1 /*
2 * Copyright (c) 2009, 2016, 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 package jdk.vm.ci.code;
24
25 import jdk.vm.ci.meta.ValueKind;
26
27 /**
28 * Represents a target machine register.
29 */
30 public final class Register implements Comparable<Register> {
31
32 public static final RegisterCategory SPECIAL = new RegisterCategory("SPECIAL");
33
34 /**
35 * Invalid register.
36 */
37 public static final Register None = new Register(-1, -1, "noreg", SPECIAL);
38
39 /**
40 * The identifier for this register that is unique across all the registers in a
41 * {@link Architecture}. A valid register has {@code number >= 0}.
42 */
43 public final int number;
44
45 /**
46 * The mnemonic of this register.
47 */
48 public final String name;
49
50 /**
51 * The actual encoding in a target machine instruction for this register, which may or may not
52 * be the same as {@link #number}.
53 */
54 public final int encoding;
55
56 /**
57 * The assembler calls this method to get the register's encoding.
58 */
59 public int encoding() {
60 return encoding;
61 }
62
63 /**
64 * A platform specific register category that describes which values can be stored in a
65 * register.
66 */
67 private final RegisterCategory registerCategory;
68
69 /**
70 * A platform specific register type that describes which values can be stored in a register.
71 */
72 public static class RegisterCategory {
73
74 private final String name;
75 private final boolean mayContainReference;
76
77 public RegisterCategory(String name) {
78 this(name, true);
79 }
80
81 public RegisterCategory(String name, boolean mayContainReference) {
82 this.name = name;
83 this.mayContainReference = mayContainReference;
84 }
85
86 @Override
87 public String toString() {
88 return name;
89 }
90
91 @Override
92 public int hashCode() {
93 return 23 + name.hashCode();
94 }
95
96 @Override
97 public boolean equals(Object obj) {
98 if (obj instanceof RegisterCategory) {
99 RegisterCategory that = (RegisterCategory) obj;
100 return this.name.equals(that.name);
101 }
102 return false;
103 }
104 }
105
106 /**
107 * Creates a {@link Register} instance.
108 *
109 * @param number unique identifier for the register
110 * @param encoding the target machine encoding for the register
111 * @param name the mnemonic name for the register
112 * @param registerCategory the register category
113 */
114 public Register(int number, int encoding, String name, RegisterCategory registerCategory) {
115 this.number = number;
116 this.name = name;
117 this.registerCategory = registerCategory;
118 this.encoding = encoding;
119 }
120
121 public RegisterCategory getRegisterCategory() {
122 return registerCategory;
123 }
124
125 /**
126 * Determine whether this register needs to be part of the reference map.
127 */
128 public boolean mayContainReference() {
129 return registerCategory.mayContainReference;
130 }
131
132 /**
133 * Gets this register as a {@linkplain RegisterValue value} with a specified kind.
134 *
135 * @param kind the specified kind
136 * @return the {@link RegisterValue}
137 */
138 public RegisterValue asValue(ValueKind<?> kind) {
139 return new RegisterValue(kind, this);
140 }
141
142 /**
143 * Gets this register as a {@linkplain RegisterValue value} with no particular kind.
144 *
145 * @return a {@link RegisterValue} with {@link ValueKind#Illegal} kind.
146 */
147 public RegisterValue asValue() {
148 return asValue(ValueKind.Illegal);
149 }
150
151 /**
152 * Determines if this is a valid register.
153 *
154 * @return {@code true} iff this register is valid
155 */
156 public boolean isValid() {
157 return number >= 0;
158 }
159
160 @Override
161 public String toString() {
162 return name;
163 }
164
165 @Override
166 public int compareTo(Register o) {
167 if (number < o.number) {
168 return -1;
169 }
170 if (number > o.number) {
171 return 1;
172 }
173 return 0;
174 }
175
176 @Override
177 public int hashCode() {
178 return 17 + name.hashCode();
179 }
180
181 @Override
182 public boolean equals(Object obj) {
183 if (obj instanceof Register) {
184 Register other = (Register) obj;
185 if (number == other.number) {
186 assert name.equals(other.name);
187 assert encoding == other.encoding;
188 assert registerCategory.equals(other.registerCategory);
189 return true;
190 }
191 }
192 return false;
193 }
194 }