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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is free software; you can redistribute it and/or modify it
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 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * 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.
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package org.graalvm.compiler.hotspot.test;

import static org.junit.Assume.assumeTrue;

import org.graalvm.compiler.debug.DebugContext;
import org.graalvm.compiler.hotspot.GraalHotSpotVMConfig;
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.java.AbstractNewObjectNode;
import org.graalvm.compiler.nodes.spi.LoweringTool;
import org.graalvm.compiler.options.OptionValues;
import org.graalvm.compiler.phases.OptimisticOptimizations;
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.virtual.phases.ea.PartialEscapePhase;
import org.junit.Assert;
import org.junit.Test;

import jdk.vm.ci.meta.ResolvedJavaMethod;

This tests that barriers which are deferrable because of ReduceInitialCardMarks are properly
omitted. The rule is simply that only writes to the very last allocated object can skip the card
mark. By creating references between objects only one write can skip the card mark and the other
must emit a card mark.
/**
 * This tests that barriers which are deferrable because of ReduceInitialCardMarks are properly
 * omitted. The rule is simply that only writes to the very last allocated object can skip the card
 * mark. By creating references between objects only one write can skip the card mark and the other
 * must emit a card mark.
 */
public class DeferredBarrierAdditionTest extends HotSpotGraalCompilerTest {

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

    public static Object testCrossReferences() {
        Object[] a = new Object[1];
        Object[] b = new Object[1];
        a[0] = b;
        b[0] = a;
        return a;
    }

    @Test
    public void testGroupAllocation() throws Exception {
        testHelper("testCrossReferences", 1, getInitialOptions());
    }

    @SuppressWarnings("try")
    protected void testHelper(final String snippetName, final int expectedBarriers, OptionValues options) {
        ResolvedJavaMethod snippet = getResolvedJavaMethod(snippetName);
        DebugContext debug = getDebugContext(options, null, snippet);
        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(), createCanonicalizerPhase()).apply(graph, highContext);
            this.createCanonicalizerPhase().apply(graph, highContext);
            new PartialEscapePhase(false, createCanonicalizerPhase(), debug.getOptions()).apply(graph, highContext);
            new LoweringPhase(createCanonicalizerPhase(), LoweringTool.StandardLoweringStage.HIGH_TIER).apply(graph, highContext);
            new GuardLoweringPhase().apply(graph, midContext);
            new LoweringPhase(createCanonicalizerPhase(), LoweringTool.StandardLoweringStage.MID_TIER).apply(graph, midContext);
            new WriteBarrierAdditionPhase().apply(graph, midContext);
            debug.dump(DebugContext.BASIC_LEVEL, graph, "After Write Barrier Addition");

            checkAssumptions(graph);

            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);
            }
        } catch (Throwable e) {
            throw debug.handle(e);
        }
    }

    protected void checkAssumptions(StructuredGraph graph) {
        assumeTrue(graph.getNodes().filter(AbstractNewObjectNode.class).isNotEmpty());
    }

}