/*
 * 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
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */
package com.oracle.truffle.sl.nodes.call;

import com.oracle.truffle.api.*;
import com.oracle.truffle.api.dsl.NodeChild;
import com.oracle.truffle.api.dsl.NodeChildren;
import com.oracle.truffle.api.dsl.Specialization;
import com.oracle.truffle.api.frame.*;
import com.oracle.truffle.api.interop.ForeignAccess;
import com.oracle.truffle.api.interop.Message;
import com.oracle.truffle.api.interop.TruffleObject;
import com.oracle.truffle.api.nodes.*;
import com.oracle.truffle.api.source.*;
import com.oracle.truffle.sl.nodes.*;
import com.oracle.truffle.sl.runtime.*;

/**
 * The node for function invocation in SL. Since SL has first class functions, the
 * {@link SLFunction target function} can be computed by an arbitrary expression. This node is
 * responsible for evaluating this expression, as well as evaluating the {@link #argumentNodes
 * arguments}. The actual dispatch is then delegated to a chain of {@link SLDispatchNode} that form
 * a polymorphic inline cache.
 */
@NodeInfo(shortName = "invoke")
@NodeChildren({@NodeChild(value = "functionNode", type = SLExpressionNode.class)})
public abstract class SLInvokeNode extends SLExpressionNode {
    @Children private final SLExpressionNode[] argumentNodes;
    @Child private SLDispatchNode dispatchNode;

    SLInvokeNode(SourceSection src, SLExpressionNode[] argumentNodes) {
        super(src);
        this.argumentNodes = argumentNodes;
        this.dispatchNode = SLDispatchNodeGen.create();
    }

    @Specialization
    @ExplodeLoop
    public Object executeGeneric(VirtualFrame frame, SLFunction function) {
        /*
         * The number of arguments is constant for one invoke node. During compilation, the loop is
         * unrolled and the execute methods of all arguments are inlined. This is triggered by the
         * ExplodeLoop annotation on the method. The compiler assertion below illustrates that the
         * array length is really constant.
         */
        CompilerAsserts.compilationConstant(argumentNodes.length);

        Object[] argumentValues = new Object[argumentNodes.length];
        for (int i = 0; i < argumentNodes.length; i++) {
            argumentValues[i] = argumentNodes[i].executeGeneric(frame);
        }
        return dispatchNode.executeDispatch(frame, function, argumentValues);
    }

    @Child private Node crossLanguageCall;

    @Specialization
    @ExplodeLoop
    protected Object executeGeneric(VirtualFrame frame, TruffleObject function) {
        /*
         * The number of arguments is constant for one invoke node. During compilation, the loop is
         * unrolled and the execute methods of all arguments are inlined. This is triggered by the
         * ExplodeLoop annotation on the method. The compiler assertion below illustrates that the
         * array length is really constant.
         */
        CompilerAsserts.compilationConstant(argumentNodes.length);

        Object[] argumentValues = new Object[argumentNodes.length];
        for (int i = 0; i < argumentNodes.length; i++) {
            argumentValues[i] = argumentNodes[i].executeGeneric(frame);
        }
        if (crossLanguageCall == null) {
            crossLanguageCall = insert(Message.createExecute(argumentValues.length).createNode());
        }
        return ForeignAccess.execute(crossLanguageCall, frame, function, argumentValues);
    }
}