LLVM  11.0.0git
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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 //===----------------------------------------------------------------------===//
13 #include "BPFTargetMachine.h"
15 #include "llvm/IR/DerivedTypes.h"
16 using namespace llvm;
18 #define DEBUG_TYPE "bpf-selectiondag-info"
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();
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();
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));
41  return Dst.getValue(0);
42 }
unsigned Log2(Align A)
Returns the log2 of the alignment.
Definition: Alignment.h:217
LLVM_NODISCARD std::enable_if_t< !is_simple_type< Y >::value, typename cast_retty< X, const Y >::ret_type > dyn_cast(const Y &Val)
Definition: Casting.h:334
This class represents lattice values for constants.
Definition: AllocatorList.h:23
SDValue getNode(unsigned Opcode, const SDLoc &DL, EVT VT, ArrayRef< SDUse > Ops)
Gets or creates the specified node.
SDVTList getVTList(EVT VT)
Return an SDVTList that represents the list of values specified.
This represents a list of ValueType&#39;s that has been intern&#39;d by a SelectionDAG.
uint64_t value() const
This is a hole in the type system and should not be abused.
Definition: Alignment.h:85
unsigned getCommonMaxStoresPerMemFunc() const
This class contains a discriminated union of information about pointers in memory operands...
This struct is a compact representation of a valid (non-zero power of two) alignment.
Definition: Alignment.h:39
This is used to represent a portion of an LLVM function in a low-level Data Dependence DAG representa...
Definition: SelectionDAG.h:223
Wrapper class for IR location info (IR ordering and DebugLoc) to be passed into SDNode creation funct...
SDValue EmitTargetCodeForMemcpy(SelectionDAG &DAG, const SDLoc &dl, SDValue Chain, SDValue Dst, SDValue Src, SDValue Size, Align Alignment, bool isVolatile, bool AlwaysInline, MachinePointerInfo DstPtrInfo, MachinePointerInfo SrcPtrInfo) const override
Emit target-specific code that performs a memcpy.
uint64_t alignTo(uint64_t Size, Align A)
Returns a multiple of A needed to store Size bytes.
Definition: Alignment.h:158
uint32_t Size
Definition: Profile.cpp:46
SDValue getValue(unsigned R) const
SDValue getConstant(uint64_t Val, const SDLoc &DL, EVT VT, bool isTarget=false, bool isOpaque=false)
Create a ConstantSDNode wrapping a constant value.
static bool isVolatile(Instruction *Inst)
uint64_t getZExtValue() const
Unlike LLVM values, Selection DAG nodes may return multiple values as the result of a computation...