1 /*
2 * Copyright (c) 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
25 package org.graalvm.compiler.lir.aarch64;
26
27 import static jdk.vm.ci.aarch64.AArch64.zr;
28 import static jdk.vm.ci.code.ValueUtil.asRegister;
29 import static org.graalvm.compiler.lir.LIRInstruction.OperandFlag.REG;
30
31 import org.graalvm.compiler.asm.Label;
32 import org.graalvm.compiler.asm.aarch64.AArch64Address;
33 import org.graalvm.compiler.asm.aarch64.AArch64Assembler.ConditionFlag;
34 import org.graalvm.compiler.asm.aarch64.AArch64MacroAssembler;
35 import org.graalvm.compiler.core.common.LIRKind;
36 import org.graalvm.compiler.lir.LIRInstructionClass;
37 import org.graalvm.compiler.lir.Opcode;
38 import org.graalvm.compiler.lir.asm.CompilationResultBuilder;
39 import org.graalvm.compiler.lir.gen.LIRGeneratorTool;
40
41 import jdk.vm.ci.code.Register;
42 import jdk.vm.ci.meta.JavaKind;
43 import jdk.vm.ci.meta.Value;
44
45 /**
46 * Emits code which compares two arrays lexicographically. If the CPU supports any vector
47 * instructions specialized code is emitted to leverage these instructions.
48 */
49 @Opcode("ARRAY_COMPARE_TO")
50 public final class AArch64ArrayCompareToOp extends AArch64LIRInstruction {
51 public static final LIRInstructionClass<AArch64ArrayCompareToOp> TYPE = LIRInstructionClass.create(AArch64ArrayCompareToOp.class);
52
53 private final JavaKind kind1;
54 private final JavaKind kind2;
55
56 private final int array1BaseOffset;
57 private final int array2BaseOffset;
58
59 @Def({REG}) protected Value resultValue;
60
61 @Alive({REG}) protected Value array1Value;
62 @Alive({REG}) protected Value array2Value;
63 @Use({REG}) protected Value length1Value;
64 @Use({REG}) protected Value length2Value;
65 @Temp({REG}) protected Value length1ValueTemp;
66 @Temp({REG}) protected Value length2ValueTemp;
67
68 @Temp({REG}) protected Value temp1;
69 @Temp({REG}) protected Value temp2;
70 @Temp({REG}) protected Value temp3;
71 @Temp({REG}) protected Value temp4;
72 @Temp({REG}) protected Value temp5;
73 @Temp({REG}) protected Value temp6;
74
75 public AArch64ArrayCompareToOp(LIRGeneratorTool tool, JavaKind kind1, JavaKind kind2, Value result, Value array1, Value array2, Value length1, Value length2) {
76 super(TYPE);
77 this.kind1 = kind1;
78 this.kind2 = kind2;
79
80 // Both offsets should be the same but better be safe than sorry.
81 this.array1BaseOffset = tool.getProviders().getMetaAccess().getArrayBaseOffset(kind1);
82 this.array2BaseOffset = tool.getProviders().getMetaAccess().getArrayBaseOffset(kind2);
83
84 this.resultValue = result;
85
86 this.array1Value = array1;
87 this.array2Value = array2;
88
89 /*
90 * The length values are inputs but are also killed like temporaries so need both Use and
91 * Temp annotations, which will only work with fixed registers.
92 */
93
94 this.length1Value = length1;
95 this.length2Value = length2;
96 this.length1ValueTemp = length1;
97 this.length2ValueTemp = length2;
98
99 // Allocate some temporaries.
100 this.temp1 = tool.newVariable(LIRKind.unknownReference(tool.target().arch.getWordKind()));
101 this.temp2 = tool.newVariable(LIRKind.unknownReference(tool.target().arch.getWordKind()));
102 this.temp3 = tool.newVariable(LIRKind.unknownReference(tool.target().arch.getWordKind()));
103 this.temp4 = tool.newVariable(LIRKind.unknownReference(tool.target().arch.getWordKind()));
104 this.temp5 = tool.newVariable(LIRKind.unknownReference(tool.target().arch.getWordKind()));
105 this.temp6 = tool.newVariable(LIRKind.unknownReference(tool.target().arch.getWordKind()));
106 }
107
108 @Override
109 protected void emitCode(CompilationResultBuilder crb, AArch64MacroAssembler masm) {
110
111 Register result = asRegister(resultValue);
112 Register length1 = asRegister(length1Value);
113 Register length2 = asRegister(length2Value);
114
115 Register array1 = asRegister(temp1);
116 Register array2 = asRegister(temp2);
117 Register length = asRegister(temp3);
118 Register temp = asRegister(temp4);
119 Register tailCount = asRegister(temp5);
120 Register vecCount = asRegister(temp6);
121
122 // Checkstyle: stop
123 final Label BREAK_LABEL = new Label();
124 final Label STRING_DIFFER_LABEL = new Label();
125 final Label LENGTH_DIFFER_LABEL = new Label();
126 final Label MAIN_LOOP_LABEL = new Label();
127 final Label COMPARE_SHORT_LABEL = new Label();
128 // Checkstyle: resume
129
130 // Checkstyle: stop
131 int CHAR_SIZE_BYTES = 1;
132 int VECTOR_SIZE_BYTES = 8;
133 int VECTOR_COUNT_BYTES = 8;
134 // Checkstyle: resume
135
136 // Byte is expanded to short if we compare strings with different encoding
137 if (kind1 != kind2 || kind1 == JavaKind.Char) {
138 CHAR_SIZE_BYTES = 2;
139 }
140
141 if (kind1 != kind2) {
142 VECTOR_COUNT_BYTES = 4;
143 }
144
145 // Load array base addresses.
146 masm.lea(array1, AArch64Address.createUnscaledImmediateAddress(asRegister(array1Value), array1BaseOffset));
147 masm.lea(array2, AArch64Address.createUnscaledImmediateAddress(asRegister(array2Value), array2BaseOffset));
148
149 // Calculate minimal length in chars for different kind case
150 // Conditions could be squashed but lets keep it readable
151 if (kind1 != kind2) {
152 masm.lshr(64, length2, length2, 1);
153 }
154
155 if (kind1 == kind2 && kind1 == JavaKind.Char) {
156 masm.lshr(64, length1, length1, 1);
157 masm.lshr(64, length2, length2, 1);
158 }
159
160 masm.cmp(64, length1, length2);
161 masm.cmov(64, length, length1, length2, ConditionFlag.LT);
162
163 // One of strings is empty
164 masm.cbz(64, length, LENGTH_DIFFER_LABEL);
165
166 // Go back to bytes if necessary
167 if (kind1 != kind2 || kind1 == JavaKind.Char) {
168 masm.shl(64, length, length, 1);
169 }
170
171 masm.mov(64, vecCount, zr);
172 masm.and(64, tailCount, length, VECTOR_SIZE_BYTES - 1); // tail count (in bytes)
173 masm.ands(64, length, length, ~(VECTOR_SIZE_BYTES - 1)); // vector count (in bytes)
174
175 // Length of string is less than VECTOR_SIZE, go to simple compare
176 masm.branchConditionally(ConditionFlag.EQ, COMPARE_SHORT_LABEL);
177
178 // MAIN_LOOP - read strings by 8 byte.
179 masm.bind(MAIN_LOOP_LABEL);
180 if (kind1 != kind2) {
181 // Load 32 bits ad unpack it to entire 64bit register
182 masm.ldr(32, result, AArch64Address.createRegisterOffsetAddress(array1, vecCount, false));
183 masm.ubfm(64, temp, result, 0, 7);
184 masm.lshr(64, result, result, 8);
185 masm.bfm(64, temp, result, 48, 7);
186 masm.lshr(64, result, result, 8);
187 masm.bfm(64, temp, result, 32, 7);
188 masm.lshr(64, result, result, 8);
189 masm.bfm(64, temp, result, 16, 7);
190 // Unpacked value placed in temp now
191
192 masm.shl(64, result, vecCount, 1);
193 masm.ldr(64, result, AArch64Address.createRegisterOffsetAddress(array2, result, false));
194 } else {
195 masm.ldr(64, temp, AArch64Address.createRegisterOffsetAddress(array1, vecCount, false));
196 masm.ldr(64, result, AArch64Address.createRegisterOffsetAddress(array2, vecCount, false));
197 }
198 masm.eor(64, result, temp, result);
199 masm.cbnz(64, result, STRING_DIFFER_LABEL);
200 masm.add(64, vecCount, vecCount, VECTOR_COUNT_BYTES);
201 masm.cmp(64, vecCount, length);
202 masm.branchConditionally(ConditionFlag.LT, MAIN_LOOP_LABEL);
203 // End of MAIN_LOOP
204
205 // Strings are equal and no TAIL go to END
206 masm.cbz(64, tailCount, LENGTH_DIFFER_LABEL);
207
208 // Compaire tail of long string ...
209 masm.lea(array1, AArch64Address.createRegisterOffsetAddress(array1, length, false));
210 masm.lea(array2, AArch64Address.createRegisterOffsetAddress(array2, length, false));
211
212 // ... or string less than vector length
213 masm.bind(COMPARE_SHORT_LABEL);
214 for (int i = 0; i < VECTOR_COUNT_BYTES; i += CHAR_SIZE_BYTES) {
215 if (kind1 != kind2) {
216 masm.ldr(8, temp, AArch64Address.createUnscaledImmediateAddress(array1, i / 2));
217 } else {
218 masm.ldr(8 * CHAR_SIZE_BYTES, temp, AArch64Address.createUnscaledImmediateAddress(array1, i));
219 }
220
221 masm.ldr(8 * CHAR_SIZE_BYTES, result, AArch64Address.createUnscaledImmediateAddress(array2, i));
222
223 if (kind1 != kind2 && kind1 == JavaKind.Char) {
224 // Weird swap of substraction order
225 masm.subs(64, result, result, temp);
226 } else {
227 masm.subs(64, result, temp, result);
228 }
229
230 masm.branchConditionally(ConditionFlag.NE, BREAK_LABEL);
231 masm.subs(64, tailCount, tailCount, CHAR_SIZE_BYTES);
232 masm.branchConditionally(ConditionFlag.EQ, LENGTH_DIFFER_LABEL);
233 }
234
235 // STRING_DIFFER extract exact value of a difference
236 masm.bind(STRING_DIFFER_LABEL);
237 masm.rbit(64, tailCount, result);
238 masm.clz(64, vecCount, tailCount);
239 masm.and(64, vecCount, vecCount, ~((8 * CHAR_SIZE_BYTES) - 1)); // Round to byte or short
240
241 masm.eor(64, result, temp, result);
242 masm.ashr(64, result, result, vecCount);
243 masm.ashr(64, temp, temp, vecCount);
244
245 masm.and(64, result, result, 0xFFFF >>> (16 - (8 * CHAR_SIZE_BYTES))); // 0xFF or 0xFFFF
246 masm.and(64, temp, temp, 0xFFFF >>> (16 - (8 * CHAR_SIZE_BYTES)));
247
248 masm.sub(64, result, temp, result);
249 masm.branchConditionally(ConditionFlag.AL, BREAK_LABEL);
250 // End of STRING_DIFFER
251
252 // Strings are equials up to length,
253 // return length difference in chars
254 masm.bind(LENGTH_DIFFER_LABEL);
255 if (kind1 != kind2 && kind1 == JavaKind.Char) {
256 // Weird swap of substraction order
257 masm.sub(64, result, length2, length1);
258 } else {
259 masm.sub(64, result, length1, length2);
260 }
261
262 // We are done
263 masm.bind(BREAK_LABEL);
264 }
265
266 } // class