jdk-24/hotspot/test/compiler/unsafe/JdkInternalMiscUnsafeAccessTestChar.java

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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/*
 * @test
 * @bug 8143628
 * @summary Test unsafe access for char
 * @modules java.base/jdk.internal.misc
 * @run testng/othervm -Diters=100   -Xint                   JdkInternalMiscUnsafeAccessTestChar
 * @run testng/othervm -Diters=20000 -XX:TieredStopAtLevel=1 JdkInternalMiscUnsafeAccessTestChar
 * @run testng/othervm -Diters=20000 -XX:-TieredCompilation  JdkInternalMiscUnsafeAccessTestChar
 * @run testng/othervm -Diters=20000                         JdkInternalMiscUnsafeAccessTestChar
 */

import org.testng.annotations.Test;

import java.lang.reflect.Field;

import static org.testng.Assert.*;

public class JdkInternalMiscUnsafeAccessTestChar {
    static final int ITERS = Integer.getInteger("iters", 1);
    static final int WEAK_ATTEMPTS = Integer.getInteger("weakAttempts", 10);

    static final jdk.internal.misc.Unsafe UNSAFE;

    static final long V_OFFSET;

    static final Object STATIC_V_BASE;

    static final long STATIC_V_OFFSET;

    static int ARRAY_OFFSET;

    static int ARRAY_SHIFT;

    static {
        try {
            Field f = jdk.internal.misc.Unsafe.class.getDeclaredField("theUnsafe");
            f.setAccessible(true);
            UNSAFE = (jdk.internal.misc.Unsafe) f.get(null);
        } catch (Exception e) {
            throw new RuntimeException("Unable to get Unsafe instance.", e);
        }

        try {
            Field staticVField = JdkInternalMiscUnsafeAccessTestChar.class.getDeclaredField("static_v");
            STATIC_V_BASE = UNSAFE.staticFieldBase(staticVField);
            STATIC_V_OFFSET = UNSAFE.staticFieldOffset(staticVField);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }

        try {
            Field vField = JdkInternalMiscUnsafeAccessTestChar.class.getDeclaredField("v");
            V_OFFSET = UNSAFE.objectFieldOffset(vField);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }

        ARRAY_OFFSET = UNSAFE.arrayBaseOffset(char[].class);
        int ascale = UNSAFE.arrayIndexScale(char[].class);
        ARRAY_SHIFT = 31 - Integer.numberOfLeadingZeros(ascale);
    }

    static char static_v;

    char v;

    @Test
    public void testFieldInstance() {
        JdkInternalMiscUnsafeAccessTestChar t = new JdkInternalMiscUnsafeAccessTestChar();
        for (int c = 0; c < ITERS; c++) {
            testAccess(t, V_OFFSET);
        }
    }

    @Test
    public void testFieldStatic() {
        for (int c = 0; c < ITERS; c++) {
            testAccess(STATIC_V_BASE, STATIC_V_OFFSET);
        }
    }

    @Test
    public void testArray() {
        char[] array = new char[10];
        for (int c = 0; c < ITERS; c++) {
            for (int i = 0; i < array.length; i++) {
                testAccess(array, (((long) i) << ARRAY_SHIFT) + ARRAY_OFFSET);
            }
        }
    }

    @Test
    public void testArrayOffHeap() {
        int size = 10;
        long address = UNSAFE.allocateMemory(size << ARRAY_SHIFT);
        try {
            for (int c = 0; c < ITERS; c++) {
                for (int i = 0; i < size; i++) {
                    testAccess(null, (((long) i) << ARRAY_SHIFT) + address);
                }
            }
        } finally {
            UNSAFE.freeMemory(address);
        }
    }

    @Test
    public void testArrayOffHeapDirect() {
        int size = 10;
        long address = UNSAFE.allocateMemory(size << ARRAY_SHIFT);
        try {
            for (int c = 0; c < ITERS; c++) {
                for (int i = 0; i < size; i++) {
                    testAccess((((long) i) << ARRAY_SHIFT) + address);
                }
            }
        } finally {
            UNSAFE.freeMemory(address);
        }
    }

    static void testAccess(Object base, long offset) {
        // Plain
        {
            UNSAFE.putChar(base, offset, 'a');
            char x = UNSAFE.getChar(base, offset);
            assertEquals(x, 'a', "set char value");
        }

        // Volatile
        {
            UNSAFE.putCharVolatile(base, offset, 'b');
            char x = UNSAFE.getCharVolatile(base, offset);
            assertEquals(x, 'b', "putVolatile char value");
        }


        // Lazy
        {
            UNSAFE.putCharRelease(base, offset, 'a');
            char x = UNSAFE.getCharAcquire(base, offset);
            assertEquals(x, 'a', "putRelease char value");
        }

        // Opaque
        {
            UNSAFE.putCharOpaque(base, offset, 'b');
            char x = UNSAFE.getCharOpaque(base, offset);
            assertEquals(x, 'b', "putOpaque char value");
        }

        // Unaligned
        {
            UNSAFE.putCharUnaligned(base, offset, 'b');
            char x = UNSAFE.getCharUnaligned(base, offset);
            assertEquals(x, 'b', "putUnaligned char value");
        }

        {
            UNSAFE.putCharUnaligned(base, offset, 'a', true);
            char x = UNSAFE.getCharUnaligned(base, offset, true);
            assertEquals(x, 'a', "putUnaligned big endian char value");
        }

        {
            UNSAFE.putCharUnaligned(base, offset, 'b', false);
            char x = UNSAFE.getCharUnaligned(base, offset, false);
            assertEquals(x, 'b', "putUnaligned little endian char value");
        }


    }

    static void testAccess(long address) {
        // Plain
        {
            UNSAFE.putChar(address, 'a');
            char x = UNSAFE.getChar(address);
            assertEquals(x, 'a', "set char value");
        }
    }
}