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 * Frame pointer of the current method. All spill slots and outgoing stack-based arguments are
41 * addressed relative to this register.
42 */
43 public static final Register Frame = new Register(-2, -2, "framereg", SPECIAL);
44
45 public static final Register CallerFrame = new Register(-3, -3, "callerframereg", SPECIAL);
46
47 /**
48 * The identifier for this register that is unique across all the registers in a
49 * {@link Architecture}. A valid register has {@code number > 0}.
50 */
51 public final int number;
52
53 /**
54 * The mnemonic of this register.
55 */
56 public final String name;
57
58 /**
59 * The actual encoding in a target machine instruction for this register, which may or may not
60 * be the same as {@link #number}.
61 */
62 public final int encoding;
63
64 /**
65 * The assembler calls this method to get the register's encoding.
66 */
67 public int encoding() {
68 return encoding;
69 }
70
71 /**
72 * A platform specific register category that describes which values can be stored in a
73 * register.
74 */
75 private final RegisterCategory registerCategory;
76
77 /**
78 * A platform specific register type that describes which values can be stored in a register.
79 */
80 public static class RegisterCategory {
81
82 private final String name;
83 private final boolean mayContainReference;
84
85 public RegisterCategory(String name) {
86 this(name, true);
87 }
88
89 public RegisterCategory(String name, boolean mayContainReference) {
90 this.name = name;
91 this.mayContainReference = mayContainReference;
92 }
93
94 @Override
95 public String toString() {
96 return name;
97 }
98
99 @Override
100 public int hashCode() {
101 return 23 + name.hashCode();
102 }
103
104 @Override
105 public boolean equals(Object obj) {
106 if (obj instanceof RegisterCategory) {
107 RegisterCategory that = (RegisterCategory) obj;
108 return this.name.equals(that.name);
109 }
110 return false;
111 }
112 }
113
114 /**
115 * Creates a {@link Register} instance.
116 *
117 * @param number unique identifier for the register
118 * @param encoding the target machine encoding for the register
119 * @param name the mnemonic name for the register
120 * @param registerCategory the register category
121 */
122 public Register(int number, int encoding, String name, RegisterCategory registerCategory) {
123 this.number = number;
124 this.name = name;
125 this.registerCategory = registerCategory;
126 this.encoding = encoding;
127 }
128
129 public RegisterCategory getRegisterCategory() {
130 return registerCategory;
131 }
132
133 /**
134 * Determine whether this register needs to be part of the reference map.
135 */
136 public boolean mayContainReference() {
137 return registerCategory.mayContainReference;
138 }
139
140 /**
141 * Gets this register as a {@linkplain RegisterValue value} with a specified kind.
142 *
143 * @param kind the specified kind
144 * @return the {@link RegisterValue}
145 */
146 public RegisterValue asValue(ValueKind<?> kind) {
147 return new RegisterValue(kind, this);
148 }
149
150 /**
151 * Gets this register as a {@linkplain RegisterValue value} with no particular kind.
152 *
153 * @return a {@link RegisterValue} with {@link ValueKind#Illegal} kind.
154 */
155 public RegisterValue asValue() {
156 return asValue(ValueKind.Illegal);
157 }
158
159 /**
160 * Determines if this is a valid register.
161 *
162 * @return {@code true} iff this register is valid
163 */
164 public boolean isValid() {
165 return number >= 0;
166 }
167
168 /**
169 * Gets the maximum register {@linkplain #number number} in a given set of registers.
170 *
171 * @param registers the set of registers to process
172 * @return the maximum register number for any register in {@code registers}
173 */
174 public static int maxRegisterNumber(Register[] registers) {
175 int max = Integer.MIN_VALUE;
176 for (Register r : registers) {
177 if (r.number > max) {
178 max = r.number;
179 }
180 }
181 return max;
182 }
183
184 /**
185 * Gets the maximum register {@linkplain #encoding encoding} in a given set of registers.
186 *
187 * @param registers the set of registers to process
188 * @return the maximum register encoding for any register in {@code registers}
189 */
190 public static int maxRegisterEncoding(Register[] registers) {
191 int max = Integer.MIN_VALUE;
192 for (Register r : registers) {
193 if (r.encoding > max) {
194 max = r.encoding;
195 }
196 }
197 return max;
198 }
199
200 @Override
201 public String toString() {
202 return name;
203 }
204
205 @Override
206 public int compareTo(Register o) {
207 if (number < o.number) {
208 return -1;
209 }
210 if (number > o.number) {
211 return 1;
212 }
213 return 0;
214 }
215
216 @Override
217 public int hashCode() {
218 return 17 + name.hashCode();
219 }
220
221 @Override
222 public boolean equals(Object obj) {
223 if (obj instanceof Register) {
224 Register other = (Register) obj;
225 if (number == other.number) {
226 assert name.equals(other.name);
227 assert encoding == other.encoding;
228 assert registerCategory.equals(other.registerCategory);
229 return true;
230 }
231 }
232 return false;
233 }
234 }