1 //===-- FunctionLoweringInfo.h - Lower functions from LLVM IR to CodeGen --===// 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 implements routines for translating functions from LLVM IR into 11 // Machine IR. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #ifndef LLVM_CODEGEN_FUNCTIONLOWERINGINFO_H 16 #define LLVM_CODEGEN_FUNCTIONLOWERINGINFO_H 17 18 #include "llvm/ADT/APInt.h" 19 #include "llvm/ADT/DenseMap.h" 20 #include "llvm/ADT/IndexedMap.h" 21 #include "llvm/ADT/SmallPtrSet.h" 22 #include "llvm/ADT/SmallVector.h" 23 #include "llvm/CodeGen/MachineBasicBlock.h" 24 #include "llvm/CodeGen/ValueTypes.h" 25 #include "llvm/IR/InlineAsm.h" 26 #include "llvm/IR/Instructions.h" 27 #include "llvm/Target/TargetRegisterInfo.h" 28 #include <vector> 29 30 namespace llvm { 31 32 class AllocaInst; 33 class BasicBlock; 34 class BranchProbabilityInfo; 35 class CallInst; 36 class Function; 37 class GlobalVariable; 38 class Instruction; 39 class MachineInstr; 40 class MachineBasicBlock; 41 class MachineFunction; 42 class MachineModuleInfo; 43 class MachineRegisterInfo; 44 class TargetLowering; 45 class Value; 46 47 //===--------------------------------------------------------------------===// 48 /// FunctionLoweringInfo - This contains information that is global to a 49 /// function that is used when lowering a region of the function. 50 /// 51 class FunctionLoweringInfo { 52 const TargetMachine &TM; 53 public: 54 const Function *Fn; 55 MachineFunction *MF; 56 MachineRegisterInfo *RegInfo; 57 BranchProbabilityInfo *BPI; 58 /// CanLowerReturn - true iff the function's return value can be lowered to 59 /// registers. 60 bool CanLowerReturn; 61 62 /// DemoteRegister - if CanLowerReturn is false, DemoteRegister is a vreg 63 /// allocated to hold a pointer to the hidden sret parameter. 64 unsigned DemoteRegister; 65 66 /// MBBMap - A mapping from LLVM basic blocks to their machine code entry. 67 DenseMap<const BasicBlock*, MachineBasicBlock *> MBBMap; 68 69 /// ValueMap - Since we emit code for the function a basic block at a time, 70 /// we must remember which virtual registers hold the values for 71 /// cross-basic-block values. 72 DenseMap<const Value*, unsigned> ValueMap; 73 74 /// StaticAllocaMap - Keep track of frame indices for fixed sized allocas in 75 /// the entry block. This allows the allocas to be efficiently referenced 76 /// anywhere in the function. 77 DenseMap<const AllocaInst*, int> StaticAllocaMap; 78 79 /// ByValArgFrameIndexMap - Keep track of frame indices for byval arguments. 80 DenseMap<const Argument*, int> ByValArgFrameIndexMap; 81 82 /// ArgDbgValues - A list of DBG_VALUE instructions created during isel for 83 /// function arguments that are inserted after scheduling is completed. 84 SmallVector<MachineInstr*, 8> ArgDbgValues; 85 86 /// RegFixups - Registers which need to be replaced after isel is done. 87 DenseMap<unsigned, unsigned> RegFixups; 88 89 /// MBB - The current block. 90 MachineBasicBlock *MBB; 91 92 /// MBB - The current insert position inside the current block. 93 MachineBasicBlock::iterator InsertPt; 94 95 #ifndef NDEBUG 96 SmallPtrSet<const Instruction *, 8> CatchInfoLost; 97 SmallPtrSet<const Instruction *, 8> CatchInfoFound; 98 #endif 99 100 struct LiveOutInfo { 101 unsigned NumSignBits : 31; 102 bool IsValid : 1; 103 APInt KnownOne, KnownZero; 104 LiveOutInfo() : NumSignBits(0), IsValid(true), KnownOne(1, 0), 105 KnownZero(1, 0) {} 106 }; 107 108 /// VisitedBBs - The set of basic blocks visited thus far by instruction 109 /// selection. 110 SmallPtrSet<const BasicBlock*, 4> VisitedBBs; 111 112 /// PHINodesToUpdate - A list of phi instructions whose operand list will 113 /// be updated after processing the current basic block. 114 /// TODO: This isn't per-function state, it's per-basic-block state. But 115 /// there's no other convenient place for it to live right now. 116 std::vector<std::pair<MachineInstr*, unsigned> > PHINodesToUpdate; 117 118 /// If the current MBB is a landing pad, the exception pointer and exception 119 /// selector registers are copied into these virtual registers by 120 /// SelectionDAGISel::PrepareEHLandingPad(). 121 unsigned ExceptionPointerVirtReg, ExceptionSelectorVirtReg; 122 123 explicit FunctionLoweringInfo(const TargetMachine &TM) : TM(TM) {} 124 125 /// set - Initialize this FunctionLoweringInfo with the given Function 126 /// and its associated MachineFunction. 127 /// 128 void set(const Function &Fn, MachineFunction &MF); 129 130 /// clear - Clear out all the function-specific state. This returns this 131 /// FunctionLoweringInfo to an empty state, ready to be used for a 132 /// different function. 133 void clear(); 134 135 /// isExportedInst - Return true if the specified value is an instruction 136 /// exported from its block. 137 bool isExportedInst(const Value *V) { 138 return ValueMap.count(V); 139 } 140 141 unsigned CreateReg(MVT VT); 142 143 unsigned CreateRegs(Type *Ty); 144 145 unsigned InitializeRegForValue(const Value *V) { 146 unsigned &R = ValueMap[V]; 147 assert(R == 0 && "Already initialized this value register!"); 148 return R = CreateRegs(V->getType()); 149 } 150 151 /// GetLiveOutRegInfo - Gets LiveOutInfo for a register, returning NULL if the 152 /// register is a PHI destination and the PHI's LiveOutInfo is not valid. 153 const LiveOutInfo *GetLiveOutRegInfo(unsigned Reg) { 154 if (!LiveOutRegInfo.inBounds(Reg)) 155 return NULL; 156 157 const LiveOutInfo *LOI = &LiveOutRegInfo[Reg]; 158 if (!LOI->IsValid) 159 return NULL; 160 161 return LOI; 162 } 163 164 /// GetLiveOutRegInfo - Gets LiveOutInfo for a register, returning NULL if the 165 /// register is a PHI destination and the PHI's LiveOutInfo is not valid. If 166 /// the register's LiveOutInfo is for a smaller bit width, it is extended to 167 /// the larger bit width by zero extension. The bit width must be no smaller 168 /// than the LiveOutInfo's existing bit width. 169 const LiveOutInfo *GetLiveOutRegInfo(unsigned Reg, unsigned BitWidth); 170 171 /// AddLiveOutRegInfo - Adds LiveOutInfo for a register. 172 void AddLiveOutRegInfo(unsigned Reg, unsigned NumSignBits, 173 const APInt &KnownZero, const APInt &KnownOne) { 174 // Only install this information if it tells us something. 175 if (NumSignBits == 1 && KnownZero == 0 && KnownOne == 0) 176 return; 177 178 LiveOutRegInfo.grow(Reg); 179 LiveOutInfo &LOI = LiveOutRegInfo[Reg]; 180 LOI.NumSignBits = NumSignBits; 181 LOI.KnownOne = KnownOne; 182 LOI.KnownZero = KnownZero; 183 } 184 185 /// ComputePHILiveOutRegInfo - Compute LiveOutInfo for a PHI's destination 186 /// register based on the LiveOutInfo of its operands. 187 void ComputePHILiveOutRegInfo(const PHINode*); 188 189 /// InvalidatePHILiveOutRegInfo - Invalidates a PHI's LiveOutInfo, to be 190 /// called when a block is visited before all of its predecessors. 191 void InvalidatePHILiveOutRegInfo(const PHINode *PN) { 192 // PHIs with no uses have no ValueMap entry. 193 DenseMap<const Value*, unsigned>::const_iterator It = ValueMap.find(PN); 194 if (It == ValueMap.end()) 195 return; 196 197 unsigned Reg = It->second; 198 LiveOutRegInfo.grow(Reg); 199 LiveOutRegInfo[Reg].IsValid = false; 200 } 201 202 /// setArgumentFrameIndex - Record frame index for the byval 203 /// argument. 204 void setArgumentFrameIndex(const Argument *A, int FI); 205 206 /// getArgumentFrameIndex - Get frame index for the byval argument. 207 int getArgumentFrameIndex(const Argument *A); 208 209 private: 210 /// LiveOutRegInfo - Information about live out vregs. 211 IndexedMap<LiveOutInfo, VirtReg2IndexFunctor> LiveOutRegInfo; 212 }; 213 214 /// ComputeUsesVAFloatArgument - Determine if any floating-point values are 215 /// being passed to this variadic function, and set the MachineModuleInfo's 216 /// usesVAFloatArgument flag if so. This flag is used to emit an undefined 217 /// reference to _fltused on Windows, which will link in MSVCRT's 218 /// floating-point support. 219 void ComputeUsesVAFloatArgument(const CallInst &I, MachineModuleInfo *MMI); 220 221 /// AddCatchInfo - Extract the personality and type infos from an eh.selector 222 /// call, and add them to the specified machine basic block. 223 void AddCatchInfo(const CallInst &I, 224 MachineModuleInfo *MMI, MachineBasicBlock *MBB); 225 226 /// AddLandingPadInfo - Extract the exception handling information from the 227 /// landingpad instruction and add them to the specified machine module info. 228 void AddLandingPadInfo(const LandingPadInst &I, MachineModuleInfo &MMI, 229 MachineBasicBlock *MBB); 230 231 } // end namespace llvm 232 233 #endif 234
