/* * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package org.openjdk.bench.vm.compiler; import org.openjdk.jmh.annotations.*; import java.util.Arrays; import java.util.Random; import java.util.concurrent.ThreadLocalRandom; import java.util.concurrent.TimeUnit; /** * Examine issues with (potentially) uninitialized locals interfering with * loop optimizations */ @BenchmarkMode(Mode.AverageTime) @OutputTimeUnit(TimeUnit.NANOSECONDS) @Fork(value = 3) @Warmup(iterations = 5, time = 2) @Measurement(iterations = 5, time = 3) @State(Scope.Thread) public class LoopLocals { public char[] bytesStartingWithNegative = """ \uFF11 Lorem ipsum dolor sit amet, consectetur adipiscing elit. Aliquam ac sem eu urna egestas placerat. Etiam finibus ipsum nulla, non mattis dolor cursus a. Nulla nec nisl consectetur, lacinia neque id, accumsan ante. Curabitur et sapien in magna porta ultricies. Sed vel pellentesque nibh. Pellentesque dictum dignissim diam eu ultricies. Class aptent taciti sociosqu ad litora torquent per conubia nostra, per inceptos himenaeos. Suspendisse erat diam, fringilla sed massa sed, posuere viverra orci. Suspendisse tempor libero non gravida efficitur. Vivamus lacinia risus non orci viverra, at consectetur odio laoreet. Suspendisse potenti. Phasellus vel nisi iaculis, accumsan quam sed, bibendum eros. Sed venenatis nulla tortor, et eleifend urna sodales id. Nullam tempus ac metus sit amet sollicitudin. Nam sed ex diam. Praesent vitae eros et neque condimentum consectetur eget non tortor. Praesent bibendum vel felis nec dignissim. Maecenas a enim diam. Suspendisse quis ligula at nisi accumsan lacinia id hendrerit sapien. Donec aliquam mattis lectus eu ultrices. Duis eu nisl euismod, blandit mauris vel, placerat urna. Etiam malesuada enim purus, tristique mollis odio blandit quis. Vivamus posuere. """.toCharArray(); public char[] bytesEndingWithNegative = """ Lorem ipsum dolor sit amet, consectetur adipiscing elit. Aliquam ac sem eu urna egestas placerat. Etiam finibus ipsum nulla, non mattis dolor cursus a. Nulla nec nisl consectetur, lacinia neque id, accumsan ante. Curabitur et sapien in magna porta ultricies. Sed vel pellentesque nibh. Pellentesque dictum dignissim diam eu ultricies. Class aptent taciti sociosqu ad litora torquent per conubia nostra, per inceptos himenaeos. Suspendisse erat diam, fringilla sed massa sed, posuere viverra orci. Suspendisse tempor libero non gravida efficitur. Vivamus lacinia risus non orci viverra, at consectetur odio laoreet. Suspendisse potenti. Phasellus vel nisi iaculis, accumsan quam sed, bibendum eros. Sed venenatis nulla tortor, et eleifend urna sodales id. Nullam tempus ac metus sit amet sollicitudin. Nam sed ex diam. Praesent vitae eros et neque condimentum consectetur eget non tortor. Praesent bibendum vel felis nec dignissim. Maecenas a enim diam. Suspendisse quis ligula at nisi accumsan lacinia id hendrerit sapien. Donec aliquam mattis lectus eu ultrices. Duis eu nisl euismod, blandit mauris vel, placerat urna. Etiam malesuada enim purus, tristique mollis odio blandit quis. Vivamus posuere. \uFF11 """.toCharArray(); @Param({"startNonASCII", "endNonASCII", "mixed"}) private String variant; private char[] val; @Setup public void setup() { val = switch (variant) { case "startNonASCII" -> bytesStartingWithNegative; case "endNonASCII" -> bytesEndingWithNegative; case "mixed" -> { char[] chars = bytesEndingWithNegative.clone(); var random = new Random(0L); for (int i = 0; i < chars.length; i++) { if (random.nextInt(100) < 30) { chars[i] = (char)(chars[i] + random.nextInt(0x2F00)); } } yield chars; } default -> throw new RuntimeException("Unknown variant: " + variant); }; } @Benchmark public byte[] loopsWithSharedLocal() { int dp = 0; int sp = 0; int sl = val.length >> 1; byte[] dst = new byte[sl * 3]; char c; while (sp < sl && (c = getChar(val, sp)) < '\u0080') { dst[dp++] = (byte)c; sp++; } while (sp < sl) { c = getChar(val, sp++); if (c < 0x80) { dst[dp++] = (byte)c; } else if (c < 0x800) { dst[dp++] = (byte)(0xc0 | (c >> 6)); dst[dp++] = (byte)(0x80 | (c & 0x3f)); } else if (Character.isSurrogate(c)) { int uc = -1; char c2; if (Character.isHighSurrogate(c) && sp < sl && Character.isLowSurrogate(c2 = getChar(val, sp))) { uc = Character.toCodePoint(c, c2); } if (uc < 0) { dst[dp++] = '?'; } else { dst[dp++] = (byte)(0xf0 | ((uc >> 18))); dst[dp++] = (byte)(0x80 | ((uc >> 12) & 0x3f)); dst[dp++] = (byte)(0x80 | ((uc >> 6) & 0x3f)); dst[dp++] = (byte)(0x80 | (uc & 0x3f)); sp++; // 2 chars } } else { // 3 bytes, 16 bits dst[dp++] = (byte)(0xe0 | ((c >> 12))); dst[dp++] = (byte)(0x80 | ((c >> 6) & 0x3f)); dst[dp++] = (byte)(0x80 | (c & 0x3f)); } } if (dp == dst.length) { return dst; } return Arrays.copyOf(dst, dp); } @Benchmark public byte[] loopsWithScopedLocal() { int dp = 0; int sp = 0; int sl = val.length >> 1; byte[] dst = new byte[sl * 3]; while (sp < sl) { // ascii fast loop; char c = getChar(val, sp); if (c >= '\u0080') { break; } dst[dp++] = (byte)c; sp++; } while (sp < sl) { char c = getChar(val, sp++); if (c < 0x80) { dst[dp++] = (byte)c; } else if (c < 0x800) { dst[dp++] = (byte)(0xc0 | (c >> 6)); dst[dp++] = (byte)(0x80 | (c & 0x3f)); } else if (Character.isSurrogate(c)) { int uc = -1; char c2; if (Character.isHighSurrogate(c) && sp < sl && Character.isLowSurrogate(c2 = getChar(val, sp))) { uc = Character.toCodePoint(c, c2); } if (uc < 0) { dst[dp++] = '?'; } else { dst[dp++] = (byte)(0xf0 | ((uc >> 18))); dst[dp++] = (byte)(0x80 | ((uc >> 12) & 0x3f)); dst[dp++] = (byte)(0x80 | ((uc >> 6) & 0x3f)); dst[dp++] = (byte)(0x80 | (uc & 0x3f)); sp++; // 2 chars } } else { // 3 bytes, 16 bits dst[dp++] = (byte)(0xe0 | ((c >> 12))); dst[dp++] = (byte)(0x80 | ((c >> 6) & 0x3f)); dst[dp++] = (byte)(0x80 | (c & 0x3f)); } } if (dp == dst.length) { return dst; } return Arrays.copyOf(dst, dp); } static char getChar(char[] val, int index) { return val[index]; } }