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 void* base_addr();
68 inline const void* base_addr() const;
69
70 inline markWord mark() const;
71 inline markWord mark_acquire() const;
72
73 inline void set_mark(markWord m);
74 static inline void set_mark(HeapWord* mem, markWord m);
75 static inline void release_set_mark(HeapWord* mem, markWord m);
76
77 inline void release_set_mark(markWord m);
78 inline markWord cas_set_mark(markWord new_mark, markWord old_mark);
79 inline markWord cas_set_mark(markWord new_mark, markWord old_mark, atomic_memory_order order);
80
81 // Returns the prototype mark that should be used for this object.
82 inline markWord prototype_mark() const;
83
84 // Used only to re-initialize the mark word (e.g., of promoted
85 // objects during a GC) -- requires a valid klass pointer
86 inline void init_mark();
87
88 inline Klass* klass() const;
89 inline Klass* klass_or_null() const;
90 inline Klass* klass_or_null_acquire() const;
91 // Get the klass without running any asserts.
92 inline Klass* klass_without_asserts() const;
93
94 void set_narrow_klass(narrowKlass nk) NOT_CDS_JAVA_HEAP_RETURN;
97 static inline void release_set_klass(HeapWord* mem, Klass* k);
98
99 // For klass field compression
100 static inline void set_klass_gap(HeapWord* mem, int z);
101
102 // Size of object header, aligned to platform wordSize
103 static int header_size() {
104 if (UseCompactObjectHeaders) {
105 return sizeof(markWord) / HeapWordSize;
106 } else {
107 return sizeof(oopDesc) / HeapWordSize;
108 }
109 }
110
111 // Returns whether this is an instance of k or an instance of a subclass of k
112 inline bool is_a(Klass* k) const;
113
114 // Returns the actual oop size of the object in machine words
115 inline size_t size();
116
117 // Sometimes (for complicated concurrency-related reasons), it is useful
118 // to be able to figure out the size of an object knowing its klass.
119 inline size_t size_given_klass(Klass* klass);
120
121 // type test operations (inlined in oop.inline.hpp)
122 inline bool is_instance() const;
123 inline bool is_instanceRef() const;
124 inline bool is_stackChunk() const;
125 inline bool is_array() const;
126 inline bool is_objArray() const;
127 inline bool is_typeArray() const;
128
129 // type test operations that don't require inclusion of oop.inline.hpp.
130 bool is_instance_noinline() const;
131 bool is_instanceRef_noinline() const;
132 bool is_stackChunk_noinline() const;
133 bool is_array_noinline() const;
134 bool is_objArray_noinline() const;
135 bool is_typeArray_noinline() const;
136
137 protected:
138 inline oop as_oop() const { return const_cast<oopDesc*>(this); }
139
267 inline bool is_gc_marked() const;
268
269 // Forward pointer operations for scavenge
270 inline bool is_forwarded() const;
271 inline bool is_self_forwarded() const;
272
273 inline void forward_to(oop p);
274 inline void forward_to_self();
275
276 // Like "forward_to", but inserts the forwarding pointer atomically.
277 // Exactly one thread succeeds in inserting the forwarding pointer, and
278 // this call returns null for that thread; any other thread has the
279 // value of the forwarding pointer returned and does not modify "this".
280 inline oop forward_to_atomic(oop p, markWord compare, atomic_memory_order order = memory_order_conservative);
281 inline oop forward_to_self_atomic(markWord compare, atomic_memory_order order = memory_order_conservative);
282
283 inline oop forwardee() const;
284 inline oop forwardee(markWord header) const;
285
286 inline void unset_self_forwarded();
287
288 // Age of object during scavenge
289 inline uint age() const;
290 inline void incr_age();
291
292 template <typename OopClosureType>
293 inline void oop_iterate(OopClosureType* cl);
294
295 template <typename OopClosureType>
296 inline void oop_iterate(OopClosureType* cl, MemRegion mr);
297
298 template <typename OopClosureType>
299 inline size_t oop_iterate_size(OopClosureType* cl);
300
301 template <typename OopClosureType>
302 inline size_t oop_iterate_size(OopClosureType* cl, MemRegion mr);
303
304 template <typename OopClosureType>
305 inline void oop_iterate_backwards(OopClosureType* cl);
306
307 template <typename OopClosureType>
308 inline void oop_iterate_backwards(OopClosureType* cl, Klass* klass);
309
310 inline static bool is_instanceof_or_null(oop obj, Klass* klass);
311
312 // identity hash; returns the identity hash key (computes it if necessary)
313 inline intptr_t identity_hash();
314 intptr_t slow_identity_hash();
315 inline bool fast_no_hash_check();
316
317 // marks are forwarded to stack when object is locked
318 inline bool has_displaced_mark() const;
319 inline markWord displaced_mark() const;
320 inline void set_displaced_mark(markWord m);
321
322 // Checks if the mark word needs to be preserved
323 inline bool mark_must_be_preserved() const;
324 inline bool mark_must_be_preserved(markWord m) const;
325
326 inline static bool has_klass_gap() {
327 return ObjLayout::oop_has_klass_gap();
328 }
329
330 // for code generation
331 static int mark_offset_in_bytes() { return (int)offset_of(oopDesc, _mark); }
332 static int klass_offset_in_bytes() {
333 #ifdef _LP64
334 if (UseCompactObjectHeaders) {
335 // NOTE: The only places where this is used with compact headers are the C2
336 // compiler and JVMCI.
337 return mark_offset_in_bytes() + markWord::klass_offset_in_bytes;
338 } else
339 #endif
340 {
341 return (int)offset_of(oopDesc, _metadata._klass);
342 }
343 }
344 static int klass_gap_offset_in_bytes() {
345 assert(has_klass_gap(), "only applicable to compressed klass pointers");
346 return klass_offset_in_bytes() + sizeof(narrowKlass);
347 }
348
349 static int base_offset_in_bytes() {
350 return ObjLayout::oop_base_offset_in_bytes();
351 }
352
353 // for error reporting
354 static void* load_oop_raw(oop obj, int offset);
355 };
356
357 // An oopDesc is not initialized via a constructor. Space is allocated in
358 // the Java heap, and static functions provided here on HeapWord* are used
359 // to fill in certain parts of that memory. The allocated memory is then
360 // treated as referring to an oopDesc. For that to be valid, the oopDesc
361 // class must have a trivial default constructor (C++14 3.8/1).
362 static_assert(std::is_trivially_default_constructible<oopDesc>::value, "required");
363
364 #endif // SHARE_OOPS_OOP_HPP
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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 void* base_addr();
68 inline const void* base_addr() const;
69
70 inline markWord mark() const;
71 inline markWord mark_acquire() const;
72
73 inline void set_mark(markWord m);
74 static inline void set_mark(HeapWord* mem, markWord m);
75 inline void set_mark_full(markWord m);
76 static inline void release_set_mark(HeapWord* mem, markWord m);
77
78 inline void release_set_mark(markWord m);
79 inline markWord cas_set_mark(markWord new_mark, markWord old_mark);
80 inline markWord cas_set_mark(markWord new_mark, markWord old_mark, atomic_memory_order order);
81
82 // Returns the prototype mark that should be used for this object.
83 inline markWord prototype_mark() const;
84
85 // Used only to re-initialize the mark word (e.g., of promoted
86 // objects during a GC) -- requires a valid klass pointer
87 inline void init_mark();
88
89 inline Klass* klass() const;
90 inline Klass* klass_or_null() const;
91 inline Klass* klass_or_null_acquire() const;
92 // Get the klass without running any asserts.
93 inline Klass* klass_without_asserts() const;
94
95 void set_narrow_klass(narrowKlass nk) NOT_CDS_JAVA_HEAP_RETURN;
98 static inline void release_set_klass(HeapWord* mem, Klass* k);
99
100 // For klass field compression
101 static inline void set_klass_gap(HeapWord* mem, int z);
102
103 // Size of object header, aligned to platform wordSize
104 static int header_size() {
105 if (UseCompactObjectHeaders) {
106 return sizeof(markWord) / HeapWordSize;
107 } else {
108 return sizeof(oopDesc) / HeapWordSize;
109 }
110 }
111
112 // Returns whether this is an instance of k or an instance of a subclass of k
113 inline bool is_a(Klass* k) const;
114
115 // Returns the actual oop size of the object in machine words
116 inline size_t size();
117
118 // Returns the size that a copy of this object requires, in machine words.
119 // It can be 1 word larger than its current size to accomodate
120 // an additional 4-byte-field for the identity hash-code.
121 //
122 // size: the current size of this object, we're passing this here for performance
123 // reasons, because all callers compute this anyway, and we want to avoid
124 // recomputing it.
125 // mark: the mark-word of this object. Some callers (e.g. G1ParScanThreadState::do_copy_to_survivor_space())
126 // need to use a known markWord because of racing GC threads that can change
127 // the markWord at any time.
128 inline size_t copy_size(size_t size, markWord mark) const;
129 // Special version to deal with scratch classes in CDS. There we allocate
130 // temporary scratch classes (which are skeleton versions of InstanceMirrorKlass,
131 // which represent java.lang.Class objects in the CDS archive). At that point, we
132 // don't know whether or not the final archived version will be hashed or expanded,
133 // and therefore we allocate them in the special state not-hashed-but-expanded.
134 // When creating the final copy of those objects, we either populate the hidden hash
135 // field and make the object 'expanded', or we turn it back to 'not-hashed'
136 // and reduce the object's size. We do this by providing a separate method for CDS
137 // so that we don't affect GC performance.
138 inline size_t copy_size_cds(size_t size, markWord mark) const;
139
140 // Sometimes (for complicated concurrency-related reasons), it is useful
141 // to be able to figure out the size of an object knowing its klass.
142 inline size_t base_size_given_klass(markWord m, const Klass* klass);
143 inline size_t size_given_mark_and_klass(markWord mrk, const Klass* kls);
144
145 // Returns the size of a forwarded object in its original (source) space.
146 // Only valid for scavenge-style forwarding (oopDesc::forward_to(/_atomic)).
147 inline size_t size_forwarded();
148
149 // type test operations (inlined in oop.inline.hpp)
150 inline bool is_instance() const;
151 inline bool is_instanceRef() const;
152 inline bool is_stackChunk() const;
153 inline bool is_array() const;
154 inline bool is_objArray() const;
155 inline bool is_typeArray() const;
156
157 // type test operations that don't require inclusion of oop.inline.hpp.
158 bool is_instance_noinline() const;
159 bool is_instanceRef_noinline() const;
160 bool is_stackChunk_noinline() const;
161 bool is_array_noinline() const;
162 bool is_objArray_noinline() const;
163 bool is_typeArray_noinline() const;
164
165 protected:
166 inline oop as_oop() const { return const_cast<oopDesc*>(this); }
167
295 inline bool is_gc_marked() const;
296
297 // Forward pointer operations for scavenge
298 inline bool is_forwarded() const;
299 inline bool is_self_forwarded() const;
300
301 inline void forward_to(oop p);
302 inline void forward_to_self();
303
304 // Like "forward_to", but inserts the forwarding pointer atomically.
305 // Exactly one thread succeeds in inserting the forwarding pointer, and
306 // this call returns null for that thread; any other thread has the
307 // value of the forwarding pointer returned and does not modify "this".
308 inline oop forward_to_atomic(oop p, markWord compare, atomic_memory_order order = memory_order_conservative);
309 inline oop forward_to_self_atomic(markWord compare, atomic_memory_order order = memory_order_conservative);
310
311 inline oop forwardee() const;
312 inline oop forwardee(markWord header) const;
313
314 inline void unset_self_forwarded();
315 inline void reset_forwarded();
316
317 // Age of object during scavenge
318 inline uint age() const;
319 inline void incr_age();
320
321 template <typename OopClosureType>
322 inline void oop_iterate(OopClosureType* cl);
323
324 template <typename OopClosureType>
325 inline void oop_iterate(OopClosureType* cl, MemRegion mr);
326
327 template <typename OopClosureType>
328 inline size_t oop_iterate_size(OopClosureType* cl);
329
330 template <typename OopClosureType>
331 inline size_t oop_iterate_size(OopClosureType* cl, MemRegion mr);
332
333 template <typename OopClosureType>
334 inline void oop_iterate_backwards(OopClosureType* cl);
335
336 template <typename OopClosureType>
337 inline void oop_iterate_backwards(OopClosureType* cl, Klass* klass);
338
339 inline static bool is_instanceof_or_null(oop obj, Klass* klass);
340
341 // identity hash; returns the identity hash key (computes it if necessary)
342 inline intptr_t identity_hash();
343 intptr_t slow_identity_hash();
344 inline bool fast_no_hash_check();
345
346 // Initialize identity hash code in hash word of object copy from original object.
347 // Returns true if the object has been expanded, false otherwise.
348 inline void initialize_hash_if_necessary(oop obj);
349 // For CDS only.
350 markWord initialize_hash_if_necessary(oop obj, Klass* k, markWord m);
351
352 // marks are forwarded to stack when object is locked
353 inline bool has_displaced_mark() const;
354 inline markWord displaced_mark() const;
355 inline void set_displaced_mark(markWord m);
356
357 // Checks if the mark word needs to be preserved
358 inline bool mark_must_be_preserved() const;
359 inline bool mark_must_be_preserved(markWord m) const;
360
361 inline static bool has_klass_gap() {
362 return ObjLayout::oop_has_klass_gap();
363 }
364
365 // for code generation
366 static int mark_offset_in_bytes() { return (int)offset_of(oopDesc, _mark); }
367 static int klass_offset_in_bytes() {
368 assert(!UseCompactObjectHeaders, "don't use this with compact headers");
369 return (int)offset_of(oopDesc, _metadata._klass);
370 }
371 static int klass_gap_offset_in_bytes() {
372 assert(has_klass_gap(), "only applicable to compressed klass pointers");
373 if (UseCompactObjectHeaders) {
374 return base_offset_in_bytes();
375 } else {
376 return klass_offset_in_bytes() + sizeof(narrowKlass);
377 }
378 }
379
380 static int base_offset_in_bytes() {
381 return ObjLayout::oop_base_offset_in_bytes();
382 }
383
384 // for error reporting
385 static void* load_oop_raw(oop obj, int offset);
386 };
387
388 // An oopDesc is not initialized via a constructor. Space is allocated in
389 // the Java heap, and static functions provided here on HeapWord* are used
390 // to fill in certain parts of that memory. The allocated memory is then
391 // treated as referring to an oopDesc. For that to be valid, the oopDesc
392 // class must have a trivial default constructor (C++14 3.8/1).
393 static_assert(std::is_trivially_default_constructible<oopDesc>::value, "required");
394
395 #endif // SHARE_OOPS_OOP_HPP
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