/*
 * Copyright (c) 2012, 2012, 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;

import com.oracle.truffle.api.*;
import com.oracle.truffle.api.frame.*;
import com.oracle.truffle.sl.runtime.*;

public class ReadUninitializedNode extends TypedNode {

    private final SLContext context;
    private final FrameSlot slot;

    public ReadUninitializedNode(SLContext context, FrameSlot slot) {
        this.context = context;
        this.slot = slot;
    }

    public FrameSlot getSlot() {
        return slot;
    }

    @Override
    public Object executeGeneric(VirtualFrame frame) {
        CompilerDirectives.transferToInterpreter();
        Object result = frame.getValue(slot);
        String identifier = (String) slot.getIdentifier();
        if (result == null) {
            // function access
            return replace(new ReadFunctionNode(context.getFunctionRegistry(), identifier)).executeGeneric(frame);
        } else {
            // local variable access
            return replace(ReadLocalNodeFactory.create(slot)).executeGeneric(frame);
        }
    }
}