src/llvm/include/llvm/CodeGen/FunctionLoweringInfo.h

   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 public:
  53   const TargetLowering &TLI;
  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   explicit FunctionLoweringInfo(const TargetLowering &TLI);
 119
 120   /// set - Initialize this FunctionLoweringInfo with the given Function
 121   /// and its associated MachineFunction.
 122   ///
 123   void set(const Function &Fn, MachineFunction &MF);
 124
 125   /// clear - Clear out all the function-specific state. This returns this
 126   /// FunctionLoweringInfo to an empty state, ready to be used for a
 127   /// different function.
 128   void clear();
 129
 130   /// isExportedInst - Return true if the specified value is an instruction
 131   /// exported from its block.
 132   bool isExportedInst(const Value *V) {
 133     return ValueMap.count(V);
 134   }
 135
 136   unsigned CreateReg(MVT VT);
 137
 138   unsigned CreateRegs(Type *Ty);
 139
 140   unsigned InitializeRegForValue(const Value *V) {
 141     unsigned &R = ValueMap[V];
 142     assert(R == 0 && "Already initialized this value register!");
 143     return R = CreateRegs(V->getType());
 144   }
 145
 146   /// GetLiveOutRegInfo - Gets LiveOutInfo for a register, returning NULL if the
 147   /// register is a PHI destination and the PHI's LiveOutInfo is not valid.
 148   const LiveOutInfo *GetLiveOutRegInfo(unsigned Reg) {
 149     if (!LiveOutRegInfo.inBounds(Reg))
 150       return NULL;
 151
 152     const LiveOutInfo *LOI = &LiveOutRegInfo[Reg];
 153     if (!LOI->IsValid)
 154       return NULL;
 155
 156     return LOI;
 157   }
 158
 159   /// GetLiveOutRegInfo - Gets LiveOutInfo for a register, returning NULL if the
 160   /// register is a PHI destination and the PHI's LiveOutInfo is not valid. If
 161   /// the register's LiveOutInfo is for a smaller bit width, it is extended to
 162   /// the larger bit width by zero extension. The bit width must be no smaller
 163   /// than the LiveOutInfo's existing bit width.
 164   const LiveOutInfo *GetLiveOutRegInfo(unsigned Reg, unsigned BitWidth);
 165
 166   /// AddLiveOutRegInfo - Adds LiveOutInfo for a register.
 167   void AddLiveOutRegInfo(unsigned Reg, unsigned NumSignBits,
 168                          const APInt &KnownZero, const APInt &KnownOne) {
 169     // Only install this information if it tells us something.
 170     if (NumSignBits == 1 && KnownZero == 0 && KnownOne == 0)
 171       return;
 172
 173     LiveOutRegInfo.grow(Reg);
 174     LiveOutInfo &LOI = LiveOutRegInfo[Reg];
 175     LOI.NumSignBits = NumSignBits;
 176     LOI.KnownOne = KnownOne;
 177     LOI.KnownZero = KnownZero;
 178   }
 179
 180   /// ComputePHILiveOutRegInfo - Compute LiveOutInfo for a PHI's destination
 181   /// register based on the LiveOutInfo of its operands.
 182   void ComputePHILiveOutRegInfo(const PHINode*);
 183
 184   /// InvalidatePHILiveOutRegInfo - Invalidates a PHI's LiveOutInfo, to be
 185   /// called when a block is visited before all of its predecessors.
 186   void InvalidatePHILiveOutRegInfo(const PHINode *PN) {
 187     // PHIs with no uses have no ValueMap entry.
 188     DenseMap<const Value*, unsigned>::const_iterator It = ValueMap.find(PN);
 189     if (It == ValueMap.end())
 190       return;
 191
 192     unsigned Reg = It->second;
 193     LiveOutRegInfo.grow(Reg);
 194     LiveOutRegInfo[Reg].IsValid = false;
 195   }
 196
 197   /// setArgumentFrameIndex - Record frame index for the byval
 198   /// argument.
 199   void setArgumentFrameIndex(const Argument *A, int FI);
 200
 201   /// getArgumentFrameIndex - Get frame index for the byval argument.
 202   int getArgumentFrameIndex(const Argument *A);
 203
 204 private:
 205   /// LiveOutRegInfo - Information about live out vregs.
 206   IndexedMap<LiveOutInfo, VirtReg2IndexFunctor> LiveOutRegInfo;
 207 };
 208
 209 /// ComputeUsesVAFloatArgument - Determine if any floating-point values are
 210 /// being passed to this variadic function, and set the MachineModuleInfo's
 211 /// usesVAFloatArgument flag if so. This flag is used to emit an undefined
 212 /// reference to _fltused on Windows, which will link in MSVCRT's
 213 /// floating-point support.
 214 void ComputeUsesVAFloatArgument(const CallInst &I, MachineModuleInfo *MMI);
 215
 216 /// AddCatchInfo - Extract the personality and type infos from an eh.selector
 217 /// call, and add them to the specified machine basic block.
 218 void AddCatchInfo(const CallInst &I,
 219                   MachineModuleInfo *MMI, MachineBasicBlock *MBB);
 220
 221 /// AddLandingPadInfo - Extract the exception handling information from the
 222 /// landingpad instruction and add them to the specified machine module info.
 223 void AddLandingPadInfo(const LandingPadInst &I, MachineModuleInfo &MMI,
 224                        MachineBasicBlock *MBB);
 225
 226 } // end namespace llvm
 227
 228 #endif