1 /*
2 * Copyright (c) 2009, 2015, 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.*;
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
84 private final int referenceMapOffset;
85 private final int referenceMapShift;
86
87 public RegisterCategory(String name) {
88 this(name, 0, 0);
89 }
90
91 public RegisterCategory(String name, int referenceMapOffset) {
92 this(name, referenceMapOffset, 0);
93 }
94
95 public RegisterCategory(String name, int referenceMapOffset, int referenceMapShift) {
96 this.name = name;
97 this.referenceMapOffset = referenceMapOffset;
98 this.referenceMapShift = referenceMapShift;
99 }
100
101 @Override
102 public String toString() {
103 return name;
104 }
105
106 @Override
107 public int hashCode() {
108 return 23 + name.hashCode();
109 }
110
111 @Override
112 public boolean equals(Object obj) {
113 if (obj instanceof RegisterCategory) {
114 RegisterCategory that = (RegisterCategory) obj;
115 return this.referenceMapOffset == that.referenceMapOffset && this.referenceMapShift == that.referenceMapShift && this.name.equals(that.name);
116 }
117 return false;
118 }
119 }
120
121 /**
122 * Creates a {@link Register} instance.
123 *
124 * @param number unique identifier for the register
125 * @param encoding the target machine encoding for the register
126 * @param name the mnemonic name for the register
127 * @param registerCategory the register category
128 */
129 public Register(int number, int encoding, String name, RegisterCategory registerCategory) {
130 this.number = number;
131 this.name = name;
132 this.registerCategory = registerCategory;
133 this.encoding = encoding;
134 }
135
136 public RegisterCategory getRegisterCategory() {
137 return registerCategory;
138 }
139
140 /**
141 * Get the start index of this register in the {@link ReferenceMap}.
142 */
143 public int getReferenceMapIndex() {
144 return (encoding << registerCategory.referenceMapShift) + registerCategory.referenceMapOffset;
145 }
146
147 /**
148 * Gets this register as a {@linkplain RegisterValue value} with a specified kind.
149 *
150 * @param kind the specified kind
151 * @return the {@link RegisterValue}
152 */
153 public RegisterValue asValue(LIRKind kind) {
154 return new RegisterValue(kind, this);
155 }
156
157 /**
158 * Gets this register as a {@linkplain RegisterValue value} with no particular kind.
159 *
160 * @return a {@link RegisterValue} with {@link JavaKind#Illegal} kind.
161 */
162 public RegisterValue asValue() {
163 return asValue(LIRKind.Illegal);
164 }
165
166 /**
167 * Determines if this is a valid register.
168 *
169 * @return {@code true} iff this register is valid
170 */
171 public boolean isValid() {
172 return number >= 0;
173 }
174
175 /**
176 * Gets the maximum register {@linkplain #number number} in a given set of registers.
177 *
178 * @param registers the set of registers to process
179 * @return the maximum register number for any register in {@code registers}
180 */
181 public static int maxRegisterNumber(Register[] registers) {
182 int max = Integer.MIN_VALUE;
183 for (Register r : registers) {
184 if (r.number > max) {
185 max = r.number;
186 }
187 }
188 return max;
189 }
190
191 /**
192 * Gets the maximum register {@linkplain #encoding encoding} in a given set of registers.
193 *
194 * @param registers the set of registers to process
195 * @return the maximum register encoding for any register in {@code registers}
196 */
197 public static int maxRegisterEncoding(Register[] registers) {
198 int max = Integer.MIN_VALUE;
199 for (Register r : registers) {
200 if (r.encoding > max) {
201 max = r.encoding;
202 }
203 }
204 return max;
205 }
206
207 @Override
208 public String toString() {
209 return name;
210 }
211
212 @Override
213 public int compareTo(Register o) {
214 if (number < o.number) {
215 return -1;
216 }
217 if (number > o.number) {
218 return 1;
219 }
220 return 0;
221 }
222
223 @Override
224 public int hashCode() {
225 return 17 + name.hashCode();
226 }
227
228 @Override
229 public boolean equals(Object obj) {
230 if (obj instanceof Register) {
231 Register other = (Register) obj;
232 if (number == other.number) {
233 assert name.equals(other.name);
234 assert encoding == other.encoding;
235 assert registerCategory.equals(other.registerCategory);
236 return true;
237 }
238 }
239 return false;
240 }
241 }