1 /* 2 * Copyright (c) 1997, 2026, 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_OOPS_OOP_INLINE_HPP 26 #define SHARE_OOPS_OOP_INLINE_HPP 27 28 #include "oops/oop.hpp" 29 30 #include "memory/iterator.inline.hpp" 31 #include "memory/universe.hpp" 32 #include "oops/access.inline.hpp" 33 #include "oops/arrayKlass.hpp" 34 #include "oops/arrayOop.hpp" 35 #include "oops/compressedKlass.inline.hpp" 36 #include "oops/flatArrayKlass.hpp" 37 #include "oops/instanceKlass.hpp" 38 #include "oops/markWord.inline.hpp" 39 #include "oops/objLayout.inline.hpp" 40 #include "oops/oopsHierarchy.hpp" 41 #include "runtime/arguments.hpp" 42 #include "runtime/atomicAccess.hpp" 43 #include "runtime/globals.hpp" 44 #include "utilities/align.hpp" 45 #include "utilities/debug.hpp" 46 #include "utilities/globalDefinitions.hpp" 47 #include "utilities/macros.hpp" 48 49 // Implementation of all inlined member functions defined in oop.hpp 50 // We need a separate file to avoid circular references 51 52 void* oopDesc::base_addr() { return this; } 53 const void* oopDesc::base_addr() const { return this; } 54 55 markWord oopDesc::mark() const { 56 return AtomicAccess::load(&_mark); 57 } 58 59 markWord oopDesc::mark_acquire() const { 60 return AtomicAccess::load_acquire(&_mark); 61 } 62 63 void oopDesc::set_mark(markWord m) { 64 AtomicAccess::store(&_mark, m); 65 } 66 67 void oopDesc::set_mark(HeapWord* mem, markWord m) { 68 *(markWord*)(((char*)mem) + mark_offset_in_bytes()) = m; 69 } 70 71 void oopDesc::release_set_mark(HeapWord* mem, markWord m) { 72 AtomicAccess::release_store((markWord*)(((char*)mem) + mark_offset_in_bytes()), m); 73 } 74 75 void oopDesc::release_set_mark(markWord m) { 76 AtomicAccess::release_store(&_mark, m); 77 } 78 79 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark) { 80 return AtomicAccess::cmpxchg(&_mark, old_mark, new_mark); 81 } 82 83 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark, atomic_memory_order order) { 84 return AtomicAccess::cmpxchg(&_mark, old_mark, new_mark, order); 85 } 86 87 markWord oopDesc::prototype_mark() const { 88 if (UseCompactObjectHeaders || Arguments::is_valhalla_enabled()) { 89 return klass()->prototype_header(); 90 } else { 91 return markWord::prototype(); 92 } 93 } 94 95 void oopDesc::init_mark() { 96 set_mark(prototype_mark()); 97 } 98 99 Klass* oopDesc::klass() const { 100 switch (ObjLayout::klass_mode()) { 101 case ObjLayout::Compact: 102 return mark().klass(); 103 case ObjLayout::Compressed: 104 return CompressedKlassPointers::decode_not_null(_compressed_klass); 105 default: 106 ShouldNotReachHere(); 107 } 108 } 109 110 Klass* oopDesc::klass_or_null() const { 111 switch (ObjLayout::klass_mode()) { 112 case ObjLayout::Compact: 113 return mark().klass_or_null(); 114 case ObjLayout::Compressed: 115 return CompressedKlassPointers::decode(_compressed_klass); 116 default: 117 ShouldNotReachHere(); 118 } 119 } 120 121 Klass* oopDesc::klass_or_null_acquire() const { 122 switch (ObjLayout::klass_mode()) { 123 case ObjLayout::Compact: 124 return mark_acquire().klass(); 125 case ObjLayout::Compressed: { 126 narrowKlass narrow_klass = AtomicAccess::load_acquire(&_compressed_klass); 127 return CompressedKlassPointers::decode(narrow_klass); 128 } 129 default: 130 ShouldNotReachHere(); 131 } 132 } 133 134 Klass* oopDesc::klass_without_asserts() const { 135 switch (ObjLayout::klass_mode()) { 136 case ObjLayout::Compact: 137 return mark().klass_without_asserts(); 138 case ObjLayout::Compressed: 139 return CompressedKlassPointers::decode_without_asserts(_compressed_klass); 140 default: 141 ShouldNotReachHere(); 142 } 143 } 144 145 narrowKlass oopDesc::narrow_klass() const { 146 switch (ObjLayout::klass_mode()) { 147 case ObjLayout::Compact: 148 return mark().narrow_klass(); 149 case ObjLayout::Compressed: 150 return _compressed_klass; 151 default: 152 ShouldNotReachHere(); 153 } 154 } 155 156 void oopDesc::set_klass(Klass* k) { 157 assert(Universe::is_bootstrapping() || (k != nullptr && k->is_klass()), "incorrect Klass"); 158 assert(!UseCompactObjectHeaders, "don't set Klass* with compact headers"); 159 _compressed_klass = CompressedKlassPointers::encode_not_null(k); 160 } 161 162 void oopDesc::release_set_klass(HeapWord* mem, Klass* k) { 163 assert(Universe::is_bootstrapping() || (k != nullptr && k->is_klass()), "incorrect Klass"); 164 assert(!UseCompactObjectHeaders, "don't set Klass* with compact headers"); 165 char* raw_mem = ((char*)mem + klass_offset_in_bytes()); 166 AtomicAccess::release_store((narrowKlass*)raw_mem, CompressedKlassPointers::encode_not_null(k)); 167 } 168 169 void oopDesc::set_klass_gap(HeapWord* mem, int v) { 170 assert(has_klass_gap(), "precondition"); 171 *(int*)(((char*)mem) + klass_gap_offset_in_bytes()) = v; 172 } 173 174 bool oopDesc::is_a(Klass* k) const { 175 return klass()->is_subtype_of(k); 176 } 177 178 size_t oopDesc::size() { 179 return size_given_klass(klass()); 180 } 181 182 size_t oopDesc::size_given_klass(Klass* klass) { 183 int lh = klass->layout_helper(); 184 size_t s; 185 186 // lh is now a value computed at class initialization that may hint 187 // at the size. For instances, this is positive and equal to the 188 // size. For arrays, this is negative and provides log2 of the 189 // array element size. For other oops, it is zero and thus requires 190 // a virtual call. 191 // 192 // We go to all this trouble because the size computation is at the 193 // heart of phase 2 of mark-compaction, and called for every object, 194 // alive or dead. So the speed here is equal in importance to the 195 // speed of allocation. 196 197 if (lh > Klass::_lh_neutral_value) { 198 if (!Klass::layout_helper_needs_slow_path(lh)) { 199 s = lh >> LogHeapWordSize; // deliver size scaled by wordSize 200 } else { 201 s = klass->oop_size(this); 202 } 203 } else if (lh <= Klass::_lh_neutral_value) { 204 // The most common case is instances; fall through if so. 205 if (lh < Klass::_lh_neutral_value) { 206 // Second most common case is arrays. We have to fetch the 207 // length of the array, shift (multiply) it appropriately, 208 // up to wordSize, add the header, and align to object size. 209 size_t size_in_bytes; 210 size_t array_length = (size_t) ((arrayOop)this)->length(); 211 size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh); 212 size_in_bytes += Klass::layout_helper_header_size(lh); 213 214 // This code could be simplified, but by keeping array_header_in_bytes 215 // in units of bytes and doing it this way we can round up just once, 216 // skipping the intermediate round to HeapWordSize. 217 s = align_up(size_in_bytes, MinObjAlignmentInBytes) / HeapWordSize; 218 219 assert(s == klass->oop_size(this), "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 %zu", s); 227 assert(is_object_aligned(s), "Oop size is not properly aligned: %zu", s); 228 return s; 229 } 230 231 bool oopDesc::is_instance() const { return klass()->is_instance_klass(); } 232 bool oopDesc::is_inline() const { return klass()->is_inline_klass(); } 233 bool oopDesc::is_instanceRef() const { return klass()->is_reference_instance_klass(); } 234 bool oopDesc::is_stackChunk() const { return klass()->is_stack_chunk_instance_klass(); } 235 bool oopDesc::is_array() const { return klass()->is_array_klass(); } 236 bool oopDesc::is_objArray() const { return klass()->is_objArray_klass(); } 237 bool oopDesc::is_refArray() const { return klass()->is_refArray_klass(); } 238 bool oopDesc::is_typeArray() const { return klass()->is_typeArray_klass(); } 239 bool oopDesc::is_refined_objArray() const { return klass()->is_refined_objArray_klass(); } 240 bool oopDesc::is_flatArray() const { return klass()->is_flatArray_klass(); } 241 242 bool oopDesc::is_array_with_oops() const { 243 if (!is_objArray()) { 244 return false; 245 } 246 247 assert(is_refined_objArray(), "Must be"); 248 return is_refArray() || FlatArrayKlass::cast(klass())->contains_oops(); 249 } 250 251 bool oopDesc::is_inline_type() const { return mark().is_inline_type(); } 252 253 template<typename T> 254 T* oopDesc::field_addr(int offset) const { return reinterpret_cast<T*>(cast_from_oop<intptr_t>(as_oop()) + offset); } 255 256 template <typename T> 257 size_t oopDesc::field_offset(T* p) const { return pointer_delta((void*)p, (void*)this, 1); } 258 259 template <DecoratorSet decorators> 260 inline oop oopDesc::obj_field_access(int offset) const { return HeapAccess<decorators>::oop_load_at(as_oop(), offset); } 261 inline oop oopDesc::obj_field(int offset) const { return HeapAccess<>::oop_load_at(as_oop(), offset); } 262 263 inline void oopDesc::obj_field_put(int offset, oop value) { HeapAccess<>::oop_store_at(as_oop(), offset, value); } 264 template <DecoratorSet decorators> 265 inline void oopDesc::obj_field_put_access(int offset, oop value) { HeapAccess<decorators>::oop_store_at(as_oop(), offset, value); } 266 267 inline jbyte oopDesc::byte_field(int offset) const { return *field_addr<jbyte>(offset); } 268 inline void oopDesc::byte_field_put(int offset, jbyte value) { *field_addr<jbyte>(offset) = value; } 269 270 inline jchar oopDesc::char_field(int offset) const { return *field_addr<jchar>(offset); } 271 inline void oopDesc::char_field_put(int offset, jchar value) { *field_addr<jchar>(offset) = value; } 272 273 inline jboolean oopDesc::bool_field(int offset) const { return *field_addr<jboolean>(offset); } 274 inline void oopDesc::bool_field_put(int offset, jboolean value) { *field_addr<jboolean>(offset) = jboolean(value & 1); } 275 inline jboolean oopDesc::bool_field_volatile(int offset) const { return RawAccess<MO_SEQ_CST>::load(field_addr<jboolean>(offset)); } 276 inline void oopDesc::bool_field_put_volatile(int offset, jboolean value) { RawAccess<MO_SEQ_CST>::store(field_addr<jboolean>(offset), jboolean(value & 1)); } 277 inline jshort oopDesc::short_field(int offset) const { return *field_addr<jshort>(offset); } 278 inline void oopDesc::short_field_put(int offset, jshort value) { *field_addr<jshort>(offset) = value; } 279 280 inline jint oopDesc::int_field(int offset) const { return *field_addr<jint>(offset); } 281 inline void oopDesc::int_field_put(int offset, jint value) { *field_addr<jint>(offset) = value; } 282 inline jint oopDesc::int_field_relaxed(int offset) const { return AtomicAccess::load(field_addr<jint>(offset)); } 283 inline void oopDesc::int_field_put_relaxed(int offset, jint value) { AtomicAccess::store(field_addr<jint>(offset), value); } 284 285 inline jlong oopDesc::long_field(int offset) const { return *field_addr<jlong>(offset); } 286 inline void oopDesc::long_field_put(int offset, jlong value) { *field_addr<jlong>(offset) = value; } 287 288 inline jfloat oopDesc::float_field(int offset) const { return *field_addr<jfloat>(offset); } 289 inline void oopDesc::float_field_put(int offset, jfloat value) { *field_addr<jfloat>(offset) = value; } 290 291 inline jdouble oopDesc::double_field(int offset) const { return *field_addr<jdouble>(offset); } 292 inline void oopDesc::double_field_put(int offset, jdouble value) { *field_addr<jdouble>(offset) = value; } 293 294 bool oopDesc::is_locked() const { 295 return mark().is_locked(); 296 } 297 298 bool oopDesc::is_unlocked() const { 299 return mark().is_unlocked(); 300 } 301 302 bool oopDesc::is_gc_marked() const { 303 return mark().is_marked(); 304 } 305 306 // Used by scavengers 307 bool oopDesc::is_forwarded() const { 308 return mark().is_forwarded(); 309 } 310 311 bool oopDesc::is_self_forwarded() const { 312 return mark().is_self_forwarded(); 313 } 314 315 // Used by scavengers 316 void oopDesc::forward_to(oop p) { 317 assert(cast_from_oop<oopDesc*>(p) != this, 318 "must not be used for self-forwarding, use forward_to_self() instead"); 319 markWord m = markWord::encode_pointer_as_mark(p); 320 assert(m.decode_pointer() == p, "encoding must be reversible"); 321 set_mark(m); 322 } 323 324 void oopDesc::forward_to_self() { 325 set_mark(mark().set_self_forwarded()); 326 } 327 328 oop oopDesc::cas_set_forwardee(markWord new_mark, markWord compare, atomic_memory_order order) { 329 markWord old_mark = cas_set_mark(new_mark, compare, order); 330 if (old_mark == compare) { 331 return nullptr; 332 } else { 333 assert(old_mark.is_forwarded(), "must be forwarded here"); 334 return forwardee(old_mark); 335 } 336 } 337 338 oop oopDesc::forward_to_atomic(oop p, markWord compare, atomic_memory_order order) { 339 assert(cast_from_oop<oopDesc*>(p) != this, 340 "must not be used for self-forwarding, use forward_to_self_atomic() instead"); 341 markWord m = markWord::encode_pointer_as_mark(p); 342 assert(forwardee(m) == p, "encoding must be reversible"); 343 return cas_set_forwardee(m, compare, order); 344 } 345 346 oop oopDesc::forward_to_self_atomic(markWord old_mark, atomic_memory_order order) { 347 markWord new_mark = old_mark.set_self_forwarded(); 348 assert(forwardee(new_mark) == cast_to_oop(this), "encoding must be reversible"); 349 return cas_set_forwardee(new_mark, old_mark, order); 350 } 351 352 oop oopDesc::forwardee(markWord mark) const { 353 assert(mark.is_forwarded(), "only decode when actually forwarded"); 354 if (mark.is_self_forwarded()) { 355 return cast_to_oop(this); 356 } else { 357 return mark.forwardee(); 358 } 359 } 360 361 // Note that the forwardee is not the same thing as the displaced_mark. 362 // The forwardee is used when copying during scavenge and mark-sweep. 363 // It does need to clear the low two locking- and GC-related bits. 364 oop oopDesc::forwardee() const { 365 return forwardee(mark()); 366 } 367 368 void oopDesc::unset_self_forwarded() { 369 set_mark(mark().unset_self_forwarded()); 370 } 371 372 // The following method needs to be MT safe. 373 uint oopDesc::age() const { 374 markWord m = mark(); 375 assert(!m.is_marked(), "Attempt to read age from forwarded mark"); 376 if (m.has_displaced_mark_helper()) { 377 return m.displaced_mark_helper().age(); 378 } else { 379 return m.age(); 380 } 381 } 382 383 void oopDesc::incr_age() { 384 markWord m = mark(); 385 assert(!m.is_marked(), "Attempt to increment age of forwarded mark"); 386 if (m.has_displaced_mark_helper()) { 387 m.set_displaced_mark_helper(m.displaced_mark_helper().incr_age()); 388 } else { 389 set_mark(m.incr_age()); 390 } 391 } 392 393 template <typename OopClosureType> 394 void oopDesc::oop_iterate(OopClosureType* cl) { 395 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass()); 396 } 397 398 template <typename OopClosureType> 399 void oopDesc::oop_iterate(OopClosureType* cl, MemRegion mr) { 400 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass(), mr); 401 } 402 403 template <typename OopClosureType> 404 size_t oopDesc::oop_iterate_size(OopClosureType* cl) { 405 Klass* k = klass(); 406 size_t size = size_given_klass(k); 407 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k); 408 return size; 409 } 410 411 template <typename OopClosureType> 412 size_t oopDesc::oop_iterate_size(OopClosureType* cl, MemRegion mr) { 413 Klass* k = klass(); 414 size_t size = size_given_klass(k); 415 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k, mr); 416 return size; 417 } 418 419 template <typename OopClosureType> 420 void oopDesc::oop_iterate_backwards(OopClosureType* cl) { 421 oop_iterate_backwards(cl, klass()); 422 } 423 424 template <typename OopClosureType> 425 void oopDesc::oop_iterate_backwards(OopClosureType* cl, Klass* k) { 426 // In this assert, we cannot safely access the Klass* with compact headers. 427 assert(k == klass(), "wrong klass"); 428 OopIteratorClosureDispatch::oop_oop_iterate_backwards(cl, this, k); 429 } 430 431 bool oopDesc::is_instanceof_or_null(oop obj, Klass* klass) { 432 return obj == nullptr || obj->klass()->is_subtype_of(klass); 433 } 434 435 intptr_t oopDesc::identity_hash() { 436 // Fast case; if the object is unlocked and the hash value is set, no locking is needed 437 // Note: The mark must be read into local variable to avoid concurrent updates. 438 markWord mrk = mark(); 439 if (mrk.is_unlocked() && !mrk.has_no_hash()) { 440 return mrk.hash(); 441 } else if (mrk.is_marked()) { 442 return mrk.hash(); 443 } else { 444 return slow_identity_hash(); 445 } 446 } 447 448 // This checks fast simple case of whether the oop has_no_hash, 449 // to optimize JVMTI table lookup. 450 bool oopDesc::fast_no_hash_check() { 451 markWord mrk = mark_acquire(); 452 assert(!mrk.is_marked(), "should never be marked"); 453 return mrk.is_unlocked() && mrk.has_no_hash(); 454 } 455 456 bool oopDesc::has_displaced_mark() const { 457 return mark().has_displaced_mark_helper(); 458 } 459 460 markWord oopDesc::displaced_mark() const { 461 return mark().displaced_mark_helper(); 462 } 463 464 void oopDesc::set_displaced_mark(markWord m) { 465 mark().set_displaced_mark_helper(m); 466 } 467 468 bool oopDesc::mark_must_be_preserved() const { 469 return mark_must_be_preserved(mark()); 470 } 471 472 bool oopDesc::mark_must_be_preserved(markWord m) const { 473 return m.must_be_preserved(); 474 } 475 476 #endif // SHARE_OOPS_OOP_INLINE_HPP --- EOF ---