM_OOPS_OOP_INLINE_HPP