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