/*
 * Copyright (c) 2011, 2018, 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.nodes;

import static org.graalvm.compiler.nodeinfo.InputType.Extension;
import static org.graalvm.compiler.nodeinfo.NodeCycles.CYCLES_0;
import static org.graalvm.compiler.nodeinfo.NodeSize.SIZE_0;

import org.graalvm.compiler.core.common.type.Stamp;
import org.graalvm.compiler.core.common.type.StampFactory;
import org.graalvm.compiler.core.common.type.StampPair;
import org.graalvm.compiler.core.common.type.TypeReference;
import org.graalvm.compiler.graph.NodeClass;
import org.graalvm.compiler.graph.NodeInputList;
import org.graalvm.compiler.nodeinfo.NodeInfo;
import org.graalvm.compiler.nodes.spi.LIRLowerable;
import org.graalvm.compiler.nodes.spi.NodeLIRBuilderTool;

import jdk.vm.ci.meta.Assumptions;
import jdk.vm.ci.meta.JavaKind;
import jdk.vm.ci.meta.JavaType;
import jdk.vm.ci.meta.ResolvedJavaMethod;
import jdk.vm.ci.meta.ResolvedJavaType;

@NodeInfo(allowedUsageTypes = Extension, cycles = CYCLES_0, size = SIZE_0)
public abstract class CallTargetNode extends ValueNode implements LIRLowerable {
    public static final NodeClass<CallTargetNode> TYPE = NodeClass.create(CallTargetNode.class);

    public enum InvokeKind {
        Interface(false),
        Special(true),
        Static(true),
        Virtual(false);

        InvokeKind(boolean direct) {
            this.direct = direct;
        }

        private final boolean direct;

        public boolean hasReceiver() {
            return this != Static;
        }

        public boolean isDirect() {
            return direct;
        }

        public boolean isIndirect() {
            return !direct;
        }

        public boolean isInterface() {
            return this == InvokeKind.Interface;
        }
    }

    @Input protected NodeInputList<ValueNode> arguments;
    protected ResolvedJavaMethod targetMethod;

    
Receiver type referenced at the interface call site.
We need to distinguish the declaring type from the type referenced at the call site. We must
use the referenced type as lower type bound when doing CHA since interface calls must throw
exception if the receiver type is not a subtype of the reference type.
Example:
interface I1 {
    void foo();
}
interface I2 extends I1 {
}
void bar(I2 o) {
    o.foo();
}
 Here at the call site the declaring type for foo() is I1, while the referenced type is I2. Only receivers of type T that is T <: I2 should be allowed at the call site. If they are not - an exception should be thrown. Since the interface types are not verified, another way to think about this call site is to rewrite it as follows: 
void bar(Object o) {
    ((I2) o).foo();
}
 So, in case the receiver is not a subtype of I2 an exception is thrown. /**
     * Receiver type referenced at the interface call site.
     *
     * We need to distinguish the declaring type from the type referenced at the call site. We must
     * use the referenced type as lower type bound when doing CHA since interface calls must throw
     * exception if the receiver type is not a subtype of the reference type.
     *
     * Example:
     *
     * <pre>
     * interface I1 {
     *     void foo();
     * }
     *
     * interface I2 extends I1 {
     * }
     *
     * void bar(I2 o) {
     *     o.foo();
     * }
     * </pre>
     *
     * Here at the call site the declaring type for {@code foo()} is {@code I1}, while the
     * referenced type is {@code I2}. Only receivers of type {@code T} that is {@code T <: I2}
     * should be allowed at the call site. If they are not - an exception should be thrown.
     *
     * Since the interface types are not verified, another way to think about this call site is to
     * rewrite it as follows:
     *
     * <pre>
     * void bar(Object o) {
     *     ((I2) o).foo();
     * }
     * </pre>
     *
     * So, in case the receiver is not a subtype of {@code I2} an exception is thrown.
     */
    protected ResolvedJavaType referencedType;

    protected InvokeKind invokeKind;
    protected final StampPair returnStamp;

    protected CallTargetNode(NodeClass<? extends CallTargetNode> c, ValueNode[] arguments, ResolvedJavaMethod targetMethod, InvokeKind invokeKind, StampPair returnStamp) {
        super(c, StampFactory.forVoid());
        this.targetMethod = targetMethod;
        this.invokeKind = invokeKind;
        this.arguments = new NodeInputList<>(this, arguments);
        this.returnStamp = returnStamp;
    }

    public NodeInputList<ValueNode> arguments() {
        return arguments;
    }

    public static Stamp createReturnStamp(Assumptions assumptions, JavaType returnType) {
        JavaKind kind = returnType.getJavaKind();
        if (kind == JavaKind.Object && returnType instanceof ResolvedJavaType) {
            return StampFactory.object(TypeReference.create(assumptions, (ResolvedJavaType) returnType));
        } else {
            return StampFactory.forKind(kind);
        }
    }

    public StampPair returnStamp() {
        return this.returnStamp;
    }

    
A human-readable representation of the target, used for debug printing only.
/**
     * A human-readable representation of the target, used for debug printing only.
     */
    public abstract String targetName();

    @Override
    public void generate(NodeLIRBuilderTool gen) {
        // nop
    }

    public void setTargetMethod(ResolvedJavaMethod targetMethod) {
        this.targetMethod = targetMethod;
    }

    
Gets the target method for this invocation instruction.
Returns:
the target method/**
     * Gets the target method for this invocation instruction.
     *
     * @return the target method
     */
    public ResolvedJavaMethod targetMethod() {
        return targetMethod;
    }

    public void setReferencedType(ResolvedJavaType referencedType) {
        this.referencedType = referencedType;
    }

    public ResolvedJavaType referencedType() {
        return referencedType;
    }

    public InvokeKind invokeKind() {
        return invokeKind;
    }

    public void setInvokeKind(InvokeKind kind) {
        this.invokeKind = kind;
    }

    public Invoke invoke() {
        return (Invoke) this.usages().first();
    }
}