src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.hotspot.test/src/org/graalvm/compiler/hotspot/test/HotSpotStampMemoryAccessTest.java

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package org.graalvm.compiler.hotspot.test;

import org.graalvm.compiler.core.common.CompressEncoding;
import org.graalvm.compiler.core.common.type.ObjectStamp;
import org.graalvm.compiler.core.common.type.Stamp;
import org.graalvm.compiler.core.common.type.StampFactory;
import org.graalvm.compiler.hotspot.nodes.type.HotSpotNarrowOopStamp;
import org.junit.Assume;
import org.junit.Test;

import jdk.vm.ci.meta.JavaConstant;
import jdk.vm.ci.meta.JavaKind;
import jdk.vm.ci.meta.MemoryAccessProvider;

public class HotSpotStampMemoryAccessTest extends HotSpotGraalCompilerTest {

    @Test
    public void testReadNarrowObject() {
        CompressEncoding oopEncoding = runtime().getVMConfig().getOopEncoding();
        Assume.assumeTrue("Compressed oops must be enabled", runtime().getVMConfig().useCompressedOops);
        MemoryAccessProvider memory = getConstantReflection().getMemoryAccessProvider();
        JavaConstant base = getSnippetReflection().forObject("");
        ObjectStamp stamp = (ObjectStamp) StampFactory.forKind(JavaKind.Object);
        Stamp narrowStamp = HotSpotNarrowOopStamp.compressed(stamp, oopEncoding);
        assertTrue(narrowStamp.readConstant(memory, base, 128) == null);
    }
}