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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7 * published by the Free Software Foundation.
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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13 * accompanied this code).
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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(m, &_mark);
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(new_mark.value(), as_oop(), mark_offset_in_bytes(), old_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(new_mark, &_mark, old_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(OrderAccess::load_acquire(xaddr));
114 } else {
115 return OrderAccess::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 OrderAccess::release_store(compressed_klass_addr(mem),
160 CompressedKlassPointers::encode_not_null(klass));
161 } else {
162 OrderAccess::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 void oopDesc::set_klass_to_list_ptr(oop k) {
183 // This is only to be used during GC, for from-space objects, so no
184 // barrier is needed.
185 if (UseCompressedClassPointers) {
186 _metadata._compressed_klass = (narrowKlass)CompressedOops::encode(k);
187 } else {
188 _metadata._klass = (Klass*)(address)k;
189 }
190 }
191
192 oop oopDesc::list_ptr_from_klass() {
193 // This is only to be used during GC, for from-space objects.
194 if (UseCompressedClassPointers) {
195 return CompressedOops::decode((narrowOop)_metadata._compressed_klass);
196 } else {
197 // Special case for GC
198 return (oop)(address)_metadata._klass;
199 }
200 }
201
202 bool oopDesc::is_a(Klass* k) const {
203 return klass()->is_subtype_of(k);
204 }
205
206 int oopDesc::size() {
207 return size_given_klass(klass());
208 }
209
210 int oopDesc::size_given_klass(Klass* klass) {
211 int lh = klass->layout_helper();
212 int s;
213
214 // lh is now a value computed at class initialization that may hint
215 // at the size. For instances, this is positive and equal to the
216 // size. For arrays, this is negative and provides log2 of the
217 // array element size. For other oops, it is zero and thus requires
218 // a virtual call.
219 //
220 // We go to all this trouble because the size computation is at the
221 // heart of phase 2 of mark-compaction, and called for every object,
222 // alive or dead. So the speed here is equal in importance to the
223 // speed of allocation.
224
225 if (lh > Klass::_lh_neutral_value) {
226 if (!Klass::layout_helper_needs_slow_path(lh)) {
227 s = lh >> LogHeapWordSize; // deliver size scaled by wordSize
228 } else {
229 s = klass->oop_size(this);
230 }
231 } else if (lh <= Klass::_lh_neutral_value) {
232 // The most common case is instances; fall through if so.
233 if (lh < Klass::_lh_neutral_value) {
234 // Second most common case is arrays. We have to fetch the
235 // length of the array, shift (multiply) it appropriately,
236 // up to wordSize, add the header, and align to object size.
237 size_t size_in_bytes;
238 size_t array_length = (size_t) ((arrayOop)this)->length();
239 size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh);
240 size_in_bytes += Klass::layout_helper_header_size(lh);
241
242 // This code could be simplified, but by keeping array_header_in_bytes
243 // in units of bytes and doing it this way we can round up just once,
244 // skipping the intermediate round to HeapWordSize.
245 s = (int)(align_up(size_in_bytes, MinObjAlignmentInBytes) / HeapWordSize);
246
247 // UseParallelGC and UseG1GC can change the length field
248 // of an "old copy" of an object array in the young gen so it indicates
249 // the grey portion of an already copied array. This will cause the first
250 // disjunct below to fail if the two comparands are computed across such
251 // a concurrent change.
252 assert((s == klass->oop_size(this)) ||
253 (Universe::heap()->is_gc_active() && is_objArray() && is_forwarded() && (UseParallelGC || UseG1GC)),
254 "wrong array object size");
255 } else {
256 // Must be zero, so bite the bullet and take the virtual call.
257 s = klass->oop_size(this);
258 }
259 }
260
261 assert(s > 0, "Oop size must be greater than zero, not %d", s);
262 assert(is_object_aligned(s), "Oop size is not properly aligned: %d", s);
263 return s;
264 }
265
266 bool oopDesc::is_instance() const { return klass()->is_instance_klass(); }
267 bool oopDesc::is_array() const { return klass()->is_array_klass(); }
268 bool oopDesc::is_objArray() const { return klass()->is_objArray_klass(); }
269 bool oopDesc::is_typeArray() const { return klass()->is_typeArray_klass(); }
270
271 void* oopDesc::field_addr_raw(int offset) const { return reinterpret_cast<void*>(cast_from_oop<intptr_t>(as_oop()) + offset); }
272 void* oopDesc::field_addr(int offset) const { return Access<>::resolve(as_oop())->field_addr_raw(offset); }
273
274 template <class T>
275 T* oopDesc::obj_field_addr_raw(int offset) const { return (T*) field_addr_raw(offset); }
276
277 template <typename T>
278 size_t oopDesc::field_offset(T* p) const { return pointer_delta((void*)p, (void*)this, 1); }
279
280 template <DecoratorSet decorators>
281 inline oop oopDesc::obj_field_access(int offset) const { return HeapAccess<decorators>::oop_load_at(as_oop(), offset); }
282 inline oop oopDesc::obj_field(int offset) const { return HeapAccess<>::oop_load_at(as_oop(), offset); }
283
284 inline void oopDesc::obj_field_put(int offset, oop value) { HeapAccess<>::oop_store_at(as_oop(), offset, value); }
285
286 inline jbyte oopDesc::byte_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
287 inline void oopDesc::byte_field_put(int offset, jbyte value) { HeapAccess<>::store_at(as_oop(), offset, value); }
288
289 inline jchar oopDesc::char_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
290 inline void oopDesc::char_field_put(int offset, jchar value) { HeapAccess<>::store_at(as_oop(), offset, value); }
291
292 inline jboolean oopDesc::bool_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
293 inline void oopDesc::bool_field_put(int offset, jboolean value) { HeapAccess<>::store_at(as_oop(), offset, jboolean(value & 1)); }
294
295 inline jshort oopDesc::short_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
296 inline void oopDesc::short_field_put(int offset, jshort value) { HeapAccess<>::store_at(as_oop(), offset, value); }
297
298 inline jint oopDesc::int_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
299 inline jint oopDesc::int_field_raw(int offset) const { return RawAccess<>::load_at(as_oop(), offset); }
300 inline void oopDesc::int_field_put(int offset, jint value) { HeapAccess<>::store_at(as_oop(), offset, value); }
301
302 inline jlong oopDesc::long_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
303 inline void oopDesc::long_field_put(int offset, jlong value) { HeapAccess<>::store_at(as_oop(), offset, value); }
304
305 inline jfloat oopDesc::float_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
306 inline void oopDesc::float_field_put(int offset, jfloat value) { HeapAccess<>::store_at(as_oop(), offset, value); }
307
308 inline jdouble oopDesc::double_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
309 inline void oopDesc::double_field_put(int offset, jdouble value) { HeapAccess<>::store_at(as_oop(), offset, value); }
310
311 bool oopDesc::is_locked() const {
312 return mark().is_locked();
313 }
314
315 bool oopDesc::is_unlocked() const {
316 return mark().is_unlocked();
317 }
318
319 bool oopDesc::has_bias_pattern() const {
320 return mark().has_bias_pattern();
321 }
322
323 bool oopDesc::has_bias_pattern_raw() const {
324 return mark_raw().has_bias_pattern();
325 }
326
327 // Used only for markSweep, scavenging
328 bool oopDesc::is_gc_marked() const {
329 return mark_raw().is_marked();
330 }
331
332 // Used by scavengers
333 bool oopDesc::is_forwarded() const {
334 // The extra heap check is needed since the obj might be locked, in which case the
335 // mark would point to a stack location and have the sentinel bit cleared
336 return mark_raw().is_marked();
337 }
338
339 // Used by scavengers
340 void oopDesc::forward_to(oop p) {
341 verify_forwardee(p);
342 markWord m = markWord::encode_pointer_as_mark(p);
343 assert(m.decode_pointer() == p, "encoding must be reversable");
344 set_mark_raw(m);
345 }
346
347 // Used by parallel scavengers
348 bool oopDesc::cas_forward_to(oop p, markWord compare, atomic_memory_order order) {
349 verify_forwardee(p);
350 markWord m = markWord::encode_pointer_as_mark(p);
351 assert(m.decode_pointer() == p, "encoding must be reversable");
352 return cas_set_mark_raw(m, compare, order) == compare;
353 }
354
355 oop oopDesc::forward_to_atomic(oop p, markWord compare, atomic_memory_order order) {
356 verify_forwardee(p);
357 markWord m = markWord::encode_pointer_as_mark(p);
358 assert(m.decode_pointer() == p, "encoding must be reversable");
359 markWord old_mark = cas_set_mark_raw(m, compare, order);
360 if (old_mark == compare) {
361 return NULL;
362 } else {
363 return (oop)old_mark.decode_pointer();
364 }
365 }
366
367 // Note that the forwardee is not the same thing as the displaced_mark.
368 // The forwardee is used when copying during scavenge and mark-sweep.
369 // It does need to clear the low two locking- and GC-related bits.
370 oop oopDesc::forwardee() const {
371 return (oop) mark_raw().decode_pointer();
372 }
373
374 // Note that the forwardee is not the same thing as the displaced_mark.
375 // The forwardee is used when copying during scavenge and mark-sweep.
376 // It does need to clear the low two locking- and GC-related bits.
377 oop oopDesc::forwardee_acquire() const {
378 return (oop) OrderAccess::load_acquire(&_mark).decode_pointer();
379 }
380
381 // The following method needs to be MT safe.
382 uint oopDesc::age() const {
383 assert(!is_forwarded(), "Attempt to read age from forwarded mark");
384 if (has_displaced_mark_raw()) {
385 return displaced_mark_raw().age();
386 } else {
387 return mark_raw().age();
388 }
389 }
390
391 void oopDesc::incr_age() {
392 assert(!is_forwarded(), "Attempt to increment age of forwarded mark");
393 if (has_displaced_mark_raw()) {
394 set_displaced_mark_raw(displaced_mark_raw().incr_age());
395 } else {
396 set_mark_raw(mark_raw().incr_age());
397 }
398 }
399
400 template <typename OopClosureType>
401 void oopDesc::oop_iterate(OopClosureType* cl) {
402 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass());
403 }
404
405 template <typename OopClosureType>
406 void oopDesc::oop_iterate(OopClosureType* cl, MemRegion mr) {
407 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass(), mr);
408 }
409
410 template <typename OopClosureType>
411 int oopDesc::oop_iterate_size(OopClosureType* cl) {
412 Klass* k = klass();
413 int size = size_given_klass(k);
414 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k);
415 return size;
416 }
417
418 template <typename OopClosureType>
419 int oopDesc::oop_iterate_size(OopClosureType* cl, MemRegion mr) {
420 Klass* k = klass();
421 int size = size_given_klass(k);
422 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k, mr);
423 return size;
424 }
425
426 template <typename OopClosureType>
427 void oopDesc::oop_iterate_backwards(OopClosureType* cl) {
428 OopIteratorClosureDispatch::oop_oop_iterate_backwards(cl, this, klass());
429 }
430
431 bool oopDesc::is_instanceof_or_null(oop obj, Klass* klass) {
432 return obj == NULL || 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 bool oopDesc::has_displaced_mark_raw() const {
449 return mark_raw().has_displaced_mark_helper();
450 }
451
452 markWord oopDesc::displaced_mark_raw() const {
453 return mark_raw().displaced_mark_helper();
454 }
455
456 void oopDesc::set_displaced_mark_raw(markWord m) {
457 mark_raw().set_displaced_mark_helper(m);
458 }
459
460 // Supports deferred calling of obj->klass().
461 class DeferredObjectToKlass {
462 const oopDesc* _obj;
463
464 public:
465 DeferredObjectToKlass(const oopDesc* obj) : _obj(obj) {}
466
467 // Implicitly convertible to const Klass*.
468 operator const Klass*() const {
469 return _obj->klass();
470 }
471 };
472
473 bool oopDesc::mark_must_be_preserved() const {
474 return mark_must_be_preserved(mark_raw());
475 }
476
477 bool oopDesc::mark_must_be_preserved(markWord m) const {
478 // There's a circular dependency between oop.inline.hpp and
479 // markWord.inline.hpp because markWord::must_be_preserved wants to call
480 // oopDesc::klass(). This could be solved by calling klass() here. However,
481 // not all paths inside must_be_preserved calls klass(). Defer the call until
482 // the klass is actually needed.
483 return m.must_be_preserved(DeferredObjectToKlass(this));
484 }
485
486 bool oopDesc::mark_must_be_preserved_for_promotion_failure(markWord m) const {
487 return m.must_be_preserved_for_promotion_failure(DeferredObjectToKlass(this));
488 }
489
490 #endif // SHARE_OOPS_OOP_INLINE_HPP