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      1 //===-- ARMSubtarget.h - Define Subtarget for the ARM ----------*- 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 ARM specific subclass of TargetSubtargetInfo.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #ifndef LLVM_LIB_TARGET_ARM_ARMSUBTARGET_H
     15 #define LLVM_LIB_TARGET_ARM_ARMSUBTARGET_H
     16 
     17 
     18 #include "ARMFrameLowering.h"
     19 #include "ARMISelLowering.h"
     20 #include "ARMInstrInfo.h"
     21 #include "ARMSelectionDAGInfo.h"
     22 #include "ARMSubtarget.h"
     23 #include "MCTargetDesc/ARMMCTargetDesc.h"
     24 #include "Thumb1FrameLowering.h"
     25 #include "Thumb1InstrInfo.h"
     26 #include "Thumb2InstrInfo.h"
     27 #include "llvm/ADT/Triple.h"
     28 #include "llvm/IR/DataLayout.h"
     29 #include "llvm/MC/MCInstrItineraries.h"
     30 #include "llvm/Target/TargetSubtargetInfo.h"
     31 #include <string>
     32 
     33 #define GET_SUBTARGETINFO_HEADER
     34 #include "ARMGenSubtargetInfo.inc"
     35 
     36 namespace llvm {
     37 class GlobalValue;
     38 class StringRef;
     39 class TargetOptions;
     40 class ARMBaseTargetMachine;
     41 
     42 class ARMSubtarget : public ARMGenSubtargetInfo {
     43 protected:
     44   enum ARMProcFamilyEnum {
     45     Others, CortexA5, CortexA7, CortexA8, CortexA9, CortexA12, CortexA15,
     46     CortexA17, CortexR4, CortexR4F, CortexR5, CortexR7, CortexA35, CortexA53,
     47     CortexA57, CortexA72, Krait, Swift
     48   };
     49   enum ARMProcClassEnum {
     50     None, AClass, RClass, MClass
     51   };
     52   enum ARMArchEnum {
     53     ARMv2, ARMv2a, ARMv3, ARMv3m, ARMv4, ARMv4t, ARMv5, ARMv5t, ARMv5te,
     54     ARMv5tej, ARMv6, ARMv6k, ARMv6kz, ARMv6t2, ARMv6m, ARMv6sm, ARMv7a, ARMv7r,
     55     ARMv7m, ARMv7em, ARMv8a, ARMv81a, ARMv82a
     56   };
     57 
     58   /// ARMProcFamily - ARM processor family: Cortex-A8, Cortex-A9, and others.
     59   ARMProcFamilyEnum ARMProcFamily;
     60 
     61   /// ARMProcClass - ARM processor class: None, AClass, RClass or MClass.
     62   ARMProcClassEnum ARMProcClass;
     63 
     64   /// ARMArch - ARM architecture
     65   ARMArchEnum ARMArch;
     66 
     67   /// HasV4TOps, HasV5TOps, HasV5TEOps,
     68   /// HasV6Ops, HasV6MOps, HasV6KOps, HasV6T2Ops, HasV7Ops, HasV8Ops -
     69   /// Specify whether target support specific ARM ISA variants.
     70   bool HasV4TOps;
     71   bool HasV5TOps;
     72   bool HasV5TEOps;
     73   bool HasV6Ops;
     74   bool HasV6MOps;
     75   bool HasV6KOps;
     76   bool HasV6T2Ops;
     77   bool HasV7Ops;
     78   bool HasV8Ops;
     79   bool HasV8_1aOps;
     80   bool HasV8_2aOps;
     81 
     82   /// HasVFPv2, HasVFPv3, HasVFPv4, HasFPARMv8, HasNEON - Specify what
     83   /// floating point ISAs are supported.
     84   bool HasVFPv2;
     85   bool HasVFPv3;
     86   bool HasVFPv4;
     87   bool HasFPARMv8;
     88   bool HasNEON;
     89 
     90   /// UseNEONForSinglePrecisionFP - if the NEONFP attribute has been
     91   /// specified. Use the method useNEONForSinglePrecisionFP() to
     92   /// determine if NEON should actually be used.
     93   bool UseNEONForSinglePrecisionFP;
     94 
     95   /// UseMulOps - True if non-microcoded fused integer multiply-add and
     96   /// multiply-subtract instructions should be used.
     97   bool UseMulOps;
     98 
     99   /// SlowFPVMLx - If the VFP2 / NEON instructions are available, indicates
    100   /// whether the FP VML[AS] instructions are slow (if so, don't use them).
    101   bool SlowFPVMLx;
    102 
    103   /// HasVMLxForwarding - If true, NEON has special multiplier accumulator
    104   /// forwarding to allow mul + mla being issued back to back.
    105   bool HasVMLxForwarding;
    106 
    107   /// SlowFPBrcc - True if floating point compare + branch is slow.
    108   bool SlowFPBrcc;
    109 
    110   /// InThumbMode - True if compiling for Thumb, false for ARM.
    111   bool InThumbMode;
    112 
    113   /// UseSoftFloat - True if we're using software floating point features.
    114   bool UseSoftFloat;
    115 
    116   /// HasThumb2 - True if Thumb2 instructions are supported.
    117   bool HasThumb2;
    118 
    119   /// NoARM - True if subtarget does not support ARM mode execution.
    120   bool NoARM;
    121 
    122   /// ReserveR9 - True if R9 is not available as a general purpose register.
    123   bool ReserveR9;
    124 
    125   /// NoMovt - True if MOVT / MOVW pairs are not used for materialization of
    126   /// 32-bit imms (including global addresses).
    127   bool NoMovt;
    128 
    129   /// SupportsTailCall - True if the OS supports tail call. The dynamic linker
    130   /// must be able to synthesize call stubs for interworking between ARM and
    131   /// Thumb.
    132   bool SupportsTailCall;
    133 
    134   /// HasFP16 - True if subtarget supports half-precision FP conversions
    135   bool HasFP16;
    136 
    137   /// HasFullFP16 - True if subtarget supports half-precision FP operations
    138   bool HasFullFP16;
    139 
    140   /// HasD16 - True if subtarget is limited to 16 double precision
    141   /// FP registers for VFPv3.
    142   bool HasD16;
    143 
    144   /// HasHardwareDivide - True if subtarget supports [su]div
    145   bool HasHardwareDivide;
    146 
    147   /// HasHardwareDivideInARM - True if subtarget supports [su]div in ARM mode
    148   bool HasHardwareDivideInARM;
    149 
    150   /// HasT2ExtractPack - True if subtarget supports thumb2 extract/pack
    151   /// instructions.
    152   bool HasT2ExtractPack;
    153 
    154   /// HasDataBarrier - True if the subtarget supports DMB / DSB data barrier
    155   /// instructions.
    156   bool HasDataBarrier;
    157 
    158   /// Pref32BitThumb - If true, codegen would prefer 32-bit Thumb instructions
    159   /// over 16-bit ones.
    160   bool Pref32BitThumb;
    161 
    162   /// AvoidCPSRPartialUpdate - If true, codegen would avoid using instructions
    163   /// that partially update CPSR and add false dependency on the previous
    164   /// CPSR setting instruction.
    165   bool AvoidCPSRPartialUpdate;
    166 
    167   /// AvoidMOVsShifterOperand - If true, codegen should avoid using flag setting
    168   /// movs with shifter operand (i.e. asr, lsl, lsr).
    169   bool AvoidMOVsShifterOperand;
    170 
    171   /// HasRAS - Some processors perform return stack prediction. CodeGen should
    172   /// avoid issue "normal" call instructions to callees which do not return.
    173   bool HasRAS;
    174 
    175   /// HasMPExtension - True if the subtarget supports Multiprocessing
    176   /// extension (ARMv7 only).
    177   bool HasMPExtension;
    178 
    179   /// HasVirtualization - True if the subtarget supports the Virtualization
    180   /// extension.
    181   bool HasVirtualization;
    182 
    183   /// FPOnlySP - If true, the floating point unit only supports single
    184   /// precision.
    185   bool FPOnlySP;
    186 
    187   /// If true, the processor supports the Performance Monitor Extensions. These
    188   /// include a generic cycle-counter as well as more fine-grained (often
    189   /// implementation-specific) events.
    190   bool HasPerfMon;
    191 
    192   /// HasTrustZone - if true, processor supports TrustZone security extensions
    193   bool HasTrustZone;
    194 
    195   /// HasCrypto - if true, processor supports Cryptography extensions
    196   bool HasCrypto;
    197 
    198   /// HasCRC - if true, processor supports CRC instructions
    199   bool HasCRC;
    200 
    201   /// If true, the instructions "vmov.i32 d0, #0" and "vmov.i32 q0, #0" are
    202   /// particularly effective at zeroing a VFP register.
    203   bool HasZeroCycleZeroing;
    204 
    205   /// StrictAlign - If true, the subtarget disallows unaligned memory
    206   /// accesses for some types.  For details, see
    207   /// ARMTargetLowering::allowsMisalignedMemoryAccesses().
    208   bool StrictAlign;
    209 
    210   /// RestrictIT - If true, the subtarget disallows generation of deprecated IT
    211   ///  blocks to conform to ARMv8 rule.
    212   bool RestrictIT;
    213 
    214   /// HasDSP - If true, the subtarget supports the DSP (saturating arith
    215   /// and such) instructions.
    216   bool HasDSP;
    217 
    218   /// NaCl TRAP instruction is generated instead of the regular TRAP.
    219   bool UseNaClTrap;
    220 
    221   /// Force long to be a 64-bit type (RenderScript-specific)
    222   bool UseLong64;
    223 
    224   /// Generate calls via indirect call instructions.
    225   bool GenLongCalls;
    226 
    227   /// Target machine allowed unsafe FP math (such as use of NEON fp)
    228   bool UnsafeFPMath;
    229 
    230   /// UseSjLjEH - If true, the target uses SjLj exception handling (e.g. iOS).
    231   bool UseSjLjEH;
    232 
    233   /// stackAlignment - The minimum alignment known to hold of the stack frame on
    234   /// entry to the function and which must be maintained by every function.
    235   unsigned stackAlignment;
    236 
    237   /// CPUString - String name of used CPU.
    238   std::string CPUString;
    239 
    240   /// IsLittle - The target is Little Endian
    241   bool IsLittle;
    242 
    243   /// TargetTriple - What processor and OS we're targeting.
    244   Triple TargetTriple;
    245 
    246   /// SchedModel - Processor specific instruction costs.
    247   MCSchedModel SchedModel;
    248 
    249   /// Selected instruction itineraries (one entry per itinerary class.)
    250   InstrItineraryData InstrItins;
    251 
    252   /// Options passed via command line that could influence the target
    253   const TargetOptions &Options;
    254 
    255   const ARMBaseTargetMachine &TM;
    256 
    257 public:
    258   /// This constructor initializes the data members to match that
    259   /// of the specified triple.
    260   ///
    261   ARMSubtarget(const Triple &TT, const std::string &CPU, const std::string &FS,
    262                const ARMBaseTargetMachine &TM, bool IsLittle);
    263 
    264   /// getMaxInlineSizeThreshold - Returns the maximum memset / memcpy size
    265   /// that still makes it profitable to inline the call.
    266   unsigned getMaxInlineSizeThreshold() const {
    267     return 64;
    268   }
    269   /// ParseSubtargetFeatures - Parses features string setting specified
    270   /// subtarget options.  Definition of function is auto generated by tblgen.
    271   void ParseSubtargetFeatures(StringRef CPU, StringRef FS);
    272 
    273   /// initializeSubtargetDependencies - Initializes using a CPU and feature string
    274   /// so that we can use initializer lists for subtarget initialization.
    275   ARMSubtarget &initializeSubtargetDependencies(StringRef CPU, StringRef FS);
    276 
    277   const ARMSelectionDAGInfo *getSelectionDAGInfo() const override {
    278     return &TSInfo;
    279   }
    280   const ARMBaseInstrInfo *getInstrInfo() const override {
    281     return InstrInfo.get();
    282   }
    283   const ARMTargetLowering *getTargetLowering() const override {
    284     return &TLInfo;
    285   }
    286   const ARMFrameLowering *getFrameLowering() const override {
    287     return FrameLowering.get();
    288   }
    289   const ARMBaseRegisterInfo *getRegisterInfo() const override {
    290     return &InstrInfo->getRegisterInfo();
    291   }
    292 
    293 private:
    294   ARMSelectionDAGInfo TSInfo;
    295   // Either Thumb1FrameLowering or ARMFrameLowering.
    296   std::unique_ptr<ARMFrameLowering> FrameLowering;
    297   // Either Thumb1InstrInfo or Thumb2InstrInfo.
    298   std::unique_ptr<ARMBaseInstrInfo> InstrInfo;
    299   ARMTargetLowering   TLInfo;
    300 
    301   void initializeEnvironment();
    302   void initSubtargetFeatures(StringRef CPU, StringRef FS);
    303   ARMFrameLowering *initializeFrameLowering(StringRef CPU, StringRef FS);
    304 
    305 public:
    306   void computeIssueWidth();
    307 
    308   bool hasV4TOps()  const { return HasV4TOps;  }
    309   bool hasV5TOps()  const { return HasV5TOps;  }
    310   bool hasV5TEOps() const { return HasV5TEOps; }
    311   bool hasV6Ops()   const { return HasV6Ops;   }
    312   bool hasV6MOps()  const { return HasV6MOps;  }
    313   bool hasV6KOps()  const { return HasV6KOps; }
    314   bool hasV6T2Ops() const { return HasV6T2Ops; }
    315   bool hasV7Ops()   const { return HasV7Ops;  }
    316   bool hasV8Ops()   const { return HasV8Ops;  }
    317   bool hasV8_1aOps() const { return HasV8_1aOps; }
    318   bool hasV8_2aOps() const { return HasV8_2aOps; }
    319 
    320   bool isCortexA5() const { return ARMProcFamily == CortexA5; }
    321   bool isCortexA7() const { return ARMProcFamily == CortexA7; }
    322   bool isCortexA8() const { return ARMProcFamily == CortexA8; }
    323   bool isCortexA9() const { return ARMProcFamily == CortexA9; }
    324   bool isCortexA15() const { return ARMProcFamily == CortexA15; }
    325   bool isSwift()    const { return ARMProcFamily == Swift; }
    326   bool isCortexM3() const { return CPUString == "cortex-m3"; }
    327   bool isLikeA9() const { return isCortexA9() || isCortexA15() || isKrait(); }
    328   bool isCortexR5() const { return ARMProcFamily == CortexR5; }
    329   bool isKrait() const { return ARMProcFamily == Krait; }
    330 
    331   bool hasARMOps() const { return !NoARM; }
    332 
    333   bool hasVFP2() const { return HasVFPv2; }
    334   bool hasVFP3() const { return HasVFPv3; }
    335   bool hasVFP4() const { return HasVFPv4; }
    336   bool hasFPARMv8() const { return HasFPARMv8; }
    337   bool hasNEON() const { return HasNEON;  }
    338   bool hasCrypto() const { return HasCrypto; }
    339   bool hasCRC() const { return HasCRC; }
    340   bool hasVirtualization() const { return HasVirtualization; }
    341   bool useNEONForSinglePrecisionFP() const {
    342     return hasNEON() && UseNEONForSinglePrecisionFP;
    343   }
    344 
    345   bool hasDivide() const { return HasHardwareDivide; }
    346   bool hasDivideInARMMode() const { return HasHardwareDivideInARM; }
    347   bool hasT2ExtractPack() const { return HasT2ExtractPack; }
    348   bool hasDataBarrier() const { return HasDataBarrier; }
    349   bool hasAnyDataBarrier() const {
    350     return HasDataBarrier || (hasV6Ops() && !isThumb());
    351   }
    352   bool useMulOps() const { return UseMulOps; }
    353   bool useFPVMLx() const { return !SlowFPVMLx; }
    354   bool hasVMLxForwarding() const { return HasVMLxForwarding; }
    355   bool isFPBrccSlow() const { return SlowFPBrcc; }
    356   bool isFPOnlySP() const { return FPOnlySP; }
    357   bool hasPerfMon() const { return HasPerfMon; }
    358   bool hasTrustZone() const { return HasTrustZone; }
    359   bool hasZeroCycleZeroing() const { return HasZeroCycleZeroing; }
    360   bool prefers32BitThumb() const { return Pref32BitThumb; }
    361   bool avoidCPSRPartialUpdate() const { return AvoidCPSRPartialUpdate; }
    362   bool avoidMOVsShifterOperand() const { return AvoidMOVsShifterOperand; }
    363   bool hasRAS() const { return HasRAS; }
    364   bool hasMPExtension() const { return HasMPExtension; }
    365   bool hasDSP() const { return HasDSP; }
    366   bool useNaClTrap() const { return UseNaClTrap; }
    367   bool useSjLjEH() const { return UseSjLjEH; }
    368   bool genLongCalls() const { return GenLongCalls; }
    369 
    370   bool hasFP16() const { return HasFP16; }
    371   bool hasD16() const { return HasD16; }
    372   bool hasFullFP16() const { return HasFullFP16; }
    373 
    374   const Triple &getTargetTriple() const { return TargetTriple; }
    375 
    376   bool isTargetDarwin() const { return TargetTriple.isOSDarwin(); }
    377   bool isTargetIOS() const { return TargetTriple.isiOS(); }
    378   bool isTargetWatchOS() const { return TargetTriple.isWatchOS(); }
    379   bool isTargetLinux() const { return TargetTriple.isOSLinux(); }
    380   bool isTargetNaCl() const { return TargetTriple.isOSNaCl(); }
    381   bool isTargetNetBSD() const { return TargetTriple.isOSNetBSD(); }
    382   bool isTargetWindows() const { return TargetTriple.isOSWindows(); }
    383 
    384   bool isTargetCOFF() const { return TargetTriple.isOSBinFormatCOFF(); }
    385   bool isTargetELF() const { return TargetTriple.isOSBinFormatELF(); }
    386   bool isTargetMachO() const { return TargetTriple.isOSBinFormatMachO(); }
    387 
    388   // ARM EABI is the bare-metal EABI described in ARM ABI documents and
    389   // can be accessed via -target arm-none-eabi. This is NOT GNUEABI.
    390   // FIXME: Add a flag for bare-metal for that target and set Triple::EABI
    391   // even for GNUEABI, so we can make a distinction here and still conform to
    392   // the EABI on GNU (and Android) mode. This requires change in Clang, too.
    393   // FIXME: The Darwin exception is temporary, while we move users to
    394   // "*-*-*-macho" triples as quickly as possible.
    395   bool isTargetAEABI() const {
    396     return (TargetTriple.getEnvironment() == Triple::EABI ||
    397             TargetTriple.getEnvironment() == Triple::EABIHF) &&
    398            !isTargetDarwin() && !isTargetWindows();
    399   }
    400   bool isTargetGNUAEABI() const {
    401     return (TargetTriple.getEnvironment() == Triple::GNUEABI ||
    402             TargetTriple.getEnvironment() == Triple::GNUEABIHF) &&
    403            !isTargetDarwin() && !isTargetWindows();
    404   }
    405 
    406   // ARM Targets that support EHABI exception handling standard
    407   // Darwin uses SjLj. Other targets might need more checks.
    408   bool isTargetEHABICompatible() const {
    409     return (TargetTriple.getEnvironment() == Triple::EABI ||
    410             TargetTriple.getEnvironment() == Triple::GNUEABI ||
    411             TargetTriple.getEnvironment() == Triple::EABIHF ||
    412             TargetTriple.getEnvironment() == Triple::GNUEABIHF ||
    413             isTargetAndroid()) &&
    414            !isTargetDarwin() && !isTargetWindows();
    415   }
    416 
    417   bool isTargetHardFloat() const {
    418     // FIXME: this is invalid for WindowsCE
    419     return TargetTriple.getEnvironment() == Triple::GNUEABIHF ||
    420            TargetTriple.getEnvironment() == Triple::EABIHF ||
    421            isTargetWindows() || isAAPCS16_ABI();
    422   }
    423   bool isTargetAndroid() const { return TargetTriple.isAndroid(); }
    424 
    425   bool isAPCS_ABI() const;
    426   bool isAAPCS_ABI() const;
    427   bool isAAPCS16_ABI() const;
    428 
    429   bool useSoftFloat() const { return UseSoftFloat; }
    430   bool isThumb() const { return InThumbMode; }
    431   bool isThumb1Only() const { return InThumbMode && !HasThumb2; }
    432   bool isThumb2() const { return InThumbMode && HasThumb2; }
    433   bool hasThumb2() const { return HasThumb2; }
    434   bool isMClass() const { return ARMProcClass == MClass; }
    435   bool isRClass() const { return ARMProcClass == RClass; }
    436   bool isAClass() const { return ARMProcClass == AClass; }
    437 
    438   bool isR9Reserved() const {
    439     return isTargetMachO() ? (ReserveR9 || !HasV6Ops) : ReserveR9;
    440   }
    441 
    442   bool useStride4VFPs(const MachineFunction &MF) const;
    443 
    444   bool useMovt(const MachineFunction &MF) const;
    445 
    446   bool supportsTailCall() const { return SupportsTailCall; }
    447 
    448   bool allowsUnalignedMem() const { return !StrictAlign; }
    449 
    450   bool restrictIT() const { return RestrictIT; }
    451 
    452   const std::string & getCPUString() const { return CPUString; }
    453 
    454   bool isLittle() const { return IsLittle; }
    455 
    456   unsigned getMispredictionPenalty() const;
    457 
    458   /// This function returns true if the target has sincos() routine in its
    459   /// compiler runtime or math libraries.
    460   bool hasSinCos() const;
    461 
    462   /// Returns true if machine scheduler should be enabled.
    463   bool enableMachineScheduler() const override;
    464 
    465   /// True for some subtargets at > -O0.
    466   bool enablePostRAScheduler() const override;
    467 
    468   // enableAtomicExpand- True if we need to expand our atomics.
    469   bool enableAtomicExpand() const override;
    470 
    471   /// getInstrItins - Return the instruction itineraries based on subtarget
    472   /// selection.
    473   const InstrItineraryData *getInstrItineraryData() const override {
    474     return &InstrItins;
    475   }
    476 
    477   /// getStackAlignment - Returns the minimum alignment known to hold of the
    478   /// stack frame on entry to the function and which must be maintained by every
    479   /// function for this subtarget.
    480   unsigned getStackAlignment() const { return stackAlignment; }
    481 
    482   /// GVIsIndirectSymbol - true if the GV will be accessed via an indirect
    483   /// symbol.
    484   bool GVIsIndirectSymbol(const GlobalValue *GV, Reloc::Model RelocM) const;
    485 
    486   /// True if fast-isel is used.
    487   bool useFastISel() const;
    488 };
    489 } // End llvm namespace
    490 
    491 #endif  // ARMSUBTARGET_H
    492