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src/hotspot/share/oops/oop.hpp

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 40 //
 41 // no virtual functions allowed
 42 
 43 // Forward declarations.
 44 class OopClosure;
 45 class FilteringClosure;
 46 
 47 class PSPromotionManager;
 48 class ParCompactionManager;
 49 
 50 class oopDesc {
 51   friend class VMStructs;
 52   friend class JVMCIVMStructs;
 53  private:
 54   volatile markWord _mark;
 55   union _metadata {
 56     Klass*      _klass;
 57     narrowKlass _compressed_klass;
 58   } _metadata;
 59 
 60  public:
 61   inline markWord  mark()          const;

 62   inline markWord* mark_addr() const;
 63 
 64   inline void set_mark(markWord m);
 65   static inline void set_mark(HeapWord* mem, markWord m);
 66 
 67   inline void release_set_mark(markWord m);

 68   inline markWord cas_set_mark(markWord new_mark, markWord old_mark);
 69   inline markWord cas_set_mark(markWord new_mark, markWord old_mark, atomic_memory_order order);
 70 


 71   // Used only to re-initialize the mark word (e.g., of promoted
 72   // objects during a GC) -- requires a valid klass pointer
 73   inline void init_mark();
 74 
 75   inline Klass* klass() const;
 76   inline Klass* klass_or_null() const;
 77   inline Klass* klass_or_null_acquire() const;
 78 
 79   void set_narrow_klass(narrowKlass nk) NOT_CDS_JAVA_HEAP_RETURN;
 80   inline void set_klass(Klass* k);
 81   static inline void release_set_klass(HeapWord* mem, Klass* k);
 82 
 83   // For klass field compression
 84   inline int klass_gap() const;
 85   inline void set_klass_gap(int z);
 86   static inline void set_klass_gap(HeapWord* mem, int z);
 87 
 88   // size of object header, aligned to platform wordSize
 89   static int header_size() { return sizeof(oopDesc)/HeapWordSize; }







 90 
 91   // Returns whether this is an instance of k or an instance of a subclass of k
 92   inline bool is_a(Klass* k) const;
 93 
 94   // Returns the actual oop size of the object
 95   inline int size();
 96 
 97   // Sometimes (for complicated concurrency-related reasons), it is useful
 98   // to be able to figure out the size of an object knowing its klass.
 99   inline int size_given_klass(Klass* klass);
100 
101   // type test operations (inlined in oop.inline.hpp)
102   inline bool is_instance()            const;
103   inline bool is_array()               const;
104   inline bool is_objArray()            const;
105   inline bool is_typeArray()           const;
106 
107   // type test operations that don't require inclusion of oop.inline.hpp.
108   bool is_instance_noinline()          const;
109   bool is_array_noinline()             const;

232 
233   // locking operations
234   inline bool is_locked()   const;
235   inline bool is_unlocked() const;
236   inline bool has_bias_pattern() const;
237 
238   // asserts and guarantees
239   static bool is_oop(oop obj, bool ignore_mark_word = false);
240   static bool is_oop_or_null(oop obj, bool ignore_mark_word = false);
241 
242   // garbage collection
243   inline bool is_gc_marked() const;
244 
245   // Forward pointer operations for scavenge
246   inline bool is_forwarded() const;
247 
248   void verify_forwardee(oop forwardee) NOT_DEBUG_RETURN;
249 
250   inline void forward_to(oop p);
251   inline bool cas_forward_to(oop p, markWord compare, atomic_memory_order order = memory_order_conservative);

252 
253   // Like "forward_to", but inserts the forwarding pointer atomically.
254   // Exactly one thread succeeds in inserting the forwarding pointer, and
255   // this call returns "NULL" for that thread; any other thread has the
256   // value of the forwarding pointer returned and does not modify "this".
257   inline oop forward_to_atomic(oop p, markWord compare, atomic_memory_order order = memory_order_conservative);

258 
259   inline oop forwardee() const;

260 
261   // Age of object during scavenge
262   inline uint age() const;
263   inline void incr_age();
264 
265   template <typename OopClosureType>
266   inline void oop_iterate(OopClosureType* cl);
267 
268   template <typename OopClosureType>
269   inline void oop_iterate(OopClosureType* cl, MemRegion mr);
270 
271   template <typename OopClosureType>
272   inline int oop_iterate_size(OopClosureType* cl);
273 
274   template <typename OopClosureType>
275   inline int oop_iterate_size(OopClosureType* cl, MemRegion mr);
276 
277   template <typename OopClosureType>
278   inline void oop_iterate_backwards(OopClosureType* cl);
279 

285   // identity hash; returns the identity hash key (computes it if necessary)
286   // NOTE with the introduction of UseBiasedLocking that identity_hash() might reach a
287   // safepoint if called on a biased object. Calling code must be aware of that.
288   inline intptr_t identity_hash();
289   intptr_t slow_identity_hash();
290 
291   // marks are forwarded to stack when object is locked
292   inline bool     has_displaced_mark() const;
293   inline markWord displaced_mark() const;
294   inline void     set_displaced_mark(markWord m);
295 
296   // Checks if the mark word needs to be preserved
297   inline bool mark_must_be_preserved() const;
298   inline bool mark_must_be_preserved(markWord m) const;
299   inline bool mark_must_be_preserved_for_promotion_failure(markWord m) const;
300 
301   static bool has_klass_gap();
302 
303   // for code generation
304   static int mark_offset_in_bytes()      { return offset_of(oopDesc, _mark); }
305   static int klass_offset_in_bytes()     { return offset_of(oopDesc, _metadata._klass); }
306   static int klass_gap_offset_in_bytes() {
307     assert(has_klass_gap(), "only applicable to compressed klass pointers");

308     return klass_offset_in_bytes() + sizeof(narrowKlass);
309   }
310 
























311   // for error reporting
312   static void* load_klass_raw(oop obj);
313   static void* load_oop_raw(oop obj, int offset);
314 
315   // Avoid include gc_globals.hpp in oop.inline.hpp
316   DEBUG_ONLY(bool get_UseParallelGC();)
317   DEBUG_ONLY(bool get_UseG1GC();)
318 };
319 
320 #endif // SHARE_OOPS_OOP_HPP

 40 //
 41 // no virtual functions allowed
 42 
 43 // Forward declarations.
 44 class OopClosure;
 45 class FilteringClosure;
 46 
 47 class PSPromotionManager;
 48 class ParCompactionManager;
 49 
 50 class oopDesc {
 51   friend class VMStructs;
 52   friend class JVMCIVMStructs;
 53  private:
 54   volatile markWord _mark;
 55   union _metadata {
 56     Klass*      _klass;
 57     narrowKlass _compressed_klass;
 58   } _metadata;
 59 
 60 public:
 61   inline markWord  mark()          const;
 62   inline markWord  mark_acquire()  const;
 63   inline markWord* mark_addr() const;
 64 
 65   inline void set_mark(markWord m);
 66   static inline void set_mark(HeapWord* mem, markWord m);
 67 
 68   inline void release_set_mark(markWord m);
 69   static inline void release_set_mark(HeapWord* mem, markWord m);
 70   inline markWord cas_set_mark(markWord new_mark, markWord old_mark);
 71   inline markWord cas_set_mark(markWord new_mark, markWord old_mark, atomic_memory_order order);
 72 
 73   inline markWord resolve_mark() const;
 74 
 75   // Used only to re-initialize the mark word (e.g., of promoted
 76   // objects during a GC) -- requires a valid klass pointer
 77   inline void init_mark();
 78 
 79   inline Klass* klass() const;
 80   inline Klass* klass_or_null() const;
 81   inline Klass* klass_or_null_acquire() const;
 82 
 83   void set_narrow_klass(narrowKlass nk) NOT_CDS_JAVA_HEAP_RETURN;
 84   inline void set_klass(Klass* k);
 85   static inline void release_set_klass(HeapWord* mem, Klass* k);
 86 
 87   // For klass field compression


 88   static inline void set_klass_gap(HeapWord* mem, int z);
 89 
 90   // size of object header, aligned to platform wordSize
 91   static int header_size() {
 92 #ifdef _LP64
 93     if (UseCompactObjectHeaders) {
 94       return sizeof(markWord) / HeapWordSize;
 95     } else
 96 #endif
 97     return sizeof(oopDesc)/HeapWordSize;
 98   }
 99 
100   // Returns whether this is an instance of k or an instance of a subclass of k
101   inline bool is_a(Klass* k) const;
102 
103   // Returns the actual oop size of the object
104   inline int size();
105 
106   // Sometimes (for complicated concurrency-related reasons), it is useful
107   // to be able to figure out the size of an object knowing its klass.
108   inline int size_given_klass(Klass* klass);
109 
110   // type test operations (inlined in oop.inline.hpp)
111   inline bool is_instance()            const;
112   inline bool is_array()               const;
113   inline bool is_objArray()            const;
114   inline bool is_typeArray()           const;
115 
116   // type test operations that don't require inclusion of oop.inline.hpp.
117   bool is_instance_noinline()          const;
118   bool is_array_noinline()             const;

241 
242   // locking operations
243   inline bool is_locked()   const;
244   inline bool is_unlocked() const;
245   inline bool has_bias_pattern() const;
246 
247   // asserts and guarantees
248   static bool is_oop(oop obj, bool ignore_mark_word = false);
249   static bool is_oop_or_null(oop obj, bool ignore_mark_word = false);
250 
251   // garbage collection
252   inline bool is_gc_marked() const;
253 
254   // Forward pointer operations for scavenge
255   inline bool is_forwarded() const;
256 
257   void verify_forwardee(oop forwardee) NOT_DEBUG_RETURN;
258 
259   inline void forward_to(oop p);
260   inline bool cas_forward_to(oop p, markWord compare, atomic_memory_order order = memory_order_conservative);
261   inline void forward_to_self();
262 
263   // Like "forward_to", but inserts the forwarding pointer atomically.
264   // Exactly one thread succeeds in inserting the forwarding pointer, and
265   // this call returns "NULL" for that thread; any other thread has the
266   // value of the forwarding pointer returned and does not modify "this".
267   inline oop forward_to_atomic(oop p, markWord compare, atomic_memory_order order = memory_order_conservative);
268   inline oop forward_to_self_atomic(markWord compare, atomic_memory_order order = memory_order_conservative);
269 
270   inline oop forwardee() const;
271   inline oop forwardee(markWord header) const;
272 
273   // Age of object during scavenge
274   inline uint age() const;
275   inline void incr_age();
276 
277   template <typename OopClosureType>
278   inline void oop_iterate(OopClosureType* cl);
279 
280   template <typename OopClosureType>
281   inline void oop_iterate(OopClosureType* cl, MemRegion mr);
282 
283   template <typename OopClosureType>
284   inline int oop_iterate_size(OopClosureType* cl);
285 
286   template <typename OopClosureType>
287   inline int oop_iterate_size(OopClosureType* cl, MemRegion mr);
288 
289   template <typename OopClosureType>
290   inline void oop_iterate_backwards(OopClosureType* cl);
291 

297   // identity hash; returns the identity hash key (computes it if necessary)
298   // NOTE with the introduction of UseBiasedLocking that identity_hash() might reach a
299   // safepoint if called on a biased object. Calling code must be aware of that.
300   inline intptr_t identity_hash();
301   intptr_t slow_identity_hash();
302 
303   // marks are forwarded to stack when object is locked
304   inline bool     has_displaced_mark() const;
305   inline markWord displaced_mark() const;
306   inline void     set_displaced_mark(markWord m);
307 
308   // Checks if the mark word needs to be preserved
309   inline bool mark_must_be_preserved() const;
310   inline bool mark_must_be_preserved(markWord m) const;
311   inline bool mark_must_be_preserved_for_promotion_failure(markWord m) const;
312 
313   static bool has_klass_gap();
314 
315   // for code generation
316   static int mark_offset_in_bytes()      { return offset_of(oopDesc, _mark); }

317   static int klass_gap_offset_in_bytes() {
318     assert(has_klass_gap(), "only applicable to compressed klass pointers");
319     assert(!UseCompactObjectHeaders, "don't use klass_offset_in_bytes() with compact headers");
320     return klass_offset_in_bytes() + sizeof(narrowKlass);
321   }
322 
323   static int klass_offset_in_bytes()     {
324 #ifdef _LP64
325     if (UseCompactObjectHeaders) {
326       STATIC_ASSERT(markWord::klass_shift % 8 == 0);
327       return mark_offset_in_bytes() + markWord::klass_shift / 8;
328     } else
329 #endif
330     return offset_of(oopDesc, _metadata._klass);
331   }
332 
333   static int base_offset_in_bytes() {
334 #ifdef _LP64
335     if (UseCompactObjectHeaders) {
336       // With compact headers, the Klass* field is not used for the Klass*
337       // and is used for the object fields instead.
338       assert(sizeof(markWord) == 8, "sanity");
339       return sizeof(markWord);
340     } else if (UseCompressedClassPointers) {
341       return sizeof(markWord) + sizeof(narrowKlass);
342     } else
343 #endif
344     return sizeof(oopDesc);
345   }
346 
347   // for error reporting
348   static void* load_klass_raw(oop obj);
349   static void* load_oop_raw(oop obj, int offset);
350 
351   // Avoid include gc_globals.hpp in oop.inline.hpp
352   DEBUG_ONLY(bool get_UseParallelGC();)
353   DEBUG_ONLY(bool get_UseG1GC();)
354 };
355 
356 #endif // SHARE_OOPS_OOP_HPP
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