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/IR/InlineAsm.h" 25 #include "llvm/IR/Instructions.h" 26 #include "llvm/Target/TargetRegisterInfo.h" 27 #include <vector> 28 29 namespace llvm { 30 31 class AllocaInst; 32 class BasicBlock; 33 class BranchProbabilityInfo; 34 class CallInst; 35 class Function; 36 class GlobalVariable; 37 class Instruction; 38 class MachineInstr; 39 class MachineBasicBlock; 40 class MachineFunction; 41 class MachineModuleInfo; 42 class MachineRegisterInfo; 43 class SelectionDAG; 44 class MVT; 45 class TargetLowering; 46 class Value; 47 48 //===--------------------------------------------------------------------===// 49 /// FunctionLoweringInfo - This contains information that is global to a 50 /// function that is used when lowering a region of the function. 51 /// 52 class FunctionLoweringInfo { 53 const TargetMachine &TM; 54 public: 55 const Function *Fn; 56 MachineFunction *MF; 57 MachineRegisterInfo *RegInfo; 58 BranchProbabilityInfo *BPI; 59 /// CanLowerReturn - true iff the function's return value can be lowered to 60 /// registers. 61 bool CanLowerReturn; 62 63 /// DemoteRegister - if CanLowerReturn is false, DemoteRegister is a vreg 64 /// allocated to hold a pointer to the hidden sret parameter. 65 unsigned DemoteRegister; 66 67 /// MBBMap - A mapping from LLVM basic blocks to their machine code entry. 68 DenseMap<const BasicBlock*, MachineBasicBlock *> MBBMap; 69 70 /// ValueMap - Since we emit code for the function a basic block at a time, 71 /// we must remember which virtual registers hold the values for 72 /// cross-basic-block values. 73 DenseMap<const Value*, unsigned> ValueMap; 74 75 /// StaticAllocaMap - Keep track of frame indices for fixed sized allocas in 76 /// the entry block. This allows the allocas to be efficiently referenced 77 /// anywhere in the function. 78 DenseMap<const AllocaInst*, int> StaticAllocaMap; 79 80 /// ByValArgFrameIndexMap - Keep track of frame indices for byval arguments. 81 DenseMap<const Argument*, int> ByValArgFrameIndexMap; 82 83 /// ArgDbgValues - A list of DBG_VALUE instructions created during isel for 84 /// function arguments that are inserted after scheduling is completed. 85 SmallVector<MachineInstr*, 8> ArgDbgValues; 86 87 /// RegFixups - Registers which need to be replaced after isel is done. 88 DenseMap<unsigned, unsigned> RegFixups; 89 90 /// MBB - The current block. 91 MachineBasicBlock *MBB; 92 93 /// MBB - The current insert position inside the current block. 94 MachineBasicBlock::iterator InsertPt; 95 96 #ifndef NDEBUG 97 SmallPtrSet<const Instruction *, 8> CatchInfoLost; 98 SmallPtrSet<const Instruction *, 8> CatchInfoFound; 99 #endif 100 101 struct LiveOutInfo { 102 unsigned NumSignBits : 31; 103 bool IsValid : 1; 104 APInt KnownOne, KnownZero; 105 LiveOutInfo() : NumSignBits(0), IsValid(true), KnownOne(1, 0), 106 KnownZero(1, 0) {} 107 }; 108 109 /// VisitedBBs - The set of basic blocks visited thus far by instruction 110 /// selection. 111 SmallPtrSet<const BasicBlock*, 4> VisitedBBs; 112 113 /// PHINodesToUpdate - A list of phi instructions whose operand list will 114 /// be updated after processing the current basic block. 115 /// TODO: This isn't per-function state, it's per-basic-block state. But 116 /// there's no other convenient place for it to live right now. 117 std::vector<std::pair<MachineInstr*, unsigned> > PHINodesToUpdate; 118 119 /// If the current MBB is a landing pad, the exception pointer and exception 120 /// selector registers are copied into these virtual registers by 121 /// SelectionDAGISel::PrepareEHLandingPad(). 122 unsigned ExceptionPointerVirtReg, ExceptionSelectorVirtReg; 123 124 explicit FunctionLoweringInfo(const TargetMachine &TM) : TM(TM) {} 125 126 /// set - Initialize this FunctionLoweringInfo with the given Function 127 /// and its associated MachineFunction. 128 /// 129 void set(const Function &Fn, MachineFunction &MF, SelectionDAG *DAG); 130 131 /// clear - Clear out all the function-specific state. This returns this 132 /// FunctionLoweringInfo to an empty state, ready to be used for a 133 /// different function. 134 void clear(); 135 136 /// isExportedInst - Return true if the specified value is an instruction 137 /// exported from its block. 138 bool isExportedInst(const Value *V) { 139 return ValueMap.count(V); 140 } 141 142 unsigned CreateReg(MVT VT); 143 144 unsigned CreateRegs(Type *Ty); 145 146 unsigned InitializeRegForValue(const Value *V) { 147 unsigned &R = ValueMap[V]; 148 assert(R == 0 && "Already initialized this value register!"); 149 return R = CreateRegs(V->getType()); 150 } 151 152 /// GetLiveOutRegInfo - Gets LiveOutInfo for a register, returning NULL if the 153 /// register is a PHI destination and the PHI's LiveOutInfo is not valid. 154 const LiveOutInfo *GetLiveOutRegInfo(unsigned Reg) { 155 if (!LiveOutRegInfo.inBounds(Reg)) 156 return nullptr; 157 158 const LiveOutInfo *LOI = &LiveOutRegInfo[Reg]; 159 if (!LOI->IsValid) 160 return nullptr; 161 162 return LOI; 163 } 164 165 /// GetLiveOutRegInfo - Gets LiveOutInfo for a register, returning NULL if the 166 /// register is a PHI destination and the PHI's LiveOutInfo is not valid. If 167 /// the register's LiveOutInfo is for a smaller bit width, it is extended to 168 /// the larger bit width by zero extension. The bit width must be no smaller 169 /// than the LiveOutInfo's existing bit width. 170 const LiveOutInfo *GetLiveOutRegInfo(unsigned Reg, unsigned BitWidth); 171 172 /// AddLiveOutRegInfo - Adds LiveOutInfo for a register. 173 void AddLiveOutRegInfo(unsigned Reg, unsigned NumSignBits, 174 const APInt &KnownZero, const APInt &KnownOne) { 175 // Only install this information if it tells us something. 176 if (NumSignBits == 1 && KnownZero == 0 && KnownOne == 0) 177 return; 178 179 LiveOutRegInfo.grow(Reg); 180 LiveOutInfo &LOI = LiveOutRegInfo[Reg]; 181 LOI.NumSignBits = NumSignBits; 182 LOI.KnownOne = KnownOne; 183 LOI.KnownZero = KnownZero; 184 } 185 186 /// ComputePHILiveOutRegInfo - Compute LiveOutInfo for a PHI's destination 187 /// register based on the LiveOutInfo of its operands. 188 void ComputePHILiveOutRegInfo(const PHINode*); 189 190 /// InvalidatePHILiveOutRegInfo - Invalidates a PHI's LiveOutInfo, to be 191 /// called when a block is visited before all of its predecessors. 192 void InvalidatePHILiveOutRegInfo(const PHINode *PN) { 193 // PHIs with no uses have no ValueMap entry. 194 DenseMap<const Value*, unsigned>::const_iterator It = ValueMap.find(PN); 195 if (It == ValueMap.end()) 196 return; 197 198 unsigned Reg = It->second; 199 LiveOutRegInfo.grow(Reg); 200 LiveOutRegInfo[Reg].IsValid = false; 201 } 202 203 /// setArgumentFrameIndex - Record frame index for the byval 204 /// argument. 205 void setArgumentFrameIndex(const Argument *A, int FI); 206 207 /// getArgumentFrameIndex - Get frame index for the byval argument. 208 int getArgumentFrameIndex(const Argument *A); 209 210 private: 211 /// LiveOutRegInfo - Information about live out vregs. 212 IndexedMap<LiveOutInfo, VirtReg2IndexFunctor> LiveOutRegInfo; 213 }; 214 215 /// ComputeUsesVAFloatArgument - Determine if any floating-point values are 216 /// being passed to this variadic function, and set the MachineModuleInfo's 217 /// usesVAFloatArgument flag if so. This flag is used to emit an undefined 218 /// reference to _fltused on Windows, which will link in MSVCRT's 219 /// floating-point support. 220 void ComputeUsesVAFloatArgument(const CallInst &I, MachineModuleInfo *MMI); 221 222 /// AddCatchInfo - Extract the personality and type infos from an eh.selector 223 /// call, and add them to the specified machine basic block. 224 void AddCatchInfo(const CallInst &I, 225 MachineModuleInfo *MMI, MachineBasicBlock *MBB); 226 227 /// AddLandingPadInfo - Extract the exception handling information from the 228 /// landingpad instruction and add them to the specified machine module info. 229 void AddLandingPadInfo(const LandingPadInst &I, MachineModuleInfo &MMI, 230 MachineBasicBlock *MBB); 231 232 } // end namespace llvm 233 234 #endif 235
