MipsSubtarget.h

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//===-- MipsSubtarget.h - Define Subtarget for the Mips ---------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file declares the Mips specific subclass of TargetSubtargetInfo.
//
//===----------------------------------------------------------------------===//

#ifndef MIPSSUBTARGET_H
#define MIPSSUBTARGET_H

#include "MCTargetDesc/MipsReginfo.h"
#include "llvm/MC/MCInstrItineraries.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Target/TargetSubtargetInfo.h"

#include <string>

#define GET_SUBTARGETINFO_HEADER
#include "MipsGenSubtargetInfo.inc"

namespace llvm {
class StringRef;

class MipsTargetMachine;

class MipsSubtarget : public MipsGenSubtargetInfo {
  virtual void anchor();

public:
  // NOTE: O64 will not be supported.
  enum MipsABIEnum {
    UnknownABI, O32, N32, N64, EABI
  };

protected:

  enum MipsArchEnum {
    Mips32, Mips32r2, Mips64, Mips64r2
  };

  // Mips architecture version
  MipsArchEnum MipsArchVersion;

  // Mips supported ABIs
  MipsABIEnum MipsABI;

  // IsLittle - The target is Little Endian
  bool IsLittle;

  // IsSingleFloat - The target only supports single precision float
  // point operations. This enable the target to use all 32 32-bit
  // floating point registers instead of only using even ones.
  bool IsSingleFloat;

  // IsFP64bit - The target processor has 64-bit floating point registers.
  bool IsFP64bit;

  // IsFP64bit - General-purpose registers are 64 bits wide
  bool IsGP64bit;

  // HasVFPU - Processor has a vector floating point unit.
  bool HasVFPU;

  // isLinux - Target system is Linux. Is false we consider ELFOS for now.
  bool IsLinux;

  // UseSmallSection - Small section is used.
  bool UseSmallSection;

  /// Features related to the presence of specific instructions.

  // HasSEInReg - SEB and SEH (signext in register) instructions.
  bool HasSEInReg;

  // HasCondMov - Conditional mov (MOVZ, MOVN) instructions.
  bool HasCondMov;

  // HasSwap - Byte and half swap instructions.
  bool HasSwap;

  // HasBitCount - Count leading '1' and '0' bits.
  bool HasBitCount;

  // HasFPIdx -- Floating point indexed load/store instructions.
  bool HasFPIdx;

  // InMips16 -- can process Mips16 instructions
  bool InMips16Mode;

  // Mips16 hard float
  bool InMips16HardFloat;

  // PreviousInMips16 -- the function we just processed was in Mips 16 Mode
  bool PreviousInMips16Mode;

  // InMicroMips -- can process MicroMips instructions
  bool InMicroMipsMode;

  // HasDSP, HasDSPR2 -- supports DSP ASE.
  bool HasDSP, HasDSPR2;

  // Allow mixed Mips16 and Mips32 in one source file
  bool AllowMixed16_32;

  // Optimize for space by compiling all functions as Mips 16 unless
  // it needs floating point. Functions needing floating point are
  // compiled as Mips32
  bool Os16;

  // HasMSA -- supports MSA ASE.
  bool HasMSA;

  InstrItineraryData InstrItins;

  // The instance to the register info section object
  MipsReginfo MRI;

  // Relocation Model
  Reloc::Model RM;

  // We can override the determination of whether we are in mips16 mode
  // as from the command line
  enum {NoOverride, Mips16Override, NoMips16Override} OverrideMode;

  MipsTargetMachine *TM;

public:
  virtual bool enablePostRAScheduler(CodeGenOpt::Level OptLevel,
                                     AntiDepBreakMode& Mode,
                                     RegClassVector& CriticalPathRCs) const;

  /// Only O32 and EABI supported right now.
  bool isABI_EABI() const { return MipsABI == EABI; }
  bool isABI_N64() const { return MipsABI == N64; }
  bool isABI_N32() const { return MipsABI == N32; }
  bool isABI_O32() const { return MipsABI == O32; }
  unsigned getTargetABI() const { return MipsABI; }

  /// This constructor initializes the data members to match that
  /// of the specified triple.
  MipsSubtarget(const std::string &TT, const std::string &CPU,
                const std::string &FS, bool little, Reloc::Model RM,
                MipsTargetMachine *TM);

  /// ParseSubtargetFeatures - Parses features string setting specified
  /// subtarget options.  Definition of function is auto generated by tblgen.
  void ParseSubtargetFeatures(StringRef CPU, StringRef FS);

  bool hasMips32() const { return MipsArchVersion >= Mips32; }
  bool hasMips32r2() const { return MipsArchVersion == Mips32r2 ||
                                   MipsArchVersion == Mips64r2; }
  bool hasMips64() const { return MipsArchVersion >= Mips64; }
  bool hasMips64r2() const { return MipsArchVersion == Mips64r2; }

  bool isLittle() const { return IsLittle; }
  bool isFP64bit() const { return IsFP64bit; }
  bool isNotFP64bit() const { return !IsFP64bit; }
  bool isGP64bit() const { return IsGP64bit; }
  bool isGP32bit() const { return !IsGP64bit; }
  bool isSingleFloat() const { return IsSingleFloat; }
  bool isNotSingleFloat() const { return !IsSingleFloat; }
  bool hasVFPU() const { return HasVFPU; }
  bool inMips16Mode() const {
    switch (OverrideMode) {
    case NoOverride:
      return InMips16Mode;
    case Mips16Override:
      return true;
    case NoMips16Override:
      return false;
    }
    llvm_unreachable("Unexpected mode");
  }
  bool inMips16ModeDefault() const {
    return InMips16Mode;
  }
  bool inMips16HardFloat() const {
    return inMips16Mode() && InMips16HardFloat;
  }
  bool inMicroMipsMode() const { return InMicroMipsMode; }
  bool hasDSP() const { return HasDSP; }
  bool hasDSPR2() const { return HasDSPR2; }
  bool hasMSA() const { return HasMSA; }
  bool isLinux() const { return IsLinux; }
  bool useSmallSection() const { return UseSmallSection; }

  bool hasStandardEncoding() const { return !inMips16Mode(); }

  bool mipsSEUsesSoftFloat() const;

  bool enableLongBranchPass() const {
    return hasStandardEncoding() || allowMixed16_32();
  }

  /// Features related to the presence of specific instructions.
  bool hasSEInReg()   const { return HasSEInReg; }
  bool hasCondMov()   const { return HasCondMov; }
  bool hasSwap()      const { return HasSwap; }
  bool hasBitCount()  const { return HasBitCount; }
  bool hasFPIdx()     const { return HasFPIdx; }
  bool hasExtractInsert() const { return !inMips16Mode() && hasMips32r2(); }

  const InstrItineraryData &getInstrItineraryData() const { return InstrItins; }
  bool allowMixed16_32() const { return inMips16ModeDefault() |
                                        AllowMixed16_32;}

  bool os16() const { return Os16;};

// for now constant islands are on for the whole compilation unit but we only
// really use them if in addition we are in mips16 mode
//
static bool useConstantIslands();

  unsigned stackAlignment() const { return hasMips64() ? 16 : 8; }

  // Grab MipsRegInfo object
  const MipsReginfo &getMReginfo() const { return MRI; }

  // Grab relocation model
  Reloc::Model getRelocationModel() const {return RM;}

  /// \brief Reset the subtarget for the Mips target.
  void resetSubtarget(MachineFunction *MF);


};
} // End llvm namespace

#endif