53 Klass* _klass;
54 narrowKlass _compressed_klass;
55 } _metadata;
56
57 // There may be ordering constraints on the initialization of fields that
58 // make use of the C++ copy/assign incorrect.
59 NONCOPYABLE(oopDesc);
60
61 inline oop cas_set_forwardee(markWord new_mark, markWord old_mark, atomic_memory_order order);
62
63 public:
64 // Must be trivial; see verifying static assert after the class.
65 oopDesc() = default;
66
67 inline markWord mark() const;
68 inline markWord mark_acquire() const;
69 inline markWord* mark_addr() const;
70
71 inline void set_mark(markWord m);
72 static inline void set_mark(HeapWord* mem, markWord m);
73 static inline void release_set_mark(HeapWord* mem, markWord m);
74
75 inline void release_set_mark(markWord m);
76 inline markWord cas_set_mark(markWord new_mark, markWord old_mark);
77 inline markWord cas_set_mark(markWord new_mark, markWord old_mark, atomic_memory_order order);
78
79 // Returns the prototype mark that should be used for this object.
80 inline markWord prototype_mark() const;
81
82 // Used only to re-initialize the mark word (e.g., of promoted
83 // objects during a GC) -- requires a valid klass pointer
84 inline void init_mark();
85
86 inline Klass* klass() const;
87 inline Klass* klass_or_null() const;
88 inline Klass* klass_or_null_acquire() const;
89 // Get the klass without running any asserts.
90 inline Klass* klass_without_asserts() const;
91
92 void set_narrow_klass(narrowKlass nk) NOT_CDS_JAVA_HEAP_RETURN;
94 static inline void release_set_klass(HeapWord* mem, Klass* k);
95
96 // For klass field compression
97 static inline void set_klass_gap(HeapWord* mem, int z);
98
99 // Size of object header, aligned to platform wordSize
100 static int header_size() {
101 if (UseCompactObjectHeaders) {
102 return sizeof(markWord) / HeapWordSize;
103 } else {
104 return sizeof(oopDesc) / HeapWordSize;
105 }
106 }
107
108 // Returns whether this is an instance of k or an instance of a subclass of k
109 inline bool is_a(Klass* k) const;
110
111 // Returns the actual oop size of the object in machine words
112 inline size_t size();
113
114 // Sometimes (for complicated concurrency-related reasons), it is useful
115 // to be able to figure out the size of an object knowing its klass.
116 inline size_t size_given_klass(Klass* klass);
117
118 // type test operations (inlined in oop.inline.hpp)
119 inline bool is_instance() const;
120 inline bool is_instanceRef() const;
121 inline bool is_stackChunk() const;
122 inline bool is_array() const;
123 inline bool is_objArray() const;
124 inline bool is_typeArray() const;
125
126 // type test operations that don't require inclusion of oop.inline.hpp.
127 bool is_instance_noinline() const;
128 bool is_instanceRef_noinline() const;
129 bool is_stackChunk_noinline() const;
130 bool is_array_noinline() const;
131 bool is_objArray_noinline() const;
132 bool is_typeArray_noinline() const;
133
134 protected:
135 inline oop as_oop() const { return const_cast<oopDesc*>(this); }
136
264 inline bool is_gc_marked() const;
265
266 // Forward pointer operations for scavenge
267 inline bool is_forwarded() const;
268 inline bool is_self_forwarded() const;
269
270 inline void forward_to(oop p);
271 inline void forward_to_self();
272
273 // Like "forward_to", but inserts the forwarding pointer atomically.
274 // Exactly one thread succeeds in inserting the forwarding pointer, and
275 // this call returns null for that thread; any other thread has the
276 // value of the forwarding pointer returned and does not modify "this".
277 inline oop forward_to_atomic(oop p, markWord compare, atomic_memory_order order = memory_order_conservative);
278 inline oop forward_to_self_atomic(markWord compare, atomic_memory_order order = memory_order_conservative);
279
280 inline oop forwardee() const;
281 inline oop forwardee(markWord header) const;
282
283 inline void unset_self_forwarded();
284
285 // Age of object during scavenge
286 inline uint age() const;
287 inline void incr_age();
288
289 template <typename OopClosureType>
290 inline void oop_iterate(OopClosureType* cl);
291
292 template <typename OopClosureType>
293 inline void oop_iterate(OopClosureType* cl, MemRegion mr);
294
295 template <typename OopClosureType>
296 inline size_t oop_iterate_size(OopClosureType* cl);
297
298 template <typename OopClosureType>
299 inline size_t oop_iterate_size(OopClosureType* cl, MemRegion mr);
300
301 template <typename OopClosureType>
302 inline void oop_iterate_backwards(OopClosureType* cl);
303
304 template <typename OopClosureType>
305 inline void oop_iterate_backwards(OopClosureType* cl, Klass* klass);
306
307 inline static bool is_instanceof_or_null(oop obj, Klass* klass);
308
309 // identity hash; returns the identity hash key (computes it if necessary)
310 inline intptr_t identity_hash();
311 intptr_t slow_identity_hash();
312 inline bool fast_no_hash_check();
313
314 // marks are forwarded to stack when object is locked
315 inline bool has_displaced_mark() const;
316 inline markWord displaced_mark() const;
317 inline void set_displaced_mark(markWord m);
318
319 // Checks if the mark word needs to be preserved
320 inline bool mark_must_be_preserved() const;
321 inline bool mark_must_be_preserved(markWord m) const;
322
323 inline static bool has_klass_gap() {
324 return ObjLayout::oop_has_klass_gap();
325 }
326
327 // for code generation
328 static int mark_offset_in_bytes() { return (int)offset_of(oopDesc, _mark); }
329 static int klass_offset_in_bytes() {
330 #ifdef _LP64
331 if (UseCompactObjectHeaders) {
332 // NOTE: The only places where this is used with compact headers are the C2
333 // compiler and JVMCI.
334 return mark_offset_in_bytes() + markWord::klass_offset_in_bytes;
335 } else
336 #endif
337 {
338 return (int)offset_of(oopDesc, _metadata._klass);
339 }
340 }
341 static int klass_gap_offset_in_bytes() {
342 assert(has_klass_gap(), "only applicable to compressed klass pointers");
343 return klass_offset_in_bytes() + sizeof(narrowKlass);
344 }
345
346 static int base_offset_in_bytes() {
347 return ObjLayout::oop_base_offset_in_bytes();
348 }
349
350 // for error reporting
351 static void* load_oop_raw(oop obj, int offset);
352 };
353
354 // An oopDesc is not initialized via a constructor. Space is allocated in
355 // the Java heap, and static functions provided here on HeapWord* are used
356 // to fill in certain parts of that memory. The allocated memory is then
357 // treated as referring to an oopDesc. For that to be valid, the oopDesc
358 // class must have a trivial default constructor (C++14 3.8/1).
359 static_assert(std::is_trivially_default_constructible<oopDesc>::value, "required");
360
361 #endif // SHARE_OOPS_OOP_HPP
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53 Klass* _klass;
54 narrowKlass _compressed_klass;
55 } _metadata;
56
57 // There may be ordering constraints on the initialization of fields that
58 // make use of the C++ copy/assign incorrect.
59 NONCOPYABLE(oopDesc);
60
61 inline oop cas_set_forwardee(markWord new_mark, markWord old_mark, atomic_memory_order order);
62
63 public:
64 // Must be trivial; see verifying static assert after the class.
65 oopDesc() = default;
66
67 inline markWord mark() const;
68 inline markWord mark_acquire() const;
69 inline markWord* mark_addr() const;
70
71 inline void set_mark(markWord m);
72 static inline void set_mark(HeapWord* mem, markWord m);
73 inline void set_mark_full(markWord m);
74 static inline void release_set_mark(HeapWord* mem, markWord m);
75
76 inline void release_set_mark(markWord m);
77 inline markWord cas_set_mark(markWord new_mark, markWord old_mark);
78 inline markWord cas_set_mark(markWord new_mark, markWord old_mark, atomic_memory_order order);
79
80 // Returns the prototype mark that should be used for this object.
81 inline markWord prototype_mark() const;
82
83 // Used only to re-initialize the mark word (e.g., of promoted
84 // objects during a GC) -- requires a valid klass pointer
85 inline void init_mark();
86
87 inline Klass* klass() const;
88 inline Klass* klass_or_null() const;
89 inline Klass* klass_or_null_acquire() const;
90 // Get the klass without running any asserts.
91 inline Klass* klass_without_asserts() const;
92
93 void set_narrow_klass(narrowKlass nk) NOT_CDS_JAVA_HEAP_RETURN;
95 static inline void release_set_klass(HeapWord* mem, Klass* k);
96
97 // For klass field compression
98 static inline void set_klass_gap(HeapWord* mem, int z);
99
100 // Size of object header, aligned to platform wordSize
101 static int header_size() {
102 if (UseCompactObjectHeaders) {
103 return sizeof(markWord) / HeapWordSize;
104 } else {
105 return sizeof(oopDesc) / HeapWordSize;
106 }
107 }
108
109 // Returns whether this is an instance of k or an instance of a subclass of k
110 inline bool is_a(Klass* k) const;
111
112 // Returns the actual oop size of the object in machine words
113 inline size_t size();
114
115 // Returns the size that a copy of this object requires, in machine words.
116 // It can be 1 word larger than its current size to accomodate
117 // an additional 4-byte-field for the identity hash-code.
118 //
119 // size: the current size of this object, we're passing this here for performance
120 // reasons, because all callers compute this anyway, and we want to avoid
121 // recomputing it.
122 // mark: the mark-word of this object. Some callers (e.g. G1ParScanThreadState::do_copy_to_survivor_space())
123 // need to use a known markWord because of racing GC threads that can change
124 // the markWord at any time.
125 inline size_t copy_size(size_t size, markWord mark) const;
126 // Special version to deal with scratch classes in CDS. There we allocate
127 // temporary scratch classes (which are skeleton versions of InstanceMirrorKlass,
128 // which represent java.lang.Class objects in the CDS archive). At that point, we
129 // don't know whether or not the final archived version will be hashed or expanded,
130 // and therefore we allocate them in the special state not-hashed-but-expanded.
131 // When creating the final copy of those objects, we either populate the hidden hash
132 // field and make the object 'expanded', or we turn it back to 'not-hashed'
133 // and reduce the object's size. We do this by providing a separate method for CDS
134 // so that we don't affect GC performance.
135 inline size_t copy_size_cds(size_t size, markWord mark) const;
136
137 // Sometimes (for complicated concurrency-related reasons), it is useful
138 // to be able to figure out the size of an object knowing its klass.
139 inline size_t base_size_given_klass(markWord m, const Klass* klass);
140 inline size_t size_given_mark_and_klass(markWord mrk, const Klass* kls);
141
142 // type test operations (inlined in oop.inline.hpp)
143 inline bool is_instance() const;
144 inline bool is_instanceRef() const;
145 inline bool is_stackChunk() const;
146 inline bool is_array() const;
147 inline bool is_objArray() const;
148 inline bool is_typeArray() const;
149
150 // type test operations that don't require inclusion of oop.inline.hpp.
151 bool is_instance_noinline() const;
152 bool is_instanceRef_noinline() const;
153 bool is_stackChunk_noinline() const;
154 bool is_array_noinline() const;
155 bool is_objArray_noinline() const;
156 bool is_typeArray_noinline() const;
157
158 protected:
159 inline oop as_oop() const { return const_cast<oopDesc*>(this); }
160
288 inline bool is_gc_marked() const;
289
290 // Forward pointer operations for scavenge
291 inline bool is_forwarded() const;
292 inline bool is_self_forwarded() const;
293
294 inline void forward_to(oop p);
295 inline void forward_to_self();
296
297 // Like "forward_to", but inserts the forwarding pointer atomically.
298 // Exactly one thread succeeds in inserting the forwarding pointer, and
299 // this call returns null for that thread; any other thread has the
300 // value of the forwarding pointer returned and does not modify "this".
301 inline oop forward_to_atomic(oop p, markWord compare, atomic_memory_order order = memory_order_conservative);
302 inline oop forward_to_self_atomic(markWord compare, atomic_memory_order order = memory_order_conservative);
303
304 inline oop forwardee() const;
305 inline oop forwardee(markWord header) const;
306
307 inline void unset_self_forwarded();
308 inline void reset_forwarded();
309
310 // Age of object during scavenge
311 inline uint age() const;
312 inline void incr_age();
313
314 template <typename OopClosureType>
315 inline void oop_iterate(OopClosureType* cl);
316
317 template <typename OopClosureType>
318 inline void oop_iterate(OopClosureType* cl, MemRegion mr);
319
320 template <typename OopClosureType>
321 inline size_t oop_iterate_size(OopClosureType* cl);
322
323 template <typename OopClosureType>
324 inline size_t oop_iterate_size(OopClosureType* cl, MemRegion mr);
325
326 template <typename OopClosureType>
327 inline void oop_iterate_backwards(OopClosureType* cl);
328
329 template <typename OopClosureType>
330 inline void oop_iterate_backwards(OopClosureType* cl, Klass* klass);
331
332 inline static bool is_instanceof_or_null(oop obj, Klass* klass);
333
334 // identity hash; returns the identity hash key (computes it if necessary)
335 inline intptr_t identity_hash();
336 intptr_t slow_identity_hash();
337 inline bool fast_no_hash_check();
338
339 // Initialize identity hash code in hash word of object copy from original object.
340 // Returns true if the object has been expanded, false otherwise.
341 inline void initialize_hash_if_necessary(oop obj);
342 // For CDS only.
343 void initialize_hash_if_necessary(oop obj, Klass* k, markWord m);
344
345 // marks are forwarded to stack when object is locked
346 inline bool has_displaced_mark() const;
347 inline markWord displaced_mark() const;
348 inline void set_displaced_mark(markWord m);
349
350 // Checks if the mark word needs to be preserved
351 inline bool mark_must_be_preserved() const;
352 inline bool mark_must_be_preserved(markWord m) const;
353
354 inline static bool has_klass_gap() {
355 return ObjLayout::oop_has_klass_gap();
356 }
357
358 // for code generation
359 static int mark_offset_in_bytes() { return (int)offset_of(oopDesc, _mark); }
360 static int klass_offset_in_bytes() {
361 assert(!UseCompactObjectHeaders, "don't use this with compact headers");
362 return (int)offset_of(oopDesc, _metadata._klass);
363 }
364 static int klass_gap_offset_in_bytes() {
365 assert(has_klass_gap(), "only applicable to compressed klass pointers");
366 if (UseCompactObjectHeaders) {
367 return base_offset_in_bytes();
368 } else {
369 return klass_offset_in_bytes() + sizeof(narrowKlass);
370 }
371 }
372
373 static int base_offset_in_bytes() {
374 return ObjLayout::oop_base_offset_in_bytes();
375 }
376
377 // for error reporting
378 static void* load_oop_raw(oop obj, int offset);
379 };
380
381 // An oopDesc is not initialized via a constructor. Space is allocated in
382 // the Java heap, and static functions provided here on HeapWord* are used
383 // to fill in certain parts of that memory. The allocated memory is then
384 // treated as referring to an oopDesc. For that to be valid, the oopDesc
385 // class must have a trivial default constructor (C++14 3.8/1).
386 static_assert(std::is_trivially_default_constructible<oopDesc>::value, "required");
387
388 #endif // SHARE_OOPS_OOP_HPP
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