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/collectedHeap.hpp" 29 #include "oops/access.inline.hpp" 30 #include "oops/arrayKlass.hpp" 31 #include "oops/arrayOop.hpp" 32 #include "oops/compressedOops.inline.hpp" 33 #include "oops/klass.inline.hpp" 34 #include "oops/markOop.inline.hpp" 35 #include "oops/oop.hpp" 36 #include "runtime/atomic.hpp" 37 #include "runtime/orderAccess.hpp" 38 #include "runtime/os.hpp" 39 #include "utilities/align.hpp" 40 #include "utilities/macros.hpp" 41 42 // Implementation of all inlined member functions defined in oop.hpp 43 // We need a separate file to avoid circular references 44 45 markOop oopDesc::mark() const { 46 return HeapAccess<MO_VOLATILE>::load_at(as_oop(), mark_offset_in_bytes()); 47 } 48 49 markOop oopDesc::mark_raw() const { 50 return _mark; 51 } 52 53 markOop* oopDesc::mark_addr_raw() const { 54 return (markOop*) &_mark; 55 } 56 57 void oopDesc::set_mark(volatile markOop m) { 58 HeapAccess<MO_VOLATILE>::store_at(as_oop(), mark_offset_in_bytes(), m); 59 } 60 61 void oopDesc::set_mark_raw(volatile markOop m) { 62 _mark = m; 63 } 64 65 void oopDesc::set_mark_raw(HeapWord* mem, markOop m) { 66 *(markOop*)(((char*)mem) + mark_offset_in_bytes()) = m; 67 } 68 69 void oopDesc::release_set_mark(markOop m) { 70 HeapAccess<MO_RELEASE>::store_at(as_oop(), mark_offset_in_bytes(), m); 71 } 72 73 markOop oopDesc::cas_set_mark(markOop new_mark, markOop old_mark) { 74 return HeapAccess<>::atomic_cmpxchg_at(new_mark, as_oop(), mark_offset_in_bytes(), old_mark); 75 } 76 77 markOop oopDesc::cas_set_mark_raw(markOop new_mark, markOop old_mark, atomic_memory_order order) { 78 return Atomic::cmpxchg(new_mark, &_mark, old_mark, order); 79 } 80 81 void oopDesc::init_mark() { 82 set_mark(markOopDesc::prototype_for_object(this)); 83 } 84 85 void oopDesc::init_mark_raw() { 86 set_mark_raw(markOopDesc::prototype_for_object(this)); 87 } 88 89 Klass* oopDesc::klass() const { 90 if (UseCompressedClassPointers) { 91 return Klass::decode_klass_not_null(_metadata._compressed_klass); 92 } else { 93 return _metadata._klass; 94 } 95 } 96 97 Klass* oopDesc::klass_or_null() const volatile { 98 if (UseCompressedClassPointers) { 99 return Klass::decode_klass(_metadata._compressed_klass); 100 } else { 101 return _metadata._klass; 102 } 103 } 104 105 Klass* oopDesc::klass_or_null_acquire() const volatile { 106 if (UseCompressedClassPointers) { 107 // Workaround for non-const load_acquire parameter. 108 const volatile narrowKlass* addr = &_metadata._compressed_klass; 109 volatile narrowKlass* xaddr = const_cast<volatile narrowKlass*>(addr); 110 return Klass::decode_klass(OrderAccess::load_acquire(xaddr)); 111 } else { 112 return OrderAccess::load_acquire(&_metadata._klass); 113 } 114 } 115 116 Klass** oopDesc::klass_addr(HeapWord* mem) { 117 // Only used internally and with CMS and will not work with 118 // UseCompressedOops 119 assert(!UseCompressedClassPointers, "only supported with uncompressed klass pointers"); 120 ByteSize offset = byte_offset_of(oopDesc, _metadata._klass); 121 return (Klass**) (((char*)mem) + in_bytes(offset)); 122 } 123 124 narrowKlass* oopDesc::compressed_klass_addr(HeapWord* mem) { 125 assert(UseCompressedClassPointers, "only called by compressed klass pointers"); 126 ByteSize offset = byte_offset_of(oopDesc, _metadata._compressed_klass); 127 return (narrowKlass*) (((char*)mem) + in_bytes(offset)); 128 } 129 130 Klass** oopDesc::klass_addr() { 131 return klass_addr((HeapWord*)this); 132 } 133 134 narrowKlass* oopDesc::compressed_klass_addr() { 135 return compressed_klass_addr((HeapWord*)this); 136 } 137 138 #define CHECK_SET_KLASS(k) \ 139 do { \ 140 assert(Universe::is_bootstrapping() || k != NULL, "NULL Klass"); \ 141 assert(Universe::is_bootstrapping() || k->is_klass(), "not a Klass"); \ 142 } while (0) 143 144 void oopDesc::set_klass(Klass* k) { 145 CHECK_SET_KLASS(k); 146 if (UseCompressedClassPointers) { 147 *compressed_klass_addr() = Klass::encode_klass_not_null(k); 148 } else { 149 *klass_addr() = k; 150 } 151 } 152 153 void oopDesc::release_set_klass(HeapWord* mem, Klass* klass) { 154 CHECK_SET_KLASS(klass); 155 if (UseCompressedClassPointers) { 156 OrderAccess::release_store(compressed_klass_addr(mem), 157 Klass::encode_klass_not_null(klass)); 158 } else { 159 OrderAccess::release_store(klass_addr(mem), klass); 160 } 161 } 162 163 #undef CHECK_SET_KLASS 164 165 int oopDesc::klass_gap() const { 166 return *(int*)(((intptr_t)this) + klass_gap_offset_in_bytes()); 167 } 168 169 void oopDesc::set_klass_gap(HeapWord* mem, int v) { 170 if (UseCompressedClassPointers) { 171 *(int*)(((char*)mem) + klass_gap_offset_in_bytes()) = v; 172 } 173 } 174 175 void oopDesc::set_klass_gap(int v) { 176 set_klass_gap((HeapWord*)this, v); 177 } 178 179 void oopDesc::set_klass_to_list_ptr(oop k) { 180 // This is only to be used during GC, for from-space objects, so no 181 // barrier is needed. 182 if (UseCompressedClassPointers) { 183 _metadata._compressed_klass = (narrowKlass)CompressedOops::encode(k); // may be null (parnew overflow handling) 184 } else { 185 _metadata._klass = (Klass*)(address)k; 186 } 187 } 188 189 oop oopDesc::list_ptr_from_klass() { 190 // This is only to be used during GC, for from-space objects. 191 if (UseCompressedClassPointers) { 192 return CompressedOops::decode((narrowOop)_metadata._compressed_klass); 193 } else { 194 // Special case for GC 195 return (oop)(address)_metadata._klass; 196 } 197 } 198 199 bool oopDesc::is_a(Klass* k) const { 200 return klass()->is_subtype_of(k); 201 } 202 203 int oopDesc::size() { 204 return size_given_klass(klass()); 205 } 206 207 int oopDesc::size_given_klass(Klass* klass) { 208 int lh = klass->layout_helper(); 209 int s; 210 211 // lh is now a value computed at class initialization that may hint 212 // at the size. For instances, this is positive and equal to the 213 // size. For arrays, this is negative and provides log2 of the 214 // array element size. For other oops, it is zero and thus requires 215 // a virtual call. 216 // 217 // We go to all this trouble because the size computation is at the 218 // heart of phase 2 of mark-compaction, and called for every object, 219 // alive or dead. So the speed here is equal in importance to the 220 // speed of allocation. 221 222 if (lh > Klass::_lh_neutral_value) { 223 if (!Klass::layout_helper_needs_slow_path(lh)) { 224 s = lh >> LogHeapWordSize; // deliver size scaled by wordSize 225 } else { 226 s = klass->oop_size(this); 227 } 228 } else if (lh <= Klass::_lh_neutral_value) { 229 // The most common case is instances; fall through if so. 230 if (lh < Klass::_lh_neutral_value) { 231 // Second most common case is arrays. We have to fetch the 232 // length of the array, shift (multiply) it appropriately, 233 // up to wordSize, add the header, and align to object size. 234 size_t size_in_bytes; 235 size_t array_length = (size_t) ((arrayOop)this)->length(); 236 size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh); 237 size_in_bytes += Klass::layout_helper_header_size(lh); 238 239 // This code could be simplified, but by keeping array_header_in_bytes 240 // in units of bytes and doing it this way we can round up just once, 241 // skipping the intermediate round to HeapWordSize. 242 s = (int)(align_up(size_in_bytes, MinObjAlignmentInBytes) / HeapWordSize); 243 244 // ParNew (used by CMS), UseParallelGC and UseG1GC can change the length field 245 // of an "old copy" of an object array in the young gen so it indicates 246 // the grey portion of an already copied array. This will cause the first 247 // disjunct below to fail if the two comparands are computed across such 248 // a concurrent change. 249 // ParNew also runs with promotion labs (which look like int 250 // filler arrays) which are subject to changing their declared size 251 // when finally retiring a PLAB; this also can cause the first disjunct 252 // to fail for another worker thread that is concurrently walking the block 253 // offset table. Both these invariant failures are benign for their 254 // current uses; we relax the assertion checking to cover these two cases below: 255 // is_objArray() && is_forwarded() // covers first scenario above 256 // || is_typeArray() // covers second scenario above 257 // If and when UseParallelGC uses the same obj array oop stealing/chunking 258 // technique, we will need to suitably modify the assertion. 259 assert((s == klass->oop_size(this)) || 260 (Universe::heap()->is_gc_active() && 261 ((is_typeArray() && UseConcMarkSweepGC) || 262 (is_objArray() && is_forwarded() && (UseConcMarkSweepGC || UseParallelGC || UseG1GC)))), 263 "wrong array object size"); 264 } else { 265 // Must be zero, so bite the bullet and take the virtual call. 266 s = klass->oop_size(this); 267 } 268 } 269 270 assert(s > 0, "Oop size must be greater than zero, not %d", s); 271 assert(is_object_aligned(s), "Oop size is not properly aligned: %d", s); 272 return s; 273 } 274 275 bool oopDesc::is_instance() const { return klass()->is_instance_klass(); } 276 bool oopDesc::is_array() const { return klass()->is_array_klass(); } 277 bool oopDesc::is_objArray() const { return klass()->is_objArray_klass(); } 278 bool oopDesc::is_typeArray() const { return klass()->is_typeArray_klass(); } 279 280 void* oopDesc::field_addr_raw(int offset) const { return reinterpret_cast<void*>(cast_from_oop<intptr_t>(as_oop()) + offset); } 281 void* oopDesc::field_addr(int offset) const { return Access<>::resolve(as_oop())->field_addr_raw(offset); } 282 283 template <class T> 284 T* oopDesc::obj_field_addr_raw(int offset) const { return (T*) field_addr_raw(offset); } 285 286 template <typename T> 287 size_t oopDesc::field_offset(T* p) const { return pointer_delta((void*)p, (void*)this, 1); } 288 289 template <DecoratorSet decorators> 290 inline oop oopDesc::obj_field_access(int offset) const { return HeapAccess<decorators>::oop_load_at(as_oop(), offset); } 291 inline oop oopDesc::obj_field(int offset) const { return HeapAccess<>::oop_load_at(as_oop(), offset); } 292 293 inline void oopDesc::obj_field_put(int offset, oop value) { HeapAccess<>::oop_store_at(as_oop(), offset, value); } 294 295 inline jbyte oopDesc::byte_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); } 296 inline void oopDesc::byte_field_put(int offset, jbyte value) { HeapAccess<>::store_at(as_oop(), offset, value); } 297 298 inline jchar oopDesc::char_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); } 299 inline void oopDesc::char_field_put(int offset, jchar value) { HeapAccess<>::store_at(as_oop(), offset, value); } 300 301 inline jboolean oopDesc::bool_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); } 302 inline void oopDesc::bool_field_put(int offset, jboolean value) { HeapAccess<>::store_at(as_oop(), offset, jboolean(value & 1)); } 303 304 inline jshort oopDesc::short_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); } 305 inline void oopDesc::short_field_put(int offset, jshort value) { HeapAccess<>::store_at(as_oop(), offset, value); } 306 307 inline jint oopDesc::int_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); } 308 inline jint oopDesc::int_field_raw(int offset) const { return RawAccess<>::load_at(as_oop(), offset); } 309 inline void oopDesc::int_field_put(int offset, jint value) { HeapAccess<>::store_at(as_oop(), offset, value); } 310 311 inline jlong oopDesc::long_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); } 312 inline void oopDesc::long_field_put(int offset, jlong value) { HeapAccess<>::store_at(as_oop(), offset, value); } 313 314 inline jfloat oopDesc::float_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); } 315 inline void oopDesc::float_field_put(int offset, jfloat value) { HeapAccess<>::store_at(as_oop(), offset, value); } 316 317 inline jdouble oopDesc::double_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); } 318 inline void oopDesc::double_field_put(int offset, jdouble value) { HeapAccess<>::store_at(as_oop(), offset, value); } 319 320 bool oopDesc::is_locked() const { 321 return mark()->is_locked(); 322 } 323 324 bool oopDesc::is_unlocked() const { 325 return mark()->is_unlocked(); 326 } 327 328 bool oopDesc::has_bias_pattern() const { 329 return mark()->has_bias_pattern(); 330 } 331 332 bool oopDesc::has_bias_pattern_raw() const { 333 return mark_raw()->has_bias_pattern(); 334 } 335 336 // Used only for markSweep, scavenging 337 bool oopDesc::is_gc_marked() const { 338 return mark_raw()->is_marked(); 339 } 340 341 // Used by scavengers 342 bool oopDesc::is_forwarded() const { 343 // The extra heap check is needed since the obj might be locked, in which case the 344 // mark would point to a stack location and have the sentinel bit cleared 345 return mark_raw()->is_marked(); 346 } 347 348 // Used by scavengers 349 void oopDesc::forward_to(oop p) { 350 assert(check_obj_alignment(p), 351 "forwarding to something not aligned"); 352 assert(Universe::heap()->is_in_reserved(p), 353 "forwarding to something not in heap"); 354 assert(!is_archived_object(oop(this)) && 355 !is_archived_object(p), 356 "forwarding archive object"); 357 markOop m = markOopDesc::encode_pointer_as_mark(p); 358 assert(m->decode_pointer() == p, "encoding must be reversable"); 359 set_mark_raw(m); 360 } 361 362 // Used by parallel scavengers 363 bool oopDesc::cas_forward_to(oop p, markOop compare, atomic_memory_order order) { 364 assert(check_obj_alignment(p), 365 "forwarding to something not aligned"); 366 assert(Universe::heap()->is_in_reserved(p), 367 "forwarding to something not in heap"); 368 markOop m = markOopDesc::encode_pointer_as_mark(p); 369 assert(m->decode_pointer() == p, "encoding must be reversable"); 370 return cas_set_mark_raw(m, compare, order) == compare; 371 } 372 373 oop oopDesc::forward_to_atomic(oop p, atomic_memory_order order) { 374 markOop oldMark = mark_raw(); 375 markOop forwardPtrMark = markOopDesc::encode_pointer_as_mark(p); 376 markOop curMark; 377 378 assert(forwardPtrMark->decode_pointer() == p, "encoding must be reversable"); 379 assert(sizeof(markOop) == sizeof(intptr_t), "CAS below requires this."); 380 381 while (!oldMark->is_marked()) { 382 curMark = cas_set_mark_raw(forwardPtrMark, oldMark, order); 383 assert(is_forwarded(), "object should have been forwarded"); 384 if (curMark == oldMark) { 385 return NULL; 386 } 387 // If the CAS was unsuccessful then curMark->is_marked() 388 // should return true as another thread has CAS'd in another 389 // forwarding pointer. 390 oldMark = curMark; 391 } 392 return forwardee(); 393 } 394 395 // Note that the forwardee is not the same thing as the displaced_mark. 396 // The forwardee is used when copying during scavenge and mark-sweep. 397 // It does need to clear the low two locking- and GC-related bits. 398 oop oopDesc::forwardee() const { 399 return (oop) mark_raw()->decode_pointer(); 400 } 401 402 // Note that the forwardee is not the same thing as the displaced_mark. 403 // The forwardee is used when copying during scavenge and mark-sweep. 404 // It does need to clear the low two locking- and GC-related bits. 405 oop oopDesc::forwardee_acquire() const { 406 markOop m = OrderAccess::load_acquire(&_mark); 407 return (oop) m->decode_pointer(); 408 } 409 410 // The following method needs to be MT safe. 411 uint oopDesc::age() const { 412 assert(!is_forwarded(), "Attempt to read age from forwarded mark"); 413 if (has_displaced_mark_raw()) { 414 return displaced_mark_raw()->age(); 415 } else { 416 return mark_raw()->age(); 417 } 418 } 419 420 void oopDesc::incr_age() { 421 assert(!is_forwarded(), "Attempt to increment age of forwarded mark"); 422 if (has_displaced_mark_raw()) { 423 set_displaced_mark_raw(displaced_mark_raw()->incr_age()); 424 } else { 425 set_mark_raw(mark_raw()->incr_age()); 426 } 427 } 428 429 template <typename OopClosureType> 430 void oopDesc::oop_iterate(OopClosureType* cl) { 431 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass()); 432 } 433 434 template <typename OopClosureType> 435 void oopDesc::oop_iterate(OopClosureType* cl, MemRegion mr) { 436 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass(), mr); 437 } 438 439 template <typename OopClosureType> 440 int oopDesc::oop_iterate_size(OopClosureType* cl) { 441 Klass* k = klass(); 442 int size = size_given_klass(k); 443 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k); 444 return size; 445 } 446 447 template <typename OopClosureType> 448 int oopDesc::oop_iterate_size(OopClosureType* cl, MemRegion mr) { 449 Klass* k = klass(); 450 int size = size_given_klass(k); 451 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k, mr); 452 return size; 453 } 454 455 template <typename OopClosureType> 456 void oopDesc::oop_iterate_backwards(OopClosureType* cl) { 457 OopIteratorClosureDispatch::oop_oop_iterate_backwards(cl, this, klass()); 458 } 459 460 bool oopDesc::is_instanceof_or_null(oop obj, Klass* klass) { 461 return obj == NULL || obj->klass()->is_subtype_of(klass); 462 } 463 464 intptr_t oopDesc::identity_hash() { 465 // Fast case; if the object is unlocked and the hash value is set, no locking is needed 466 // Note: The mark must be read into local variable to avoid concurrent updates. 467 markOop mrk = mark(); 468 if (mrk->is_unlocked() && !mrk->has_no_hash()) { 469 return mrk->hash(); 470 } else if (mrk->is_marked()) { 471 return mrk->hash(); 472 } else { 473 return slow_identity_hash(); 474 } 475 } 476 477 bool oopDesc::has_displaced_mark_raw() const { 478 return mark_raw()->has_displaced_mark_helper(); 479 } 480 481 markOop oopDesc::displaced_mark_raw() const { 482 return mark_raw()->displaced_mark_helper(); 483 } 484 485 void oopDesc::set_displaced_mark_raw(markOop m) { 486 mark_raw()->set_displaced_mark_helper(m); 487 } 488 489 #endif // SHARE_VM_OOPS_OOP_INLINE_HPP