/*

 * Copyright (c) 2015, 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.hotspot;

import static org.graalvm.compiler.lir.LIRValueUtil.asJavaConstant;

import static org.graalvm.compiler.lir.LIRValueUtil.isJavaConstant;

import java.util.Arrays;

import org.graalvm.compiler.asm.Assembler;

import org.graalvm.compiler.core.common.NumUtil;

import org.graalvm.compiler.debug.GraalError;

import org.graalvm.compiler.hotspot.debug.BenchmarkCounters;

import org.graalvm.compiler.hotspot.meta.HotSpotRegistersProvider;

import org.graalvm.compiler.lir.LIRInstruction;

import org.graalvm.compiler.lir.LIRInstructionClass;

import jdk.vm.ci.code.Register;

import jdk.vm.ci.code.TargetDescription;

import jdk.vm.ci.meta.JavaConstant;

import jdk.vm.ci.meta.JavaKind;

import jdk.vm.ci.meta.Value;

public abstract class HotSpotCounterOp extends LIRInstruction {

    public static final LIRInstructionClass<HotSpotCounterOp> TYPE = LIRInstructionClass.create(HotSpotCounterOp.class);

    private final String[] names;

    private final String[] groups;

    protected final Register thread;

    protected final GraalHotSpotVMConfig config;

    @Alive({OperandFlag.CONST, OperandFlag.REG}) protected Value[] increments;

    public HotSpotCounterOp(LIRInstructionClass<? extends HotSpotCounterOp> c, String name, String group, Value increment, HotSpotRegistersProvider registers, GraalHotSpotVMConfig config) {

        this(c, new String[]{name}, new String[]{group}, new Value[]{increment}, registers, config);

    }

    public HotSpotCounterOp(LIRInstructionClass<? extends HotSpotCounterOp> c, String[] names, String[] groups, Value[] increments, HotSpotRegistersProvider registers, GraalHotSpotVMConfig config) {

        super(c);

        assert names.length == groups.length;

        assert groups.length == increments.length;

        this.names = names;

        this.groups = groups;

        this.increments = increments;

        this.thread = registers.getThreadRegister();

        this.config = config;

    }

    protected static int getDisplacementForLongIndex(TargetDescription target, long index) {

        long finalDisp = index * target.arch.getPlatformKind(JavaKind.Long).getSizeInBytes();

        if (!NumUtil.isInt(finalDisp)) {

            throw GraalError.unimplemented("cannot deal with indices that big: " + index);

        }

        return (int) finalDisp;

    }

    protected interface CounterProcedure {

        /**

         * Lambda interface for iterating over counters declared in this op.

         *

         * @param counterIndex Index in this CounterOp object.

         * @param increment Value for increment

         * @param displacement Displacement in bytes in the counter array

         */

        void apply(int counterIndex, Value increment, int displacement);

    }

    /**

     * Calls the {@link CounterProcedure} for each counter in ascending order of their displacement

     * in the counter array.

     *

     * @param proc The procedure to be called

     * @param target Target architecture (used to calculate the array displacements)

     */

    protected void forEachCounter(CounterProcedure proc, TargetDescription target) {

        if (names.length == 1) { // fast path

            int arrayIndex = getIndex(names[0], groups[0], increments[0]);

            int displacement = getDisplacementForLongIndex(target, arrayIndex);

            proc.apply(0, increments[0], displacement);

        } else { // Slow path with sort by displacements ascending

            int[] displacements = new int[names.length];

            EconomicMap<Integer, Integer> offsetMap = EconomicMap.create();

            for (int i = 0; i < names.length; i++) {

                int arrayIndex = getIndex(names[i], groups[i], increments[i]);

                displacements[i] = getDisplacementForLongIndex(target, arrayIndex);

                offsetMap.put(displacements[i], i);

            }

            Arrays.sort(displacements);

            // Now apply in order

            for (int offset : displacements) {

                int idx = offsetMap.get(offset);

                proc.apply(idx, increments[idx], displacements[idx]);

            }

        }

    }

    protected int getIndex(String name, String group, Value increment) {

        if (isJavaConstant(increment)) {

            // get index for the counter

            return BenchmarkCounters.getIndexConstantIncrement(name, group, config, asLong(asJavaConstant(increment)));

        }

        assert isRegister(increment) : "Unexpected Value: " + increment;

        // get index for the counter

        return BenchmarkCounters.getIndex(name, group, config);

    }

    /**

     * Patches the increment value in the instruction emitted by this instruction. Use only, if

     * patching is needed after assembly.

     *

     * @param asm

     * @param increment

     */

    public void patchCounterIncrement(Assembler asm, int[] increment) {

        throw GraalError.unimplemented();

    }

    private static long asLong(JavaConstant value) {

        JavaKind kind = value.getJavaKind();

        switch (kind) {

            case Byte:

            case Short:

            case Char:

            case Int:

                return value.asInt();

            case Long:

                return value.asLong();

            default:

                throw new IllegalArgumentException("not an integer kind: " + kind);

        }

    }

    protected static int asInt(JavaConstant value) {

        long l = asLong(value);

        if (!NumUtil.isInt(l)) {

            throw GraalError.shouldNotReachHere("value does not fit into int: " + l);

        }

        return (int) l;

    }

    public String[] getNames() {

        return names;

    }

    public String[] getGroups() {

        return groups;

    }

}