/*

 * Copyright (c) 2018, Red Hat Inc. 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.replacements.aarch64;

import org.graalvm.compiler.api.replacements.Snippet;

import org.graalvm.compiler.api.replacements.Snippet.ConstantParameter;

import org.graalvm.compiler.api.replacements.SnippetReflectionProvider;

import org.graalvm.compiler.core.common.type.IntegerStamp;

import org.graalvm.compiler.debug.DebugHandlersFactory;

import org.graalvm.compiler.debug.GraalError;

import org.graalvm.compiler.graph.Node.NodeIntrinsic;

import org.graalvm.compiler.graph.NodeClass;

import org.graalvm.compiler.nodeinfo.NodeInfo;

import org.graalvm.compiler.nodes.DeoptimizeNode;

import org.graalvm.compiler.nodes.NodeView;

import org.graalvm.compiler.nodes.StructuredGraph;

import org.graalvm.compiler.nodes.ValueNode;

import org.graalvm.compiler.nodes.calc.IntegerDivRemNode;

import org.graalvm.compiler.nodes.calc.SignedDivNode;

import org.graalvm.compiler.nodes.calc.SignedRemNode;

import org.graalvm.compiler.nodes.calc.UnsignedDivNode;

import org.graalvm.compiler.nodes.calc.UnsignedRemNode;

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

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

import org.graalvm.compiler.options.OptionValues;

import org.graalvm.compiler.phases.util.Providers;

import org.graalvm.compiler.replacements.SnippetTemplate;

import org.graalvm.compiler.replacements.SnippetTemplate.AbstractTemplates;

import org.graalvm.compiler.replacements.SnippetTemplate.Arguments;

import org.graalvm.compiler.replacements.Snippets;

import jdk.vm.ci.code.TargetDescription;

import jdk.vm.ci.meta.DeoptimizationAction;

import jdk.vm.ci.meta.DeoptimizationReason;

import jdk.vm.ci.meta.JavaKind;

/**

 * Division in AArch64 ISA does not generate a trap when dividing by zero, but instead sets the

 * result to 0. These snippets throw an ArithmethicException if the denominator is 0 and otherwise

 * forward to the LIRGenerator.

 */

public class AArch64IntegerArithmeticSnippets extends AbstractTemplates implements Snippets {

    private final SnippetTemplate.SnippetInfo idiv;

    private final SnippetTemplate.SnippetInfo ldiv;

    private final SnippetTemplate.SnippetInfo irem;

    private final SnippetTemplate.SnippetInfo lrem;

    private final SnippetTemplate.SnippetInfo uidiv;

    private final SnippetTemplate.SnippetInfo uldiv;

    private final SnippetTemplate.SnippetInfo uirem;

    private final SnippetTemplate.SnippetInfo ulrem;

    public AArch64IntegerArithmeticSnippets(OptionValues options, Iterable<DebugHandlersFactory> factories, Providers providers, SnippetReflectionProvider snippetReflection,

                    TargetDescription target) {

        super(options, factories, providers, snippetReflection, target);

        idiv = snippet(AArch64IntegerArithmeticSnippets.class, "idivSnippet");

        ldiv = snippet(AArch64IntegerArithmeticSnippets.class, "ldivSnippet");

        irem = snippet(AArch64IntegerArithmeticSnippets.class, "iremSnippet");

        lrem = snippet(AArch64IntegerArithmeticSnippets.class, "lremSnippet");

        uidiv = snippet(AArch64IntegerArithmeticSnippets.class, "uidivSnippet");

        uldiv = snippet(AArch64IntegerArithmeticSnippets.class, "uldivSnippet");

        uirem = snippet(AArch64IntegerArithmeticSnippets.class, "uiremSnippet");

        ulrem = snippet(AArch64IntegerArithmeticSnippets.class, "ulremSnippet");

    }

    public void lower(IntegerDivRemNode node, LoweringTool tool) {

        JavaKind kind = node.stamp(NodeView.DEFAULT).getStackKind();

        assert kind == JavaKind.Int || kind == JavaKind.Long;

        SnippetTemplate.SnippetInfo snippet;

        if (node instanceof SafeNode) {

            // We already introduced the zero division check, nothing to do.

            return;

        } else if (node instanceof SignedDivNode) {

            snippet = kind == JavaKind.Int ? idiv : ldiv;

        } else if (node instanceof SignedRemNode) {

            snippet = kind == JavaKind.Int ? irem : lrem;

        } else if (node instanceof UnsignedDivNode) {

            snippet = kind == JavaKind.Int ? uidiv : uldiv;

        } else if (node instanceof UnsignedRemNode) {

            snippet = kind == JavaKind.Int ? uirem : ulrem;

        } else {

            throw GraalError.shouldNotReachHere();

        }

        StructuredGraph graph = node.graph();

        Arguments args = new Arguments(snippet, graph.getGuardsStage(), tool.getLoweringStage());

        args.add("x", node.getX());

        args.add("y", node.getY());

        IntegerStamp yStamp = (IntegerStamp) node.getY().stamp(NodeView.DEFAULT);

        args.addConst("needsZeroCheck", node.getZeroCheck() == null && yStamp.contains(0));

        template(node, args).instantiate(providers.getMetaAccess(), node, SnippetTemplate.DEFAULT_REPLACER, args);

    }

    @Snippet

    public static int idivSnippet(int x, int y, @ConstantParameter boolean needsZeroCheck) {

        if (needsZeroCheck) {

            checkForZero(y);

        }

        return safeDiv(x, y);

    }

    @Snippet

    public static long ldivSnippet(long x, long y, @ConstantParameter boolean needsZeroCheck) {

        if (needsZeroCheck) {

            checkForZero(y);

        }

        return safeDiv(x, y);

    }

    @Snippet

    public static int iremSnippet(int x, int y, @ConstantParameter boolean needsZeroCheck) {

        if (needsZeroCheck) {

            checkForZero(y);

        }

        return safeRem(x, y);

    }

    @Snippet

    public static long lremSnippet(long x, long y, @ConstantParameter boolean needsZeroCheck) {

        if (needsZeroCheck) {

            checkForZero(y);

        }

        return safeRem(x, y);

    }

    @Snippet

    public static int uidivSnippet(int x, int y, @ConstantParameter boolean needsZeroCheck) {

        if (needsZeroCheck) {

            checkForZero(y);

        }

        return safeUDiv(x, y);

    }

    @Snippet

    public static long uldivSnippet(long x, long y, @ConstantParameter boolean needsZeroCheck) {

        if (needsZeroCheck) {

            checkForZero(y);

        }

        return safeUDiv(x, y);

    }

    @Snippet

    public static int uiremSnippet(int x, int y, @ConstantParameter boolean needsZeroCheck) {

        if (needsZeroCheck) {

            checkForZero(y);

        }

        return safeURem(x, y);

    }

    @Snippet

    public static long ulremSnippet(long x, long y, @ConstantParameter boolean needsZeroCheck) {

        if (needsZeroCheck) {

            checkForZero(y);

        }

        return safeURem(x, y);

    }

    private static void checkForZero(int y) {

            // "/ by zero"

            DeoptimizeNode.deopt(DeoptimizationAction.InvalidateReprofile, DeoptimizationReason.ArithmeticException);

        }

    }

    private static void checkForZero(long y) {

            // "/ by zero"

            DeoptimizeNode.deopt(DeoptimizationAction.InvalidateReprofile, DeoptimizationReason.ArithmeticException);

        }

    }

    @NodeIntrinsic(SafeSignedDivNode.class)

    private static native int safeDiv(int x, int y);

    @NodeIntrinsic(SafeSignedDivNode.class)

    private static native long safeDiv(long x, long y);

    @NodeIntrinsic(SafeSignedRemNode.class)

    private static native int safeRem(int x, int y);

    @NodeIntrinsic(SafeSignedRemNode.class)

    private static native long safeRem(long x, long y);

    @NodeIntrinsic(SafeUnsignedDivNode.class)

    private static native int safeUDiv(int x, int y);

    @NodeIntrinsic(SafeUnsignedDivNode.class)

    private static native long safeUDiv(long x, long y);

    @NodeIntrinsic(SafeUnsignedRemNode.class)

    private static native int safeURem(int x, int y);

    @NodeIntrinsic(SafeUnsignedRemNode.class)

    private static native long safeURem(long x, long y);

    /**

     * Marker interface to distinguish untreated nodes from ones where we have installed the

     * additional checks.

     */

    private interface SafeNode {

    }

    @NodeInfo

    static class SafeSignedDivNode extends SignedDivNode implements SafeNode {

        public static final NodeClass<SafeSignedDivNode> TYPE = NodeClass.create(SafeSignedDivNode.class);

        protected SafeSignedDivNode(ValueNode x, ValueNode y) {

            super(TYPE, x, y, null);

        }

        @Override

        public void generate(NodeLIRBuilderTool gen) {

            // override to ensure we always pass a null frame state

            // the parent method expects to create one from a non null before state

            gen.setResult(this, gen.getLIRGeneratorTool().getArithmetic().emitDiv(gen.operand(getX()), gen.operand(getY()), null));

        }

    }

    @NodeInfo

    static class SafeSignedRemNode extends SignedRemNode implements SafeNode {

        public static final NodeClass<SafeSignedRemNode> TYPE = NodeClass.create(SafeSignedRemNode.class);

        protected SafeSignedRemNode(ValueNode x, ValueNode y) {

            super(TYPE, x, y, null);

        }

        @Override

        public void generate(NodeLIRBuilderTool gen) {

            // override to ensure we always pass a null frame state

            // the parent method expects to create one from a non null before state

            gen.setResult(this, gen.getLIRGeneratorTool().getArithmetic().emitRem(gen.operand(getX()), gen.operand(getY()), null));

        }

    }

    @NodeInfo

    static class SafeUnsignedDivNode extends UnsignedDivNode implements SafeNode {

        public static final NodeClass<SafeUnsignedDivNode> TYPE = NodeClass.create(SafeUnsignedDivNode.class);

        protected SafeUnsignedDivNode(ValueNode x, ValueNode y) {

            super(TYPE, x, y, null);

        }

        @Override

        public void generate(NodeLIRBuilderTool gen) {

            // override to ensure we always pass a null frame state

            // the parent method expects to create one from a non null before state

            gen.setResult(this, gen.getLIRGeneratorTool().getArithmetic().emitUDiv(gen.operand(getX()), gen.operand(getY()), null));

        }

    }

    @NodeInfo

    static class SafeUnsignedRemNode extends UnsignedRemNode implements SafeNode {

        public static final NodeClass<SafeUnsignedRemNode> TYPE = NodeClass.create(SafeUnsignedRemNode.class);

        protected SafeUnsignedRemNode(ValueNode x, ValueNode y) {

            super(TYPE, x, y, null);

        }

        @Override

        public void generate(NodeLIRBuilderTool gen) {

            // override to ensure we always pass a null frame state

            // the parent method expects to create one from a non null before state

            gen.setResult(this, gen.getLIRGeneratorTool().getArithmetic().emitURem(gen.operand(getX()), gen.operand(getY()), null));

        }

    }

}