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"
15using namespace llvm;
16
17#define DEBUG_TYPE "bpf-selectiondag-info"
18
19SDValue 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>(Val&: Size);
25 if (!ConstantSize)
26 return SDValue();
27
28 unsigned CopyLen = ConstantSize->getZExtValue();
29 unsigned StoresNumEstimate = alignTo(Size: CopyLen, A: Alignment) >> Log2(A: Alignment);
30 // Impose the same copy length limit as MaxStoresPerMemcpy.
31 if (StoresNumEstimate > getCommonMaxStoresPerMemFunc())
32 return SDValue();
33
34 SDVTList VTs = DAG.getVTList(VT1: MVT::Other, VT2: MVT::Glue);
35
36 Dst = DAG.getNode(Opcode: BPFISD::MEMCPY, DL: dl, VTList: VTs, N1: Chain, N2: Dst, N3: Src,
37 N4: DAG.getConstant(Val: CopyLen, DL: dl, VT: MVT::i64),
38 N5: DAG.getConstant(Val: Alignment.value(), DL: dl, VT: MVT::i64));
39
40 return Dst.getValue(R: 0);
41}
42