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 * This code is free software; you can redistribute it and/or modify it

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 * published by the Free Software Foundation.

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 * 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.

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package org.graalvm.compiler.lir.amd64;

import static org.graalvm.compiler.lir.LIRInstruction.OperandFlag.STACK;

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

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

import java.util.Arrays;

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

import org.graalvm.compiler.lir.LIRInstructionClass;

import org.graalvm.compiler.lir.LIRValueUtil;

import org.graalvm.compiler.lir.Opcode;

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

import jdk.vm.ci.amd64.AMD64Kind;

import jdk.vm.ci.code.Register;

import jdk.vm.ci.code.StackSlot;

import jdk.vm.ci.meta.AllocatableValue;

/**

 * Restores registers from stack slots.

 */

@Opcode("RESTORE_REGISTER")

public class AMD64RestoreRegistersOp extends AMD64LIRInstruction {

    public static final LIRInstructionClass<AMD64RestoreRegistersOp> TYPE = LIRInstructionClass.create(AMD64RestoreRegistersOp.class);

    /**

     * The slots from which the registers are restored.

     */

    @Use(STACK) protected final AllocatableValue[] slots;

    /**

     * The operation that saved the registers restored by this operation.

     */

    private final AMD64SaveRegistersOp save;

    public AMD64RestoreRegistersOp(AllocatableValue[] values, AMD64SaveRegistersOp save) {

        this(TYPE, values, save);

    }

    protected AMD64RestoreRegistersOp(LIRInstructionClass<? extends AMD64RestoreRegistersOp> c, AllocatableValue[] values, AMD64SaveRegistersOp save) {

        super(c);

        assert Arrays.asList(values).stream().allMatch(LIRValueUtil::isVirtualStackSlot);

        this.slots = values;

        this.save = save;

    }

    protected Register[] getSavedRegisters() {

        return save.savedRegisters;

    }

    protected void restoreRegister(CompilationResultBuilder crb, AMD64MacroAssembler masm, Register result, StackSlot input) {

        AMD64Move.stack2reg((AMD64Kind) input.getPlatformKind(), crb, masm, result, input);

    }

    @Override

    public void emitCode(CompilationResultBuilder crb, AMD64MacroAssembler masm) {

        Register[] savedRegisters = getSavedRegisters();

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

            if (savedRegisters[i] != null) {

                assert isStackSlot(slots[i]) : "not a StackSlot: " + slots[i];

                restoreRegister(crb, masm, savedRegisters[i], asStackSlot(slots[i]));

            }

        }

    }

}