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package org.graalvm.compiler.hotspot.amd64;

import static jdk.vm.ci.amd64.AMD64.rbp;
import static jdk.vm.ci.code.ValueUtil.asRegister;
import static jdk.vm.ci.code.ValueUtil.isStackSlot;
import static org.graalvm.compiler.lir.LIRInstruction.OperandFlag.ILLEGAL;
import static org.graalvm.compiler.lir.LIRInstruction.OperandFlag.REG;
import static org.graalvm.compiler.lir.LIRInstruction.OperandFlag.STACK;

import org.graalvm.compiler.asm.amd64.AMD64Address;
import org.graalvm.compiler.asm.amd64.AMD64MacroAssembler;
import org.graalvm.compiler.lir.LIRInstructionClass;
import org.graalvm.compiler.lir.amd64.AMD64FrameMap;
import org.graalvm.compiler.lir.amd64.AMD64LIRInstruction;
import org.graalvm.compiler.lir.asm.CompilationResultBuilder;

import jdk.vm.ci.code.Register;
import jdk.vm.ci.meta.AllocatableValue;
import jdk.vm.ci.meta.Value;

/**
 * Superclass for operations that use the value of RBP saved in a method's prologue.
 */
abstract class AMD64HotSpotEpilogueOp extends AMD64LIRInstruction implements AMD64HotSpotRestoreRbpOp {

    protected AMD64HotSpotEpilogueOp(LIRInstructionClass<? extends AMD64HotSpotEpilogueOp> c) {
        super(c);
    }

    @Use({REG, STACK, ILLEGAL}) private AllocatableValue savedRbp = Value.ILLEGAL;

    protected void leaveFrameAndRestoreRbp(CompilationResultBuilder crb, AMD64MacroAssembler masm) {
        leaveFrameAndRestoreRbp(savedRbp, crb, masm);
    }

    static void leaveFrameAndRestoreRbp(AllocatableValue savedRbp, CompilationResultBuilder crb, AMD64MacroAssembler masm) {
        if (Value.ILLEGAL.equals(savedRbp)) {
            // RBP will be restored in FrameContext.leave(..). Nothing to do here.
            assert ((AMD64FrameMap) crb.frameMap).useStandardFrameProlog() : "savedRbp is not initialized.";
        } else if (isStackSlot(savedRbp)) {
            // Restoring RBP from the stack must be done before the frame is removed
            masm.movq(rbp, (AMD64Address) crb.asAddress(savedRbp));
        } else {
            Register framePointer = asRegister(savedRbp);
            if (!framePointer.equals(rbp)) {
                masm.movq(rbp, framePointer);
            }
        }
        crb.frameContext.leave(crb);
    }

    @Override
    public void setSavedRbp(AllocatableValue value) {
        savedRbp = value;
    }
}
