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/access.hpp"
31 #include "oops/metadata.hpp"
32 #include "runtime/atomic.hpp"
33 #include "utilities/macros.hpp"
34
35 // oopDesc is the top baseclass for objects classes. The {name}Desc classes describe
36 // the format of Java objects so the fields can be accessed from C++.
37 // oopDesc is abstract.
38 // (see oopHierarchy for complete oop class hierarchy)
39 //
40 // no virtual functions allowed
41
42 extern bool always_do_update_barrier;
43
44 // Forward declarations.
45 class OopClosure;
46 class ScanClosure;
47 class FastScanClosure;
48 class FilteringClosure;
49 class CMSIsAliveClosure;
50
51 class PSPromotionManager;
52 class ParCompactionManager;
53
54 class oopDesc {
55 friend class VMStructs;
56 friend class JVMCIVMStructs;
57 private:
58 volatile markOop _mark;
59 union _metadata {
60 Klass* _klass;
61 narrowKlass _compressed_klass;
62 } _metadata;
63
64 public:
65 inline markOop mark() const;
66 inline markOop mark_raw() const;
67 inline markOop* mark_addr_raw() const;
68
69 inline void set_mark(volatile markOop m);
70 inline void set_mark_raw(volatile markOop m);
71 static inline void set_mark_raw(HeapWord* mem, markOop m);
72
73 inline void release_set_mark(markOop m);
74 inline markOop cas_set_mark(markOop new_mark, markOop old_mark);
75 inline markOop cas_set_mark_raw(markOop new_mark, markOop old_mark, atomic_memory_order order = memory_order_conservative);
76
77 // Used only to re-initialize the mark word (e.g., of promoted
78 // objects during a GC) -- requires a valid klass pointer
79 inline void init_mark();
80 inline void init_mark_raw();
81
82 inline Klass* klass() const;
83 inline Klass* klass_or_null() const volatile;
84 inline Klass* klass_or_null_acquire() const volatile;
85 static inline Klass** klass_addr(HeapWord* mem);
86 static inline narrowKlass* compressed_klass_addr(HeapWord* mem);
87 inline Klass** klass_addr();
88 inline narrowKlass* compressed_klass_addr();
89
90 inline void set_klass(Klass* k);
91 static inline void release_set_klass(HeapWord* mem, Klass* klass);
92
93 // For klass field compression
94 inline int klass_gap() const;
95 inline void set_klass_gap(int z);
96 static inline void set_klass_gap(HeapWord* mem, int z);
97 // For when the klass pointer is being used as a linked list "next" field.
98 inline void set_klass_to_list_ptr(oop k);
99 inline oop list_ptr_from_klass();
100
101 // size of object header, aligned to platform wordSize
102 static int header_size() { return sizeof(oopDesc)/HeapWordSize; }
103
104 // Returns whether this is an instance of k or an instance of a subclass of k
105 inline bool is_a(Klass* k) const;
106
107 // Returns the actual oop size of the object
108 inline int size();
109
110 // Sometimes (for complicated concurrency-related reasons), it is useful
111 // to be able to figure out the size of an object knowing its klass.
|
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/access.hpp"
31 #include "oops/arrayStorageProperties.hpp"
32 #include "oops/metadata.hpp"
33 #include "runtime/atomic.hpp"
34 #include "utilities/macros.hpp"
35
36 // oopDesc is the top baseclass for objects classes. The {name}Desc classes describe
37 // the format of Java objects so the fields can be accessed from C++.
38 // oopDesc is abstract.
39 // (see oopHierarchy for complete oop class hierarchy)
40 //
41 // no virtual functions allowed
42 //
43 // oopDesc::_mark - the "oop mark word" encoding to be found separately in markOop.hpp
44 //
45 // oopDesc::_metadata - encodes both the object's klass pointer and potentially
46 // "storage properties" (currently confined to arrays in the form of
47 // ArrayStorageProperties). Storage properties are peculiar to the
48 // *instance*, and not necessarily the "type".
49 //
50 // The overall size of the _metadata field is dependent on "UseCompressedClassPointers",
51 // hence the terms "narrow" (32 bits) vs "wide" (64 bits).
52 //
53 // "Wide" encoding of _metadata:
54 // bit number |63 0|
55 // bit length |--3|-----61-----|
56 // --------------------------------------
57 // _klass [xxx| Klass* ]
58 // _wide_storage_props [ sp| ]
59 // --------------------------------------
60 // with:
61 // xxx = klass_mask(), Klass* = Klass pointer to be masked
62 // sp = storage properties, bit number: wide_storage_props_shift
63 //
64 // "Narrow" encoding of _metadata:
65 // bit number |31 0|
66 // bit length |--3|-----29-----|
67 // ----------------------------------------
68 // _compressed_klass [xxx| narrowKlass]
69 // _narrow_storage_props [ sp| ]
70 // ----------------------------------------
71 // with:
72 // xxx = compressed_klass_mask(), narrowKlass = compressed Klass pointer to be masked
73 // narrowKlass may be further decoded (Klass::decode_klass()) to produce Klass*
74 // sp = storage properties, bit number: narrow_storage_props_shift
75 //
76 // Storage properties encodings are current confined to arrayStorageProperties.hpp
77
78
79 extern bool always_do_update_barrier;
80
81 // Forward declarations.
82 class OopClosure;
83 class ScanClosure;
84 class FastScanClosure;
85 class FilteringClosure;
86 class CMSIsAliveClosure;
87
88 class PSPromotionManager;
89 class ParCompactionManager;
90
91 class oopDesc {
92 friend class VMStructs;
93 friend class JVMCIVMStructs;
94 private:
95 volatile markOop _mark;
96 union _metadata {
97 Klass* _klass;
98 narrowKlass _compressed_klass;
99 uintptr_t _wide_storage_props;
100 uint32_t _narrow_storage_props;
101 } _metadata;
102
103 public:
104 inline markOop mark() const;
105 inline markOop mark_raw() const;
106 inline markOop* mark_addr_raw() const;
107
108 inline void set_mark(volatile markOop m);
109 inline void set_mark_raw(volatile markOop m);
110 static inline void set_mark_raw(HeapWord* mem, markOop m);
111
112 inline void release_set_mark(markOop m);
113 inline markOop cas_set_mark(markOop new_mark, markOop old_mark);
114 inline markOop cas_set_mark_raw(markOop new_mark, markOop old_mark, atomic_memory_order order = memory_order_conservative);
115
116 // Used only to re-initialize the mark word (e.g., of promoted
117 // objects during a GC) -- requires a valid klass pointer
118 inline void init_mark();
119 inline void init_mark_raw();
120
121 enum {
122 storage_props_nof_bits = LogKlassAlignmentInBytes, // This alignment gives us some "free bits"
123 narrow_storage_props_shift = (sizeof(narrowKlass) << 3) - storage_props_nof_bits,
124 wide_storage_props_shift = (sizeof(Klass*) << 3) - storage_props_nof_bits,
125 };
126
127 static inline narrowKlass compressed_klass_mask();
128 static inline narrowKlass compressed_klass_masked(narrowKlass raw);
129 static inline uintptr_t klass_mask();
130 static inline Klass* klass_masked(uintptr_t raw);
131
132 inline Klass* klass() const;
133 inline Klass* klass_or_null() const volatile;
134 inline Klass* klass_or_null_acquire() const volatile;
135 static inline Klass** klass_addr(HeapWord* mem);
136 static inline narrowKlass* compressed_klass_addr(HeapWord* mem);
137 inline Klass** klass_addr();
138 inline narrowKlass* compressed_klass_addr();
139
140 inline void set_klass(Klass* k);
141 static inline void release_set_klass(HeapWord* mem, Klass* klass);
142
143 // Extra container metadata specific to arrays (encoded into high bits of _metadata)
144 static inline uintptr_t* wide_metadata_addr(HeapWord* mem);
145 inline ArrayStorageProperties array_storage_properties() const;
146 inline void set_metadata(ArrayStorageProperties storage_props, Klass* k);
147 static inline void release_set_metadata(HeapWord* mem, ArrayStorageProperties storage_props, Klass* klass);
148
149
150 // For klass field compression
151 inline int klass_gap() const;
152 inline void set_klass_gap(int z);
153 static inline void set_klass_gap(HeapWord* mem, int z);
154 // For when the klass pointer is being used as a linked list "next" field.
155 inline void set_klass_to_list_ptr(oop k);
156 inline oop list_ptr_from_klass();
157
158 // size of object header, aligned to platform wordSize
159 static int header_size() { return sizeof(oopDesc)/HeapWordSize; }
160
161 // Returns whether this is an instance of k or an instance of a subclass of k
162 inline bool is_a(Klass* k) const;
163
164 // Returns the actual oop size of the object
165 inline int size();
166
167 // Sometimes (for complicated concurrency-related reasons), it is useful
168 // to be able to figure out the size of an object knowing its klass.
|