//===-- BPFSelectionDAGInfo.cpp - BPF SelectionDAG Info -------------------===//

//

// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.

// See https://llvm.org/LICENSE.txt for license information.

// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

//

//===----------------------------------------------------------------------===//

//

// This file implements the BPFSelectionDAGInfo class.

//

//===----------------------------------------------------------------------===//

#include "BPFTargetMachine.h"

#include "llvm/CodeGen/SelectionDAG.h"

#include "llvm/IR/DerivedTypes.h"

using namespace llvm;

#define DEBUG_TYPE "bpf-selectiondag-info"

SDValue BPFSelectionDAGInfo::EmitTargetCodeForMemcpy(

    SelectionDAG &DAG, const SDLoc &dl, SDValue Chain, SDValue Dst, SDValue Src,

    SDValue Size, Align Alignment, bool isVolatile, bool AlwaysInline,

    MachinePointerInfo DstPtrInfo, MachinePointerInfo SrcPtrInfo) const {

  // Requires the copy size to be a constant.

  ConstantSDNode *ConstantSize = dyn_cast<ConstantSDNode>(Size);

  if (!ConstantSize)

    return SDValue();

  unsigned CopyLen = ConstantSize->getZExtValue();

  unsigned StoresNumEstimate = alignTo(CopyLen, Alignment) >> Log2(Alignment);

  // Impose the same copy length limit as MaxStoresPerMemcpy.

  if (StoresNumEstimate > getCommonMaxStoresPerMemFunc())

    return SDValue();

  SDVTList VTs = DAG.getVTList(MVT::Other, MVT::Glue);

  Dst = DAG.getNode(BPFISD::MEMCPY, dl, VTs, Chain, Dst, Src,

                    DAG.getConstant(CopyLen, dl, MVT::i64),

                    DAG.getConstant(Alignment.value(), dl, MVT::i64));

  return Dst.getValue(0);

}