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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 LLVM_LIB_TARGET_MIPS_MIPSSUBTARGET_H
     15 #define LLVM_LIB_TARGET_MIPS_MIPSSUBTARGET_H
     16 
     17 #include "MCTargetDesc/MipsABIInfo.h"
     18 #include "MipsFrameLowering.h"
     19 #include "MipsISelLowering.h"
     20 #include "MipsInstrInfo.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   enum MipsArchEnum {
     40     MipsDefault,
     41     Mips1, Mips2, Mips32, Mips32r2, Mips32r3, Mips32r5, Mips32r6, Mips32Max,
     42     Mips3, Mips4, Mips5, Mips64, Mips64r2, Mips64r3, Mips64r5, Mips64r6
     43   };
     44 
     45   // Mips architecture version
     46   MipsArchEnum MipsArchVersion;
     47 
     48   // IsLittle - The target is Little Endian
     49   bool IsLittle;
     50 
     51   // IsSingleFloat - The target only supports single precision float
     52   // point operations. This enable the target to use all 32 32-bit
     53   // floating point registers instead of only using even ones.
     54   bool IsSingleFloat;
     55 
     56   // IsFPXX - MIPS O32 modeless ABI.
     57   bool IsFPXX;
     58 
     59   // NoABICalls - Disable SVR4-style position-independent code.
     60   bool NoABICalls;
     61 
     62   // IsFP64bit - The target processor has 64-bit floating point registers.
     63   bool IsFP64bit;
     64 
     65   /// Are odd single-precision registers permitted?
     66   /// This corresponds to -modd-spreg and -mno-odd-spreg
     67   bool UseOddSPReg;
     68 
     69   // IsNan2008 - IEEE 754-2008 NaN encoding.
     70   bool IsNaN2008bit;
     71 
     72   // IsFP64bit - General-purpose registers are 64 bits wide
     73   bool IsGP64bit;
     74 
     75   // HasVFPU - Processor has a vector floating point unit.
     76   bool HasVFPU;
     77 
     78   // CPU supports cnMIPS (Cavium Networks Octeon CPU).
     79   bool HasCnMips;
     80 
     81   // isLinux - Target system is Linux. Is false we consider ELFOS for now.
     82   bool IsLinux;
     83 
     84   // UseSmallSection - Small section is used.
     85   bool UseSmallSection;
     86 
     87   /// Features related to the presence of specific instructions.
     88 
     89   // HasMips3_32 - The subset of MIPS-III instructions added to MIPS32
     90   bool HasMips3_32;
     91 
     92   // HasMips3_32r2 - The subset of MIPS-III instructions added to MIPS32r2
     93   bool HasMips3_32r2;
     94 
     95   // HasMips4_32 - Has the subset of MIPS-IV present in MIPS32
     96   bool HasMips4_32;
     97 
     98   // HasMips4_32r2 - Has the subset of MIPS-IV present in MIPS32r2
     99   bool HasMips4_32r2;
    100 
    101   // HasMips5_32r2 - Has the subset of MIPS-V present in MIPS32r2
    102   bool HasMips5_32r2;
    103 
    104   // InMips16 -- can process Mips16 instructions
    105   bool InMips16Mode;
    106 
    107   // Mips16 hard float
    108   bool InMips16HardFloat;
    109 
    110   // PreviousInMips16 -- the function we just processed was in Mips 16 Mode
    111   bool PreviousInMips16Mode;
    112 
    113   // InMicroMips -- can process MicroMips instructions
    114   bool InMicroMipsMode;
    115 
    116   // HasDSP, HasDSPR2 -- supports DSP ASE.
    117   bool HasDSP, HasDSPR2;
    118 
    119   // Allow mixed Mips16 and Mips32 in one source file
    120   bool AllowMixed16_32;
    121 
    122   // Optimize for space by compiling all functions as Mips 16 unless
    123   // it needs floating point. Functions needing floating point are
    124   // compiled as Mips32
    125   bool Os16;
    126 
    127   // HasMSA -- supports MSA ASE.
    128   bool HasMSA;
    129 
    130   InstrItineraryData InstrItins;
    131 
    132   // We can override the determination of whether we are in mips16 mode
    133   // as from the command line
    134   enum {NoOverride, Mips16Override, NoMips16Override} OverrideMode;
    135 
    136   const MipsTargetMachine &TM;
    137 
    138   Triple TargetTriple;
    139 
    140   const MipsSelectionDAGInfo TSInfo;
    141   std::unique_ptr<const MipsInstrInfo> InstrInfo;
    142   std::unique_ptr<const MipsFrameLowering> FrameLowering;
    143   std::unique_ptr<const MipsTargetLowering> TLInfo;
    144 
    145 public:
    146   /// This overrides the PostRAScheduler bit in the SchedModel for each CPU.
    147   bool enablePostMachineScheduler() const override;
    148   void getCriticalPathRCs(RegClassVector &CriticalPathRCs) const override;
    149   CodeGenOpt::Level getOptLevelToEnablePostRAScheduler() const override;
    150 
    151   /// Only O32 and EABI supported right now.
    152   bool isABI_EABI() const;
    153   bool isABI_N64() const;
    154   bool isABI_N32() const;
    155   bool isABI_O32() const;
    156   const MipsABIInfo &getABI() const;
    157   bool isABI_FPXX() const { return isABI_O32() && IsFPXX; }
    158 
    159   /// This constructor initializes the data members to match that
    160   /// of the specified triple.
    161   MipsSubtarget(const std::string &TT, const std::string &CPU,
    162                 const std::string &FS, bool little,
    163                 const MipsTargetMachine &TM);
    164 
    165   /// ParseSubtargetFeatures - Parses features string setting specified
    166   /// subtarget options.  Definition of function is auto generated by tblgen.
    167   void ParseSubtargetFeatures(StringRef CPU, StringRef FS);
    168 
    169   bool hasMips1() const { return MipsArchVersion >= Mips1; }
    170   bool hasMips2() const { return MipsArchVersion >= Mips2; }
    171   bool hasMips3() const { return MipsArchVersion >= Mips3; }
    172   bool hasMips4() const { return MipsArchVersion >= Mips4; }
    173   bool hasMips5() const { return MipsArchVersion >= Mips5; }
    174   bool hasMips4_32() const { return HasMips4_32; }
    175   bool hasMips4_32r2() const { return HasMips4_32r2; }
    176   bool hasMips32() const {
    177     return (MipsArchVersion >= Mips32 && MipsArchVersion < Mips32Max) ||
    178            hasMips64();
    179   }
    180   bool hasMips32r2() const {
    181     return (MipsArchVersion >= Mips32r2 && MipsArchVersion < Mips32Max) ||
    182            hasMips64r2();
    183   }
    184   bool hasMips32r3() const {
    185     return (MipsArchVersion >= Mips32r3 && MipsArchVersion < Mips32Max) ||
    186            hasMips64r2();
    187   }
    188   bool hasMips32r5() const {
    189     return (MipsArchVersion >= Mips32r5 && MipsArchVersion < Mips32Max) ||
    190            hasMips64r2();
    191   }
    192   bool hasMips32r6() const {
    193     return (MipsArchVersion >= Mips32r6 && MipsArchVersion < Mips32Max) ||
    194            hasMips64r6();
    195   }
    196   bool hasMips64() const { return MipsArchVersion >= Mips64; }
    197   bool hasMips64r2() const { return MipsArchVersion >= Mips64r2; }
    198   bool hasMips64r3() const { return MipsArchVersion >= Mips64r3; }
    199   bool hasMips64r5() const { return MipsArchVersion >= Mips64r5; }
    200   bool hasMips64r6() const { return MipsArchVersion >= Mips64r6; }
    201 
    202   bool hasCnMips() const { return HasCnMips; }
    203 
    204   bool isLittle() const { return IsLittle; }
    205   bool isABICalls() const { return !NoABICalls; }
    206   bool isFPXX() const { return IsFPXX; }
    207   bool isFP64bit() const { return IsFP64bit; }
    208   bool useOddSPReg() const { return UseOddSPReg; }
    209   bool noOddSPReg() const { return !UseOddSPReg; }
    210   bool isNaN2008() const { return IsNaN2008bit; }
    211   bool isGP64bit() const { return IsGP64bit; }
    212   bool isGP32bit() const { return !IsGP64bit; }
    213   unsigned getGPRSizeInBytes() const { return isGP64bit() ? 8 : 4; }
    214   bool isSingleFloat() const { return IsSingleFloat; }
    215   bool hasVFPU() const { return HasVFPU; }
    216   bool inMips16Mode() const { return InMips16Mode; }
    217   bool inMips16ModeDefault() const {
    218     return InMips16Mode;
    219   }
    220   // Hard float for mips16 means essentially to compile as soft float
    221   // but to use a runtime library for soft float that is written with
    222   // native mips32 floating point instructions (those runtime routines
    223   // run in mips32 hard float mode).
    224   bool inMips16HardFloat() const {
    225     return inMips16Mode() && InMips16HardFloat;
    226   }
    227   bool inMicroMipsMode() const { return InMicroMipsMode; }
    228   bool hasDSP() const { return HasDSP; }
    229   bool hasDSPR2() const { return HasDSPR2; }
    230   bool hasMSA() const { return HasMSA; }
    231   bool useSmallSection() const { return UseSmallSection; }
    232 
    233   bool hasStandardEncoding() const { return !inMips16Mode(); }
    234 
    235   bool abiUsesSoftFloat() const;
    236 
    237   bool enableLongBranchPass() const {
    238     return hasStandardEncoding() || allowMixed16_32();
    239   }
    240 
    241   /// Features related to the presence of specific instructions.
    242   bool hasExtractInsert() const { return !inMips16Mode() && hasMips32r2(); }
    243   bool hasMTHC1() const { return hasMips32r2(); }
    244 
    245   bool allowMixed16_32() const { return inMips16ModeDefault() |
    246                                         AllowMixed16_32; }
    247 
    248   bool os16() const { return Os16; }
    249 
    250   bool isTargetNaCl() const { return TargetTriple.isOSNaCl(); }
    251 
    252   // for now constant islands are on for the whole compilation unit but we only
    253   // really use them if in addition we are in mips16 mode
    254   static bool useConstantIslands();
    255 
    256   unsigned stackAlignment() const { return hasMips64() ? 16 : 8; }
    257 
    258   // Grab relocation model
    259   Reloc::Model getRelocationModel() const;
    260 
    261   MipsSubtarget &initializeSubtargetDependencies(StringRef CPU, StringRef FS,
    262                                                  const TargetMachine &TM);
    263 
    264   /// Does the system support unaligned memory access.
    265   ///
    266   /// MIPS32r6/MIPS64r6 require full unaligned access support but does not
    267   /// specify which component of the system provides it. Hardware, software, and
    268   /// hybrid implementations are all valid.
    269   bool systemSupportsUnalignedAccess() const { return hasMips32r6(); }
    270 
    271   // Set helper classes
    272   void setHelperClassesMips16();
    273   void setHelperClassesMipsSE();
    274 
    275   const MipsSelectionDAGInfo *getSelectionDAGInfo() const override {
    276     return &TSInfo;
    277   }
    278   const MipsInstrInfo *getInstrInfo() const override { return InstrInfo.get(); }
    279   const TargetFrameLowering *getFrameLowering() const override {
    280     return FrameLowering.get();
    281   }
    282   const MipsRegisterInfo *getRegisterInfo() const override {
    283     return &InstrInfo->getRegisterInfo();
    284   }
    285   const MipsTargetLowering *getTargetLowering() const override {
    286     return TLInfo.get();
    287   }
    288   const InstrItineraryData *getInstrItineraryData() const override {
    289     return &InstrItins;
    290   }
    291 };
    292 } // End llvm namespace
    293 
    294 #endif
    295