1 //- WebAssemblyISelLowering.h - WebAssembly DAG Lowering Interface -*- C++ -*-//
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 /// \file
10 /// This file defines the interfaces that WebAssembly uses to lower LLVM
11 /// code into a selection DAG.
12 ///
13 //===----------------------------------------------------------------------===//
14 
15 #ifndef LLVM_LIB_TARGET_WEBASSEMBLY_WEBASSEMBLYISELLOWERING_H
16 #define LLVM_LIB_TARGET_WEBASSEMBLY_WEBASSEMBLYISELLOWERING_H
17 
18 #include "llvm/CodeGen/TargetLowering.h"
19 
20 namespace llvm {
21 
22 namespace WebAssemblyISD {
23 
24 enum NodeType : unsigned {
25   FIRST_NUMBER = ISD::BUILTIN_OP_END,
26 #define HANDLE_NODETYPE(NODE) NODE,
27 #define HANDLE_MEM_NODETYPE(NODE)
28 #include "WebAssemblyISD.def"
29   FIRST_MEM_OPCODE = ISD::FIRST_TARGET_MEMORY_OPCODE,
30 #undef HANDLE_NODETYPE
31 #undef HANDLE_MEM_NODETYPE
32 #define HANDLE_NODETYPE(NODE)
33 #define HANDLE_MEM_NODETYPE(NODE) NODE,
34 #include "WebAssemblyISD.def"
35 #undef HANDLE_NODETYPE
36 #undef HANDLE_MEM_NODETYPE
37 };
38 
39 } // end namespace WebAssemblyISD
40 
41 class WebAssemblySubtarget;
42 
43 class WebAssemblyTargetLowering final : public TargetLowering {
44 public:
45   WebAssemblyTargetLowering(const TargetMachine &TM,
46                             const WebAssemblySubtarget &STI);
47 
48   MVT getPointerTy(const DataLayout &DL, uint32_t AS = 0) const override;
49   MVT getPointerMemTy(const DataLayout &DL, uint32_t AS = 0) const override;
50 
51 private:
52   /// Keep a pointer to the WebAssemblySubtarget around so that we can make the
53   /// right decision when generating code for different targets.
54   const WebAssemblySubtarget *Subtarget;
55 
56   AtomicExpansionKind shouldExpandAtomicRMWInIR(AtomicRMWInst *) const override;
57   bool shouldScalarizeBinop(SDValue VecOp) const override;
58   FastISel *createFastISel(FunctionLoweringInfo &FuncInfo,
59                            const TargetLibraryInfo *LibInfo) const override;
60   MVT getScalarShiftAmountTy(const DataLayout &DL, EVT) const override;
61   MachineBasicBlock *
62   EmitInstrWithCustomInserter(MachineInstr &MI,
63                               MachineBasicBlock *MBB) const override;
64   const char *getTargetNodeName(unsigned Opcode) const override;
65   std::pair<unsigned, const TargetRegisterClass *>
66   getRegForInlineAsmConstraint(const TargetRegisterInfo *TRI,
67                                StringRef Constraint, MVT VT) const override;
68   bool isCheapToSpeculateCttz(Type *Ty) const override;
69   bool isCheapToSpeculateCtlz(Type *Ty) const override;
70   bool isLegalAddressingMode(const DataLayout &DL, const AddrMode &AM, Type *Ty,
71                              unsigned AS,
72                              Instruction *I = nullptr) const override;
73   bool allowsMisalignedMemoryAccesses(EVT, unsigned AddrSpace, Align Alignment,
74                                       MachineMemOperand::Flags Flags,
75                                       unsigned *Fast) const override;
76   bool isIntDivCheap(EVT VT, AttributeList Attr) const override;
77   bool isVectorLoadExtDesirable(SDValue ExtVal) const override;
78   bool isOffsetFoldingLegal(const GlobalAddressSDNode *GA) const override;
79   bool shouldSinkOperands(Instruction *I,
80                           SmallVectorImpl<Use *> &Ops) const override;
81   EVT getSetCCResultType(const DataLayout &DL, LLVMContext &Context,
82                          EVT VT) const override;
83   bool getTgtMemIntrinsic(IntrinsicInfo &Info, const CallInst &I,
84                           MachineFunction &MF,
85                           unsigned Intrinsic) const override;
86 
87   void computeKnownBitsForTargetNode(const SDValue Op, KnownBits &Known,
88                                      const APInt &DemandedElts,
89                                      const SelectionDAG &DAG,
90                                      unsigned Depth) const override;
91 
92   TargetLoweringBase::LegalizeTypeAction
93   getPreferredVectorAction(MVT VT) const override;
94 
95   SDValue LowerCall(CallLoweringInfo &CLI,
96                     SmallVectorImpl<SDValue> &InVals) const override;
97   bool CanLowerReturn(CallingConv::ID CallConv, MachineFunction &MF,
98                       bool isVarArg,
99                       const SmallVectorImpl<ISD::OutputArg> &Outs,
100                       LLVMContext &Context) const override;
101   SDValue LowerReturn(SDValue Chain, CallingConv::ID CallConv, bool isVarArg,
102                       const SmallVectorImpl<ISD::OutputArg> &Outs,
103                       const SmallVectorImpl<SDValue> &OutVals, const SDLoc &dl,
104                       SelectionDAG &DAG) const override;
105   SDValue LowerFormalArguments(SDValue Chain, CallingConv::ID CallConv,
106                                bool IsVarArg,
107                                const SmallVectorImpl<ISD::InputArg> &Ins,
108                                const SDLoc &DL, SelectionDAG &DAG,
109                                SmallVectorImpl<SDValue> &InVals) const override;
110 
111   void ReplaceNodeResults(SDNode *N, SmallVectorImpl<SDValue> &Results,
112                           SelectionDAG &DAG) const override;
113 
114   const char *getClearCacheBuiltinName() const override {
115     report_fatal_error("llvm.clear_cache is not supported on wasm");
116   }
117 
118   bool
119   shouldSimplifyDemandedVectorElts(SDValue Op,
120                                    const TargetLoweringOpt &TLO) const override;
121 
122   // Custom lowering hooks.
123   SDValue LowerOperation(SDValue Op, SelectionDAG &DAG) const override;
124   SDValue LowerFrameIndex(SDValue Op, SelectionDAG &DAG) const;
125   SDValue LowerRETURNADDR(SDValue Op, SelectionDAG &DAG) const;
126   SDValue LowerFRAMEADDR(SDValue Op, SelectionDAG &DAG) const;
127   SDValue LowerGlobalAddress(SDValue Op, SelectionDAG &DAG) const;
128   SDValue LowerGlobalTLSAddress(SDValue Op, SelectionDAG &DAG) const;
129   SDValue LowerExternalSymbol(SDValue Op, SelectionDAG &DAG) const;
130   SDValue LowerBR_JT(SDValue Op, SelectionDAG &DAG) const;
131   SDValue LowerJumpTable(SDValue Op, SelectionDAG &DAG) const;
132   SDValue LowerVASTART(SDValue Op, SelectionDAG &DAG) const;
133   SDValue LowerCopyToReg(SDValue Op, SelectionDAG &DAG) const;
134   SDValue LowerIntrinsic(SDValue Op, SelectionDAG &DAG) const;
135   SDValue LowerSIGN_EXTEND_INREG(SDValue Op, SelectionDAG &DAG) const;
136   SDValue LowerEXTEND_VECTOR_INREG(SDValue Op, SelectionDAG &DAG) const;
137   SDValue LowerBUILD_VECTOR(SDValue Op, SelectionDAG &DAG) const;
138   SDValue LowerVECTOR_SHUFFLE(SDValue Op, SelectionDAG &DAG) const;
139   SDValue LowerSETCC(SDValue Op, SelectionDAG &DAG) const;
140   SDValue LowerAccessVectorElement(SDValue Op, SelectionDAG &DAG) const;
141   SDValue LowerShift(SDValue Op, SelectionDAG &DAG) const;
142   SDValue LowerFP_TO_INT_SAT(SDValue Op, SelectionDAG &DAG) const;
143   SDValue LowerLoad(SDValue Op, SelectionDAG &DAG) const;
144   SDValue LowerStore(SDValue Op, SelectionDAG &DAG) const;
145 
146   // Custom DAG combine hooks
147   SDValue
148   PerformDAGCombine(SDNode *N,
149                     TargetLowering::DAGCombinerInfo &DCI) const override;
150 };
151 
152 namespace WebAssembly {
153 FastISel *createFastISel(FunctionLoweringInfo &funcInfo,
154                          const TargetLibraryInfo *libInfo);
155 } // end namespace WebAssembly
156 
157 } // end namespace llvm
158 
159 #endif
160