1//===-- BPFISelLowering.h - BPF DAG Lowering Interface ----------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file defines the interfaces that BPF uses to lower LLVM code into a
11// selection DAG.
12//
13//===----------------------------------------------------------------------===//
14
15#ifndef LLVM_LIB_TARGET_BPF_BPFISELLOWERING_H
16#define LLVM_LIB_TARGET_BPF_BPFISELLOWERING_H
17
18#include "BPF.h"
19#include "llvm/CodeGen/SelectionDAG.h"
20#include "llvm/Target/TargetLowering.h"
21
22namespace llvm {
23class BPFSubtarget;
24namespace BPFISD {
25enum NodeType : unsigned {
26  FIRST_NUMBER = ISD::BUILTIN_OP_END,
27  RET_FLAG,
28  CALL,
29  SELECT_CC,
30  BR_CC,
31  Wrapper
32};
33}
34
35class BPFTargetLowering : public TargetLowering {
36public:
37  explicit BPFTargetLowering(const TargetMachine &TM, const BPFSubtarget &STI);
38
39  // Provide custom lowering hooks for some operations.
40  SDValue LowerOperation(SDValue Op, SelectionDAG &DAG) const override;
41
42  // This method returns the name of a target specific DAG node.
43  const char *getTargetNodeName(unsigned Opcode) const override;
44
45  MachineBasicBlock *
46  EmitInstrWithCustomInserter(MachineInstr &MI,
47                              MachineBasicBlock *BB) const override;
48
49private:
50  SDValue LowerBR_CC(SDValue Op, SelectionDAG &DAG) const;
51  SDValue LowerSELECT_CC(SDValue Op, SelectionDAG &DAG) const;
52  SDValue LowerGlobalAddress(SDValue Op, SelectionDAG &DAG) const;
53
54  // Lower the result values of a call, copying them out of physregs into vregs
55  SDValue LowerCallResult(SDValue Chain, SDValue InFlag,
56                          CallingConv::ID CallConv, bool IsVarArg,
57                          const SmallVectorImpl<ISD::InputArg> &Ins,
58                          const SDLoc &DL, SelectionDAG &DAG,
59                          SmallVectorImpl<SDValue> &InVals) const;
60
61  // Maximum number of arguments to a call
62  static const unsigned MaxArgs;
63
64  // Lower a call into CALLSEQ_START - BPFISD:CALL - CALLSEQ_END chain
65  SDValue LowerCall(TargetLowering::CallLoweringInfo &CLI,
66                    SmallVectorImpl<SDValue> &InVals) const override;
67
68  // Lower incoming arguments, copy physregs into vregs
69  SDValue LowerFormalArguments(SDValue Chain, CallingConv::ID CallConv,
70                               bool IsVarArg,
71                               const SmallVectorImpl<ISD::InputArg> &Ins,
72                               const SDLoc &DL, SelectionDAG &DAG,
73                               SmallVectorImpl<SDValue> &InVals) const override;
74
75  SDValue LowerReturn(SDValue Chain, CallingConv::ID CallConv, bool IsVarArg,
76                      const SmallVectorImpl<ISD::OutputArg> &Outs,
77                      const SmallVectorImpl<SDValue> &OutVals, const SDLoc &DL,
78                      SelectionDAG &DAG) const override;
79
80  EVT getOptimalMemOpType(uint64_t Size, unsigned DstAlign, unsigned SrcAlign,
81                          bool IsMemset, bool ZeroMemset, bool MemcpyStrSrc,
82                          MachineFunction &MF) const override {
83    return Size >= 8 ? MVT::i64 : MVT::i32;
84  }
85
86  bool shouldConvertConstantLoadToIntImm(const APInt &Imm,
87                                         Type *Ty) const override {
88    return true;
89  }
90};
91}
92
93#endif
94