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 
22 namespace llvm {
23 class BPFSubtarget;
24 namespace BPFISD {
25 enum 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 
35 class BPFTargetLowering : public TargetLowering {
36 public:
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 
49 private:
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 
getOptimalMemOpType(uint64_t Size,unsigned DstAlign,unsigned SrcAlign,bool IsMemset,bool ZeroMemset,bool MemcpyStrSrc,MachineFunction & MF)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 
shouldConvertConstantLoadToIntImm(const APInt & Imm,Type * Ty)86   bool shouldConvertConstantLoadToIntImm(const APInt &Imm,
87                                          Type *Ty) const override {
88     return true;
89   }
90 };
91 }
92 
93 #endif
94