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, Align Alignment, 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, Alignment) >> Log2(Alignment); 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(Alignment.value(), dl, MVT::i64)); 40 41 return Dst.getValue(0); 42 } 43