/*
 * 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
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package com.oracle.graal.lir.amd64;

import static com.oracle.graal.api.code.ValueUtil.*;
import static com.oracle.graal.lir.LIRInstruction.OperandFlag.*;

import java.util.*;

import com.oracle.graal.api.code.*;
import com.oracle.graal.asm.amd64.*;
import com.oracle.graal.lir.*;
import com.oracle.graal.lir.asm.*;

/**
 * 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 StackSlotValue[] slots;

    /**
     * The operation that saved the registers restored by this operation.
     */
    private final AMD64SaveRegistersOp save;

    public AMD64RestoreRegistersOp(StackSlotValue[] values, AMD64SaveRegistersOp save) {
        this(TYPE, values, save);
    }

    protected AMD64RestoreRegistersOp(LIRInstructionClass<? extends AMD64RestoreRegistersOp> c, StackSlotValue[] values, AMD64SaveRegistersOp save) {
        super(c);
        assert Arrays.asList(values).stream().allMatch(ValueUtil::isVirtualStackSlot);
        this.slots = values;
        this.save = save;
    }

    protected Register[] getSavedRegisters() {
        return save.savedRegisters;
    }

    protected void restoreRegister(CompilationResultBuilder crb, AMD64MacroAssembler masm, Register register, StackSlot input) {
        RegisterValue result = register.asValue(input.getLIRKind());
        AMD64Move.move(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]));
            }
        }
    }
}