MipsSubtarget.h

Go to the documentation of this file.

//===-- MipsSubtarget.h - Define Subtarget for the Mips ---------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file declares the Mips specific subclass of TargetSubtargetInfo.
//
//===----------------------------------------------------------------------===//
 
#ifndef LLVM_LIB_TARGET_MIPS_MIPSSUBTARGET_H
#define LLVM_LIB_TARGET_MIPS_MIPSSUBTARGET_H
 
#include "MCTargetDesc/MipsABIInfo.h"
#include "MipsFrameLowering.h"
#include "MipsISelLowering.h"
#include "MipsInstrInfo.h"
#include "llvm/CodeGen/GlobalISel/CallLowering.h"
#include "llvm/CodeGen/GlobalISel/InstructionSelector.h"
#include "llvm/CodeGen/GlobalISel/LegalizerInfo.h"
#include "llvm/CodeGen/RegisterBankInfo.h"
#include "llvm/CodeGen/TargetSubtargetInfo.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/MC/MCInstrItineraries.h"
#include "llvm/Support/ErrorHandling.h"
 
#define GET_SUBTARGETINFO_HEADER
#include "MipsGenSubtargetInfo.inc"
 
namespace llvm {
class StringRef;
 
enum CompactBranchPolicy {
  CB_Never,   ///< The policy 'never' may in some circumstances or for some
              ///< ISAs not be absolutely adhered to.
  CB_Optimal, ///< Optimal is the default and will produce compact branches
              ///< when appropriate.
  CB_Always   ///< 'always' may in some circumstances may not be
              ///< absolutely adhered to, there may not be a corresponding
              ///< compact form of a branch.
};
 
class MipsTargetMachine;
 
class MipsSubtarget : public MipsGenSubtargetInfo {
  virtual void anchor();
 
  enum MipsArchEnum {
    MipsDefault,
    Mips1, Mips2, Mips32, Mips32r2, Mips32r3, Mips32r5, Mips32r6, Mips32Max,
    Mips3, Mips4, Mips5, Mips64, Mips64r2, Mips64r3, Mips64r5, Mips64r6
  };
 
  enum class CPU { Others, P5600, I6400, I6500 };
 
  // Used to avoid printing dsp warnings multiple times.
  static bool DspWarningPrinted;
 
  // Used to avoid printing msa warnings multiple times.
  static bool MSAWarningPrinted;
 
  // Used to avoid printing crc warnings multiple times.
  static bool CRCWarningPrinted;
 
  // Used to avoid printing ginv warnings multiple times.
  static bool GINVWarningPrinted;
 
  // Used to avoid printing Mips1 warnings multiple times.
  static bool MIPS1WarningPrinted;
 
  // Used to avoid printing virt warnings multiple times.
  static bool VirtWarningPrinted;
 
  // Mips architecture version
  MipsArchEnum MipsArchVersion;
 
  // Processor implementation
  CPU ProcImpl = CPU::Others;
 
  // IsLittle - The target is Little Endian
  bool IsLittle;
 
  // IsSoftFloat - The target does not support any floating point instructions.
  bool IsSoftFloat;
 
  // 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;
 
  // IsFPXX - MIPS O32 modeless ABI.
  bool IsFPXX;
 
  // NoABICalls - Disable SVR4-style position-independent code.
  bool NoABICalls;
 
  // Abs2008 - Use IEEE 754-2008 abs.fmt instruction.
  bool Abs2008;
 
  // IsFP64bit - The target processor has 64-bit floating point registers.
  bool IsFP64bit;
 
  /// Are odd single-precision registers permitted?
  /// This corresponds to -modd-spreg and -mno-odd-spreg
  bool UseOddSPReg;
 
  // IsNan2008 - IEEE 754-2008 NaN encoding.
  bool IsNaN2008bit;
 
  // IsGP64bit - General-purpose registers are 64 bits wide
  bool IsGP64bit;
 
  // IsPTR64bit - Pointers are 64 bit wide
  bool IsPTR64bit;
 
  // HasVFPU - Processor has a vector floating point unit.
  bool HasVFPU;
 
  // CPU supports cnMIPS (Cavium Networks Octeon CPU).
  bool HasCnMips;
 
  // CPU supports cnMIPSP (Cavium Networks Octeon+ CPU).
  bool HasCnMipsP;
 
  // 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.
 
  // HasMips3_32 - The subset of MIPS-III instructions added to MIPS32
  bool HasMips3_32;
 
  // HasMips3_32r2 - The subset of MIPS-III instructions added to MIPS32r2
  bool HasMips3_32r2;
 
  // HasMips4_32 - Has the subset of MIPS-IV present in MIPS32
  bool HasMips4_32;
 
  // HasMips4_32r2 - Has the subset of MIPS-IV present in MIPS32r2
  bool HasMips4_32r2;
 
  // HasMips5_32r2 - Has the subset of MIPS-V present in MIPS32r2
  bool HasMips5_32r2;
 
  // InMips16 -- can process Mips16 instructions
  bool InMips16Mode;
 
  // Mips16 hard float
  bool InMips16HardFloat;
 
  // InMicroMips -- can process MicroMips instructions
  bool InMicroMipsMode;
 
  // HasDSP, HasDSPR2, HasDSPR3 -- supports DSP ASE.
  bool HasDSP, HasDSPR2, HasDSPR3;
 
  // Has3D -- Supports Mips3D ASE.
  bool Has3D;
 
  // 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;
 
  // UseTCCInDIV -- Enables the use of trapping in the assembler.
  bool UseTCCInDIV;
 
  // Sym32 -- On Mips64 symbols are 32 bits.
  bool HasSym32;
 
  // HasEVA -- supports EVA ASE.
  bool HasEVA;
 
  // nomadd4 - disables generation of 4-operand madd.s, madd.d and
  // related instructions.
  bool DisableMadd4;
 
  // HasMT -- support MT ASE.
  bool HasMT;
 
  // HasCRC -- supports R6 CRC ASE
  bool HasCRC;
 
  // HasVirt -- supports Virtualization ASE
  bool HasVirt;
 
  // HasGINV -- supports R6 Global INValidate ASE
  bool HasGINV;
 
  // Use hazard variants of the jump register instructions for indirect
  // function calls and jump tables.
  bool UseIndirectJumpsHazard;
 
  // Disable use of the `jal` instruction.
  bool UseLongCalls = false;
 
  // Assume 32-bit GOT.
  bool UseXGOT = false;
 
  // Disable unaligned load store for r6.
  bool StrictAlign;
 
  // Use compact branch instructions for R6.
  bool UseCompactBranches = true;
 
  /// The minimum alignment known to hold of the stack frame on
  /// entry to the function and which must be maintained by every function.
  Align stackAlignment;
 
  /// The overridden stack alignment.
  MaybeAlign StackAlignOverride;
 
  InstrItineraryData InstrItins;
 
  // We can override the determination of whether we are in mips16 mode
  // as from the command line
  enum {NoOverride, Mips16Override, NoMips16Override} OverrideMode;
 
  const MipsTargetMachine &TM;
 
  Triple TargetTriple;
 
  std::unique_ptr<const SelectionDAGTargetInfo> TSInfo;
  std::unique_ptr<const MipsInstrInfo> InstrInfo;
  std::unique_ptr<const MipsFrameLowering> FrameLowering;
  std::unique_ptr<const MipsTargetLowering> TLInfo;
 
public:
  bool isPositionIndependent() const;
  /// This overrides the PostRAScheduler bit in the SchedModel for each CPU.
  bool enablePostRAScheduler() const override;
  void getCriticalPathRCs(RegClassVector &CriticalPathRCs) const override;
  CodeGenOptLevel getOptLevelToEnablePostRAScheduler() const override;
 
  bool isABI_N64() const;
  bool isABI_N32() const;
  bool isABI_O32() const;
  const MipsABIInfo &getABI() const;
  bool isABI_FPXX() const { return isABI_O32() && IsFPXX; }
 
  /// This constructor initializes the data members to match that
  /// of the specified triple.
  MipsSubtarget(const Triple &TT, StringRef CPU, StringRef FS, bool little,
                const MipsTargetMachine &TM, MaybeAlign StackAlignOverride);
 
  ~MipsSubtarget() override;
 
  /// ParseSubtargetFeatures - Parses features string setting specified
  /// subtarget options.  Definition of function is auto generated by tblgen.
  void ParseSubtargetFeatures(StringRef CPU, StringRef TuneCPU, StringRef FS);
 
  static const RTLIB::LibcallImpl HardFloatLibCalls[34];
 
  bool hasMips1() const { return MipsArchVersion >= Mips1; }
  bool hasMips2() const { return MipsArchVersion >= Mips2; }
  bool hasMips3() const { return MipsArchVersion >= Mips3; }
  bool hasMips4() const { return MipsArchVersion >= Mips4; }
  bool hasMips5() const { return MipsArchVersion >= Mips5; }
  bool hasMips4_32() const { return HasMips4_32; }
  bool hasMips4_32r2() const { return HasMips4_32r2; }
  bool hasMips32() const {
    return (MipsArchVersion >= Mips32 && MipsArchVersion < Mips32Max) ||
           hasMips64();
  }
  bool hasMips32r2() const {
    return (MipsArchVersion >= Mips32r2 && MipsArchVersion < Mips32Max) ||
           hasMips64r2();
  }
  bool hasMips32r3() const {
    return (MipsArchVersion >= Mips32r3 && MipsArchVersion < Mips32Max) ||
           hasMips64r2();
  }
  bool hasMips32r5() const {
    return (MipsArchVersion >= Mips32r5 && MipsArchVersion < Mips32Max) ||
           hasMips64r5();
  }
  bool hasMips32r6() const {
    return (MipsArchVersion >= Mips32r6 && MipsArchVersion < Mips32Max) ||
           hasMips64r6();
  }
  bool hasMips64() const { return MipsArchVersion >= Mips64; }
  bool hasMips64r2() const { return MipsArchVersion >= Mips64r2; }
  bool hasMips64r3() const { return MipsArchVersion >= Mips64r3; }
  bool hasMips64r5() const { return MipsArchVersion >= Mips64r5; }
  bool hasMips64r6() const { return MipsArchVersion >= Mips64r6; }
 
  bool hasCnMips() const { return HasCnMips; }
  bool hasCnMipsP() const { return HasCnMipsP; }
 
  bool isLittle() const { return IsLittle; }
  bool isABICalls() const { return !NoABICalls; }
  bool isFPXX() const { return IsFPXX; }
  bool isFP64bit() const { return IsFP64bit; }
  bool useOddSPReg() const { return UseOddSPReg; }
  bool noOddSPReg() const { return !UseOddSPReg; }
  bool isNaN2008() const { return IsNaN2008bit; }
  bool inAbs2008Mode() const { return Abs2008; }
  bool isGP64bit() const { return IsGP64bit; }
  bool isGP32bit() const { return !IsGP64bit; }
  unsigned getGPRSizeInBytes() const { return isGP64bit() ? 8 : 4; }
  bool isPTR64bit() const { return IsPTR64bit; }
  bool isPTR32bit() const { return !IsPTR64bit; }
  bool hasSym32() const {
    return (HasSym32 && isABI_N64()) || isABI_N32() || isABI_O32();
  }
  bool isSingleFloat() const { return IsSingleFloat; }
  bool isTargetCOFF() const { return TargetTriple.isOSBinFormatCOFF(); }
  bool isTargetELF() const { return TargetTriple.isOSBinFormatELF(); }
  bool hasVFPU() const { return HasVFPU; }
  bool inMips16Mode() const { return InMips16Mode; }
  bool inMips16ModeDefault() const {
    return InMips16Mode;
  }
  // Hard float for mips16 means essentially to compile as soft float
  // but to use a runtime library for soft float that is written with
  // native mips32 floating point instructions (those runtime routines
  // run in mips32 hard float mode).
  bool inMips16HardFloat() const {
    return inMips16Mode() && InMips16HardFloat;
  }
  bool inMicroMipsMode() const { return InMicroMipsMode && !InMips16Mode; }
  bool inMicroMips32r6Mode() const {
    return inMicroMipsMode() && hasMips32r6();
  }
  bool hasDSP() const { return HasDSP; }
  bool hasDSPR2() const { return HasDSPR2; }
  bool hasDSPR3() const { return HasDSPR3; }
  bool has3D() const { return Has3D; }
  bool hasMSA() const { return HasMSA; }
  bool disableMadd4() const { return DisableMadd4; }
  bool hasEVA() const { return HasEVA; }
  bool hasMT() const { return HasMT; }
  bool hasCRC() const { return HasCRC; }
  bool hasVirt() const { return HasVirt; }
  bool hasGINV() const { return HasGINV; }
  bool useIndirectJumpsHazard() const {
    return UseIndirectJumpsHazard && hasMips32r2();
  }
  bool useSmallSection() const { return UseSmallSection; }
 
  bool useCompactBranches() const {
    return UseCompactBranches && hasMips32r6();
  }
 
  bool hasStandardEncoding() const { return !InMips16Mode && !InMicroMipsMode; }
 
  bool useSoftFloat() const { return IsSoftFloat; }
 
  bool useLongCalls() const { return UseLongCalls; }
 
  bool useXGOT() const { return UseXGOT; }
 
  bool enableLongBranchPass() const {
    return hasStandardEncoding() || inMicroMipsMode() || allowMixed16_32();
  }
 
  /// Features related to the presence of specific instructions.
  bool hasExtractInsert() const { return !inMips16Mode() && hasMips32r2(); }
  bool hasMTHC1() const { return hasMips32r2(); }
 
  bool allowMixed16_32() const { return inMips16ModeDefault() |
                                        AllowMixed16_32; }
 
  bool os16() const { return Os16; }
 
  bool isTargetWindows() const { return TargetTriple.isOSWindows(); }
 
  bool isXRaySupported() const override { return true; }
 
  // 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();
 
  Align getStackAlignment() const { return stackAlignment; }
 
  // Grab relocation model
  Reloc::Model getRelocationModel() const;
 
  MipsSubtarget &initializeSubtargetDependencies(StringRef CPU, StringRef FS,
                                                 const TargetMachine &TM);
 
  /// Does the system support unaligned memory access.
  ///
  /// MIPS32r6/MIPS64r6 require full unaligned access support but does not
  /// specify which component of the system provides it. Hardware, software, and
  /// hybrid implementations are all valid.
  bool systemSupportsUnalignedAccess() const {
    return hasMips32r6() && !StrictAlign;
  }
 
  // Set helper classes
  void setHelperClassesMips16();
  void setHelperClassesMipsSE();
 
  const SelectionDAGTargetInfo *getSelectionDAGInfo() const override;
 
  const MipsInstrInfo *getInstrInfo() const override { return InstrInfo.get(); }
  const TargetFrameLowering *getFrameLowering() const override {
    return FrameLowering.get();
  }
  const MipsRegisterInfo *getRegisterInfo() const override {
    return &InstrInfo->getRegisterInfo();
  }
  const MipsTargetLowering *getTargetLowering() const override {
    return TLInfo.get();
  }
  const InstrItineraryData *getInstrItineraryData() const override {
    return &InstrItins;
  }
 
  void initLibcallLoweringInfo(LibcallLoweringInfo &Info) const override;
 
protected:
  // GlobalISel related APIs.
  std::unique_ptr<CallLowering> CallLoweringInfo;
  std::unique_ptr<LegalizerInfo> Legalizer;
  std::unique_ptr<RegisterBankInfo> RegBankInfo;
  std::unique_ptr<InstructionSelector> InstSelector;
 
public:
  const CallLowering *getCallLowering() const override;
  const LegalizerInfo *getLegalizerInfo() const override;
  const RegisterBankInfo *getRegBankInfo() const override;
  InstructionSelector *getInstructionSelector() const override;
};
} // End llvm namespace
 
#endif