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src/hotspot/share/oops/objLayout.cpp

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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 #include "oops/markWord.hpp"
26 #include "oops/objLayout.hpp"
27 #include "runtime/globals.hpp"
28 #include "utilities/debug.hpp"
29 
30 ObjLayout::Mode ObjLayout::_klass_mode = ObjLayout::Undefined;
31 int ObjLayout::_oop_base_offset_in_bytes = 0;
32 bool ObjLayout::_oop_has_klass_gap = false;
33 
34 void ObjLayout::initialize() {
35   assert(_klass_mode == Undefined, "ObjLayout initialized twice");
36   if (UseCompactObjectHeaders) {
37     _klass_mode = Compact;
38     _oop_base_offset_in_bytes = sizeof(markWord);
39     _oop_has_klass_gap = false;
40   } else if (UseCompressedClassPointers) {
41     _klass_mode = Compressed;
42     _oop_base_offset_in_bytes = sizeof(markWord) + sizeof(narrowKlass);
43     _oop_has_klass_gap = true;
44   } else {
45     _klass_mode = Uncompressed;
46     _oop_base_offset_in_bytes = sizeof(markWord) + sizeof(Klass*);
47     _oop_has_klass_gap = false;
48   }
49 }

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 #include "oops/markWord.hpp"
26 #include "oops/objLayout.hpp"
27 #include "runtime/globals.hpp"
28 #include "utilities/debug.hpp"
29 
30 ObjLayout::Mode ObjLayout::_klass_mode = ObjLayout::Undefined;
31 int ObjLayout::_oop_base_offset_in_bytes = 0;
32 bool ObjLayout::_oop_has_klass_gap = false;
33 
34 void ObjLayout::initialize() {
35   assert(_klass_mode == Undefined, "ObjLayout initialized twice");
36   if (UseCompactObjectHeaders) {
37     _klass_mode = Compact;
38     _oop_base_offset_in_bytes = sizeof(uint32_t);
39     _oop_has_klass_gap = true;
40   } else if (UseCompressedClassPointers) {
41     _klass_mode = Compressed;
42     _oop_base_offset_in_bytes = sizeof(markWord) + sizeof(narrowKlass);
43     _oop_has_klass_gap = true;
44   } else {
45     _klass_mode = Uncompressed;
46     _oop_base_offset_in_bytes = sizeof(markWord) + sizeof(Klass*);
47     _oop_has_klass_gap = false;
48   }
49 }
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