1 /*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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5 * This code is free software; you can redistribute it and/or modify it
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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13 * accompanied this code).
14 *
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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/instanceKlass.hpp"
37 #include "oops/markWord.inline.hpp"
38 #include "oops/objLayout.inline.hpp"
39 #include "oops/oopsHierarchy.hpp"
40 #include "runtime/atomic.hpp"
41 #include "runtime/globals.hpp"
42 #include "utilities/align.hpp"
43 #include "utilities/debug.hpp"
44 #include "utilities/globalDefinitions.hpp"
45 #include "utilities/macros.hpp"
46
47 // Implementation of all inlined member functions defined in oop.hpp
48 // We need a separate file to avoid circular references
49
50 void* oopDesc::base_addr() { return this; }
51 const void* oopDesc::base_addr() const { return this; }
52
53 markWord oopDesc::mark() const {
54 return Atomic::load(&_mark);
55 }
56
57 markWord oopDesc::mark_acquire() const {
58 return Atomic::load_acquire(&_mark);
59 }
60
61 void oopDesc::set_mark(markWord m) {
62 Atomic::store(&_mark, m);
63 }
64
65 void oopDesc::set_mark(HeapWord* mem, markWord m) {
66 *(markWord*)(((char*)mem) + mark_offset_in_bytes()) = m;
67 }
68
69 void oopDesc::release_set_mark(HeapWord* mem, markWord m) {
70 Atomic::release_store((markWord*)(((char*)mem) + mark_offset_in_bytes()), m);
71 }
72
73 void oopDesc::release_set_mark(markWord m) {
74 Atomic::release_store(&_mark, m);
75 }
76
77 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark) {
78 return Atomic::cmpxchg(&_mark, old_mark, new_mark);
79 }
80
81 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark, atomic_memory_order order) {
82 return Atomic::cmpxchg(&_mark, old_mark, new_mark, order);
83 }
84
85 markWord oopDesc::prototype_mark() const {
86 if (UseCompactObjectHeaders) {
87 return klass()->prototype_header();
88 } else {
89 return markWord::prototype();
90 }
91 }
92
93 void oopDesc::init_mark() {
94 set_mark(prototype_mark());
95 }
96
97 Klass* oopDesc::klass() const {
98 switch (ObjLayout::klass_mode()) {
99 case ObjLayout::Compact:
100 return mark().klass();
101 case ObjLayout::Compressed:
102 return CompressedKlassPointers::decode_not_null(_metadata._compressed_klass);
103 default:
104 return _metadata._klass;
105 }
106 }
107
108 Klass* oopDesc::klass_or_null() const {
109 switch (ObjLayout::klass_mode()) {
110 case ObjLayout::Compact:
111 return mark().klass_or_null();
112 case ObjLayout::Compressed:
113 return CompressedKlassPointers::decode(_metadata._compressed_klass);
114 default:
115 return _metadata._klass;
116 }
117 }
118
119 Klass* oopDesc::klass_or_null_acquire() const {
120 switch (ObjLayout::klass_mode()) {
121 case ObjLayout::Compact:
122 return mark_acquire().klass();
123 case ObjLayout::Compressed: {
124 narrowKlass narrow_klass = Atomic::load_acquire(&_metadata._compressed_klass);
125 return CompressedKlassPointers::decode(narrow_klass);
126 }
127 default:
128 return Atomic::load_acquire(&_metadata._klass);
129 }
130 }
131
132 Klass* oopDesc::klass_without_asserts() const {
133 switch (ObjLayout::klass_mode()) {
134 case ObjLayout::Compact:
135 return mark().klass_without_asserts();
136 case ObjLayout::Compressed:
137 return CompressedKlassPointers::decode_without_asserts(_metadata._compressed_klass);
138 default:
139 return _metadata._klass;
140 }
141 }
142
143 narrowKlass oopDesc::narrow_klass() const {
144 switch (ObjLayout::klass_mode()) {
145 case ObjLayout::Compact:
146 return mark().narrow_klass();
147 case ObjLayout::Compressed:
148 return _metadata._compressed_klass;
149 default:
150 ShouldNotReachHere();
151 }
152 }
153
154 void oopDesc::set_klass(Klass* k) {
155 assert(Universe::is_bootstrapping() || (k != nullptr && k->is_klass()), "incorrect Klass");
156 assert(!UseCompactObjectHeaders, "don't set Klass* with compact headers");
157 if (UseCompressedClassPointers) {
158 _metadata._compressed_klass = CompressedKlassPointers::encode_not_null(k);
159 } else {
160 _metadata._klass = k;
161 }
162 }
163
164 void oopDesc::release_set_klass(HeapWord* mem, Klass* k) {
165 assert(Universe::is_bootstrapping() || (k != nullptr && k->is_klass()), "incorrect Klass");
166 assert(!UseCompactObjectHeaders, "don't set Klass* with compact headers");
167 char* raw_mem = ((char*)mem + klass_offset_in_bytes());
168 if (UseCompressedClassPointers) {
169 Atomic::release_store((narrowKlass*)raw_mem,
170 CompressedKlassPointers::encode_not_null(k));
171 } else {
172 Atomic::release_store((Klass**)raw_mem, k);
173 }
174 }
175
176 void oopDesc::set_klass_gap(HeapWord* mem, int v) {
177 assert(has_klass_gap(), "precondition");
178 *(int*)(((char*)mem) + klass_gap_offset_in_bytes()) = v;
179 }
180
181 bool oopDesc::is_a(Klass* k) const {
182 return klass()->is_subtype_of(k);
183 }
184
185 size_t oopDesc::size() {
186 return size_given_klass(klass());
187 }
188
189 size_t oopDesc::size_given_klass(Klass* klass) {
190 int lh = klass->layout_helper();
191 size_t s;
192
193 // lh is now a value computed at class initialization that may hint
194 // at the size. For instances, this is positive and equal to the
195 // size. For arrays, this is negative and provides log2 of the
196 // array element size. For other oops, it is zero and thus requires
197 // a virtual call.
198 //
199 // We go to all this trouble because the size computation is at the
200 // heart of phase 2 of mark-compaction, and called for every object,
201 // alive or dead. So the speed here is equal in importance to the
202 // speed of allocation.
203
204 if (lh > Klass::_lh_neutral_value) {
205 if (!Klass::layout_helper_needs_slow_path(lh)) {
206 s = lh >> LogHeapWordSize; // deliver size scaled by wordSize
207 } else {
208 s = klass->oop_size(this);
209 }
210 } else if (lh <= Klass::_lh_neutral_value) {
211 // The most common case is instances; fall through if so.
212 if (lh < Klass::_lh_neutral_value) {
213 // Second most common case is arrays. We have to fetch the
214 // length of the array, shift (multiply) it appropriately,
215 // up to wordSize, add the header, and align to object size.
216 size_t size_in_bytes;
217 size_t array_length = (size_t) ((arrayOop)this)->length();
218 size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh);
219 size_in_bytes += Klass::layout_helper_header_size(lh);
220
221 // This code could be simplified, but by keeping array_header_in_bytes
222 // in units of bytes and doing it this way we can round up just once,
223 // skipping the intermediate round to HeapWordSize.
224 s = align_up(size_in_bytes, MinObjAlignmentInBytes) / HeapWordSize;
225
226 assert(s == klass->oop_size(this), "wrong array object size");
227 } else {
228 // Must be zero, so bite the bullet and take the virtual call.
229 s = klass->oop_size(this);
230 }
231 }
232
233 assert(s > 0, "Oop size must be greater than zero, not %zu", s);
234 assert(is_object_aligned(s), "Oop size is not properly aligned: %zu", s);
235 return s;
236 }
237
238 bool oopDesc::is_instance() const { return klass()->is_instance_klass(); }
239 bool oopDesc::is_instanceRef() const { return klass()->is_reference_instance_klass(); }
240 bool oopDesc::is_stackChunk() const { return klass()->is_stack_chunk_instance_klass(); }
241 bool oopDesc::is_array() const { return klass()->is_array_klass(); }
242 bool oopDesc::is_objArray() const { return klass()->is_objArray_klass(); }
243 bool oopDesc::is_typeArray() const { return klass()->is_typeArray_klass(); }
244
245 template<typename T>
246 T* oopDesc::field_addr(int offset) const { return reinterpret_cast<T*>(cast_from_oop<intptr_t>(as_oop()) + offset); }
247
248 template <typename T>
249 size_t oopDesc::field_offset(T* p) const { return pointer_delta((void*)p, (void*)this, 1); }
250
251 template <DecoratorSet decorators>
252 inline oop oopDesc::obj_field_access(int offset) const { return HeapAccess<decorators>::oop_load_at(as_oop(), offset); }
253 inline oop oopDesc::obj_field(int offset) const { return HeapAccess<>::oop_load_at(as_oop(), offset); }
254
255 inline void oopDesc::obj_field_put(int offset, oop value) { HeapAccess<>::oop_store_at(as_oop(), offset, value); }
256 template <DecoratorSet decorators>
257 inline void oopDesc::obj_field_put_access(int offset, oop value) { HeapAccess<decorators>::oop_store_at(as_oop(), offset, value); }
258
259 inline jbyte oopDesc::byte_field(int offset) const { return *field_addr<jbyte>(offset); }
260 inline void oopDesc::byte_field_put(int offset, jbyte value) { *field_addr<jbyte>(offset) = value; }
261
262 inline jchar oopDesc::char_field(int offset) const { return *field_addr<jchar>(offset); }
263 inline void oopDesc::char_field_put(int offset, jchar value) { *field_addr<jchar>(offset) = value; }
264
265 inline jboolean oopDesc::bool_field(int offset) const { return *field_addr<jboolean>(offset); }
266 inline void oopDesc::bool_field_put(int offset, jboolean value) { *field_addr<jboolean>(offset) = jboolean(value & 1); }
267 inline jboolean oopDesc::bool_field_volatile(int offset) const { return RawAccess<MO_SEQ_CST>::load(field_addr<jboolean>(offset)); }
268 inline void oopDesc::bool_field_put_volatile(int offset, jboolean value) { RawAccess<MO_SEQ_CST>::store(field_addr<jboolean>(offset), jboolean(value & 1)); }
269 inline jshort oopDesc::short_field(int offset) const { return *field_addr<jshort>(offset); }
270 inline void oopDesc::short_field_put(int offset, jshort value) { *field_addr<jshort>(offset) = value; }
271
272 inline jint oopDesc::int_field(int offset) const { return *field_addr<jint>(offset); }
273 inline void oopDesc::int_field_put(int offset, jint value) { *field_addr<jint>(offset) = value; }
274 inline jint oopDesc::int_field_relaxed(int offset) const { return Atomic::load(field_addr<jint>(offset)); }
275 inline void oopDesc::int_field_put_relaxed(int offset, jint value) { Atomic::store(field_addr<jint>(offset), value); }
276
277 inline jlong oopDesc::long_field(int offset) const { return *field_addr<jlong>(offset); }
278 inline void oopDesc::long_field_put(int offset, jlong value) { *field_addr<jlong>(offset) = value; }
279
280 inline jfloat oopDesc::float_field(int offset) const { return *field_addr<jfloat>(offset); }
281 inline void oopDesc::float_field_put(int offset, jfloat value) { *field_addr<jfloat>(offset) = value; }
282
283 inline jdouble oopDesc::double_field(int offset) const { return *field_addr<jdouble>(offset); }
284 inline void oopDesc::double_field_put(int offset, jdouble value) { *field_addr<jdouble>(offset) = value; }
285
286 bool oopDesc::is_locked() const {
287 return mark().is_locked();
288 }
289
290 bool oopDesc::is_unlocked() const {
291 return mark().is_unlocked();
292 }
293
294 bool oopDesc::is_gc_marked() const {
295 return mark().is_marked();
296 }
297
298 // Used by scavengers
299 bool oopDesc::is_forwarded() const {
300 return mark().is_forwarded();
301 }
302
303 bool oopDesc::is_self_forwarded() const {
304 return mark().is_self_forwarded();
305 }
306
307 // Used by scavengers
308 void oopDesc::forward_to(oop p) {
309 assert(cast_from_oop<oopDesc*>(p) != this,
310 "must not be used for self-forwarding, use forward_to_self() instead");
311 markWord m = markWord::encode_pointer_as_mark(p);
312 assert(m.decode_pointer() == p, "encoding must be reversible");
313 set_mark(m);
314 }
315
316 void oopDesc::forward_to_self() {
317 set_mark(mark().set_self_forwarded());
318 }
319
320 oop oopDesc::cas_set_forwardee(markWord new_mark, markWord compare, atomic_memory_order order) {
321 markWord old_mark = cas_set_mark(new_mark, compare, order);
322 if (old_mark == compare) {
323 return nullptr;
324 } else {
325 assert(old_mark.is_forwarded(), "must be forwarded here");
326 return forwardee(old_mark);
327 }
328 }
329
330 oop oopDesc::forward_to_atomic(oop p, markWord compare, atomic_memory_order order) {
331 assert(cast_from_oop<oopDesc*>(p) != this,
332 "must not be used for self-forwarding, use forward_to_self_atomic() instead");
333 markWord m = markWord::encode_pointer_as_mark(p);
334 assert(forwardee(m) == p, "encoding must be reversible");
335 return cas_set_forwardee(m, compare, order);
336 }
337
338 oop oopDesc::forward_to_self_atomic(markWord old_mark, atomic_memory_order order) {
339 markWord new_mark = old_mark.set_self_forwarded();
340 assert(forwardee(new_mark) == cast_to_oop(this), "encoding must be reversible");
341 return cas_set_forwardee(new_mark, old_mark, order);
342 }
343
344 oop oopDesc::forwardee(markWord mark) const {
345 assert(mark.is_forwarded(), "only decode when actually forwarded");
346 if (mark.is_self_forwarded()) {
347 return cast_to_oop(this);
348 } else {
349 return mark.forwardee();
350 }
351 }
352
353 // Note that the forwardee is not the same thing as the displaced_mark.
354 // The forwardee is used when copying during scavenge and mark-sweep.
355 // It does need to clear the low two locking- and GC-related bits.
356 oop oopDesc::forwardee() const {
357 return forwardee(mark());
358 }
359
360 void oopDesc::unset_self_forwarded() {
361 set_mark(mark().unset_self_forwarded());
362 }
363
364 // The following method needs to be MT safe.
365 uint oopDesc::age() const {
366 markWord m = mark();
367 assert(!m.is_marked(), "Attempt to read age from forwarded mark");
368 if (m.has_displaced_mark_helper()) {
369 return m.displaced_mark_helper().age();
370 } else {
371 return m.age();
372 }
373 }
374
375 void oopDesc::incr_age() {
376 markWord m = mark();
377 assert(!m.is_marked(), "Attempt to increment age of forwarded mark");
378 if (m.has_displaced_mark_helper()) {
379 m.set_displaced_mark_helper(m.displaced_mark_helper().incr_age());
380 } else {
381 set_mark(m.incr_age());
382 }
383 }
384
385 template <typename OopClosureType>
386 void oopDesc::oop_iterate(OopClosureType* cl) {
387 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass());
388 }
389
390 template <typename OopClosureType>
391 void oopDesc::oop_iterate(OopClosureType* cl, MemRegion mr) {
392 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass(), mr);
393 }
394
395 template <typename OopClosureType>
396 size_t oopDesc::oop_iterate_size(OopClosureType* cl) {
397 Klass* k = klass();
398 size_t size = size_given_klass(k);
399 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k);
400 return size;
401 }
402
403 template <typename OopClosureType>
404 size_t oopDesc::oop_iterate_size(OopClosureType* cl, MemRegion mr) {
405 Klass* k = klass();
406 size_t size = size_given_klass(k);
407 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k, mr);
408 return size;
409 }
410
411 template <typename OopClosureType>
412 void oopDesc::oop_iterate_backwards(OopClosureType* cl) {
413 oop_iterate_backwards(cl, klass());
414 }
415
416 template <typename OopClosureType>
417 void oopDesc::oop_iterate_backwards(OopClosureType* cl, Klass* k) {
418 // In this assert, we cannot safely access the Klass* with compact headers.
419 assert(k == klass(), "wrong klass");
420 OopIteratorClosureDispatch::oop_oop_iterate_backwards(cl, this, k);
421 }
422
423 bool oopDesc::is_instanceof_or_null(oop obj, Klass* klass) {
424 return obj == nullptr || obj->klass()->is_subtype_of(klass);
425 }
426
427 intptr_t oopDesc::identity_hash() {
428 // Fast case; if the object is unlocked and the hash value is set, no locking is needed
429 // Note: The mark must be read into local variable to avoid concurrent updates.
430 markWord mrk = mark();
431 if (mrk.is_unlocked() && !mrk.has_no_hash()) {
432 return mrk.hash();
433 } else if (mrk.is_marked()) {
434 return mrk.hash();
435 } else {
436 return slow_identity_hash();
437 }
438 }
439
440 // This checks fast simple case of whether the oop has_no_hash,
441 // to optimize JVMTI table lookup.
442 bool oopDesc::fast_no_hash_check() {
443 markWord mrk = mark_acquire();
444 assert(!mrk.is_marked(), "should never be marked");
445 return mrk.is_unlocked() && mrk.has_no_hash();
446 }
447
448 bool oopDesc::has_displaced_mark() const {
449 return mark().has_displaced_mark_helper();
450 }
451
452 markWord oopDesc::displaced_mark() const {
453 return mark().displaced_mark_helper();
454 }
455
456 void oopDesc::set_displaced_mark(markWord m) {
457 mark().set_displaced_mark_helper(m);
458 }
459
460 bool oopDesc::mark_must_be_preserved() const {
461 return mark_must_be_preserved(mark());
462 }
463
464 bool oopDesc::mark_must_be_preserved(markWord m) const {
465 return m.must_be_preserved();
466 }
467
468 #endif // SHARE_OOPS_OOP_INLINE_HPP