CallingConvLower.h revision 208954
1//===-- llvm/CallingConvLower.h - Calling Conventions -----------*- 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 declares the CCState and CCValAssign classes, used for lowering 11// and implementing calling conventions. 12// 13//===----------------------------------------------------------------------===// 14 15#ifndef LLVM_CODEGEN_CALLINGCONVLOWER_H 16#define LLVM_CODEGEN_CALLINGCONVLOWER_H 17 18#include "llvm/ADT/SmallVector.h" 19#include "llvm/CodeGen/ValueTypes.h" 20#include "llvm/CodeGen/SelectionDAGNodes.h" 21#include "llvm/CallingConv.h" 22 23namespace llvm { 24 class TargetRegisterInfo; 25 class TargetMachine; 26 class CCState; 27 class SDNode; 28 29/// CCValAssign - Represent assignment of one arg/retval to a location. 30class CCValAssign { 31public: 32 enum LocInfo { 33 Full, // The value fills the full location. 34 SExt, // The value is sign extended in the location. 35 ZExt, // The value is zero extended in the location. 36 AExt, // The value is extended with undefined upper bits. 37 BCvt, // The value is bit-converted in the location. 38 Indirect // The location contains pointer to the value. 39 // TODO: a subset of the value is in the location. 40 }; 41private: 42 /// ValNo - This is the value number begin assigned (e.g. an argument number). 43 unsigned ValNo; 44 45 /// Loc is either a stack offset or a register number. 46 unsigned Loc; 47 48 /// isMem - True if this is a memory loc, false if it is a register loc. 49 bool isMem : 1; 50 51 /// isCustom - True if this arg/retval requires special handling. 52 bool isCustom : 1; 53 54 /// Information about how the value is assigned. 55 LocInfo HTP : 6; 56 57 /// ValVT - The type of the value being assigned. 58 EVT ValVT; 59 60 /// LocVT - The type of the location being assigned to. 61 EVT LocVT; 62public: 63 64 static CCValAssign getReg(unsigned ValNo, EVT ValVT, 65 unsigned RegNo, EVT LocVT, 66 LocInfo HTP) { 67 CCValAssign Ret; 68 Ret.ValNo = ValNo; 69 Ret.Loc = RegNo; 70 Ret.isMem = false; 71 Ret.isCustom = false; 72 Ret.HTP = HTP; 73 Ret.ValVT = ValVT; 74 Ret.LocVT = LocVT; 75 return Ret; 76 } 77 78 static CCValAssign getCustomReg(unsigned ValNo, EVT ValVT, 79 unsigned RegNo, EVT LocVT, 80 LocInfo HTP) { 81 CCValAssign Ret; 82 Ret = getReg(ValNo, ValVT, RegNo, LocVT, HTP); 83 Ret.isCustom = true; 84 return Ret; 85 } 86 87 static CCValAssign getMem(unsigned ValNo, EVT ValVT, 88 unsigned Offset, EVT LocVT, 89 LocInfo HTP) { 90 CCValAssign Ret; 91 Ret.ValNo = ValNo; 92 Ret.Loc = Offset; 93 Ret.isMem = true; 94 Ret.isCustom = false; 95 Ret.HTP = HTP; 96 Ret.ValVT = ValVT; 97 Ret.LocVT = LocVT; 98 return Ret; 99 } 100 101 static CCValAssign getCustomMem(unsigned ValNo, EVT ValVT, 102 unsigned Offset, EVT LocVT, 103 LocInfo HTP) { 104 CCValAssign Ret; 105 Ret = getMem(ValNo, ValVT, Offset, LocVT, HTP); 106 Ret.isCustom = true; 107 return Ret; 108 } 109 110 unsigned getValNo() const { return ValNo; } 111 EVT getValVT() const { return ValVT; } 112 113 bool isRegLoc() const { return !isMem; } 114 bool isMemLoc() const { return isMem; } 115 116 bool needsCustom() const { return isCustom; } 117 118 unsigned getLocReg() const { assert(isRegLoc()); return Loc; } 119 unsigned getLocMemOffset() const { assert(isMemLoc()); return Loc; } 120 EVT getLocVT() const { return LocVT; } 121 122 LocInfo getLocInfo() const { return HTP; } 123 bool isExtInLoc() const { 124 return (HTP == AExt || HTP == SExt || HTP == ZExt); 125 } 126 127}; 128 129/// CCAssignFn - This function assigns a location for Val, updating State to 130/// reflect the change. 131typedef bool CCAssignFn(unsigned ValNo, EVT ValVT, 132 EVT LocVT, CCValAssign::LocInfo LocInfo, 133 ISD::ArgFlagsTy ArgFlags, CCState &State); 134 135/// CCCustomFn - This function assigns a location for Val, possibly updating 136/// all args to reflect changes and indicates if it handled it. It must set 137/// isCustom if it handles the arg and returns true. 138typedef bool CCCustomFn(unsigned &ValNo, EVT &ValVT, 139 EVT &LocVT, CCValAssign::LocInfo &LocInfo, 140 ISD::ArgFlagsTy &ArgFlags, CCState &State); 141 142/// CCState - This class holds information needed while lowering arguments and 143/// return values. It captures which registers are already assigned and which 144/// stack slots are used. It provides accessors to allocate these values. 145class CCState { 146 CallingConv::ID CallingConv; 147 bool IsVarArg; 148 const TargetMachine &TM; 149 const TargetRegisterInfo &TRI; 150 SmallVector<CCValAssign, 16> &Locs; 151 LLVMContext &Context; 152 153 unsigned StackOffset; 154 SmallVector<uint32_t, 16> UsedRegs; 155public: 156 CCState(CallingConv::ID CC, bool isVarArg, const TargetMachine &TM, 157 SmallVector<CCValAssign, 16> &locs, LLVMContext &C); 158 159 void addLoc(const CCValAssign &V) { 160 Locs.push_back(V); 161 } 162 163 LLVMContext &getContext() const { return Context; } 164 const TargetMachine &getTarget() const { return TM; } 165 CallingConv::ID getCallingConv() const { return CallingConv; } 166 bool isVarArg() const { return IsVarArg; } 167 168 unsigned getNextStackOffset() const { return StackOffset; } 169 170 /// isAllocated - Return true if the specified register (or an alias) is 171 /// allocated. 172 bool isAllocated(unsigned Reg) const { 173 return UsedRegs[Reg/32] & (1 << (Reg&31)); 174 } 175 176 /// AnalyzeFormalArguments - Analyze an array of argument values, 177 /// incorporating info about the formals into this state. 178 void AnalyzeFormalArguments(const SmallVectorImpl<ISD::InputArg> &Ins, 179 CCAssignFn Fn); 180 181 /// AnalyzeReturn - Analyze the returned values of a return, 182 /// incorporating info about the result values into this state. 183 void AnalyzeReturn(const SmallVectorImpl<ISD::OutputArg> &Outs, 184 CCAssignFn Fn); 185 186 /// CheckReturn - Analyze the return values of a function, returning 187 /// true if the return can be performed without sret-demotion, and 188 /// false otherwise. 189 bool CheckReturn(const SmallVectorImpl<EVT> &OutTys, 190 const SmallVectorImpl<ISD::ArgFlagsTy> &ArgsFlags, 191 CCAssignFn Fn); 192 193 /// AnalyzeCallOperands - Analyze the outgoing arguments to a call, 194 /// incorporating info about the passed values into this state. 195 void AnalyzeCallOperands(const SmallVectorImpl<ISD::OutputArg> &Outs, 196 CCAssignFn Fn); 197 198 /// AnalyzeCallOperands - Same as above except it takes vectors of types 199 /// and argument flags. 200 void AnalyzeCallOperands(SmallVectorImpl<EVT> &ArgVTs, 201 SmallVectorImpl<ISD::ArgFlagsTy> &Flags, 202 CCAssignFn Fn); 203 204 /// AnalyzeCallResult - Analyze the return values of a call, 205 /// incorporating info about the passed values into this state. 206 void AnalyzeCallResult(const SmallVectorImpl<ISD::InputArg> &Ins, 207 CCAssignFn Fn); 208 209 /// AnalyzeCallResult - Same as above except it's specialized for calls which 210 /// produce a single value. 211 void AnalyzeCallResult(EVT VT, CCAssignFn Fn); 212 213 /// getFirstUnallocated - Return the first unallocated register in the set, or 214 /// NumRegs if they are all allocated. 215 unsigned getFirstUnallocated(const unsigned *Regs, unsigned NumRegs) const { 216 for (unsigned i = 0; i != NumRegs; ++i) 217 if (!isAllocated(Regs[i])) 218 return i; 219 return NumRegs; 220 } 221 222 /// AllocateReg - Attempt to allocate one register. If it is not available, 223 /// return zero. Otherwise, return the register, marking it and any aliases 224 /// as allocated. 225 unsigned AllocateReg(unsigned Reg) { 226 if (isAllocated(Reg)) return 0; 227 MarkAllocated(Reg); 228 return Reg; 229 } 230 231 /// Version of AllocateReg with extra register to be shadowed. 232 unsigned AllocateReg(unsigned Reg, unsigned ShadowReg) { 233 if (isAllocated(Reg)) return 0; 234 MarkAllocated(Reg); 235 MarkAllocated(ShadowReg); 236 return Reg; 237 } 238 239 /// AllocateReg - Attempt to allocate one of the specified registers. If none 240 /// are available, return zero. Otherwise, return the first one available, 241 /// marking it and any aliases as allocated. 242 unsigned AllocateReg(const unsigned *Regs, unsigned NumRegs) { 243 unsigned FirstUnalloc = getFirstUnallocated(Regs, NumRegs); 244 if (FirstUnalloc == NumRegs) 245 return 0; // Didn't find the reg. 246 247 // Mark the register and any aliases as allocated. 248 unsigned Reg = Regs[FirstUnalloc]; 249 MarkAllocated(Reg); 250 return Reg; 251 } 252 253 /// Version of AllocateReg with list of registers to be shadowed. 254 unsigned AllocateReg(const unsigned *Regs, const unsigned *ShadowRegs, 255 unsigned NumRegs) { 256 unsigned FirstUnalloc = getFirstUnallocated(Regs, NumRegs); 257 if (FirstUnalloc == NumRegs) 258 return 0; // Didn't find the reg. 259 260 // Mark the register and any aliases as allocated. 261 unsigned Reg = Regs[FirstUnalloc], ShadowReg = ShadowRegs[FirstUnalloc]; 262 MarkAllocated(Reg); 263 MarkAllocated(ShadowReg); 264 return Reg; 265 } 266 267 /// AllocateStack - Allocate a chunk of stack space with the specified size 268 /// and alignment. 269 unsigned AllocateStack(unsigned Size, unsigned Align) { 270 assert(Align && ((Align-1) & Align) == 0); // Align is power of 2. 271 StackOffset = ((StackOffset + Align-1) & ~(Align-1)); 272 unsigned Result = StackOffset; 273 StackOffset += Size; 274 return Result; 275 } 276 277 // HandleByVal - Allocate a stack slot large enough to pass an argument by 278 // value. The size and alignment information of the argument is encoded in its 279 // parameter attribute. 280 void HandleByVal(unsigned ValNo, EVT ValVT, 281 EVT LocVT, CCValAssign::LocInfo LocInfo, 282 int MinSize, int MinAlign, ISD::ArgFlagsTy ArgFlags); 283 284private: 285 /// MarkAllocated - Mark a register and all of its aliases as allocated. 286 void MarkAllocated(unsigned Reg); 287}; 288 289 290 291} // end namespace llvm 292 293#endif 294