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 * Copyright (c) 2013, 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.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package org.graalvm.compiler.replacements.nodes;

import java.lang.invoke.MethodHandle;

import org.graalvm.compiler.core.common.type.StampPair;
import org.graalvm.compiler.debug.GraalError;
import org.graalvm.compiler.graph.NodeClass;
import org.graalvm.compiler.graph.NodeInputList;
import org.graalvm.compiler.nodeinfo.NodeInfo;
import org.graalvm.compiler.nodes.ValueNode;
import org.graalvm.compiler.nodes.java.MethodCallTargetNode;
import org.graalvm.compiler.nodes.spi.Lowerable;
import org.graalvm.compiler.nodes.spi.LoweringTool;
import org.graalvm.compiler.nodes.spi.NodeLIRBuilderTool;

import jdk.vm.ci.meta.ResolvedJavaMethod;

A call target that replaces itself in the graph when being lowered by restoring the original MethodHandle invocation target. Prior to https://bugs.openjdk.java.net/browse/JDK-8072008, this is required for when a MethodHandle call is resolved to a constant target but the target was not inlined. In that case, the original invocation must be restored with all of its original arguments. Why? HotSpot linkage for MethodHandle intrinsics (see MethodHandles::generate_method_handle_dispatch) expects certain implicit arguments to be on the stack such as the MemberName suffix argument for a call to one of the MethodHandle.linkTo* methods. An resolved MethodHandle invocation drops these arguments which means the interpreter won't find them. /**
 * A call target that replaces itself in the graph when being lowered by restoring the original
 * {@link MethodHandle} invocation target. Prior to
 * https://bugs.openjdk.java.net/browse/JDK-8072008, this is required for when a
 * {@link MethodHandle} call is resolved to a constant target but the target was not inlined. In
 * that case, the original invocation must be restored with all of its original arguments. Why?
 * HotSpot linkage for {@link MethodHandle} intrinsics (see
 * {@code MethodHandles::generate_method_handle_dispatch}) expects certain implicit arguments to be
 * on the stack such as the MemberName suffix argument for a call to one of the MethodHandle.linkTo*
 * methods. An {@linkplain MethodHandleNode#tryResolveTargetInvoke resolved} {@link MethodHandle}
 * invocation drops these arguments which means the interpreter won't find them.
 */
@NodeInfo
public final class ResolvedMethodHandleCallTargetNode extends MethodCallTargetNode implements Lowerable {

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

    
Creates a call target for an invocation on a direct target derived by resolving a constant MethodHandle. /**
     * Creates a call target for an invocation on a direct target derived by resolving a constant
     * {@link MethodHandle}.
     */
    public static MethodCallTargetNode create(InvokeKind invokeKind, ResolvedJavaMethod targetMethod, ValueNode[] arguments, StampPair returnStamp,
                    ResolvedJavaMethod originalTargetMethod,
                    ValueNode[] originalArguments, StampPair originalReturnStamp) {
        return new ResolvedMethodHandleCallTargetNode(invokeKind, targetMethod, arguments, returnStamp, originalTargetMethod, originalArguments, originalReturnStamp);
    }

    protected final ResolvedJavaMethod originalTargetMethod;
    protected final StampPair originalReturnStamp;
    @Input NodeInputList<ValueNode> originalArguments;

    protected ResolvedMethodHandleCallTargetNode(InvokeKind invokeKind, ResolvedJavaMethod targetMethod, ValueNode[] arguments, StampPair returnStamp,
                    ResolvedJavaMethod originalTargetMethod,
                    ValueNode[] originalArguments, StampPair originalReturnStamp) {
        super(TYPE, invokeKind, targetMethod, arguments, returnStamp, null);
        this.originalTargetMethod = originalTargetMethod;
        this.originalReturnStamp = originalReturnStamp;
        this.originalArguments = new NodeInputList<>(this, originalArguments);
    }

    @Override
    public void lower(LoweringTool tool) {
        InvokeKind replacementInvokeKind = originalTargetMethod.isStatic() ? InvokeKind.Static : InvokeKind.Special;
        MethodCallTargetNode replacement = graph().add(
                        new MethodCallTargetNode(replacementInvokeKind, originalTargetMethod, originalArguments.toArray(new ValueNode[originalArguments.size()]), originalReturnStamp, null));

        // Replace myself...
        this.replaceAndDelete(replacement);
    }

    @Override
    public void generate(NodeLIRBuilderTool gen) {
        throw GraalError.shouldNotReachHere("should have replaced itself");
    }
}