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_GC_SHENANDOAH_SHENANDOAHFORWARDING_INLINE_HPP
26 #define SHARE_GC_SHENANDOAH_SHENANDOAHFORWARDING_INLINE_HPP
27
28 #include "gc/shenandoah/shenandoahForwarding.hpp"
29
30 #include "gc/shenandoah/shenandoahAsserts.hpp"
31 #include "oops/markWord.hpp"
32 #include "runtime/javaThread.hpp"
33
34 inline oop ShenandoahForwarding::get_forwardee_raw(oop obj) {
35 shenandoah_assert_in_heap(NULL, obj);
36 return get_forwardee_raw_unchecked(obj);
37 }
38
39 inline oop ShenandoahForwarding::get_forwardee_raw_unchecked(oop obj) {
40 // JVMTI and JFR code use mark words for marking objects for their needs.
41 // On this path, we can encounter the "marked" object, but with NULL
42 // fwdptr. That object is still not forwarded, and we need to return
43 // the object itself.
44 markWord mark = obj->mark();
45 if (mark.is_marked()) {
46 HeapWord* fwdptr = (HeapWord*) mark.clear_lock_bits().to_pointer();
47 if (fwdptr != NULL) {
48 return cast_to_oop(fwdptr);
49 }
50 }
51 return obj;
52 }
59 markWord mark = obj->mark();
60 if (mark.is_marked()) {
61 HeapWord* fwdptr = (HeapWord*) mark.clear_lock_bits().to_pointer();
62 assert(fwdptr != NULL, "Forwarding pointer is never null here");
63 return cast_to_oop(fwdptr);
64 } else {
65 return obj;
66 }
67 }
68
69 inline oop ShenandoahForwarding::get_forwardee(oop obj) {
70 shenandoah_assert_correct(NULL, obj);
71 return get_forwardee_raw_unchecked(obj);
72 }
73
74 inline bool ShenandoahForwarding::is_forwarded(oop obj) {
75 return obj->mark().is_marked();
76 }
77
78 inline oop ShenandoahForwarding::try_update_forwardee(oop obj, oop update) {
79 markWord old_mark = obj->mark();
80 if (old_mark.is_marked()) {
81 return cast_to_oop(old_mark.clear_lock_bits().to_pointer());
82 }
83
84 markWord new_mark = markWord::encode_pointer_as_mark(update);
85 markWord prev_mark = obj->cas_set_mark(new_mark, old_mark, memory_order_conservative);
86 if (prev_mark == old_mark) {
87 return update;
88 } else {
89 return cast_to_oop(prev_mark.clear_lock_bits().to_pointer());
90 }
91 }
92
93 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHFORWARDING_INLINE_HPP
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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_GC_SHENANDOAH_SHENANDOAHFORWARDING_INLINE_HPP
26 #define SHARE_GC_SHENANDOAH_SHENANDOAHFORWARDING_INLINE_HPP
27
28 #include "gc/shenandoah/shenandoahForwarding.hpp"
29
30 #include "gc/shenandoah/shenandoahAsserts.hpp"
31 #include "oops/markWord.hpp"
32 #include "runtime/javaThread.hpp"
33 #include "runtime/synchronizer.hpp"
34
35 inline oop ShenandoahForwarding::get_forwardee_raw(oop obj) {
36 shenandoah_assert_in_heap(NULL, obj);
37 return get_forwardee_raw_unchecked(obj);
38 }
39
40 inline oop ShenandoahForwarding::get_forwardee_raw_unchecked(oop obj) {
41 // JVMTI and JFR code use mark words for marking objects for their needs.
42 // On this path, we can encounter the "marked" object, but with NULL
43 // fwdptr. That object is still not forwarded, and we need to return
44 // the object itself.
45 markWord mark = obj->mark();
46 if (mark.is_marked()) {
47 HeapWord* fwdptr = (HeapWord*) mark.clear_lock_bits().to_pointer();
48 if (fwdptr != NULL) {
49 return cast_to_oop(fwdptr);
50 }
51 }
52 return obj;
53 }
60 markWord mark = obj->mark();
61 if (mark.is_marked()) {
62 HeapWord* fwdptr = (HeapWord*) mark.clear_lock_bits().to_pointer();
63 assert(fwdptr != NULL, "Forwarding pointer is never null here");
64 return cast_to_oop(fwdptr);
65 } else {
66 return obj;
67 }
68 }
69
70 inline oop ShenandoahForwarding::get_forwardee(oop obj) {
71 shenandoah_assert_correct(NULL, obj);
72 return get_forwardee_raw_unchecked(obj);
73 }
74
75 inline bool ShenandoahForwarding::is_forwarded(oop obj) {
76 return obj->mark().is_marked();
77 }
78
79 inline oop ShenandoahForwarding::try_update_forwardee(oop obj, oop update) {
80
81 markWord old_mark = obj->mark_acquire();
82
83 if (old_mark.is_marked()) {
84 return cast_to_oop(old_mark.clear_lock_bits().to_pointer());
85 }
86
87 markWord new_mark = markWord::encode_pointer_as_mark(update);
88 markWord prev_mark = obj->cas_set_mark(new_mark, old_mark, memory_order_conservative);
89 if (prev_mark == old_mark) {
90 return update;
91 } else {
92 assert(prev_mark.is_marked(), "must be forwarded");
93 return cast_to_oop(prev_mark.clear_lock_bits().to_pointer());
94 }
95 }
96
97 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHFORWARDING_INLINE_HPP
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