1 /*
2 * Copyright (c) 2013, 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 org.graalvm.compiler.lir.amd64;
24
25 import static org.graalvm.compiler.lir.LIRInstruction.OperandFlag.ILLEGAL;
26 import static org.graalvm.compiler.lir.LIRInstruction.OperandFlag.REG;
27 import static jdk.vm.ci.code.ValueUtil.asRegister;
28
29 import java.lang.reflect.Array;
30 import java.lang.reflect.Field;
31
32 import org.graalvm.compiler.asm.Label;
33 import org.graalvm.compiler.asm.amd64.AMD64Address;
34 import org.graalvm.compiler.asm.amd64.AMD64Address.Scale;
35 import org.graalvm.compiler.asm.amd64.AMD64Assembler.ConditionFlag;
36 import org.graalvm.compiler.asm.amd64.AMD64MacroAssembler;
37 import org.graalvm.compiler.core.common.LIRKind;
38 import org.graalvm.compiler.lir.LIRInstructionClass;
39 import org.graalvm.compiler.lir.Opcode;
40 import org.graalvm.compiler.lir.asm.CompilationResultBuilder;
41 import org.graalvm.compiler.lir.gen.LIRGeneratorTool;
42
43 import jdk.vm.ci.amd64.AMD64;
44 import jdk.vm.ci.amd64.AMD64.CPUFeature;
45 import jdk.vm.ci.amd64.AMD64Kind;
46 import jdk.vm.ci.code.Register;
47 import jdk.vm.ci.code.TargetDescription;
48 import jdk.vm.ci.meta.JavaKind;
49 import jdk.vm.ci.meta.Value;
50 import sun.misc.Unsafe;
51
52 /**
53 * Emits code which compares two arrays of the same length. If the CPU supports any vector
54 * instructions specialized code is emitted to leverage these instructions.
55 */
56 @Opcode("ARRAY_EQUALS")
57 public final class AMD64ArrayEqualsOp extends AMD64LIRInstruction {
58 public static final LIRInstructionClass<AMD64ArrayEqualsOp> TYPE = LIRInstructionClass.create(AMD64ArrayEqualsOp.class);
59
60 private final JavaKind kind;
61 private final int arrayBaseOffset;
62 private final int arrayIndexScale;
63
64 @Def({REG}) protected Value resultValue;
65 @Alive({REG}) protected Value array1Value;
66 @Alive({REG}) protected Value array2Value;
67 @Alive({REG}) protected Value lengthValue;
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, ILLEGAL}) protected Value vectorTemp1;
73 @Temp({REG, ILLEGAL}) protected Value vectorTemp2;
74
75 public AMD64ArrayEqualsOp(LIRGeneratorTool tool, JavaKind kind, Value result, Value array1, Value array2, Value length) {
76 super(TYPE);
77 this.kind = kind;
78
79 Class<?> arrayClass = Array.newInstance(kind.toJavaClass(), 0).getClass();
80 this.arrayBaseOffset = UNSAFE.arrayBaseOffset(arrayClass);
81 this.arrayIndexScale = UNSAFE.arrayIndexScale(arrayClass);
82
83 this.resultValue = result;
84 this.array1Value = array1;
85 this.array2Value = array2;
86 this.lengthValue = length;
87
88 // Allocate some temporaries.
89 this.temp1 = tool.newVariable(LIRKind.unknownReference(tool.target().arch.getWordKind()));
90 this.temp2 = tool.newVariable(LIRKind.unknownReference(tool.target().arch.getWordKind()));
91 this.temp3 = tool.newVariable(LIRKind.value(tool.target().arch.getWordKind()));
92 this.temp4 = tool.newVariable(LIRKind.value(tool.target().arch.getWordKind()));
93
94 // We only need the vector temporaries if we generate SSE code.
95 if (supportsSSE41(tool.target())) {
96 this.vectorTemp1 = tool.newVariable(LIRKind.value(AMD64Kind.DOUBLE));
97 this.vectorTemp2 = tool.newVariable(LIRKind.value(AMD64Kind.DOUBLE));
98 } else {
99 this.vectorTemp1 = Value.ILLEGAL;
100 this.vectorTemp2 = Value.ILLEGAL;
101 }
102 }
103
104 @Override
105 public void emitCode(CompilationResultBuilder crb, AMD64MacroAssembler masm) {
106 Register result = asRegister(resultValue);
107 Register array1 = asRegister(temp1);
108 Register array2 = asRegister(temp2);
109 Register length = asRegister(temp3);
110
111 Label trueLabel = new Label();
112 Label falseLabel = new Label();
113 Label done = new Label();
114
115 // Load array base addresses.
116 masm.leaq(array1, new AMD64Address(asRegister(array1Value), arrayBaseOffset));
117 masm.leaq(array2, new AMD64Address(asRegister(array2Value), arrayBaseOffset));
118
119 // Get array length in bytes.
120 masm.imull(length, asRegister(lengthValue), arrayIndexScale);
121 masm.movl(result, length); // copy
122
123 if (supportsAVX2(crb.target)) {
124 emitAVXCompare(crb, masm, result, array1, array2, length, trueLabel, falseLabel);
125 } else if (supportsSSE41(crb.target)) {
126 emitSSE41Compare(crb, masm, result, array1, array2, length, trueLabel, falseLabel);
127 }
128
129 emit8ByteCompare(crb, masm, result, array1, array2, length, trueLabel, falseLabel);
130 emitTailCompares(masm, result, array1, array2, length, trueLabel, falseLabel);
131
132 // Return true
133 masm.bind(trueLabel);
134 masm.movl(result, 1);
135 masm.jmpb(done);
136
137 // Return false
138 masm.bind(falseLabel);
139 masm.xorl(result, result);
140
141 // That's it
142 masm.bind(done);
143 }
144
145 /**
146 * Returns if the underlying AMD64 architecture supports SSE 4.1 instructions.
147 *
148 * @param target target description of the underlying architecture
149 * @return true if the underlying architecture supports SSE 4.1
150 */
151 private static boolean supportsSSE41(TargetDescription target) {
152 AMD64 arch = (AMD64) target.arch;
153 return arch.getFeatures().contains(CPUFeature.SSE4_1);
154 }
155
156 /**
157 * Vector size used in {@link #emitSSE41Compare}.
158 */
159 private static final int SSE4_1_VECTOR_SIZE = 16;
160
161 /**
162 * Emits code that uses SSE4.1 128-bit (16-byte) vector compares.
163 */
164 private void emitSSE41Compare(CompilationResultBuilder crb, AMD64MacroAssembler masm, Register result, Register array1, Register array2, Register length, Label trueLabel, Label falseLabel) {
165 assert supportsSSE41(crb.target);
166
167 Register vector1 = asRegister(vectorTemp1, AMD64Kind.DOUBLE);
168 Register vector2 = asRegister(vectorTemp2, AMD64Kind.DOUBLE);
169
170 Label loop = new Label();
171 Label compareTail = new Label();
172
173 // Compare 16-byte vectors
174 masm.andl(result, SSE4_1_VECTOR_SIZE - 1); // tail count (in bytes)
175 masm.andl(length, ~(SSE4_1_VECTOR_SIZE - 1)); // vector count (in bytes)
176 masm.jccb(ConditionFlag.Zero, compareTail);
177
178 masm.leaq(array1, new AMD64Address(array1, length, Scale.Times1, 0));
179 masm.leaq(array2, new AMD64Address(array2, length, Scale.Times1, 0));
180 masm.negq(length);
181
182 // Align the main loop
183 masm.align(crb.target.wordSize * 2);
184 masm.bind(loop);
185 masm.movdqu(vector1, new AMD64Address(array1, length, Scale.Times1, 0));
186 masm.movdqu(vector2, new AMD64Address(array2, length, Scale.Times1, 0));
187 masm.pxor(vector1, vector2);
188 masm.ptest(vector1, vector1);
189 masm.jcc(ConditionFlag.NotZero, falseLabel);
190 masm.addq(length, SSE4_1_VECTOR_SIZE);
191 masm.jcc(ConditionFlag.NotZero, loop);
192
193 masm.testl(result, result);
194 masm.jcc(ConditionFlag.Zero, trueLabel);
195
196 /*
197 * Compare the remaining bytes with an unaligned memory load aligned to the end of the
198 * array.
199 */
200 masm.movdqu(vector1, new AMD64Address(array1, result, Scale.Times1, -SSE4_1_VECTOR_SIZE));
201 masm.movdqu(vector2, new AMD64Address(array2, result, Scale.Times1, -SSE4_1_VECTOR_SIZE));
202 masm.pxor(vector1, vector2);
203 masm.ptest(vector1, vector1);
204 masm.jcc(ConditionFlag.NotZero, falseLabel);
205 masm.jmp(trueLabel);
206
207 masm.bind(compareTail);
208 masm.movl(length, result);
209 }
210
211 /**
212 * Returns if the underlying AMD64 architecture supports AVX instructions.
213 *
214 * @param target target description of the underlying architecture
215 * @return true if the underlying architecture supports AVX
216 */
217 private static boolean supportsAVX2(TargetDescription target) {
218 AMD64 arch = (AMD64) target.arch;
219 return arch.getFeatures().contains(CPUFeature.AVX2);
220 }
221
222 /**
223 * Vector size used in {@link #emitAVXCompare}.
224 */
225 private static final int AVX_VECTOR_SIZE = 32;
226
227 private void emitAVXCompare(CompilationResultBuilder crb, AMD64MacroAssembler masm, Register result, Register array1, Register array2, Register length, Label trueLabel, Label falseLabel) {
228 assert supportsAVX2(crb.target);
229
230 Register vector1 = asRegister(vectorTemp1, AMD64Kind.DOUBLE);
231 Register vector2 = asRegister(vectorTemp2, AMD64Kind.DOUBLE);
232
233 Label loop = new Label();
234 Label compareTail = new Label();
235
236 // Compare 16-byte vectors
237 masm.andl(result, AVX_VECTOR_SIZE - 1); // tail count (in bytes)
238 masm.andl(length, ~(AVX_VECTOR_SIZE - 1)); // vector count (in bytes)
239 masm.jccb(ConditionFlag.Zero, compareTail);
240
241 masm.leaq(array1, new AMD64Address(array1, length, Scale.Times1, 0));
242 masm.leaq(array2, new AMD64Address(array2, length, Scale.Times1, 0));
243 masm.negq(length);
244
245 // Align the main loop
246 masm.align(crb.target.wordSize * 2);
247 masm.bind(loop);
248 masm.vmovdqu(vector1, new AMD64Address(array1, length, Scale.Times1, 0));
249 masm.vmovdqu(vector2, new AMD64Address(array2, length, Scale.Times1, 0));
250 masm.vpxor(vector1, vector1, vector2);
251 masm.vptest(vector1, vector1);
252 masm.jcc(ConditionFlag.NotZero, falseLabel);
253 masm.addq(length, AVX_VECTOR_SIZE);
254 masm.jcc(ConditionFlag.NotZero, loop);
255
256 masm.testl(result, result);
257 masm.jcc(ConditionFlag.Zero, trueLabel);
258
259 /*
260 * Compare the remaining bytes with an unaligned memory load aligned to the end of the
261 * array.
262 */
263 masm.vmovdqu(vector1, new AMD64Address(array1, result, Scale.Times1, -AVX_VECTOR_SIZE));
264 masm.vmovdqu(vector2, new AMD64Address(array2, result, Scale.Times1, -AVX_VECTOR_SIZE));
265 masm.vpxor(vector1, vector1, vector2);
266 masm.vptest(vector1, vector1);
267 masm.jcc(ConditionFlag.NotZero, falseLabel);
268 masm.jmp(trueLabel);
269
270 masm.bind(compareTail);
271 masm.movl(length, result);
272 }
273
274 /**
275 * Vector size used in {@link #emit8ByteCompare}.
276 */
277 private static final int VECTOR_SIZE = 8;
278
279 /**
280 * Emits code that uses 8-byte vector compares.
281 */
282 private void emit8ByteCompare(CompilationResultBuilder crb, AMD64MacroAssembler masm, Register result, Register array1, Register array2, Register length, Label trueLabel, Label falseLabel) {
283 Label loop = new Label();
284 Label compareTail = new Label();
285
286 Register temp = asRegister(temp4);
287
288 masm.andl(result, VECTOR_SIZE - 1); // tail count (in bytes)
289 masm.andl(length, ~(VECTOR_SIZE - 1)); // vector count (in bytes)
290 masm.jccb(ConditionFlag.Zero, compareTail);
291
292 masm.leaq(array1, new AMD64Address(array1, length, Scale.Times1, 0));
293 masm.leaq(array2, new AMD64Address(array2, length, Scale.Times1, 0));
294 masm.negq(length);
295
296 // Align the main loop
297 masm.align(crb.target.wordSize * 2);
298 masm.bind(loop);
299 masm.movq(temp, new AMD64Address(array1, length, Scale.Times1, 0));
300 masm.cmpq(temp, new AMD64Address(array2, length, Scale.Times1, 0));
301 masm.jccb(ConditionFlag.NotEqual, falseLabel);
302 masm.addq(length, VECTOR_SIZE);
303 masm.jccb(ConditionFlag.NotZero, loop);
304
305 masm.testl(result, result);
306 masm.jccb(ConditionFlag.Zero, trueLabel);
307
308 /*
309 * Compare the remaining bytes with an unaligned memory load aligned to the end of the
310 * array.
311 */
312 masm.movq(temp, new AMD64Address(array1, result, Scale.Times1, -VECTOR_SIZE));
313 masm.cmpq(temp, new AMD64Address(array2, result, Scale.Times1, -VECTOR_SIZE));
314 masm.jccb(ConditionFlag.NotEqual, falseLabel);
315 masm.jmpb(trueLabel);
316
317 masm.bind(compareTail);
318 masm.movl(length, result);
319 }
320
321 /**
322 * Emits code to compare the remaining 1 to 4 bytes.
323 */
324 private void emitTailCompares(AMD64MacroAssembler masm, Register result, Register array1, Register array2, Register length, Label trueLabel, Label falseLabel) {
325 Label compare2Bytes = new Label();
326 Label compare1Byte = new Label();
327
328 Register temp = asRegister(temp4);
329
330 if (kind.getByteCount() <= 4) {
331 // Compare trailing 4 bytes, if any.
332 masm.testl(result, 4);
333 masm.jccb(ConditionFlag.Zero, compare2Bytes);
334 masm.movl(temp, new AMD64Address(array1, 0));
335 masm.cmpl(temp, new AMD64Address(array2, 0));
336 masm.jccb(ConditionFlag.NotEqual, falseLabel);
337
338 if (kind.getByteCount() <= 2) {
339 // Move array pointers forward.
340 masm.leaq(array1, new AMD64Address(array1, 4));
341 masm.leaq(array2, new AMD64Address(array2, 4));
342
343 // Compare trailing 2 bytes, if any.
344 masm.bind(compare2Bytes);
345 masm.testl(result, 2);
346 masm.jccb(ConditionFlag.Zero, compare1Byte);
347 masm.movzwl(temp, new AMD64Address(array1, 0));
348 masm.movzwl(length, new AMD64Address(array2, 0));
349 masm.cmpl(temp, length);
350 masm.jccb(ConditionFlag.NotEqual, falseLabel);
351
352 // The one-byte tail compare is only required for boolean and byte arrays.
353 if (kind.getByteCount() <= 1) {
354 // Move array pointers forward before we compare the last trailing byte.
355 masm.leaq(array1, new AMD64Address(array1, 2));
356 masm.leaq(array2, new AMD64Address(array2, 2));
357
358 // Compare trailing byte, if any.
359 masm.bind(compare1Byte);
360 masm.testl(result, 1);
361 masm.jccb(ConditionFlag.Zero, trueLabel);
362 masm.movzbl(temp, new AMD64Address(array1, 0));
363 masm.movzbl(length, new AMD64Address(array2, 0));
364 masm.cmpl(temp, length);
365 masm.jccb(ConditionFlag.NotEqual, falseLabel);
366 } else {
367 masm.bind(compare1Byte);
368 }
369 } else {
370 masm.bind(compare2Bytes);
371 }
372 }
373 }
374
375 private static final Unsafe UNSAFE = initUnsafe();
376
377 private static Unsafe initUnsafe() {
378 try {
379 return Unsafe.getUnsafe();
380 } catch (SecurityException se) {
381 try {
382 Field theUnsafe = Unsafe.class.getDeclaredField("theUnsafe");
383 theUnsafe.setAccessible(true);
384 return (Unsafe) theUnsafe.get(Unsafe.class);
385 } catch (Exception e) {
386 throw new RuntimeException("exception while trying to get Unsafe", e);
387 }
388 }
389 }
390 }