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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * 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.
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package org.graalvm.compiler.hotspot.test;

import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.config;
import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.referentOffset;

import java.lang.ref.WeakReference;

import org.junit.Assert;
import org.junit.Test;

import org.graalvm.compiler.debug.Debug;
import org.graalvm.compiler.debug.Debug.Scope;
import org.graalvm.compiler.hotspot.GraalHotSpotVMConfig;
import org.graalvm.compiler.hotspot.nodes.G1PostWriteBarrier;
import org.graalvm.compiler.hotspot.nodes.G1PreWriteBarrier;
import org.graalvm.compiler.hotspot.nodes.G1ReferentFieldReadBarrier;
import org.graalvm.compiler.hotspot.nodes.SerialWriteBarrier;
import org.graalvm.compiler.hotspot.phases.WriteBarrierAdditionPhase;
import org.graalvm.compiler.nodes.StructuredGraph;
import org.graalvm.compiler.nodes.StructuredGraph.AllowAssumptions;
import org.graalvm.compiler.nodes.memory.HeapAccess.BarrierType;
import org.graalvm.compiler.nodes.memory.ReadNode;
import org.graalvm.compiler.nodes.memory.WriteNode;
import org.graalvm.compiler.nodes.memory.address.OffsetAddressNode;
import org.graalvm.compiler.nodes.spi.LoweringTool;
import org.graalvm.compiler.phases.OptimisticOptimizations;
import org.graalvm.compiler.phases.common.CanonicalizerPhase;
import org.graalvm.compiler.phases.common.GuardLoweringPhase;
import org.graalvm.compiler.phases.common.LoweringPhase;
import org.graalvm.compiler.phases.common.inlining.InliningPhase;
import org.graalvm.compiler.phases.common.inlining.policy.InlineEverythingPolicy;
import org.graalvm.compiler.phases.tiers.HighTierContext;
import org.graalvm.compiler.phases.tiers.MidTierContext;

import jdk.vm.ci.hotspot.HotSpotInstalledCode;
import jdk.vm.ci.meta.JavaConstant;
import jdk.vm.ci.meta.ResolvedJavaMethod;
import sun.misc.Unsafe;

The following unit tests assert the presence of write barriers for both Serial and G1 GCs.
Normally, the tests check for compile time inserted barriers. However, there are the cases of
unsafe loads of the java.lang.ref.Reference.referent field where runtime checks have to be
performed also. For those cases, the unit tests check the presence of the compile-time inserted
barriers. Concerning the runtime checks, the results of variable inputs (object types and
offsets) passed as input parameters can be checked against printed output from the G1 write
barrier snippets. The runtime checks have been validated offline.
/**
 * The following unit tests assert the presence of write barriers for both Serial and G1 GCs.
 * Normally, the tests check for compile time inserted barriers. However, there are the cases of
 * unsafe loads of the java.lang.ref.Reference.referent field where runtime checks have to be
 * performed also. For those cases, the unit tests check the presence of the compile-time inserted
 * barriers. Concerning the runtime checks, the results of variable inputs (object types and
 * offsets) passed as input parameters can be checked against printed output from the G1 write
 * barrier snippets. The runtime checks have been validated offline.
 */
public class WriteBarrierAdditionTest extends HotSpotGraalCompilerTest {

    private final GraalHotSpotVMConfig config = runtime().getVMConfig();
    private static final long referentOffset = referentOffset();

    public static class Container {

        public Container a;
        public Container b;
    }

    
Expected 2 barriers for the Serial GC and 4 for G1 (2 pre + 2 post).
/**
     * Expected 2 barriers for the Serial GC and 4 for G1 (2 pre + 2 post).
     */
    @Test
    public void test1() throws Exception {
        testHelper("test1Snippet", (config.useG1GC) ? 4 : 2);
    }

    public static void test1Snippet() {
        Container main = new Container();
        Container temp1 = new Container();
        Container temp2 = new Container();
        main.a = temp1;
        main.b = temp2;
    }

    
Expected 4 barriers for the Serial GC and 8 for G1 (4 pre + 4 post).
/**
     * Expected 4 barriers for the Serial GC and 8 for G1 (4 pre + 4 post).
     */
    @Test
    public void test2() throws Exception {
        testHelper("test2Snippet", config.useG1GC ? 8 : 4);
    }

    public static void test2Snippet(boolean test) {
        Container main = new Container();
        Container temp1 = new Container();
        Container temp2 = new Container();
        for (int i = 0; i < 10; i++) {
            if (test) {
                main.a = temp1;
                main.b = temp2;
            } else {
                main.a = temp2;
                main.b = temp1;
            }
        }
    }

    
Expected 4 barriers for the Serial GC and 8 for G1 (4 pre + 4 post).
/**
     * Expected 4 barriers for the Serial GC and 8 for G1 (4 pre + 4 post).
     */
    @Test
    public void test3() throws Exception {
        testHelper("test3Snippet", config.useG1GC ? 8 : 4);
    }

    public static void test3Snippet() {
        Container[] main = new Container[10];
        Container temp1 = new Container();
        Container temp2 = new Container();
        for (int i = 0; i < 10; i++) {
            main[i].a = main[i].b = temp1;
        }

        for (int i = 0; i < 10; i++) {
            main[i].a = main[i].b = temp2;
        }
    }

    
Expected 2 barriers for the Serial GC and 5 for G1 (3 pre + 2 post) The (2 or 4) barriers are
emitted while initializing the fields of the WeakReference instance. The extra pre barrier of
G1 concerns the read of the referent field.
/**
     * Expected 2 barriers for the Serial GC and 5 for G1 (3 pre + 2 post) The (2 or 4) barriers are
     * emitted while initializing the fields of the WeakReference instance. The extra pre barrier of
     * G1 concerns the read of the referent field.
     */
    @Test
    public void test4() throws Exception {
        testHelper("test4Snippet", config.useG1GC ? 5 : 2);
    }

    public static Object test4Snippet() {
        WeakReference<Object> weakRef = new WeakReference<>(new Object());
        return weakRef.get();
    }

    static WeakReference<Object> wr = new WeakReference<>(new Object());
    static Container con = new Container();

    
Expected 4 barriers for the Serial GC and 9 for G1 (1 ref + 4 pre + 4 post). In this test, we
load the correct offset of the WeakReference object so naturally we assert the presence of
the pre barrier.
/**
     * Expected 4 barriers for the Serial GC and 9 for G1 (1 ref + 4 pre + 4 post). In this test, we
     * load the correct offset of the WeakReference object so naturally we assert the presence of
     * the pre barrier.
     */
    @Test
    public void test5() throws Exception {
        testHelper("test5Snippet", config.useG1GC ? 1 : 0);
    }

    public static Object test5Snippet() throws Exception {
        return UNSAFE.getObject(wr, config(null).useCompressedOops ? 12L : 16L);
    }

    
The following test concerns the runtime checks of the unsafe loads. In this test, we unsafely
load the java.lang.ref.Reference.referent field so the pre barier has to be executed.
/**
     * The following test concerns the runtime checks of the unsafe loads. In this test, we unsafely
     * load the java.lang.ref.Reference.referent field so the pre barier has to be executed.
     */
    @Test
    public void test6() throws Exception {
        test2("testUnsafeLoad", UNSAFE, wr, new Long(referentOffset), null);
    }

    
The following test concerns the runtime checks of the unsafe loads. In this test, we unsafely
load a matching offset of a wrong object so the pre barier must not be executed.
/**
     * The following test concerns the runtime checks of the unsafe loads. In this test, we unsafely
     * load a matching offset of a wrong object so the pre barier must not be executed.
     */
    @Test
    public void test7() throws Exception {
        test2("testUnsafeLoad", UNSAFE, con, new Long(referentOffset), null);
    }

    
The following test concerns the runtime checks of the unsafe loads. In this test, we unsafely
load a non-matching offset field of the java.lang.ref.Reference object so the pre barier must
not be executed.
/**
     * The following test concerns the runtime checks of the unsafe loads. In this test, we unsafely
     * load a non-matching offset field of the java.lang.ref.Reference object so the pre barier must
     * not be executed.
     */
    @Test
    public void test8() throws Exception {
        test2("testUnsafeLoad", UNSAFE, wr, new Long(config.useCompressedOops ? 20 : 32), null);
    }

    
The following test concerns the runtime checks of the unsafe loads. In this test, we unsafely
load a matching offset+disp field of the java.lang.ref.Reference object so the pre barier
must be executed.
/**
     * The following test concerns the runtime checks of the unsafe loads. In this test, we unsafely
     * load a matching offset+disp field of the java.lang.ref.Reference object so the pre barier
     * must be executed.
     */
    @Test
    public void test10() throws Exception {
        test2("testUnsafeLoad", UNSAFE, wr, new Long(config.useCompressedOops ? 6 : 8), new Integer(config.useCompressedOops ? 6 : 8));
    }

    
The following test concerns the runtime checks of the unsafe loads. In this test, we unsafely
load a non-matching offset+disp field of the java.lang.ref.Reference object so the pre barier
must not be executed.
/**
     * The following test concerns the runtime checks of the unsafe loads. In this test, we unsafely
     * load a non-matching offset+disp field of the java.lang.ref.Reference object so the pre barier
     * must not be executed.
     */
    @Test
    public void test9() throws Exception {
        test2("testUnsafeLoad", UNSAFE, wr, new Long(config.useCompressedOops ? 10 : 16), new Integer(config.useCompressedOops ? 10 : 16));
    }

    static Object[] src = new Object[1];
    static Object[] dst = new Object[1];

    static {
        for (int i = 0; i < src.length; i++) {
            src[i] = new Object();
        }
        for (int i = 0; i < dst.length; i++) {
            dst[i] = new Object();
        }
    }

    public static void testArrayCopy(Object a, Object b, Object c) throws Exception {
        System.arraycopy(a, 0, b, 0, (int) c);
    }

    @Test
    public void test11() throws Exception {
        test2("testArrayCopy", src, dst, dst.length);
    }

    public static Object testUnsafeLoad(Unsafe theUnsafe, Object a, Object b, Object c) throws Exception {
        final int offset = (c == null ? 0 : ((Integer) c).intValue());
        final long displacement = (b == null ? 0 : ((Long) b).longValue());
        return theUnsafe.getObject(a, offset + displacement);
    }

    private HotSpotInstalledCode getInstalledCode(String name, boolean withUnsafePrefix) throws Exception {
        final ResolvedJavaMethod javaMethod = withUnsafePrefix ? getResolvedJavaMethod(WriteBarrierAdditionTest.class, name, Unsafe.class, Object.class, Object.class, Object.class)
                        : getResolvedJavaMethod(WriteBarrierAdditionTest.class, name, Object.class, Object.class, Object.class);
        final HotSpotInstalledCode installedCode = (HotSpotInstalledCode) getCode(javaMethod);
        return installedCode;
    }

    @SuppressWarnings("try")
    private void testHelper(final String snippetName, final int expectedBarriers) throws Exception, SecurityException {
        ResolvedJavaMethod snippet = getResolvedJavaMethod(snippetName);
        try (Scope s = Debug.scope("WriteBarrierAdditionTest", snippet)) {
            StructuredGraph graph = parseEager(snippet, AllowAssumptions.NO);
            HighTierContext highContext = getDefaultHighTierContext();
            MidTierContext midContext = new MidTierContext(getProviders(), getTargetProvider(), OptimisticOptimizations.ALL, graph.getProfilingInfo());
            new InliningPhase(new InlineEverythingPolicy(), new CanonicalizerPhase()).apply(graph, highContext);
            new CanonicalizerPhase().apply(graph, highContext);
            new LoweringPhase(new CanonicalizerPhase(), LoweringTool.StandardLoweringStage.HIGH_TIER).apply(graph, highContext);
            new GuardLoweringPhase().apply(graph, midContext);
            new LoweringPhase(new CanonicalizerPhase(), LoweringTool.StandardLoweringStage.MID_TIER).apply(graph, midContext);
            new WriteBarrierAdditionPhase(config).apply(graph);
            Debug.dump(Debug.BASIC_LOG_LEVEL, graph, "After Write Barrier Addition");

            int barriers = 0;
            if (config.useG1GC) {
                barriers = graph.getNodes().filter(G1ReferentFieldReadBarrier.class).count() + graph.getNodes().filter(G1PreWriteBarrier.class).count() +
                                graph.getNodes().filter(G1PostWriteBarrier.class).count();
            } else {
                barriers = graph.getNodes().filter(SerialWriteBarrier.class).count();
            }
            if (expectedBarriers != barriers) {
                Assert.assertEquals(getScheduledGraphString(graph), expectedBarriers, barriers);
            }
            for (WriteNode write : graph.getNodes().filter(WriteNode.class)) {
                if (config.useG1GC) {
                    if (write.getBarrierType() != BarrierType.NONE) {
                        Assert.assertEquals(1, write.successors().count());
                        Assert.assertTrue(write.next() instanceof G1PostWriteBarrier);
                        Assert.assertTrue(write.predecessor() instanceof G1PreWriteBarrier);
                    }
                } else {
                    if (write.getBarrierType() != BarrierType.NONE) {
                        Assert.assertEquals(1, write.successors().count());
                        Assert.assertTrue(write.next() instanceof SerialWriteBarrier);
                    }
                }
            }

            for (ReadNode read : graph.getNodes().filter(ReadNode.class)) {
                if (read.getBarrierType() != BarrierType.NONE) {
                    Assert.assertTrue(read.getAddress() instanceof OffsetAddressNode);
                    JavaConstant constDisp = ((OffsetAddressNode) read.getAddress()).getOffset().asJavaConstant();
                    Assert.assertNotNull(constDisp);
                    Assert.assertEquals(referentOffset, constDisp.asLong());
                    Assert.assertTrue(config.useG1GC);
                    Assert.assertEquals(BarrierType.PRECISE, read.getBarrierType());
                    Assert.assertTrue(read.next() instanceof G1ReferentFieldReadBarrier);
                }
            }
        } catch (Throwable e) {
            throw Debug.handle(e);
        }
    }

    private void test2(final String snippet, Object... args) throws Exception {
        HotSpotInstalledCode code = getInstalledCode(snippet, args[0] instanceof Unsafe);
        code.executeVarargs(args);
    }
}