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      1 //===-- MipsSubtarget.cpp - Mips Subtarget Information --------------------===//
      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 implements the Mips specific subclass of TargetSubtargetInfo.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #include "MipsMachineFunction.h"
     15 #include "Mips.h"
     16 #include "MipsRegisterInfo.h"
     17 #include "MipsSubtarget.h"
     18 #include "MipsTargetMachine.h"
     19 #include "llvm/IR/Attributes.h"
     20 #include "llvm/IR/Function.h"
     21 #include "llvm/Support/CommandLine.h"
     22 #include "llvm/Support/Debug.h"
     23 #include "llvm/Support/TargetRegistry.h"
     24 #include "llvm/Support/raw_ostream.h"
     25 
     26 using namespace llvm;
     27 
     28 #define DEBUG_TYPE "mips-subtarget"
     29 
     30 #define GET_SUBTARGETINFO_TARGET_DESC
     31 #define GET_SUBTARGETINFO_CTOR
     32 #include "MipsGenSubtargetInfo.inc"
     33 
     34 // FIXME: Maybe this should be on by default when Mips16 is specified
     35 //
     36 static cl::opt<bool>
     37     Mixed16_32("mips-mixed-16-32", cl::init(false),
     38                cl::desc("Allow for a mixture of Mips16 "
     39                         "and Mips32 code in a single output file"),
     40                cl::Hidden);
     41 
     42 static cl::opt<bool> Mips_Os16("mips-os16", cl::init(false),
     43                                cl::desc("Compile all functions that don't use "
     44                                         "floating point as Mips 16"),
     45                                cl::Hidden);
     46 
     47 static cl::opt<bool> Mips16HardFloat("mips16-hard-float", cl::NotHidden,
     48                                      cl::desc("Enable mips16 hard float."),
     49                                      cl::init(false));
     50 
     51 static cl::opt<bool>
     52     Mips16ConstantIslands("mips16-constant-islands", cl::NotHidden,
     53                           cl::desc("Enable mips16 constant islands."),
     54                           cl::init(true));
     55 
     56 static cl::opt<bool>
     57     GPOpt("mgpopt", cl::Hidden,
     58           cl::desc("Enable gp-relative addressing of mips small data items"));
     59 
     60 void MipsSubtarget::anchor() { }
     61 
     62 MipsSubtarget::MipsSubtarget(const Triple &TT, const std::string &CPU,
     63                              const std::string &FS, bool little,
     64                              const MipsTargetMachine &TM)
     65     : MipsGenSubtargetInfo(TT, CPU, FS), MipsArchVersion(MipsDefault),
     66       IsLittle(little), IsSoftFloat(false), IsSingleFloat(false), IsFPXX(false),
     67       NoABICalls(false), IsFP64bit(false), UseOddSPReg(true),
     68       IsNaN2008bit(false), IsGP64bit(false), HasVFPU(false), HasCnMips(false),
     69       HasMips3_32(false), HasMips3_32r2(false), HasMips4_32(false),
     70       HasMips4_32r2(false), HasMips5_32r2(false), InMips16Mode(false),
     71       InMips16HardFloat(Mips16HardFloat), InMicroMipsMode(false), HasDSP(false),
     72       HasDSPR2(false), HasDSPR3(false), AllowMixed16_32(Mixed16_32 | Mips_Os16),
     73       Os16(Mips_Os16), HasMSA(false), UseTCCInDIV(false), HasEVA(false), TM(TM),
     74       TargetTriple(TT), TSInfo(),
     75       InstrInfo(
     76           MipsInstrInfo::create(initializeSubtargetDependencies(CPU, FS, TM))),
     77       FrameLowering(MipsFrameLowering::create(*this)),
     78       TLInfo(MipsTargetLowering::create(TM, *this)) {
     79 
     80   PreviousInMips16Mode = InMips16Mode;
     81 
     82   if (MipsArchVersion == MipsDefault)
     83     MipsArchVersion = Mips32;
     84 
     85   // Don't even attempt to generate code for MIPS-I and MIPS-V. They have not
     86   // been tested and currently exist for the integrated assembler only.
     87   if (MipsArchVersion == Mips1)
     88     report_fatal_error("Code generation for MIPS-I is not implemented", false);
     89   if (MipsArchVersion == Mips5)
     90     report_fatal_error("Code generation for MIPS-V is not implemented", false);
     91 
     92   // Check if Architecture and ABI are compatible.
     93   assert(((!isGP64bit() && isABI_O32()) ||
     94           (isGP64bit() && (isABI_N32() || isABI_N64()))) &&
     95          "Invalid  Arch & ABI pair.");
     96 
     97   if (hasMSA() && !isFP64bit())
     98     report_fatal_error("MSA requires a 64-bit FPU register file (FR=1 mode). "
     99                        "See -mattr=+fp64.",
    100                        false);
    101 
    102   if (!isABI_O32() && !useOddSPReg())
    103     report_fatal_error("-mattr=+nooddspreg requires the O32 ABI.", false);
    104 
    105   if (IsFPXX && (isABI_N32() || isABI_N64()))
    106     report_fatal_error("FPXX is not permitted for the N32/N64 ABI's.", false);
    107 
    108   if (hasMips32r6()) {
    109     StringRef ISA = hasMips64r6() ? "MIPS64r6" : "MIPS32r6";
    110 
    111     assert(isFP64bit());
    112     assert(isNaN2008());
    113     if (hasDSP())
    114       report_fatal_error(ISA + " is not compatible with the DSP ASE", false);
    115   }
    116 
    117   if (NoABICalls && TM.isPositionIndependent())
    118     report_fatal_error("position-independent code requires '-mabicalls'");
    119 
    120   // Set UseSmallSection.
    121   UseSmallSection = GPOpt;
    122   if (!NoABICalls && GPOpt) {
    123     errs() << "warning: cannot use small-data accesses for '-mabicalls'"
    124            << "\n";
    125     UseSmallSection = false;
    126   }
    127 }
    128 
    129 bool MipsSubtarget::isPositionIndependent() const {
    130   return TM.isPositionIndependent();
    131 }
    132 
    133 /// This overrides the PostRAScheduler bit in the SchedModel for any CPU.
    134 bool MipsSubtarget::enablePostRAScheduler() const { return true; }
    135 
    136 void MipsSubtarget::getCriticalPathRCs(RegClassVector &CriticalPathRCs) const {
    137   CriticalPathRCs.clear();
    138   CriticalPathRCs.push_back(isGP64bit() ?
    139                             &Mips::GPR64RegClass : &Mips::GPR32RegClass);
    140 }
    141 
    142 CodeGenOpt::Level MipsSubtarget::getOptLevelToEnablePostRAScheduler() const {
    143   return CodeGenOpt::Aggressive;
    144 }
    145 
    146 MipsSubtarget &
    147 MipsSubtarget::initializeSubtargetDependencies(StringRef CPU, StringRef FS,
    148                                                const TargetMachine &TM) {
    149   std::string CPUName = MIPS_MC::selectMipsCPU(TM.getTargetTriple(), CPU);
    150 
    151   // Parse features string.
    152   ParseSubtargetFeatures(CPUName, FS);
    153   // Initialize scheduling itinerary for the specified CPU.
    154   InstrItins = getInstrItineraryForCPU(CPUName);
    155 
    156   if (InMips16Mode && !IsSoftFloat)
    157     InMips16HardFloat = true;
    158 
    159   return *this;
    160 }
    161 
    162 bool MipsSubtarget::useConstantIslands() {
    163   DEBUG(dbgs() << "use constant islands " << Mips16ConstantIslands << "\n");
    164   return Mips16ConstantIslands;
    165 }
    166 
    167 Reloc::Model MipsSubtarget::getRelocationModel() const {
    168   return TM.getRelocationModel();
    169 }
    170 
    171 bool MipsSubtarget::isABI_N64() const { return getABI().IsN64(); }
    172 bool MipsSubtarget::isABI_N32() const { return getABI().IsN32(); }
    173 bool MipsSubtarget::isABI_O32() const { return getABI().IsO32(); }
    174 const MipsABIInfo &MipsSubtarget::getABI() const { return TM.getABI(); }
    175