1 //===- llvm/CodeGen/GlobalISel/CallLowering.h - Call lowering ---*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
11 /// This file describes how to lower LLVM calls to machine code calls.
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_CODEGEN_GLOBALISEL_CALLLOWERING_H
16 #define LLVM_CODEGEN_GLOBALISEL_CALLLOWERING_H
18 #include "llvm/ADT/ArrayRef.h"
19 #include "llvm/CodeGen/CallingConvLower.h"
20 #include "llvm/CodeGen/TargetCallingConv.h"
21 #include "llvm/IR/CallSite.h"
22 #include "llvm/IR/CallingConv.h"
23 #include "llvm/Support/ErrorHandling.h"
24 #include "llvm/Support/MachineValueType.h"
32 class MachineIRBuilder;
34 struct MachinePointerInfo;
35 class MachineRegisterInfo;
41 const TargetLowering *TLI;
47 ISD::ArgFlagsTy Flags;
50 ArgInfo(unsigned Reg, Type *Ty, ISD::ArgFlagsTy Flags = ISD::ArgFlagsTy{},
52 : Reg(Reg), Ty(Ty), Flags(Flags), IsFixed(IsFixed) {}
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.
62 ValueHandler(MachineIRBuilder &MIRBuilder, MachineRegisterInfo &MRI,
64 : MIRBuilder(MIRBuilder), MRI(MRI), AssignFn(AssignFn) {}
66 virtual ~ValueHandler() = default;
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
73 virtual unsigned getStackAddress(uint64_t Size, int64_t Offset,
74 MachinePointerInfo &MPO) = 0;
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,
82 /// The specified value has been assigned to a stack
83 /// location. Load or store it there, with appropriate extension
85 virtual void assignValueToAddress(unsigned ValVReg, unsigned Addr,
86 uint64_t Size, MachinePointerInfo &MPO,
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
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");
100 unsigned extendRegister(unsigned ValReg, CCValAssign &VA);
102 virtual bool assignArg(unsigned ValNo, MVT ValVT, MVT LocVT,
103 CCValAssign::LocInfo LocInfo, const ArgInfo &Info,
105 return AssignFn(ValNo, ValVT, LocVT, LocInfo, Info.Flags, State);
108 MachineIRBuilder &MIRBuilder;
109 MachineRegisterInfo &MRI;
110 CCAssignFn *AssignFn;
114 /// Getter for generic TargetLowering class.
115 const TargetLowering *getTLI() const {
119 /// Getter for target specific TargetLowering class.
120 template <class XXXTargetLowering>
121 const XXXTargetLowering *getTLI() const {
122 return static_cast<const XXXTargetLowering *>(TLI);
125 template <typename FuncInfoTy>
126 void setArgFlags(ArgInfo &Arg, unsigned OpIdx, const DataLayout &DL,
127 const FuncInfoTy &FuncInfo) const;
129 /// Invoke Handler::assignArg on each of the given \p Args and then use
130 /// \p Callback to move them to the assigned locations.
132 /// \return True if everything has succeeded, false otherwise.
133 bool handleAssignments(MachineIRBuilder &MIRBuilder, ArrayRef<ArgInfo> Args,
134 ValueHandler &Handler) const;
137 CallLowering(const TargetLowering *TLI) : TLI(TLI) {}
138 virtual ~CallLowering() = default;
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.
144 /// \return True if the lowering succeeds, false otherwise.
145 virtual bool lowerReturn(MachineIRBuilder &MIRBuilder,
146 const Value *Val, unsigned VReg) const {
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
158 /// \return True if the lowering succeeded, false otherwise.
159 virtual bool lowerFormalArguments(MachineIRBuilder &MIRBuilder,
161 ArrayRef<unsigned> VRegs) const {
165 /// This hook must be implemented to lower the given call instruction,
166 /// including argument and return value marshalling.
168 /// \p CallConv is the calling convention to be used for the call.
170 /// \p Callee is the destination of the call. It should be either a register,
171 /// globaladdress, or externalsymbol.
173 /// \p ResTy is the type returned by the function
175 /// \p ResReg is the generic virtual register that the returned
176 /// value should be lowered into.
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.
181 /// \p ArgRegs is a list of virtual registers containing each argument that
182 /// needs to be passed.
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 {
191 /// Lower the given call instruction, including argument and return value
194 /// \p CI is the call/invoke instruction.
196 /// \p ResReg is a register where the call's return value should be stored (or
197 /// 0 if there is no return value).
199 /// \p ArgRegs is a list of virtual registers containing each argument that
200 /// needs to be passed.
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.
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;
213 } // end namespace llvm
215 #endif // LLVM_CODEGEN_GLOBALISEL_CALLLOWERING_H