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 using namespace llvm;
16
17 #define DEBUG_TYPE "bpf-selectiondag-info"
18
EmitTargetCodeForMemcpy(SelectionDAG & DAG,const SDLoc & dl,SDValue Chain,SDValue Dst,SDValue Src,SDValue Size,Align Alignment,bool isVolatile,bool AlwaysInline,MachinePointerInfo DstPtrInfo,MachinePointerInfo SrcPtrInfo) const19 SDValue BPFSelectionDAGInfo::EmitTargetCodeForMemcpy(
20 SelectionDAG &DAG, const SDLoc &dl, SDValue Chain, SDValue Dst, SDValue Src,
21 SDValue Size, Align Alignment, bool isVolatile, bool AlwaysInline,
22 MachinePointerInfo DstPtrInfo, MachinePointerInfo SrcPtrInfo) const {
23 // Requires the copy size to be a constant.
24 ConstantSDNode *ConstantSize = dyn_cast<ConstantSDNode>(Size);
25 if (!ConstantSize)
26 return SDValue();
27
28 unsigned CopyLen = ConstantSize->getZExtValue();
29 unsigned StoresNumEstimate = alignTo(CopyLen, Alignment) >> Log2(Alignment);
30 // Impose the same copy length limit as MaxStoresPerMemcpy.
31 if (StoresNumEstimate > getCommonMaxStoresPerMemFunc())
32 return SDValue();
33
34 SDVTList VTs = DAG.getVTList(MVT::Other, MVT::Glue);
35
36 Dst = DAG.getNode(BPFISD::MEMCPY, dl, VTs, Chain, Dst, Src,
37 DAG.getConstant(CopyLen, dl, MVT::i64),
38 DAG.getConstant(Alignment.value(), dl, MVT::i64));
39
40 return Dst.getValue(0);
41 }
42