lib/Target/BPF/BPFSelectionDAGInfo.cpp

   1 //===-- BPFSelectionDAGInfo.cpp - BPF SelectionDAG Info -------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file implements the BPFSelectionDAGInfo class.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "BPFTargetMachine.h"
  14 #include "llvm/CodeGen/SelectionDAG.h"
  15 #include "llvm/IR/DerivedTypes.h"
  16 using namespace llvm;
  17
  18 #define DEBUG_TYPE "bpf-selectiondag-info"
  19
  20 SDValue BPFSelectionDAGInfo::EmitTargetCodeForMemcpy(
  21     SelectionDAG &DAG, const SDLoc &dl, SDValue Chain, SDValue Dst, SDValue Src,
  22     SDValue Size, unsigned Align, bool isVolatile, bool AlwaysInline,
  23     MachinePointerInfo DstPtrInfo, MachinePointerInfo SrcPtrInfo) const {
  24   // Requires the copy size to be a constant.
  25   ConstantSDNode *ConstantSize = dyn_cast<ConstantSDNode>(Size);
  26   if (!ConstantSize)
  27     return SDValue();
  28
  29   unsigned CopyLen = ConstantSize->getZExtValue();
  30   unsigned StoresNumEstimate = alignTo(CopyLen, Align) >> Log2_32(Align);
  31   // Impose the same copy length limit as MaxStoresPerMemcpy.
  32   if (StoresNumEstimate > getCommonMaxStoresPerMemFunc())
  33     return SDValue();
  34
  35   SDVTList VTs = DAG.getVTList(MVT::Other, MVT::Glue);
  36
  37   Dst = DAG.getNode(BPFISD::MEMCPY, dl, VTs, Chain, Dst, Src,
  38                     DAG.getConstant(CopyLen, dl, MVT::i64),
  39                     DAG.getConstant(Align, dl, MVT::i64));
  40
  41   return Dst.getValue(0);
  42 }