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      1 //===-- X86RegisterInfo.h - X86 Register Information Impl -------*- 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 contains the X86 implementation of the TargetRegisterInfo class.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #ifndef X86REGISTERINFO_H
     15 #define X86REGISTERINFO_H
     16 
     17 #include "llvm/Target/TargetRegisterInfo.h"
     18 
     19 #define GET_REGINFO_HEADER
     20 #include "X86GenRegisterInfo.inc"
     21 
     22 namespace llvm {
     23   class Type;
     24   class TargetInstrInfo;
     25   class X86TargetMachine;
     26 
     27 class X86RegisterInfo : public X86GenRegisterInfo {
     28 public:
     29   X86TargetMachine &TM;
     30   const TargetInstrInfo &TII;
     31 
     32 private:
     33   /// Is64Bit - Is the target 64-bits.
     34   ///
     35   bool Is64Bit;
     36 
     37   /// IsWin64 - Is the target on of win64 flavours
     38   ///
     39   bool IsWin64;
     40 
     41   /// SlotSize - Stack slot size in bytes.
     42   ///
     43   unsigned SlotSize;
     44 
     45   /// StackPtr - X86 physical register used as stack ptr.
     46   ///
     47   unsigned StackPtr;
     48 
     49   /// FramePtr - X86 physical register used as frame ptr.
     50   ///
     51   unsigned FramePtr;
     52 
     53   /// BasePtr - X86 physical register used as a base ptr in complex stack
     54   /// frames. I.e., when we need a 3rd base, not just SP and FP, due to
     55   /// variable size stack objects.
     56   unsigned BasePtr;
     57 
     58 public:
     59   X86RegisterInfo(X86TargetMachine &tm, const TargetInstrInfo &tii);
     60 
     61   /// getX86RegNum - Returns the native X86 register number for the given LLVM
     62   /// register identifier.
     63   static unsigned getX86RegNum(unsigned RegNo);
     64 
     65   // FIXME: This should be tablegen'd like getDwarfRegNum is
     66   int getSEHRegNum(unsigned i) const;
     67 
     68   /// getCompactUnwindRegNum - This function maps the register to the number for
     69   /// compact unwind encoding. Return -1 if the register isn't valid.
     70   int getCompactUnwindRegNum(unsigned RegNum, bool isEH) const;
     71 
     72   /// Code Generation virtual methods...
     73   ///
     74   virtual bool trackLivenessAfterRegAlloc(const MachineFunction &MF) const;
     75 
     76   /// getMatchingSuperRegClass - Return a subclass of the specified register
     77   /// class A so that each register in it has a sub-register of the
     78   /// specified sub-register index which is in the specified register class B.
     79   virtual const TargetRegisterClass *
     80   getMatchingSuperRegClass(const TargetRegisterClass *A,
     81                            const TargetRegisterClass *B, unsigned Idx) const;
     82 
     83   virtual const TargetRegisterClass *
     84   getSubClassWithSubReg(const TargetRegisterClass *RC, unsigned Idx) const;
     85 
     86   const TargetRegisterClass*
     87   getLargestLegalSuperClass(const TargetRegisterClass *RC) const;
     88 
     89   /// getPointerRegClass - Returns a TargetRegisterClass used for pointer
     90   /// values.
     91   const TargetRegisterClass *
     92   getPointerRegClass(const MachineFunction &MF, unsigned Kind = 0) const;
     93 
     94   /// getCrossCopyRegClass - Returns a legal register class to copy a register
     95   /// in the specified class to or from. Returns NULL if it is possible to copy
     96   /// between a two registers of the specified class.
     97   const TargetRegisterClass *
     98   getCrossCopyRegClass(const TargetRegisterClass *RC) const;
     99 
    100   unsigned getRegPressureLimit(const TargetRegisterClass *RC,
    101                                MachineFunction &MF) const;
    102 
    103   /// getCalleeSavedRegs - Return a null-terminated list of all of the
    104   /// callee-save registers on this target.
    105   const uint16_t *getCalleeSavedRegs(const MachineFunction* MF = 0) const;
    106   const uint32_t *getCallPreservedMask(CallingConv::ID) const;
    107 
    108   /// getReservedRegs - Returns a bitset indexed by physical register number
    109   /// indicating if a register is a special register that has particular uses and
    110   /// should be considered unavailable at all times, e.g. SP, RA. This is used by
    111   /// register scavenger to determine what registers are free.
    112   BitVector getReservedRegs(const MachineFunction &MF) const;
    113 
    114   bool hasBasePointer(const MachineFunction &MF) const;
    115 
    116   bool canRealignStack(const MachineFunction &MF) const;
    117 
    118   bool needsStackRealignment(const MachineFunction &MF) const;
    119 
    120   bool hasReservedSpillSlot(const MachineFunction &MF, unsigned Reg,
    121                             int &FrameIdx) const;
    122 
    123   void eliminateCallFramePseudoInstr(MachineFunction &MF,
    124                                      MachineBasicBlock &MBB,
    125                                      MachineBasicBlock::iterator MI) const;
    126 
    127   void eliminateFrameIndex(MachineBasicBlock::iterator MI,
    128                            int SPAdj, RegScavenger *RS = NULL) const;
    129 
    130   // Debug information queries.
    131   unsigned getFrameRegister(const MachineFunction &MF) const;
    132   unsigned getStackRegister() const { return StackPtr; }
    133   unsigned getBaseRegister() const { return BasePtr; }
    134   // FIXME: Move to FrameInfok
    135   unsigned getSlotSize() const { return SlotSize; }
    136 
    137   // Exception handling queries.
    138   unsigned getEHExceptionRegister() const;
    139   unsigned getEHHandlerRegister() const;
    140 };
    141 
    142 // getX86SubSuperRegister - X86 utility function. It returns the sub or super
    143 // register of a specific X86 register.
    144 // e.g. getX86SubSuperRegister(X86::EAX, EVT::i16) return X86:AX
    145 unsigned getX86SubSuperRegister(unsigned, EVT, bool High=false);
    146 
    147 } // End llvm namespace
    148 
    149 #endif
    150