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src/hotspot/share/runtime/basicLock.hpp

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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_RUNTIME_BASICLOCK_HPP
26 #define SHARE_RUNTIME_BASICLOCK_HPP
27 
28 #include "oops/markWord.hpp"
29 #include "runtime/atomic.hpp"
30 #include "runtime/handles.hpp"
31 
32 class BasicLock {
33   friend class VMStructs;
34   friend class JVMCIVMStructs;
35  private:
36   volatile markWord _displaced_header;
37  public:
38   markWord displaced_header() const {
39     return Atomic::load(&_displaced_header);
40   }
41 
42   void set_displaced_header(markWord header) {
43     Atomic::store(&_displaced_header, header);
44   }
45 
46   void print_on(outputStream* st, oop owner) const;
47 
48   // move a basic lock (used during deoptimization
49   void move_to(oop obj, BasicLock* dest);
50 
51   static int displaced_header_offset_in_bytes()       { return offset_of(BasicLock, _displaced_header); }
52 };
53 
54 // A BasicObjectLock associates a specific Java object with a BasicLock.
55 // It is currently embedded in an interpreter frame.
56 
57 // Because some machines have alignment restrictions on the control stack,
58 // the actual space allocated by the interpreter may include padding words
59 // after the end of the BasicObjectLock.  Also, in order to guarantee
60 // alignment of the embedded BasicLock objects on such machines, we
61 // put the embedded BasicLock at the beginning of the struct.
62 
63 class BasicObjectLock {
64   friend class VMStructs;
65  private:
66   BasicLock _lock;                                    // the lock, must be double word aligned
67   oop       _obj;                                     // object holds the lock;





68 
69  public:
70   // Manipulation
71   oop      obj() const                                { return _obj;  }
72   void set_obj(oop obj)                               { _obj = obj; }
73   BasicLock* lock()                                   { return &_lock; }
74 
75   // Note: Use frame::interpreter_frame_monitor_size() for the size of BasicObjectLocks
76   //       in interpreter activation frames since it includes machine-specific padding.
77   static int size()                                   { return sizeof(BasicObjectLock)/wordSize; }
78 
79   // GC support
80   void oops_do(OopClosure* f) { f->do_oop(&_obj); }
81 
82   static int obj_offset_in_bytes()                    { return offset_of(BasicObjectLock, _obj);  }
83   static int lock_offset_in_bytes()                   { return offset_of(BasicObjectLock, _lock); }
84 };
85 
86 
87 #endif // SHARE_RUNTIME_BASICLOCK_HPP

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_RUNTIME_BASICLOCK_HPP
26 #define SHARE_RUNTIME_BASICLOCK_HPP
27 
28 #include "oops/markWord.hpp"
29 #include "runtime/atomic.hpp"
30 #include "runtime/handles.hpp"
31 
32 // A BasicObjectLock represents a locked object.






















33 // It is currently embedded in an interpreter frame.
34 
35 // Because some machines have alignment restrictions on the control stack,
36 // the actual space allocated by the interpreter may include padding words
37 // after the end of the BasicObjectLock.


38 
39 class BasicObjectLock {
40   friend class VMStructs;
41  private:

42   oop       _obj;                                     // object holds the lock;
43 #if defined(AARCH64) || defined(RISCV64)
44   // Stack needs to be 16-byte-aligned. Inserting a dummy field here is
45   // the simplest way to achieve that.
46   intptr_t _dummy;
47 #endif
48 
49  public:
50   // Manipulation
51   oop      obj() const                                { return _obj;  }
52   void set_obj(oop obj)                               { _obj = obj; }

53 
54   // Note: Use frame::interpreter_frame_monitor_size() for the size of BasicObjectLocks
55   //       in interpreter activation frames since it includes machine-specific padding.
56   static int size()                                   { return sizeof(BasicObjectLock)/wordSize; }
57 
58   // GC support
59   void oops_do(OopClosure* f) { f->do_oop(&_obj); }
60 
61   static int obj_offset_in_bytes()                    { return offset_of(BasicObjectLock, _obj);  }

62 };
63 
64 
65 #endif // SHARE_RUNTIME_BASICLOCK_HPP
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