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/ISDOpcodes.h" 24 #include "llvm/CodeGen/MachineBasicBlock.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 SelectionDAG; 45 class MVT; 46 class TargetLowering; 47 class Value; 48 49 //===--------------------------------------------------------------------===// 50 /// FunctionLoweringInfo - This contains information that is global to a 51 /// function that is used when lowering a region of the function. 52 /// 53 class FunctionLoweringInfo { 54 public: 55 const Function *Fn; 56 MachineFunction *MF; 57 const TargetLowering *TLI; 58 MachineRegisterInfo *RegInfo; 59 BranchProbabilityInfo *BPI; 60 /// CanLowerReturn - true iff the function's return value can be lowered to 61 /// registers. 62 bool CanLowerReturn; 63 64 /// DemoteRegister - if CanLowerReturn is false, DemoteRegister is a vreg 65 /// allocated to hold a pointer to the hidden sret parameter. 66 unsigned DemoteRegister; 67 68 /// MBBMap - A mapping from LLVM basic blocks to their machine code entry. 69 DenseMap<const BasicBlock*, MachineBasicBlock *> MBBMap; 70 71 /// ValueMap - Since we emit code for the function a basic block at a time, 72 /// we must remember which virtual registers hold the values for 73 /// cross-basic-block values. 74 DenseMap<const Value*, unsigned> ValueMap; 75 76 /// StaticAllocaMap - Keep track of frame indices for fixed sized allocas in 77 /// the entry block. This allows the allocas to be efficiently referenced 78 /// anywhere in the function. 79 DenseMap<const AllocaInst*, int> StaticAllocaMap; 80 81 /// ByValArgFrameIndexMap - Keep track of frame indices for byval arguments. 82 DenseMap<const Argument*, int> ByValArgFrameIndexMap; 83 84 /// ArgDbgValues - A list of DBG_VALUE instructions created during isel for 85 /// function arguments that are inserted after scheduling is completed. 86 SmallVector<MachineInstr*, 8> ArgDbgValues; 87 88 /// RegFixups - Registers which need to be replaced after isel is done. 89 DenseMap<unsigned, unsigned> RegFixups; 90 91 /// StatepointStackSlots - A list of temporary stack slots (frame indices) 92 /// used to spill values at a statepoint. We store them here to enable 93 /// reuse of the same stack slots across different statepoints in different 94 /// basic blocks. 95 SmallVector<unsigned, 50> StatepointStackSlots; 96 97 /// MBB - The current block. 98 MachineBasicBlock *MBB; 99 100 /// MBB - The current insert position inside the current block. 101 MachineBasicBlock::iterator InsertPt; 102 103 #ifndef NDEBUG 104 SmallPtrSet<const Instruction *, 8> CatchInfoLost; 105 SmallPtrSet<const Instruction *, 8> CatchInfoFound; 106 #endif 107 108 struct LiveOutInfo { 109 unsigned NumSignBits : 31; 110 bool IsValid : 1; 111 APInt KnownOne, KnownZero; 112 LiveOutInfo() : NumSignBits(0), IsValid(true), KnownOne(1, 0), 113 KnownZero(1, 0) {} 114 }; 115 116 /// Record the preferred extend type (ISD::SIGN_EXTEND or ISD::ZERO_EXTEND) 117 /// for a value. 118 DenseMap<const Value *, ISD::NodeType> PreferredExtendType; 119 120 /// VisitedBBs - The set of basic blocks visited thus far by instruction 121 /// selection. 122 SmallPtrSet<const BasicBlock*, 4> VisitedBBs; 123 124 /// PHINodesToUpdate - A list of phi instructions whose operand list will 125 /// be updated after processing the current basic block. 126 /// TODO: This isn't per-function state, it's per-basic-block state. But 127 /// there's no other convenient place for it to live right now. 128 std::vector<std::pair<MachineInstr*, unsigned> > PHINodesToUpdate; 129 unsigned OrigNumPHINodesToUpdate; 130 131 /// If the current MBB is a landing pad, the exception pointer and exception 132 /// selector registers are copied into these virtual registers by 133 /// SelectionDAGISel::PrepareEHLandingPad(). 134 unsigned ExceptionPointerVirtReg, ExceptionSelectorVirtReg; 135 136 /// set - Initialize this FunctionLoweringInfo with the given Function 137 /// and its associated MachineFunction. 138 /// 139 void set(const Function &Fn, MachineFunction &MF, SelectionDAG *DAG); 140 141 /// clear - Clear out all the function-specific state. This returns this 142 /// FunctionLoweringInfo to an empty state, ready to be used for a 143 /// different function. 144 void clear(); 145 146 /// isExportedInst - Return true if the specified value is an instruction 147 /// exported from its block. 148 bool isExportedInst(const Value *V) { 149 return ValueMap.count(V); 150 } 151 152 unsigned CreateReg(MVT VT); 153 154 unsigned CreateRegs(Type *Ty); 155 156 unsigned InitializeRegForValue(const Value *V) { 157 unsigned &R = ValueMap[V]; 158 assert(R == 0 && "Already initialized this value register!"); 159 return R = CreateRegs(V->getType()); 160 } 161 162 /// GetLiveOutRegInfo - Gets LiveOutInfo for a register, returning NULL if the 163 /// register is a PHI destination and the PHI's LiveOutInfo is not valid. 164 const LiveOutInfo *GetLiveOutRegInfo(unsigned Reg) { 165 if (!LiveOutRegInfo.inBounds(Reg)) 166 return nullptr; 167 168 const LiveOutInfo *LOI = &LiveOutRegInfo[Reg]; 169 if (!LOI->IsValid) 170 return nullptr; 171 172 return LOI; 173 } 174 175 /// GetLiveOutRegInfo - Gets LiveOutInfo for a register, returning NULL if the 176 /// register is a PHI destination and the PHI's LiveOutInfo is not valid. If 177 /// the register's LiveOutInfo is for a smaller bit width, it is extended to 178 /// the larger bit width by zero extension. The bit width must be no smaller 179 /// than the LiveOutInfo's existing bit width. 180 const LiveOutInfo *GetLiveOutRegInfo(unsigned Reg, unsigned BitWidth); 181 182 /// AddLiveOutRegInfo - Adds LiveOutInfo for a register. 183 void AddLiveOutRegInfo(unsigned Reg, unsigned NumSignBits, 184 const APInt &KnownZero, const APInt &KnownOne) { 185 // Only install this information if it tells us something. 186 if (NumSignBits == 1 && KnownZero == 0 && KnownOne == 0) 187 return; 188 189 LiveOutRegInfo.grow(Reg); 190 LiveOutInfo &LOI = LiveOutRegInfo[Reg]; 191 LOI.NumSignBits = NumSignBits; 192 LOI.KnownOne = KnownOne; 193 LOI.KnownZero = KnownZero; 194 } 195 196 /// ComputePHILiveOutRegInfo - Compute LiveOutInfo for a PHI's destination 197 /// register based on the LiveOutInfo of its operands. 198 void ComputePHILiveOutRegInfo(const PHINode*); 199 200 /// InvalidatePHILiveOutRegInfo - Invalidates a PHI's LiveOutInfo, to be 201 /// called when a block is visited before all of its predecessors. 202 void InvalidatePHILiveOutRegInfo(const PHINode *PN) { 203 // PHIs with no uses have no ValueMap entry. 204 DenseMap<const Value*, unsigned>::const_iterator It = ValueMap.find(PN); 205 if (It == ValueMap.end()) 206 return; 207 208 unsigned Reg = It->second; 209 if (Reg == 0) 210 return; 211 212 LiveOutRegInfo.grow(Reg); 213 LiveOutRegInfo[Reg].IsValid = false; 214 } 215 216 /// setArgumentFrameIndex - Record frame index for the byval 217 /// argument. 218 void setArgumentFrameIndex(const Argument *A, int FI); 219 220 /// getArgumentFrameIndex - Get frame index for the byval argument. 221 int getArgumentFrameIndex(const Argument *A); 222 223 private: 224 /// LiveOutRegInfo - Information about live out vregs. 225 IndexedMap<LiveOutInfo, VirtReg2IndexFunctor> LiveOutRegInfo; 226 }; 227 228 /// ComputeUsesVAFloatArgument - Determine if any floating-point values are 229 /// being passed to this variadic function, and set the MachineModuleInfo's 230 /// usesVAFloatArgument flag if so. This flag is used to emit an undefined 231 /// reference to _fltused on Windows, which will link in MSVCRT's 232 /// floating-point support. 233 void ComputeUsesVAFloatArgument(const CallInst &I, MachineModuleInfo *MMI); 234 235 /// AddLandingPadInfo - Extract the exception handling information from the 236 /// landingpad instruction and add them to the specified machine module info. 237 void AddLandingPadInfo(const LandingPadInst &I, MachineModuleInfo &MMI, 238 MachineBasicBlock *MBB); 239 240 } // end namespace llvm 241 242 #endif 243
