1 //===- llvm/CodeGen/GlobalISel/CallLowering.h - Call lowering ---*- 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 /// \file 11 /// This file describes how to lower LLVM calls to machine code calls. 12 /// 13 //===----------------------------------------------------------------------===// 14 15 #ifndef LLVM_CODEGEN_GLOBALISEL_CALLLOWERING_H 16 #define LLVM_CODEGEN_GLOBALISEL_CALLLOWERING_H 17 18 #include "llvm/ADT/ArrayRef.h" 19 #include "llvm/CodeGen/CallingConvLower.h" 20 #include "llvm/CodeGen/MachineValueType.h" 21 #include "llvm/IR/CallSite.h" 22 #include "llvm/IR/CallingConv.h" 23 #include "llvm/Support/ErrorHandling.h" 24 #include "llvm/Target/TargetCallingConv.h" 25 #include <cstdint> 26 #include <functional> 27 28 namespace llvm { 29 30 class DataLayout; 31 class Function; 32 class MachineIRBuilder; 33 class MachineOperand; 34 struct MachinePointerInfo; 35 class MachineRegisterInfo; 36 class TargetLowering; 37 class Type; 38 class Value; 39 40 class CallLowering { 41 const TargetLowering *TLI; 42 43 public: 44 struct ArgInfo { 45 unsigned Reg; 46 Type *Ty; 47 ISD::ArgFlagsTy Flags; 48 bool IsFixed; 49 50 ArgInfo(unsigned Reg, Type *Ty, ISD::ArgFlagsTy Flags = ISD::ArgFlagsTy{}, 51 bool IsFixed = true) 52 : Reg(Reg), Ty(Ty), Flags(Flags), IsFixed(IsFixed) {} 53 }; 54 55 /// Argument handling is mostly uniform between the four places that 56 /// make these decisions: function formal arguments, call 57 /// instruction args, call instruction returns and function 58 /// returns. However, once a decision has been made on where an 59 /// arugment should go, exactly what happens can vary slightly. This 60 /// class abstracts the differences. 61 struct ValueHandler { 62 ValueHandler(MachineIRBuilder &MIRBuilder, MachineRegisterInfo &MRI, 63 CCAssignFn *AssignFn) 64 : MIRBuilder(MIRBuilder), MRI(MRI), AssignFn(AssignFn) {} 65 66 virtual ~ValueHandler() = default; 67 68 /// Materialize a VReg containing the address of the specified 69 /// stack-based object. This is either based on a FrameIndex or 70 /// direct SP manipulation, depending on the context. \p MPO 71 /// should be initialized to an appropriate description of the 72 /// address created. 73 virtual unsigned getStackAddress(uint64_t Size, int64_t Offset, 74 MachinePointerInfo &MPO) = 0; 75 76 /// The specified value has been assigned to a physical register, 77 /// handle the appropriate COPY (either to or from) and mark any 78 /// relevant uses/defines as needed. 79 virtual void assignValueToReg(unsigned ValVReg, unsigned PhysReg, 80 CCValAssign &VA) = 0; 81 82 /// The specified value has been assigned to a stack 83 /// location. Load or store it there, with appropriate extension 84 /// if necessary. 85 virtual void assignValueToAddress(unsigned ValVReg, unsigned Addr, 86 uint64_t Size, MachinePointerInfo &MPO, 87 CCValAssign &VA) = 0; 88 89 /// Handle custom values, which may be passed into one or more of \p VAs. 90 /// \return The number of \p VAs that have been assigned after the first 91 /// one, and which should therefore be skipped from further 92 /// processing. 93 virtual unsigned assignCustomValue(const ArgInfo &Arg, 94 ArrayRef<CCValAssign> VAs) { 95 // This is not a pure virtual method because not all targets need to worry 96 // about custom values. 97 llvm_unreachable("Custom values not supported"); 98 } 99 100 unsigned extendRegister(unsigned ValReg, CCValAssign &VA); 101 102 virtual bool assignArg(unsigned ValNo, MVT ValVT, MVT LocVT, 103 CCValAssign::LocInfo LocInfo, const ArgInfo &Info, 104 CCState &State) { 105 return AssignFn(ValNo, ValVT, LocVT, LocInfo, Info.Flags, State); 106 } 107 108 MachineIRBuilder &MIRBuilder; 109 MachineRegisterInfo &MRI; 110 CCAssignFn *AssignFn; 111 }; 112 113 protected: 114 /// Getter for generic TargetLowering class. 115 const TargetLowering *getTLI() const { 116 return TLI; 117 } 118 119 /// Getter for target specific TargetLowering class. 120 template <class XXXTargetLowering> 121 const XXXTargetLowering *getTLI() const { 122 return static_cast<const XXXTargetLowering *>(TLI); 123 } 124 125 template <typename FuncInfoTy> 126 void setArgFlags(ArgInfo &Arg, unsigned OpNum, const DataLayout &DL, 127 const FuncInfoTy &FuncInfo) const; 128 129 /// Invoke Handler::assignArg on each of the given \p Args and then use 130 /// \p Callback to move them to the assigned locations. 131 /// 132 /// \return True if everything has succeeded, false otherwise. 133 bool handleAssignments(MachineIRBuilder &MIRBuilder, ArrayRef<ArgInfo> Args, 134 ValueHandler &Callback) const; 135 136 public: 137 CallLowering(const TargetLowering *TLI) : TLI(TLI) {} 138 virtual ~CallLowering() = default; 139 140 /// This hook must be implemented to lower outgoing return values, described 141 /// by \p Val, into the specified virtual register \p VReg. 142 /// This hook is used by GlobalISel. 143 /// 144 /// \return True if the lowering succeeds, false otherwise. 145 virtual bool lowerReturn(MachineIRBuilder &MIRBuilder, 146 const Value *Val, unsigned VReg) const { 147 return false; 148 } 149 150 /// This hook must be implemented to lower the incoming (formal) 151 /// arguments, described by \p Args, for GlobalISel. Each argument 152 /// must end up in the related virtual register described by VRegs. 153 /// In other words, the first argument should end up in VRegs[0], 154 /// the second in VRegs[1], and so on. 155 /// \p MIRBuilder is set to the proper insertion for the argument 156 /// lowering. 157 /// 158 /// \return True if the lowering succeeded, false otherwise. 159 virtual bool lowerFormalArguments(MachineIRBuilder &MIRBuilder, 160 const Function &F, 161 ArrayRef<unsigned> VRegs) const { 162 return false; 163 } 164 165 /// This hook must be implemented to lower the given call instruction, 166 /// including argument and return value marshalling. 167 /// 168 /// \p CallConv is the calling convention to be used for the call. 169 /// 170 /// \p Callee is the destination of the call. It should be either a register, 171 /// globaladdress, or externalsymbol. 172 /// 173 /// \p ResTy is the type returned by the function 174 /// 175 /// \p ResReg is the generic virtual register that the returned 176 /// value should be lowered into. 177 /// 178 /// \p ArgTys is a list of the types each member of \p ArgRegs has; used by 179 /// the target to decide which register/stack slot should be allocated. 180 /// 181 /// \p ArgRegs is a list of virtual registers containing each argument that 182 /// needs to be passed. 183 /// 184 /// \return true if the lowering succeeded, false otherwise. 185 virtual bool lowerCall(MachineIRBuilder &MIRBuilder, CallingConv::ID CallConv, 186 const MachineOperand &Callee, const ArgInfo &OrigRet, 187 ArrayRef<ArgInfo> OrigArgs) const { 188 return false; 189 } 190 191 /// Lower the given call instruction, including argument and return value 192 /// marshalling. 193 /// 194 /// \p CI is the call/invoke instruction. 195 /// 196 /// \p ResReg is a register where the call's return value should be stored (or 197 /// 0 if there is no return value). 198 /// 199 /// \p ArgRegs is a list of virtual registers containing each argument that 200 /// needs to be passed. 201 /// 202 /// \p GetCalleeReg is a callback to materialize a register for the callee if 203 /// the target determines it cannot jump to the destination based purely on \p 204 /// CI. This might be because \p CI is indirect, or because of the limited 205 /// range of an immediate jump. 206 /// 207 /// \return true if the lowering succeeded, false otherwise. 208 bool lowerCall(MachineIRBuilder &MIRBuilder, ImmutableCallSite CS, 209 unsigned ResReg, ArrayRef<unsigned> ArgRegs, 210 std::function<unsigned()> GetCalleeReg) const; 211 }; 212 213 } // end namespace llvm 214 215 #endif // LLVM_CODEGEN_GLOBALISEL_CALLLOWERING_H 216
