1 /*
2 * Copyright (c) 2017, 2018, 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 #ifndef SHARE_GC_Z_ZNMETHODTABLEENTRY_HPP
25 #define SHARE_GC_Z_ZNMETHODTABLEENTRY_HPP
26
27 #include "gc/z/zBitField.hpp"
28 #include "memory/allocation.hpp"
29
30 //
31 // NMethod table entry layout
32 // --------------------------
33 //
34 // 6
35 // 3 2 1 0
36 // +---------------------------------------------------------------------+-+-+
37 // |11111111 11111111 11111111 11111111 11111111 11111111 11111111 111111|1|1|
38 // +---------------------------------------------------------------------+-+-+
39 // | | |
40 // | | |
41 // | | |
42 // | 1-1 Unregistered Flag (1-bits) * |
43 // | |
44 // | 0-0 Registered Flag (1-bits) *
45 // |
46 // * 63-3 NMethod Address (61-bits)
47 //
48
49 class nmethod;
50
51 class ZNMethodTableEntry : public CHeapObj<mtGC> {
52 private:
53 typedef ZBitField<uint64_t, bool, 0, 1> field_registered;
54 typedef ZBitField<uint64_t, bool, 1, 1> field_unregistered;
55 typedef ZBitField<uint64_t, nmethod*, 2, 62, 2> field_method;
56
57 uint64_t _entry;
58
59 public:
60 explicit ZNMethodTableEntry(bool unregistered = false) :
61 _entry(field_registered::encode(false) |
62 field_unregistered::encode(unregistered) |
63 field_method::encode(NULL)) {}
64
65 explicit ZNMethodTableEntry(nmethod* method) :
66 _entry(field_registered::encode(true) |
67 field_unregistered::encode(false) |
68 field_method::encode(method)) {}
69
70 bool registered() const {
71 return field_registered::decode(_entry);
72 }
73
74 bool unregistered() const {
75 return field_unregistered::decode(_entry);
76 }
77
78 nmethod* method() const {
79 return field_method::decode(_entry);
80 }
81 };
82
83 #endif // SHARE_GC_Z_ZNMETHODTABLEENTRY_HPP