/*

 * Copyright (c) 2013, 2019, 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.

 *

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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package org.graalvm.compiler.core.test;

import org.graalvm.compiler.debug.DebugContext;

import org.graalvm.compiler.debug.DebugDumpScope;

import org.graalvm.compiler.nodes.ParameterNode;

import org.graalvm.compiler.nodes.StructuredGraph;

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

import org.graalvm.compiler.nodes.memory.FloatingReadNode;

import org.graalvm.compiler.nodes.spi.CoreProviders;

import org.graalvm.compiler.nodes.spi.LoweringTool;

import org.graalvm.compiler.phases.common.CanonicalizerPhase;

import org.graalvm.compiler.phases.common.FloatingReadPhase;

import org.graalvm.compiler.phases.common.LoweringPhase;

import org.junit.Assert;

import org.junit.Test;

/* consider

 *     B b = (B) a;

 *     return b.x10;

 *

 * With snippets a typecheck is performed and if it was successful, a PiNode is created.

 * For the read node, however, there is only a dependency to the PiNode, but not to the

 * typecheck itself. With special crafting, it's possible to get the scheduler moving the

 * FloatingReadNode before the typecheck. Assuming the object is of the wrong type (here for

 * example A), an invalid field read is done.

 *

 * In order to avoid this situation, an anchor node is introduced in CheckCastSnippts.

 */

public class ReadAfterCheckCastTest extends GraphScheduleTest {

    public static long foo = 0;

    public static class A {

        public long x1;

    }

    public static class B extends A {

        public long x10;

    }

    public static long test1Snippet(A a) {

        if (foo > 4) {

            B b = (B) a;

            b.x10 += 1;

            return b.x10;

        } else {

            B b = (B) a;

            b.x10 += 1;

            return b.x10;

        }

    }

    @Test

    public void test1() {

        test("test1Snippet");

    }

    @SuppressWarnings("try")

    private void test(final String snippet) {

        DebugContext debug = getDebugContext();

        try (DebugContext.Scope s = debug.scope("ReadAfterCheckCastTest", new DebugDumpScope(snippet))) {

            // check shape of graph, with lots of assumptions. will probably fail if graph

            // structure changes significantly

            StructuredGraph graph = parseEager(snippet, AllowAssumptions.YES);

            CoreProviders context = getProviders();

            CanonicalizerPhase canonicalizer = new CanonicalizerPhase();

            new LoweringPhase(canonicalizer, LoweringTool.StandardLoweringStage.HIGH_TIER).apply(graph, context);

            new FloatingReadPhase().apply(graph);

            canonicalizer.apply(graph, context);

            debug.dump(DebugContext.BASIC_LEVEL, graph, "After lowering");

            for (FloatingReadNode node : graph.getNodes(ParameterNode.TYPE).first().usages().filter(FloatingReadNode.class)) {

                // Checking that the parameter a is not directly used for the access to field

                // x10 (because x10 must be guarded by the checkcast).

                Assert.assertTrue(node.getLocationIdentity().isImmutable());

            }

        } catch (Throwable e) {

            throw debug.handle(e);

        }

    }

}