/*

 * 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 org.graalvm.compiler.lir.amd64;

import static org.graalvm.compiler.lir.amd64.AMD64SaveRegistersOp.prune;

import org.graalvm.compiler.asm.amd64.AMD64MacroAssembler;

import org.graalvm.compiler.lir.LIRInstructionClass;

import org.graalvm.compiler.lir.Opcode;

import org.graalvm.compiler.lir.StandardOp.SaveRegistersOp;

import org.graalvm.compiler.lir.asm.CompilationResultBuilder;

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

import jdk.vm.ci.code.Register;

import jdk.vm.ci.code.RegisterSaveLayout;

import jdk.vm.ci.meta.JavaConstant;

/**

 * Writes well known garbage values to registers.

 */

@Opcode("ZAP_REGISTER")

public final class AMD64ZapRegistersOp extends AMD64LIRInstruction implements SaveRegistersOp {

    public static final LIRInstructionClass<AMD64ZapRegistersOp> TYPE = LIRInstructionClass.create(AMD64ZapRegistersOp.class);

    /**

     * The registers that are zapped.

     */

    protected final Register[] zappedRegisters;

    /**

     * The garbage values that are written to the registers.

     */

    protected final JavaConstant[] zapValues;

    public AMD64ZapRegistersOp(Register[] zappedRegisters, JavaConstant[] zapValues) {

        super(TYPE);

        this.zappedRegisters = zappedRegisters;

        this.zapValues = zapValues;

    }

    @Override

    public void emitCode(CompilationResultBuilder crb, AMD64MacroAssembler masm) {

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

            Register reg = zappedRegisters[i];

            if (reg != null) {

                AMD64Move.const2reg(crb, masm, reg, zapValues[i]);

            }

        }

    }

    @Override

    public boolean supportsRemove() {

        return true;

    }

    @Override

    public int remove(EconomicSet<Register> doNotSave) {

        return prune(doNotSave, zappedRegisters);

    }

    @Override

    public RegisterSaveLayout getMap(FrameMap frameMap) {

        return new RegisterSaveLayout(new Register[0], new int[0]);

    }

}