/*

 * Copyright (c) 2014, 2019, 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.lir.dfa;

import static jdk.vm.ci.code.ValueUtil.asRegister;

import static jdk.vm.ci.code.ValueUtil.isRegister;

import static jdk.vm.ci.code.ValueUtil.isStackSlot;

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

import org.graalvm.compiler.lir.LIR;

import org.graalvm.compiler.lir.LIRFrameState;

import org.graalvm.compiler.lir.LIRInstruction;

import org.graalvm.compiler.lir.framemap.FrameMap;

import org.graalvm.compiler.lir.framemap.ReferenceMapBuilder;

import org.graalvm.compiler.lir.gen.LIRGenerationResult;

import org.graalvm.compiler.lir.phases.AllocationPhase;

import jdk.vm.ci.code.ReferenceMap;

import jdk.vm.ci.code.Register;

import jdk.vm.ci.code.RegisterAttributes;

import jdk.vm.ci.code.TargetDescription;

import jdk.vm.ci.meta.Value;

/**

 * Mark all live references for a frame state. The frame state uses this information to build the

 * {@link ReferenceMap}s.

 */

public final class LocationMarkerPhase extends AllocationPhase {

    @Override

    protected void run(TargetDescription target, LIRGenerationResult lirGenRes, AllocationContext context) {

        new Marker(lirGenRes.getLIR(), lirGenRes.getFrameMap()).build();

    }

    static final class Marker extends LocationMarker<RegStackValueSet> {

        private final RegisterAttributes[] registerAttributes;

        private Marker(LIR lir, FrameMap frameMap) {

            super(lir, frameMap);

            this.registerAttributes = frameMap.getRegisterConfig().getAttributesMap();

        }

        @Override

        protected RegStackValueSet newLiveValueSet() {

            return new RegStackValueSet(frameMap);

        }

        @Override

        protected boolean shouldProcessValue(Value operand) {

            if (isRegister(operand)) {

                Register reg = asRegister(operand);

                if (!reg.mayContainReference() || !attributes(reg).isAllocatable()) {

                    // register that's not allocatable or not part of the reference map

                    return false;

                }

            } else if (!isStackSlot(operand)) {

                // neither register nor stack slot

                return false;

            }

            return !operand.getValueKind().equals(LIRKind.Illegal);

        }

        /**

         * This method does the actual marking.

         */

        @Override

        protected void processState(LIRInstruction op, LIRFrameState info, RegStackValueSet values) {

            if (!info.hasDebugInfo()) {

                info.initDebugInfo(frameMap, !op.destroysCallerSavedRegisters() || !frameMap.getRegisterConfig().areAllAllocatableRegistersCallerSaved());

            }

            ReferenceMapBuilder refMap = frameMap.newReferenceMapBuilder();

            values.addLiveValues(refMap);

            info.debugInfo().setReferenceMap(refMap.finish(info));

        }

        /**

         * Gets an object describing the attributes of a given register according to this register

         * configuration.

         */

        private RegisterAttributes attributes(Register reg) {

            return registerAttributes[reg.number];

        }

    }

}