1 /*
 2  * Copyright (c) 2021, Oracle and/or its affiliates. All rights reserved.
 3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 4  *
 5  * This code is free software; you can redistribute it and/or modify it
 6  * under the terms of the GNU General Public License version 2 only, as
 7  * published by the Free Software Foundation.
 8  *
 9  * This code is distributed in the hope that it will be useful, but WITHOUT
10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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_MARKWORD_INLINE_HPP
26 #define SHARE_OOPS_MARKWORD_INLINE_HPP
27 
28 #include "oops/compressedOops.inline.hpp"
29 #include "oops/markWord.hpp"
30 #include "runtime/safepoint.hpp"
31 
32 #ifdef _LP64
33 narrowKlass markWord::narrow_klass() const {
34   return narrowKlass(value() >> klass_shift);
35 }
36 
37 Klass* markWord::klass() const {
38   return CompressedKlassPointers::decode_not_null(narrow_klass());
39 }
40 
41 Klass* markWord::klass_or_null() const {
42   return CompressedKlassPointers::decode(narrow_klass());
43 }
44 
45 markWord markWord::set_narrow_klass(const narrowKlass nklass) const {
46   return markWord((value() & ~klass_mask_in_place) | ((uintptr_t) nklass << klass_shift));
47 }
48 
49 Klass* markWord::safe_klass() const {
50   assert(SafepointSynchronize::is_at_safepoint(), "only call at safepoint");
51   markWord m = *this;
52   if (m.has_displaced_mark_helper()) {
53     m = m.displaced_mark_helper();
54   }
55   return CompressedKlassPointers::decode_not_null(m.narrow_klass());
56 }
57 
58 markWord markWord::set_klass(const Klass* klass) const {
59   assert(UseCompressedClassPointers, "expect compressed klass pointers");
60   // TODO: Don't cast to non-const, change CKP::encode() to accept const Klass* instead.
61   narrowKlass nklass = CompressedKlassPointers::encode(const_cast<Klass*>(klass));
62   return set_narrow_klass(nklass);
63 }
64 #endif
65 
66 #endif // SHARE_OOPS_MARKWORD_INLINE_HPP