1 /* 2 * Copyright (c) 1997, 2019, 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 "gc/shared/collectedHeap.hpp" 29 #include "memory/universe.hpp" 30 #include "oops/access.inline.hpp" 31 #include "oops/arrayKlass.hpp" 32 #include "oops/arrayOop.hpp" 33 #include "oops/compressedOops.inline.hpp" 34 #include "oops/klass.inline.hpp" 35 #include "oops/markWord.inline.hpp" 36 #include "oops/oop.hpp" 37 #include "runtime/atomic.hpp" 38 #include "runtime/orderAccess.hpp" 39 #include "runtime/os.hpp" 40 #include "utilities/align.hpp" 41 #include "utilities/macros.hpp" 42 43 // Implementation of all inlined member functions defined in oop.hpp 44 // We need a separate file to avoid circular references 45 46 markWord oopDesc::mark() const { 47 uintptr_t v = HeapAccess<MO_VOLATILE>::load_at(as_oop(), mark_offset_in_bytes()); 48 return markWord(v); 49 } 50 51 markWord oopDesc::mark_raw() const { 52 return Atomic::load(&_mark); 53 } 54 55 markWord* oopDesc::mark_addr_raw() const { 56 return (markWord*) &_mark; 57 } 58 59 void oopDesc::set_mark(markWord m) { 60 HeapAccess<MO_VOLATILE>::store_at(as_oop(), mark_offset_in_bytes(), m.value()); 61 } 62 63 void oopDesc::set_mark_raw(markWord m) { 64 Atomic::store(&_mark, m); 65 } 66 67 void oopDesc::set_mark_raw(HeapWord* mem, markWord m) { 68 *(markWord*)(((char*)mem) + mark_offset_in_bytes()) = m; 69 } 70 71 void oopDesc::release_set_mark(markWord m) { 72 HeapAccess<MO_RELEASE>::store_at(as_oop(), mark_offset_in_bytes(), m.value()); 73 } 74 75 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark) { 76 uintptr_t v = HeapAccess<>::atomic_cmpxchg_at(as_oop(), mark_offset_in_bytes(), old_mark.value(), new_mark.value()); 77 return markWord(v); 78 } 79 80 markWord oopDesc::cas_set_mark_raw(markWord new_mark, markWord old_mark, atomic_memory_order order) { 81 return Atomic::cmpxchg(&_mark, old_mark, new_mark, order); 82 } 83 84 void oopDesc::init_mark() { 85 set_mark(markWord::prototype_for_klass(klass())); 86 } 87 88 void oopDesc::init_mark_raw() { 89 set_mark_raw(markWord::prototype_for_klass(klass())); 90 } 91 92 Klass* oopDesc::klass() const { 93 if (UseCompressedClassPointers) { 94 return CompressedKlassPointers::decode_not_null(_metadata._compressed_klass); 95 } else { 96 return _metadata._klass; 97 } 98 } 99 100 Klass* oopDesc::klass_or_null() const volatile { 101 if (UseCompressedClassPointers) { 102 return CompressedKlassPointers::decode(_metadata._compressed_klass); 103 } else { 104 return _metadata._klass; 105 } 106 } 107 108 Klass* oopDesc::klass_or_null_acquire() const volatile { 109 if (UseCompressedClassPointers) { 110 // Workaround for non-const load_acquire parameter. 111 const volatile narrowKlass* addr = &_metadata._compressed_klass; 112 volatile narrowKlass* xaddr = const_cast<volatile narrowKlass*>(addr); 113 return CompressedKlassPointers::decode(Atomic::load_acquire(xaddr)); 114 } else { 115 return Atomic::load_acquire(&_metadata._klass); 116 } 117 } 118 119 Klass** oopDesc::klass_addr(HeapWord* mem) { 120 // Only used internally and with CMS and will not work with 121 // UseCompressedOops 122 assert(!UseCompressedClassPointers, "only supported with uncompressed klass pointers"); 123 ByteSize offset = byte_offset_of(oopDesc, _metadata._klass); 124 return (Klass**) (((char*)mem) + in_bytes(offset)); 125 } 126 127 narrowKlass* oopDesc::compressed_klass_addr(HeapWord* mem) { 128 assert(UseCompressedClassPointers, "only called by compressed klass pointers"); 129 ByteSize offset = byte_offset_of(oopDesc, _metadata._compressed_klass); 130 return (narrowKlass*) (((char*)mem) + in_bytes(offset)); 131 } 132 133 Klass** oopDesc::klass_addr() { 134 return klass_addr((HeapWord*)this); 135 } 136 137 narrowKlass* oopDesc::compressed_klass_addr() { 138 return compressed_klass_addr((HeapWord*)this); 139 } 140 141 #define CHECK_SET_KLASS(k) \ 142 do { \ 143 assert(Universe::is_bootstrapping() || k != NULL, "NULL Klass"); \ 144 assert(Universe::is_bootstrapping() || k->is_klass(), "not a Klass"); \ 145 } while (0) 146 147 void oopDesc::set_klass(Klass* k) { 148 CHECK_SET_KLASS(k); 149 if (UseCompressedClassPointers) { 150 *compressed_klass_addr() = CompressedKlassPointers::encode_not_null(k); 151 } else { 152 *klass_addr() = k; 153 } 154 } 155 156 void oopDesc::release_set_klass(HeapWord* mem, Klass* klass) { 157 CHECK_SET_KLASS(klass); 158 if (UseCompressedClassPointers) { 159 Atomic::release_store(compressed_klass_addr(mem), 160 CompressedKlassPointers::encode_not_null(klass)); 161 } else { 162 Atomic::release_store(klass_addr(mem), klass); 163 } 164 } 165 166 #undef CHECK_SET_KLASS 167 168 int oopDesc::klass_gap() const { 169 return *(int*)(((intptr_t)this) + klass_gap_offset_in_bytes()); 170 } 171 172 void oopDesc::set_klass_gap(HeapWord* mem, int v) { 173 if (UseCompressedClassPointers) { 174 *(int*)(((char*)mem) + klass_gap_offset_in_bytes()) = v; 175 } 176 } 177 178 void oopDesc::set_klass_gap(int v) { 179 set_klass_gap((HeapWord*)this, v); 180 } 181 182 bool oopDesc::is_a(Klass* k) const { 183 return klass()->is_subtype_of(k); 184 } 185 186 int oopDesc::size() { 187 return size_given_klass(klass()); 188 } 189 190 int oopDesc::size_given_klass(Klass* klass) { 191 int lh = klass->layout_helper(); 192 int s; 193 194 // lh is now a value computed at class initialization that may hint 195 // at the size. For instances, this is positive and equal to the 196 // size. For arrays, this is negative and provides log2 of the 197 // array element size. For other oops, it is zero and thus requires 198 // a virtual call. 199 // 200 // We go to all this trouble because the size computation is at the 201 // heart of phase 2 of mark-compaction, and called for every object, 202 // alive or dead. So the speed here is equal in importance to the 203 // speed of allocation. 204 205 if (lh > Klass::_lh_neutral_value) { 206 if (!Klass::layout_helper_needs_slow_path(lh)) { 207 s = lh >> LogHeapWordSize; // deliver size scaled by wordSize 208 } else { 209 s = klass->oop_size(this); 210 } 211 } else if (lh <= Klass::_lh_neutral_value) { 212 // The most common case is instances; fall through if so. 213 if (lh < Klass::_lh_neutral_value) { 214 // Second most common case is arrays. We have to fetch the 215 // length of the array, shift (multiply) it appropriately, 216 // up to wordSize, add the header, and align to object size. 217 size_t size_in_bytes; 218 size_t array_length = (size_t) ((arrayOop)this)->length(); 219 size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh); 220 size_in_bytes += Klass::layout_helper_header_size(lh); 221 222 // This code could be simplified, but by keeping array_header_in_bytes 223 // in units of bytes and doing it this way we can round up just once, 224 // skipping the intermediate round to HeapWordSize. 225 s = (int)(align_up(size_in_bytes, MinObjAlignmentInBytes) / HeapWordSize); 226 227 // UseParallelGC and UseG1GC can change the length field 228 // of an "old copy" of an object array in the young gen so it indicates 229 // the grey portion of an already copied array. This will cause the first 230 // disjunct below to fail if the two comparands are computed across such 231 // a concurrent change. 232 assert((s == klass->oop_size(this)) || 233 (Universe::heap()->is_gc_active() && is_objArray() && is_forwarded() && (UseParallelGC || UseG1GC)), 234 "wrong array object size"); 235 } else { 236 // Must be zero, so bite the bullet and take the virtual call. 237 s = klass->oop_size(this); 238 } 239 } 240 241 assert(s > 0, "Oop size must be greater than zero, not %d", s); 242 assert(is_object_aligned(s), "Oop size is not properly aligned: %d", s); 243 return s; 244 } 245 246 bool oopDesc::is_instance() const { return klass()->is_instance_klass(); } 247 bool oopDesc::is_array() const { return klass()->is_array_klass(); } 248 bool oopDesc::is_objArray() const { return klass()->is_objArray_klass(); } 249 bool oopDesc::is_typeArray() const { return klass()->is_typeArray_klass(); } 250 251 void* oopDesc::field_addr_raw(int offset) const { return reinterpret_cast<void*>(cast_from_oop<intptr_t>(as_oop()) + offset); } 252 void* oopDesc::field_addr(int offset) const { return Access<>::resolve(as_oop())->field_addr_raw(offset); } 253 254 template <class T> 255 T* oopDesc::obj_field_addr_raw(int offset) const { return (T*) field_addr_raw(offset); } 256 257 template <typename T> 258 size_t oopDesc::field_offset(T* p) const { return pointer_delta((void*)p, (void*)this, 1); } 259 260 template <DecoratorSet decorators> 261 inline oop oopDesc::obj_field_access(int offset) const { return HeapAccess<decorators>::oop_load_at(as_oop(), offset); } 262 inline oop oopDesc::obj_field(int offset) const { return HeapAccess<>::oop_load_at(as_oop(), offset); } 263 264 inline void oopDesc::obj_field_put(int offset, oop value) { HeapAccess<>::oop_store_at(as_oop(), offset, value); } 265 266 inline jbyte oopDesc::byte_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); } 267 inline void oopDesc::byte_field_put(int offset, jbyte value) { HeapAccess<>::store_at(as_oop(), offset, value); } 268 269 inline jchar oopDesc::char_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); } 270 inline void oopDesc::char_field_put(int offset, jchar value) { HeapAccess<>::store_at(as_oop(), offset, value); } 271 272 inline jboolean oopDesc::bool_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); } 273 inline void oopDesc::bool_field_put(int offset, jboolean value) { HeapAccess<>::store_at(as_oop(), offset, jboolean(value & 1)); } 274 inline jboolean oopDesc::bool_field_volatile(int offset) const { return HeapAccess<MO_SEQ_CST>::load_at(as_oop(), offset); } 275 inline void oopDesc::bool_field_put_volatile(int offset, jboolean value) { HeapAccess<MO_SEQ_CST>::store_at(as_oop(), offset, jboolean(value & 1)); } 276 inline jshort oopDesc::short_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); } 277 inline void oopDesc::short_field_put(int offset, jshort value) { HeapAccess<>::store_at(as_oop(), offset, value); } 278 279 inline jint oopDesc::int_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); } 280 inline jint oopDesc::int_field_raw(int offset) const { return RawAccess<>::load_at(as_oop(), offset); } 281 inline void oopDesc::int_field_put(int offset, jint value) { HeapAccess<>::store_at(as_oop(), offset, value); } 282 283 inline jlong oopDesc::long_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); } 284 inline void oopDesc::long_field_put(int offset, jlong value) { HeapAccess<>::store_at(as_oop(), offset, value); } 285 286 inline jfloat oopDesc::float_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); } 287 inline void oopDesc::float_field_put(int offset, jfloat value) { HeapAccess<>::store_at(as_oop(), offset, value); } 288 289 inline jdouble oopDesc::double_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); } 290 inline void oopDesc::double_field_put(int offset, jdouble value) { HeapAccess<>::store_at(as_oop(), offset, value); } 291 292 bool oopDesc::is_locked() const { 293 return mark().is_locked(); 294 } 295 296 bool oopDesc::is_unlocked() const { 297 return mark().is_unlocked(); 298 } 299 300 bool oopDesc::has_bias_pattern() const { 301 return mark().has_bias_pattern(); 302 } 303 304 bool oopDesc::has_bias_pattern_raw() const { 305 return mark_raw().has_bias_pattern(); 306 } 307 308 // Used only for markSweep, scavenging 309 bool oopDesc::is_gc_marked() const { 310 return mark_raw().is_marked(); 311 } 312 313 // Used by scavengers 314 bool oopDesc::is_forwarded() const { 315 // The extra heap check is needed since the obj might be locked, in which case the 316 // mark would point to a stack location and have the sentinel bit cleared 317 return mark_raw().is_marked(); 318 } 319 320 // Used by scavengers 321 void oopDesc::forward_to(oop p) { 322 verify_forwardee(p); 323 markWord m = markWord::encode_pointer_as_mark(p); 324 assert(m.decode_pointer() == p, "encoding must be reversable"); 325 set_mark_raw(m); 326 } 327 328 // Used by parallel scavengers 329 bool oopDesc::cas_forward_to(oop p, markWord compare, atomic_memory_order order) { 330 verify_forwardee(p); 331 markWord m = markWord::encode_pointer_as_mark(p); 332 assert(m.decode_pointer() == p, "encoding must be reversable"); 333 return cas_set_mark_raw(m, compare, order) == compare; 334 } 335 336 oop oopDesc::forward_to_atomic(oop p, markWord compare, atomic_memory_order order) { 337 verify_forwardee(p); 338 markWord m = markWord::encode_pointer_as_mark(p); 339 assert(m.decode_pointer() == p, "encoding must be reversable"); 340 markWord old_mark = cas_set_mark_raw(m, compare, order); 341 if (old_mark == compare) { 342 return NULL; 343 } else { 344 return (oop)old_mark.decode_pointer(); 345 } 346 } 347 348 // Note that the forwardee is not the same thing as the displaced_mark. 349 // The forwardee is used when copying during scavenge and mark-sweep. 350 // It does need to clear the low two locking- and GC-related bits. 351 oop oopDesc::forwardee() const { 352 return (oop) mark_raw().decode_pointer(); 353 } 354 355 // Note that the forwardee is not the same thing as the displaced_mark. 356 // The forwardee is used when copying during scavenge and mark-sweep. 357 // It does need to clear the low two locking- and GC-related bits. 358 oop oopDesc::forwardee_acquire() const { 359 return (oop) Atomic::load_acquire(&_mark).decode_pointer(); 360 } 361 362 // The following method needs to be MT safe. 363 uint oopDesc::age() const { 364 assert(!is_forwarded(), "Attempt to read age from forwarded mark"); 365 if (has_displaced_mark_raw()) { 366 return displaced_mark_raw().age(); 367 } else { 368 return mark_raw().age(); 369 } 370 } 371 372 void oopDesc::incr_age() { 373 assert(!is_forwarded(), "Attempt to increment age of forwarded mark"); 374 if (has_displaced_mark_raw()) { 375 set_displaced_mark_raw(displaced_mark_raw().incr_age()); 376 } else { 377 set_mark_raw(mark_raw().incr_age()); 378 } 379 } 380 381 template <typename OopClosureType> 382 void oopDesc::oop_iterate(OopClosureType* cl) { 383 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass()); 384 } 385 386 template <typename OopClosureType> 387 void oopDesc::oop_iterate(OopClosureType* cl, MemRegion mr) { 388 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass(), mr); 389 } 390 391 template <typename OopClosureType> 392 int oopDesc::oop_iterate_size(OopClosureType* cl) { 393 Klass* k = klass(); 394 int size = size_given_klass(k); 395 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k); 396 return size; 397 } 398 399 template <typename OopClosureType> 400 int oopDesc::oop_iterate_size(OopClosureType* cl, MemRegion mr) { 401 Klass* k = klass(); 402 int size = size_given_klass(k); 403 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k, mr); 404 return size; 405 } 406 407 template <typename OopClosureType> 408 void oopDesc::oop_iterate_backwards(OopClosureType* cl) { 409 OopIteratorClosureDispatch::oop_oop_iterate_backwards(cl, this, klass()); 410 } 411 412 bool oopDesc::is_instanceof_or_null(oop obj, Klass* klass) { 413 return obj == NULL || obj->klass()->is_subtype_of(klass); 414 } 415 416 intptr_t oopDesc::identity_hash() { 417 // Fast case; if the object is unlocked and the hash value is set, no locking is needed 418 // Note: The mark must be read into local variable to avoid concurrent updates. 419 markWord mrk = mark(); 420 if (mrk.is_unlocked() && !mrk.has_no_hash()) { 421 return mrk.hash(); 422 } else if (mrk.is_marked()) { 423 return mrk.hash(); 424 } else { 425 return slow_identity_hash(); 426 } 427 } 428 429 bool oopDesc::has_displaced_mark_raw() const { 430 return mark_raw().has_displaced_mark_helper(); 431 } 432 433 markWord oopDesc::displaced_mark_raw() const { 434 return mark_raw().displaced_mark_helper(); 435 } 436 437 void oopDesc::set_displaced_mark_raw(markWord m) { 438 mark_raw().set_displaced_mark_helper(m); 439 } 440 441 // Supports deferred calling of obj->klass(). 442 class DeferredObjectToKlass { 443 const oopDesc* _obj; 444 445 public: 446 DeferredObjectToKlass(const oopDesc* obj) : _obj(obj) {} 447 448 // Implicitly convertible to const Klass*. 449 operator const Klass*() const { 450 return _obj->klass(); 451 } 452 }; 453 454 bool oopDesc::mark_must_be_preserved() const { 455 return mark_must_be_preserved(mark_raw()); 456 } 457 458 bool oopDesc::mark_must_be_preserved(markWord m) const { 459 // There's a circular dependency between oop.inline.hpp and 460 // markWord.inline.hpp because markWord::must_be_preserved wants to call 461 // oopDesc::klass(). This could be solved by calling klass() here. However, 462 // not all paths inside must_be_preserved calls klass(). Defer the call until 463 // the klass is actually needed. 464 return m.must_be_preserved(DeferredObjectToKlass(this)); 465 } 466 467 bool oopDesc::mark_must_be_preserved_for_promotion_failure(markWord m) const { 468 return m.must_be_preserved_for_promotion_failure(DeferredObjectToKlass(this)); 469 } 470 471 #endif // SHARE_OOPS_OOP_INLINE_HPP