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 * Copyright (c) 2015, 2015, Oracle and/or its affiliates. All rights reserved.

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

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * 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.api.directives.test;

import java.lang.annotation.ElementType;

import java.lang.annotation.Repeatable;

import java.lang.annotation.Retention;

import java.lang.annotation.RetentionPolicy;

import java.lang.annotation.Target;

import java.util.Arrays;

import java.util.Collections;

import java.util.List;

import org.junit.Assert;

import org.junit.Test;

import org.graalvm.compiler.api.directives.GraalDirectives;

import org.graalvm.compiler.core.test.GraalCompilerTest;

import org.graalvm.compiler.graph.Node;

import org.graalvm.compiler.graph.iterators.NodeIterable;

import org.graalvm.compiler.nodes.IfNode;

import org.graalvm.compiler.nodes.LoopBeginNode;

import org.graalvm.compiler.nodes.ReturnNode;

import org.graalvm.compiler.nodes.StructuredGraph;

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

import org.graalvm.compiler.nodes.debug.ControlFlowAnchorNode;

import jdk.vm.ci.meta.ResolvedJavaMethod;

public class ControlFlowAnchorDirectiveTest extends GraalCompilerTest {

    @Retention(RetentionPolicy.RUNTIME)

    @Target(ElementType.METHOD)

    @Repeatable(AnchorSnippet.class)

    private @interface NodeCount {

        Class<? extends Node> nodeClass();

        int expectedCount();

    }

    @Retention(RetentionPolicy.RUNTIME)

    @Target(ElementType.METHOD)

    private @interface AnchorSnippet {

        NodeCount[] value();

    }

    @NodeCount(nodeClass = ReturnNode.class, expectedCount = 1)

    public static int verifyMergeSnippet(int arg) {

        if (arg > 5) {

            return 1;

        } else {

            return 2;

        }

    }

    @NodeCount(nodeClass = ControlFlowAnchorNode.class, expectedCount = 2)

    @NodeCount(nodeClass = ReturnNode.class, expectedCount = 2)

    public static int preventMergeSnippet(int arg) {

        if (arg > 5) {

            GraalDirectives.controlFlowAnchor();

            return 1;

        } else {

            GraalDirectives.controlFlowAnchor();

            return 2;

        }

    }

    @Test

    public void testMerge() {

        test("verifyMergeSnippet", 42);

        test("preventMergeSnippet", 42);

    }

    @NodeCount(nodeClass = ReturnNode.class, expectedCount = 2)

    public static int verifyDuplicateSnippet(int arg) {

        int ret;

        if (arg > 5) {

            ret = 17;

        } else {

            ret = arg;

        }

        return 42 / ret;

    }

    @NodeCount(nodeClass = ControlFlowAnchorNode.class, expectedCount = 1)

    @NodeCount(nodeClass = ReturnNode.class, expectedCount = 1)

    public static int preventDuplicateSnippet(int arg) {

        int ret;

        if (arg > 5) {

            ret = 17;

        } else {

            ret = arg;

        }

        GraalDirectives.controlFlowAnchor();

        return 42 / ret;

    }

    @Test

    public void testDuplicate() {

        // test("verifyDuplicateSnippet", 42);

        test("preventDuplicateSnippet", 42);

    }

    @NodeCount(nodeClass = LoopBeginNode.class, expectedCount = 0)

    public static int verifyFullUnrollSnippet(int arg) {

        int ret = arg;

        for (int i = 0; i < 5; i++) {

            ret = ret * 3 + 1;

        }

        return ret;

    }

    @NodeCount(nodeClass = LoopBeginNode.class, expectedCount = 1)

    @NodeCount(nodeClass = ControlFlowAnchorNode.class, expectedCount = 1)

    public static int preventFullUnrollSnippet(int arg) {

        int ret = arg;

        for (int i = 0; i < 5; i++) {

            GraalDirectives.controlFlowAnchor();

            ret = ret * 3 + 1;

        }

        return ret;

    }

    @Test

    public void testFullUnroll() {

        test("verifyFullUnrollSnippet", 42);

        test("preventFullUnrollSnippet", 42);

    }

    @NodeCount(nodeClass = LoopBeginNode.class, expectedCount = 1)

    @NodeCount(nodeClass = IfNode.class, expectedCount = 4)

    public static void verifyPeelSnippet(int arg) {

        int ret = arg;

        while (ret > 1) {

            if (ret % 2 == 0) {

                ret /= 2;

            } else {

                ret = 3 * ret + 1;

            }

        }

    }

    @NodeCount(nodeClass = LoopBeginNode.class, expectedCount = 1)

    @NodeCount(nodeClass = IfNode.class, expectedCount = 2)

    public static void preventPeelSnippet(int arg) {

        int ret = arg;

        while (ret > 1) {

            GraalDirectives.controlFlowAnchor();

            if (ret % 2 == 0) {

                GraalDirectives.controlFlowAnchor();

                ret /= 2;

            } else {

                ret = 3 * ret + 1;

            }

        }

    }

    @Test

    public void testPeel() {

        test("preventPeelSnippet", 42);

    }

    @NodeCount(nodeClass = LoopBeginNode.class, expectedCount = 2)

    public static void verifyUnswitchSnippet(int arg, boolean flag) {

        int ret = arg;

        while (GraalDirectives.injectBranchProbability(0.9999, ret < 1000)) {

            if (flag) {

                ret = ret * 2 + 1;

            } else {

                ret = ret * 3 + 1;

            }

        }

    }

    @NodeCount(nodeClass = LoopBeginNode.class, expectedCount = 1)

    @NodeCount(nodeClass = IfNode.class, expectedCount = 2)

    public static void preventUnswitchSnippet(int arg, boolean flag) {

        int ret = arg;

        while (GraalDirectives.injectBranchProbability(0.9999, ret < 1000)) {

            if (flag) {

                GraalDirectives.controlFlowAnchor();

                ret++;

            } else {

                ret += 2;

            }

        }

    }

    @Test

    public void testUnswitch() {

        test("verifyUnswitchSnippet", 0, false);

        test("preventUnswitchSnippet", 0, false);

    }

    /**

     * Cloning a ControlFlowAnchorNode is not allowed but cloning a whole graph containing one is

     * ok.

     */

    @Test

    public void testClone() {

        StructuredGraph g = parseEager("preventPeelSnippet", AllowAssumptions.NO);

        g.copy(g.getDebug());

    }

    private static List<NodeCount> getNodeCountAnnotations(StructuredGraph graph) {

        ResolvedJavaMethod method = graph.method();

        AnchorSnippet snippet = method.getAnnotation(AnchorSnippet.class);

        if (snippet != null) {

            return Arrays.asList(snippet.value());

        }

        NodeCount single = method.getAnnotation(NodeCount.class);

        if (single != null) {

            return Collections.singletonList(single);

        }

        return Collections.emptyList();

    }

    @Override

    protected boolean checkLowTierGraph(StructuredGraph graph) {

        List<ControlFlowAnchorNode> anchors = graph.getNodes().filter(ControlFlowAnchorNode.class).snapshot();

        for (int i = 0; i < anchors.size(); i++) {

            ControlFlowAnchorNode a = anchors.get(i);

            for (int j = i + 1; j < anchors.size(); j++) {

                ControlFlowAnchorNode b = anchors.get(j);

                if (a.valueEquals(b)) {

                    Assert.fail("found duplicated control flow anchors (" + a + " and " + b + ")");

                }

            }

        }

        for (NodeCount nodeCount : getNodeCountAnnotations(graph)) {

            NodeIterable<? extends Node> nodes = graph.getNodes().filter(nodeCount.nodeClass());

            Assert.assertEquals(nodeCount.nodeClass().getSimpleName(), nodeCount.expectedCount(), nodes.count());

        }

        return true;

    }

}