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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

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 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

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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.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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package org.graalvm.compiler.hotspot.test;

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

import java.lang.ref.WeakReference;

import org.graalvm.compiler.api.test.Graal;

import org.graalvm.compiler.debug.DebugContext;

import org.graalvm.compiler.hotspot.GraalHotSpotVMConfig;

import org.graalvm.compiler.hotspot.HotSpotBackend;

import org.graalvm.compiler.nodes.StructuredGraph;

import org.graalvm.compiler.nodes.StructuredGraph.AllowAssumptions;

import org.graalvm.compiler.nodes.gc.G1PostWriteBarrier;

import org.graalvm.compiler.nodes.gc.G1PreWriteBarrier;

import org.graalvm.compiler.nodes.gc.G1ReferentFieldReadBarrier;

import org.graalvm.compiler.nodes.gc.SerialWriteBarrier;

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.WriteBarrierAdditionPhase;

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 org.graalvm.compiler.runtime.RuntimeProvider;

import org.junit.Assert;

import org.junit.Test;

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.

 */

public class WriteBarrierAdditionTest extends HotSpotGraalCompilerTest {

    private final GraalHotSpotVMConfig config = runtime().getVMConfig();

    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).

     */

    @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).

     */

    @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).

     */

    @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.

     */

    @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 0 barrier for the Serial GC and 1 for G1. 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);

    }

    private static final boolean useCompressedOops = ((HotSpotBackend) Graal.getRequiredCapability(RuntimeProvider.class).getHostBackend()).getRuntime().getVMConfig().useCompressedOops;

    public Object test5Snippet() {

        return UNSAFE.getObject(wr, 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.

     */

    @Test

    public void test6() throws Exception {

        test2("testUnsafeLoad", UNSAFE, wr, Long.valueOf(referentOffset(getMetaAccess())), 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.

     */

    @Test

    public void test7() throws Exception {

        test2("testUnsafeLoad", UNSAFE, con, Long.valueOf(referentOffset(getMetaAccess())), 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.

     */

    @Test

    public void test8() throws Exception {

        test2("testUnsafeLoad", UNSAFE, wr, Long.valueOf(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.

     */

    @Test

    public void test10() throws Exception {

        test2("testUnsafeLoad", UNSAFE, wr, Long.valueOf(config.useCompressedOops ? 6 : 8), Integer.valueOf(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.

     */

    @Test

    public void test9() throws Exception {

        test2("testUnsafeLoad", UNSAFE, wr, Long.valueOf(config.useCompressedOops ? 10 : 16), Integer.valueOf(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);

        DebugContext debug = getDebugContext();

        try (DebugContext.Scope s = debug.scope("WriteBarrierAdditionTest", snippet)) {

            StructuredGraph graph = parseEager(snippet, AllowAssumptions.NO, debug);

            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().apply(graph, midContext);

            debug.dump(DebugContext.BASIC_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(getMetaAccess()), constDisp.asLong());

                    Assert.assertEquals(BarrierType.WEAK_FIELD, read.getBarrierType());

                    if (config.useG1GC) {

                        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);

    }

}