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 "BPFSelectionDAGInfo.h"
14#include "BPFTargetMachine.h"
15#include "llvm/CodeGen/SelectionDAG.h"
16
17#define GET_SDNODE_DESC
18#include "BPFGenSDNodeInfo.inc"
19
20using namespace llvm;
21
22#define DEBUG_TYPE "bpf-selectiondag-info"
23
24BPFSelectionDAGInfo::BPFSelectionDAGInfo()
25 : SelectionDAGGenTargetInfo(BPFGenSDNodeInfo) {}
26
27SDValue BPFSelectionDAGInfo::EmitTargetCodeForMemcpy(
28 SelectionDAG &DAG, const SDLoc &dl, SDValue Chain, SDValue Dst, SDValue Src,
29 SDValue Size, Align Alignment, bool isVolatile, bool AlwaysInline,
30 MachinePointerInfo DstPtrInfo, MachinePointerInfo SrcPtrInfo) const {
31 // Requires the copy size to be a constant.
32 ConstantSDNode *ConstantSize = dyn_cast<ConstantSDNode>(Val&: Size);
33 if (!ConstantSize)
34 return SDValue();
35
36 unsigned CopyLen = ConstantSize->getZExtValue();
37 unsigned StoresNumEstimate = alignTo(Size: CopyLen, A: Alignment) >> Log2(A: Alignment);
38 // Impose the same copy length limit as MaxStoresPerMemcpy.
39 if (StoresNumEstimate > getCommonMaxStoresPerMemFunc())
40 return SDValue();
41
42 return DAG.getNode(Opcode: BPFISD::MEMCPY, DL: dl, VT: MVT::Other, N1: Chain, N2: Dst, N3: Src,
43 N4: DAG.getConstant(Val: CopyLen, DL: dl, VT: MVT::i64),
44 N5: DAG.getConstant(Val: Alignment.value(), DL: dl, VT: MVT::i64));
45}
46