11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #ifndef SHARE_OOPS_OOP_HPP
26 #define SHARE_OOPS_OOP_HPP
27
28 #include "memory/iterator.hpp"
29 #include "memory/memRegion.hpp"
30 #include "oops/accessDecorators.hpp"
31 #include "oops/markWord.hpp"
32 #include "oops/metadata.hpp"
33 #include "runtime/atomic.hpp"
34 #include "utilities/globalDefinitions.hpp"
35 #include "utilities/macros.hpp"
36 #include <type_traits>
37
38 // oopDesc is the top baseclass for objects classes. The {name}Desc classes describe
39 // the format of Java objects so the fields can be accessed from C++.
40 // oopDesc is abstract.
41 // (see oopHierarchy for complete oop class hierarchy)
42 //
43 // no virtual functions allowed
44
45 // Forward declarations.
46 class OopClosure;
47 class FilteringClosure;
48
49 class PSPromotionManager;
50 class ParCompactionManager;
51
52 class oopDesc {
53 friend class VMStructs;
54 friend class JVMCIVMStructs;
55 private:
56 volatile markWord _mark;
57 union _metadata {
58 Klass* _klass;
59 narrowKlass _compressed_klass;
60 } _metadata;
61
62 // There may be ordering constraints on the initialization of fields that
63 // make use of the C++ copy/assign incorrect.
64 NONCOPYABLE(oopDesc);
65
66 public:
67 // Must be trivial; see verifying static assert after the class.
68 oopDesc() = default;
69
70 inline markWord mark() const;
71 inline markWord mark_acquire() const;
72 inline markWord* mark_addr() const;
73
74 inline void set_mark(markWord m);
75 static inline void 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 // Used only to re-initialize the mark word (e.g., of promoted
82 // objects during a GC) -- requires a valid klass pointer
83 inline void init_mark();
84
85 inline Klass* klass() const;
86 inline Klass* klass_or_null() const;
87 inline Klass* klass_or_null_acquire() const;
88
89 void set_narrow_klass(narrowKlass nk) NOT_CDS_JAVA_HEAP_RETURN;
90 inline void set_klass(Klass* k);
91 static inline void release_set_klass(HeapWord* mem, Klass* k);
92
93 // For klass field compression
94 static inline void set_klass_gap(HeapWord* mem, int z);
95
96 // size of object header, aligned to platform wordSize
97 static constexpr int header_size() { return sizeof(oopDesc)/HeapWordSize; }
98
99 // Returns whether this is an instance of k or an instance of a subclass of k
100 inline bool is_a(Klass* k) const;
101
102 // Returns the actual oop size of the object in machine words
103 inline size_t size();
104
105 // Sometimes (for complicated concurrency-related reasons), it is useful
106 // to be able to figure out the size of an object knowing its klass.
107 inline size_t size_given_klass(Klass* klass);
108
109 // type test operations (inlined in oop.inline.hpp)
110 inline bool is_instance() const;
111 inline bool is_instanceRef() const;
112 inline bool is_stackChunk() const;
113 inline bool is_array() const;
114 inline bool is_objArray() const;
240 static void verify_on(outputStream* st, oopDesc* oop_desc);
241 static void verify(oopDesc* oopDesc);
242
243 // locking operations
244 inline bool is_locked() const;
245 inline bool is_unlocked() 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
261 // Like "forward_to", but inserts the forwarding pointer atomically.
262 // Exactly one thread succeeds in inserting the forwarding pointer, and
263 // this call returns "NULL" for that thread; any other thread has the
264 // value of the forwarding pointer returned and does not modify "this".
265 inline oop forward_to_atomic(oop p, markWord compare, atomic_memory_order order = memory_order_conservative);
266
267 inline oop forwardee() const;
268
269 // Age of object during scavenge
270 inline uint age() const;
271 inline void incr_age();
272
273 template <typename OopClosureType>
274 inline void oop_iterate(OopClosureType* cl);
275
276 template <typename OopClosureType>
277 inline void oop_iterate(OopClosureType* cl, MemRegion mr);
278
279 template <typename OopClosureType>
280 inline size_t oop_iterate_size(OopClosureType* cl);
281
282 template <typename OopClosureType>
283 inline size_t oop_iterate_size(OopClosureType* cl, MemRegion mr);
284
285 template <typename OopClosureType>
286 inline void oop_iterate_backwards(OopClosureType* cl);
287
288 template <typename OopClosureType>
289 inline void oop_iterate_backwards(OopClosureType* cl, Klass* klass);
290
291 inline static bool is_instanceof_or_null(oop obj, Klass* klass);
292
293 // identity hash; returns the identity hash key (computes it if necessary)
294 inline intptr_t identity_hash();
295 intptr_t slow_identity_hash();
296
297 // marks are forwarded to stack when object is locked
298 inline bool has_displaced_mark() const;
299 inline markWord displaced_mark() const;
300 inline void set_displaced_mark(markWord m);
301
302 // Checks if the mark word needs to be preserved
303 inline bool mark_must_be_preserved() const;
304 inline bool mark_must_be_preserved(markWord m) const;
305
306 static bool has_klass_gap();
307
308 // for code generation
309 static int mark_offset_in_bytes() { return offset_of(oopDesc, _mark); }
310 static int klass_offset_in_bytes() { return offset_of(oopDesc, _metadata._klass); }
311 static int klass_gap_offset_in_bytes() {
312 assert(has_klass_gap(), "only applicable to compressed klass pointers");
313 return klass_offset_in_bytes() + sizeof(narrowKlass);
314 }
315
316 // for error reporting
317 static void* load_klass_raw(oop obj);
318 static void* load_oop_raw(oop obj, int offset);
319
320 DEBUG_ONLY(bool size_might_change();)
321 };
322
323 // An oopDesc is not initialized via a constructor. Space is allocated in
324 // the Java heap, and static functions provided here on HeapWord* are used
325 // to fill in certain parts of that memory. The allocated memory is then
326 // treated as referring to an oopDesc. For that to be valid, the oopDesc
327 // class must have a trivial default constructor (C++14 3.8/1).
328 static_assert(std::is_trivially_default_constructible<oopDesc>::value, "required");
329
330 #endif // SHARE_OOPS_OOP_HPP
|
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #ifndef SHARE_OOPS_OOP_HPP
26 #define SHARE_OOPS_OOP_HPP
27
28 #include "memory/iterator.hpp"
29 #include "memory/memRegion.hpp"
30 #include "oops/accessDecorators.hpp"
31 #include "oops/compressedKlass.hpp"
32 #include "oops/markWord.hpp"
33 #include "oops/metadata.hpp"
34 #include "runtime/atomic.hpp"
35 #include "utilities/globalDefinitions.hpp"
36 #include "utilities/macros.hpp"
37 #include <type_traits>
38
39 // oopDesc is the top baseclass for objects classes. The {name}Desc classes describe
40 // the format of Java objects so the fields can be accessed from C++.
41 // oopDesc is abstract.
42 // (see oopHierarchy for complete oop class hierarchy)
43 //
44 // no virtual functions allowed
45
46 // Forward declarations.
47 class OopClosure;
48 class FilteringClosure;
49
50 class PSPromotionManager;
51 class ParCompactionManager;
52
53 class oopDesc {
54 friend class VMStructs;
55 friend class JVMCIVMStructs;
56 private:
57 volatile markWord _mark;
58 #ifndef _LP64
59 Klass* _klass;
60 #endif
61
62 // There may be ordering constraints on the initialization of fields that
63 // make use of the C++ copy/assign incorrect.
64 NONCOPYABLE(oopDesc);
65
66 public:
67 // Must be trivial; see verifying static assert after the class.
68 oopDesc() = default;
69
70 inline markWord mark() const;
71 inline markWord mark_acquire() const;
72 inline markWord* mark_addr() const;
73
74 inline void set_mark(markWord m);
75 static inline void set_mark(HeapWord* mem, markWord m);
76
77 inline void release_set_mark(markWord m);
78 static inline void release_set_mark(HeapWord* mem, 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 // 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
90 #ifndef _LP64
91 inline void set_klass(Klass* k);
92 static inline void release_set_klass(HeapWord* mem, Klass* k);
93 #endif
94
95 // size of object header, aligned to platform wordSize
96 static constexpr int header_size() { return sizeof(oopDesc)/HeapWordSize; }
97
98 // Returns whether this is an instance of k or an instance of a subclass of k
99 inline bool is_a(Klass* k) const;
100
101 // Returns the actual oop size of the object in machine words
102 inline size_t size();
103
104 // Sometimes (for complicated concurrency-related reasons), it is useful
105 // to be able to figure out the size of an object knowing its klass.
106 inline size_t size_given_klass(Klass* klass);
107
108 // type test operations (inlined in oop.inline.hpp)
109 inline bool is_instance() const;
110 inline bool is_instanceRef() const;
111 inline bool is_stackChunk() const;
112 inline bool is_array() const;
113 inline bool is_objArray() const;
239 static void verify_on(outputStream* st, oopDesc* oop_desc);
240 static void verify(oopDesc* oopDesc);
241
242 // locking operations
243 inline bool is_locked() const;
244 inline bool is_unlocked() const;
245
246 // asserts and guarantees
247 static bool is_oop(oop obj, bool ignore_mark_word = false);
248 static bool is_oop_or_null(oop obj, bool ignore_mark_word = false);
249
250 // garbage collection
251 inline bool is_gc_marked() const;
252
253 // Forward pointer operations for scavenge
254 inline bool is_forwarded() const;
255
256 void verify_forwardee(oop forwardee) NOT_DEBUG_RETURN;
257
258 inline void forward_to(oop p);
259 inline void forward_to_self();
260
261 // Like "forward_to", but inserts the forwarding pointer atomically.
262 // Exactly one thread succeeds in inserting the forwarding pointer, and
263 // this call returns "NULL" for that thread; any other thread has the
264 // value of the forwarding pointer returned and does not modify "this".
265 inline oop forward_to_atomic(oop p, markWord compare, atomic_memory_order order = memory_order_conservative);
266 inline oop forward_to_self_atomic(markWord compare, atomic_memory_order order = memory_order_conservative);
267
268 inline oop forwardee() const;
269 inline oop forwardee(markWord header) const;
270
271 // Age of object during scavenge
272 inline uint age() const;
273 inline void incr_age();
274
275 template <typename OopClosureType>
276 inline void oop_iterate(OopClosureType* cl);
277
278 template <typename OopClosureType>
279 inline void oop_iterate(OopClosureType* cl, MemRegion mr);
280
281 template <typename OopClosureType>
282 inline size_t oop_iterate_size(OopClosureType* cl);
283
284 template <typename OopClosureType>
285 inline size_t oop_iterate_size(OopClosureType* cl, MemRegion mr);
286
287 template <typename OopClosureType>
288 inline void oop_iterate_backwards(OopClosureType* cl);
289
290 template <typename OopClosureType>
291 inline void oop_iterate_backwards(OopClosureType* cl, Klass* klass);
292
293 inline static bool is_instanceof_or_null(oop obj, Klass* klass);
294
295 // identity hash; returns the identity hash key (computes it if necessary)
296 inline intptr_t identity_hash();
297 intptr_t slow_identity_hash();
298
299 // marks are forwarded to stack when object is locked
300 inline bool has_displaced_mark() const;
301 inline markWord displaced_mark() const;
302 inline void set_displaced_mark(markWord m);
303
304 // Checks if the mark word needs to be preserved
305 inline bool mark_must_be_preserved() const;
306 inline bool mark_must_be_preserved(markWord m) const;
307
308 // for code generation
309 static int mark_offset_in_bytes() { return offset_of(oopDesc, _mark); }
310 static int klass_offset_in_bytes() {
311 #ifdef _LP64
312 STATIC_ASSERT(markWord::klass_shift % 8 == 0);
313 return mark_offset_in_bytes() + markWord::klass_shift / 8;
314 #else
315 return offset_of(oopDesc, _klass);
316 #endif
317 }
318
319 // for error reporting
320 static void* load_klass_raw(oop obj);
321 static void* load_oop_raw(oop obj, int offset);
322
323 // Runtime entry
324 #ifdef _LP64
325 static narrowKlass load_nklass_runtime(oopDesc* o);
326 #endif
327
328 DEBUG_ONLY(bool size_might_change();)
329 };
330
331 // An oopDesc is not initialized via a constructor. Space is allocated in
332 // the Java heap, and static functions provided here on HeapWord* are used
333 // to fill in certain parts of that memory. The allocated memory is then
334 // treated as referring to an oopDesc. For that to be valid, the oopDesc
335 // class must have a trivial default constructor (C++14 3.8/1).
336 static_assert(std::is_trivially_default_constructible<oopDesc>::value, "required");
337
338 #endif // SHARE_OOPS_OOP_HPP
|