/*

 * Copyright (c) 2009, 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.java;

import org.graalvm.compiler.java.BciBlockMapping.BciBlock;

public final class SmallLocalLiveness extends LocalLiveness {

    /*

     * local n is represented by the bit accessible as (1 << n)

     */

    private final long[] localsLiveIn;

    private final long[] localsLiveOut;

    private final long[] localsLiveGen;

    private final long[] localsLiveKill;

    private final long[] localsChangedInLoop;

    private final int maxLocals;

    public SmallLocalLiveness(BciBlock[] blocks, int maxLocals, int loopCount) {

        super(blocks);

        this.maxLocals = maxLocals;

        int blockSize = blocks.length;

        localsLiveIn = new long[blockSize];

        localsLiveOut = new long[blockSize];

        localsLiveGen = new long[blockSize];

        localsLiveKill = new long[blockSize];

        localsChangedInLoop = new long[loopCount];

    }

    private String debugString(long value) {

        StringBuilder str = new StringBuilder("{");

        long current = value;

        for (int i = 0; i < maxLocals; i++) {

            if ((current & 1L) == 1L) {

                if (str.length() > 1) {

                    str.append(", ");

                }

                str.append(i);

            }

            current >>= 1;

        }

        return str.append('}').toString();

    }

    @Override

    protected String debugLiveIn(int blockID) {

        return debugString(localsLiveIn[blockID]);

    }

    @Override

    protected String debugLiveOut(int blockID) {

        return debugString(localsLiveOut[blockID]);

    }

    @Override

    protected String debugLiveGen(int blockID) {

        return debugString(localsLiveGen[blockID]);

    }

    @Override

    protected String debugLiveKill(int blockID) {

        return debugString(localsLiveKill[blockID]);

    }

    @Override

    protected int liveOutCardinality(int blockID) {

        return Long.bitCount(localsLiveOut[blockID]);

    }

    @Override

    protected void propagateLiveness(int blockID, int successorID) {

        localsLiveOut[blockID] |= localsLiveIn[successorID];

    }

    @Override

    protected void updateLiveness(int blockID) {

        localsLiveIn[blockID] = (localsLiveOut[blockID] & ~localsLiveKill[blockID]) | localsLiveGen[blockID];

    }

    @Override

    protected void loadOne(int blockID, int local) {

        long bit = 1L << local;

        if ((localsLiveKill[blockID] & bit) == 0L) {

            localsLiveGen[blockID] |= bit;

        }

    }

    @Override

    protected void storeOne(int blockID, int local) {

        long bit = 1L << local;

        if ((localsLiveGen[blockID] & bit) == 0L) {

            localsLiveKill[blockID] |= bit;

        }

        BciBlock block = blocks[blockID];

        long tmp = block.loops;

        int pos = 0;

        while (tmp != 0) {

            if ((tmp & 1L) == 1L) {

                this.localsChangedInLoop[pos] |= bit;

            }

            tmp >>>= 1;

            ++pos;

        }

    }

    @Override

    public boolean localIsLiveIn(BciBlock block, int local) {

        int blockID = block.getId();

        return blockID >= Integer.MAX_VALUE ? false : (localsLiveIn[blockID] & (1L << local)) != 0L;

    }

    @Override

    public boolean localIsLiveOut(BciBlock block, int local) {

        int blockID = block.getId();

        return blockID >= Integer.MAX_VALUE ? false : (localsLiveOut[blockID] & (1L << local)) != 0L;

    }

    @Override

    public boolean localIsChangedInLoop(int loopId, int local) {

        return (localsChangedInLoop[loopId] & (1L << local)) != 0L;

    }

}