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      1 //===-- MipsSubtarget.h - Define Subtarget for the Mips ---------*- 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 declares the Mips specific subclass of TargetSubtargetInfo.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #ifndef MIPSSUBTARGET_H
     15 #define MIPSSUBTARGET_H
     16 
     17 #include "MipsFrameLowering.h"
     18 #include "MipsISelLowering.h"
     19 #include "MipsInstrInfo.h"
     20 #include "MipsJITInfo.h"
     21 #include "MipsSelectionDAGInfo.h"
     22 #include "llvm/IR/DataLayout.h"
     23 #include "llvm/MC/MCInstrItineraries.h"
     24 #include "llvm/Support/ErrorHandling.h"
     25 #include "llvm/Target/TargetSubtargetInfo.h"
     26 #include <string>
     27 
     28 #define GET_SUBTARGETINFO_HEADER
     29 #include "MipsGenSubtargetInfo.inc"
     30 
     31 namespace llvm {
     32 class StringRef;
     33 
     34 class MipsTargetMachine;
     35 
     36 class MipsSubtarget : public MipsGenSubtargetInfo {
     37   virtual void anchor();
     38 
     39 public:
     40   // NOTE: O64 will not be supported.
     41   enum MipsABIEnum {
     42     UnknownABI, O32, N32, N64, EABI
     43   };
     44 
     45 protected:
     46   enum MipsArchEnum {
     47     Mips1, Mips2, Mips32, Mips32r2, Mips32r6, Mips3, Mips4, Mips5, Mips64,
     48     Mips64r2, Mips64r6
     49   };
     50 
     51   // Mips architecture version
     52   MipsArchEnum MipsArchVersion;
     53 
     54   // Mips supported ABIs
     55   MipsABIEnum MipsABI;
     56 
     57   // IsLittle - The target is Little Endian
     58   bool IsLittle;
     59 
     60   // IsSingleFloat - The target only supports single precision float
     61   // point operations. This enable the target to use all 32 32-bit
     62   // floating point registers instead of only using even ones.
     63   bool IsSingleFloat;
     64 
     65   // IsFPXX - MIPS O32 modeless ABI.
     66   bool IsFPXX;
     67 
     68   // IsFP64bit - The target processor has 64-bit floating point registers.
     69   bool IsFP64bit;
     70 
     71   /// Are odd single-precision registers permitted?
     72   /// This corresponds to -modd-spreg and -mno-odd-spreg
     73   bool UseOddSPReg;
     74 
     75   // IsNan2008 - IEEE 754-2008 NaN encoding.
     76   bool IsNaN2008bit;
     77 
     78   // IsFP64bit - General-purpose registers are 64 bits wide
     79   bool IsGP64bit;
     80 
     81   // HasVFPU - Processor has a vector floating point unit.
     82   bool HasVFPU;
     83 
     84   // CPU supports cnMIPS (Cavium Networks Octeon CPU).
     85   bool HasCnMips;
     86 
     87   // isLinux - Target system is Linux. Is false we consider ELFOS for now.
     88   bool IsLinux;
     89 
     90   // UseSmallSection - Small section is used.
     91   bool UseSmallSection;
     92 
     93   /// Features related to the presence of specific instructions.
     94 
     95   // HasMips3_32 - The subset of MIPS-III instructions added to MIPS32
     96   bool HasMips3_32;
     97 
     98   // HasMips3_32r2 - The subset of MIPS-III instructions added to MIPS32r2
     99   bool HasMips3_32r2;
    100 
    101   // HasMips4_32 - Has the subset of MIPS-IV present in MIPS32
    102   bool HasMips4_32;
    103 
    104   // HasMips4_32r2 - Has the subset of MIPS-IV present in MIPS32r2
    105   bool HasMips4_32r2;
    106 
    107   // HasMips5_32r2 - Has the subset of MIPS-V present in MIPS32r2
    108   bool HasMips5_32r2;
    109 
    110   // InMips16 -- can process Mips16 instructions
    111   bool InMips16Mode;
    112 
    113   // Mips16 hard float
    114   bool InMips16HardFloat;
    115 
    116   // PreviousInMips16 -- the function we just processed was in Mips 16 Mode
    117   bool PreviousInMips16Mode;
    118 
    119   // InMicroMips -- can process MicroMips instructions
    120   bool InMicroMipsMode;
    121 
    122   // HasDSP, HasDSPR2 -- supports DSP ASE.
    123   bool HasDSP, HasDSPR2;
    124 
    125   // Allow mixed Mips16 and Mips32 in one source file
    126   bool AllowMixed16_32;
    127 
    128   // Optimize for space by compiling all functions as Mips 16 unless
    129   // it needs floating point. Functions needing floating point are
    130   // compiled as Mips32
    131   bool Os16;
    132 
    133   // HasMSA -- supports MSA ASE.
    134   bool HasMSA;
    135 
    136   InstrItineraryData InstrItins;
    137 
    138   // Relocation Model
    139   Reloc::Model RM;
    140 
    141   // We can override the determination of whether we are in mips16 mode
    142   // as from the command line
    143   enum {NoOverride, Mips16Override, NoMips16Override} OverrideMode;
    144 
    145   MipsTargetMachine *TM;
    146 
    147   Triple TargetTriple;
    148 
    149   const DataLayout DL; // Calculates type size & alignment
    150   const MipsSelectionDAGInfo TSInfo;
    151   MipsJITInfo JITInfo;
    152   std::unique_ptr<const MipsInstrInfo> InstrInfo;
    153   std::unique_ptr<const MipsFrameLowering> FrameLowering;
    154   std::unique_ptr<const MipsTargetLowering> TLInfo;
    155   std::unique_ptr<const MipsInstrInfo> InstrInfo16;
    156   std::unique_ptr<const MipsFrameLowering> FrameLowering16;
    157   std::unique_ptr<const MipsTargetLowering> TLInfo16;
    158   std::unique_ptr<const MipsInstrInfo> InstrInfoSE;
    159   std::unique_ptr<const MipsFrameLowering> FrameLoweringSE;
    160   std::unique_ptr<const MipsTargetLowering> TLInfoSE;
    161 
    162 public:
    163   bool enablePostRAScheduler(CodeGenOpt::Level OptLevel,
    164                              AntiDepBreakMode& Mode,
    165                              RegClassVector& CriticalPathRCs) const override;
    166 
    167   /// Only O32 and EABI supported right now.
    168   bool isABI_EABI() const { return MipsABI == EABI; }
    169   bool isABI_N64() const { return MipsABI == N64; }
    170   bool isABI_N32() const { return MipsABI == N32; }
    171   bool isABI_O32() const { return MipsABI == O32; }
    172   bool isABI_FPXX() const { return false; } // TODO: add check for FPXX
    173   unsigned getTargetABI() const { return MipsABI; }
    174 
    175   /// This constructor initializes the data members to match that
    176   /// of the specified triple.
    177   MipsSubtarget(const std::string &TT, const std::string &CPU,
    178                 const std::string &FS, bool little, Reloc::Model RM,
    179                 MipsTargetMachine *TM);
    180 
    181   /// ParseSubtargetFeatures - Parses features string setting specified
    182   /// subtarget options.  Definition of function is auto generated by tblgen.
    183   void ParseSubtargetFeatures(StringRef CPU, StringRef FS);
    184 
    185   bool hasMips1() const { return MipsArchVersion >= Mips1; }
    186   bool hasMips2() const { return MipsArchVersion >= Mips2; }
    187   bool hasMips3() const { return MipsArchVersion >= Mips3; }
    188   bool hasMips4() const { return MipsArchVersion >= Mips4; }
    189   bool hasMips5() const { return MipsArchVersion >= Mips5; }
    190   bool hasMips4_32() const { return HasMips4_32; }
    191   bool hasMips4_32r2() const { return HasMips4_32r2; }
    192   bool hasMips32() const {
    193     return MipsArchVersion >= Mips32 && MipsArchVersion != Mips3 &&
    194            MipsArchVersion != Mips4 && MipsArchVersion != Mips5;
    195   }
    196   bool hasMips32r2() const {
    197     return MipsArchVersion == Mips32r2 || MipsArchVersion == Mips32r6 ||
    198            MipsArchVersion == Mips64r2 || MipsArchVersion == Mips64r6;
    199   }
    200   bool hasMips32r6() const {
    201     return MipsArchVersion == Mips32r6 || MipsArchVersion == Mips64r6;
    202   }
    203   bool hasMips64() const { return MipsArchVersion >= Mips64; }
    204   bool hasMips64r2() const {
    205     return MipsArchVersion == Mips64r2 || MipsArchVersion == Mips64r6;
    206   }
    207   bool hasMips64r6() const { return MipsArchVersion == Mips64r6; }
    208 
    209   bool hasCnMips() const { return HasCnMips; }
    210 
    211   bool isLittle() const { return IsLittle; }
    212   bool isFPXX() const { return IsFPXX; }
    213   bool isFP64bit() const { return IsFP64bit; }
    214   bool useOddSPReg() const { return UseOddSPReg; }
    215   bool isNaN2008() const { return IsNaN2008bit; }
    216   bool isNotFP64bit() const { return !IsFP64bit; }
    217   bool isGP64bit() const { return IsGP64bit; }
    218   bool isGP32bit() const { return !IsGP64bit; }
    219   bool isSingleFloat() const { return IsSingleFloat; }
    220   bool isNotSingleFloat() const { return !IsSingleFloat; }
    221   bool hasVFPU() const { return HasVFPU; }
    222   bool inMips16Mode() const {
    223     switch (OverrideMode) {
    224     case NoOverride:
    225       return InMips16Mode;
    226     case Mips16Override:
    227       return true;
    228     case NoMips16Override:
    229       return false;
    230     }
    231     llvm_unreachable("Unexpected mode");
    232   }
    233   bool inMips16ModeDefault() const {
    234     return InMips16Mode;
    235   }
    236   bool inMips16HardFloat() const {
    237     return inMips16Mode() && InMips16HardFloat;
    238   }
    239   bool inMicroMipsMode() const { return InMicroMipsMode; }
    240   bool hasDSP() const { return HasDSP; }
    241   bool hasDSPR2() const { return HasDSPR2; }
    242   bool hasMSA() const { return HasMSA; }
    243   bool isLinux() const { return IsLinux; }
    244   bool useSmallSection() const { return UseSmallSection; }
    245 
    246   bool hasStandardEncoding() const { return !inMips16Mode(); }
    247 
    248   bool mipsSEUsesSoftFloat() const;
    249 
    250   bool enableLongBranchPass() const {
    251     return hasStandardEncoding() || allowMixed16_32();
    252   }
    253 
    254   /// Features related to the presence of specific instructions.
    255   bool hasExtractInsert() const { return !inMips16Mode() && hasMips32r2(); }
    256 
    257   const InstrItineraryData &getInstrItineraryData() const { return InstrItins; }
    258   bool allowMixed16_32() const { return inMips16ModeDefault() |
    259                                         AllowMixed16_32;}
    260 
    261   bool os16() const { return Os16;};
    262 
    263   bool isTargetNaCl() const { return TargetTriple.isOSNaCl(); }
    264   bool isNotTargetNaCl() const { return !TargetTriple.isOSNaCl(); }
    265 
    266   // for now constant islands are on for the whole compilation unit but we only
    267   // really use them if in addition we are in mips16 mode
    268   static bool useConstantIslands();
    269 
    270   unsigned stackAlignment() const { return hasMips64() ? 16 : 8; }
    271 
    272   // Grab relocation model
    273   Reloc::Model getRelocationModel() const {return RM;}
    274 
    275   /// \brief Reset the subtarget for the Mips target.
    276   void resetSubtarget(MachineFunction *MF);
    277 
    278   MipsSubtarget &initializeSubtargetDependencies(StringRef CPU, StringRef FS,
    279                                                  const TargetMachine *TM);
    280 
    281   /// Does the system support unaligned memory access.
    282   ///
    283   /// MIPS32r6/MIPS64r6 require full unaligned access support but does not
    284   /// specify which component of the system provides it. Hardware, software, and
    285   /// hybrid implementations are all valid.
    286   bool systemSupportsUnalignedAccess() const { return hasMips32r6(); }
    287 
    288   // Set helper classes
    289   void setHelperClassesMips16();
    290   void setHelperClassesMipsSE();
    291 
    292   MipsJITInfo *getJITInfo() { return &JITInfo; }
    293   const MipsSelectionDAGInfo *getSelectionDAGInfo() const { return &TSInfo; }
    294   const DataLayout *getDataLayout() const { return &DL; }
    295   const MipsInstrInfo *getInstrInfo() const { return InstrInfo.get(); }
    296   const TargetFrameLowering *getFrameLowering() const {
    297     return FrameLowering.get();
    298   }
    299   const MipsRegisterInfo *getRegisterInfo() const {
    300     return &InstrInfo->getRegisterInfo();
    301   }
    302   const MipsTargetLowering *getTargetLowering() const { return TLInfo.get(); }
    303 };
    304 } // End llvm namespace
    305 
    306 #endif
    307