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      1 //===-- PPCMCTargetDesc.cpp - PowerPC Target Descriptions -----------------===//
      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 provides PowerPC specific target descriptions.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #include "PPCMCTargetDesc.h"
     15 #include "InstPrinter/PPCInstPrinter.h"
     16 #include "PPCMCAsmInfo.h"
     17 #include "PPCTargetStreamer.h"
     18 #include "llvm/MC/MCCodeGenInfo.h"
     19 #include "llvm/MC/MCContext.h"
     20 #include "llvm/MC/MCELFStreamer.h"
     21 #include "llvm/MC/MCExpr.h"
     22 #include "llvm/MC/MCInstrInfo.h"
     23 #include "llvm/MC/MCRegisterInfo.h"
     24 #include "llvm/MC/MCStreamer.h"
     25 #include "llvm/MC/MCSubtargetInfo.h"
     26 #include "llvm/MC/MCSymbolELF.h"
     27 #include "llvm/MC/MachineLocation.h"
     28 #include "llvm/Support/ELF.h"
     29 #include "llvm/Support/ErrorHandling.h"
     30 #include "llvm/Support/FormattedStream.h"
     31 #include "llvm/Support/TargetRegistry.h"
     32 
     33 using namespace llvm;
     34 
     35 #define GET_INSTRINFO_MC_DESC
     36 #include "PPCGenInstrInfo.inc"
     37 
     38 #define GET_SUBTARGETINFO_MC_DESC
     39 #include "PPCGenSubtargetInfo.inc"
     40 
     41 #define GET_REGINFO_MC_DESC
     42 #include "PPCGenRegisterInfo.inc"
     43 
     44 // Pin the vtable to this file.
     45 PPCTargetStreamer::~PPCTargetStreamer() {}
     46 PPCTargetStreamer::PPCTargetStreamer(MCStreamer &S) : MCTargetStreamer(S) {}
     47 
     48 static MCInstrInfo *createPPCMCInstrInfo() {
     49   MCInstrInfo *X = new MCInstrInfo();
     50   InitPPCMCInstrInfo(X);
     51   return X;
     52 }
     53 
     54 static MCRegisterInfo *createPPCMCRegisterInfo(const Triple &TT) {
     55   bool isPPC64 =
     56       (TT.getArch() == Triple::ppc64 || TT.getArch() == Triple::ppc64le);
     57   unsigned Flavour = isPPC64 ? 0 : 1;
     58   unsigned RA = isPPC64 ? PPC::LR8 : PPC::LR;
     59 
     60   MCRegisterInfo *X = new MCRegisterInfo();
     61   InitPPCMCRegisterInfo(X, RA, Flavour, Flavour);
     62   return X;
     63 }
     64 
     65 static MCSubtargetInfo *createPPCMCSubtargetInfo(const Triple &TT,
     66                                                  StringRef CPU, StringRef FS) {
     67   return createPPCMCSubtargetInfoImpl(TT, CPU, FS);
     68 }
     69 
     70 static MCAsmInfo *createPPCMCAsmInfo(const MCRegisterInfo &MRI,
     71                                      const Triple &TheTriple) {
     72   bool isPPC64 = (TheTriple.getArch() == Triple::ppc64 ||
     73                   TheTriple.getArch() == Triple::ppc64le);
     74 
     75   MCAsmInfo *MAI;
     76   if (TheTriple.isOSDarwin())
     77     MAI = new PPCMCAsmInfoDarwin(isPPC64, TheTriple);
     78   else
     79     MAI = new PPCELFMCAsmInfo(isPPC64, TheTriple);
     80 
     81   // Initial state of the frame pointer is R1.
     82   unsigned Reg = isPPC64 ? PPC::X1 : PPC::R1;
     83   MCCFIInstruction Inst =
     84       MCCFIInstruction::createDefCfa(nullptr, MRI.getDwarfRegNum(Reg, true), 0);
     85   MAI->addInitialFrameState(Inst);
     86 
     87   return MAI;
     88 }
     89 
     90 static MCCodeGenInfo *createPPCMCCodeGenInfo(const Triple &TT, Reloc::Model RM,
     91                                              CodeModel::Model CM,
     92                                              CodeGenOpt::Level OL) {
     93   MCCodeGenInfo *X = new MCCodeGenInfo();
     94 
     95   if (RM == Reloc::Default) {
     96     if (TT.isOSDarwin())
     97       RM = Reloc::DynamicNoPIC;
     98     else
     99       RM = Reloc::Static;
    100   }
    101   if (CM == CodeModel::Default) {
    102     if (!TT.isOSDarwin() &&
    103         (TT.getArch() == Triple::ppc64 || TT.getArch() == Triple::ppc64le))
    104       CM = CodeModel::Medium;
    105   }
    106   X->initMCCodeGenInfo(RM, CM, OL);
    107   return X;
    108 }
    109 
    110 namespace {
    111 class PPCTargetAsmStreamer : public PPCTargetStreamer {
    112   formatted_raw_ostream &OS;
    113 
    114 public:
    115   PPCTargetAsmStreamer(MCStreamer &S, formatted_raw_ostream &OS)
    116       : PPCTargetStreamer(S), OS(OS) {}
    117   void emitTCEntry(const MCSymbol &S) override {
    118     OS << "\t.tc ";
    119     OS << S.getName();
    120     OS << "[TC],";
    121     OS << S.getName();
    122     OS << '\n';
    123   }
    124   void emitMachine(StringRef CPU) override {
    125     OS << "\t.machine " << CPU << '\n';
    126   }
    127   void emitAbiVersion(int AbiVersion) override {
    128     OS << "\t.abiversion " << AbiVersion << '\n';
    129   }
    130   void emitLocalEntry(MCSymbolELF *S, const MCExpr *LocalOffset) override {
    131     const MCAsmInfo *MAI = Streamer.getContext().getAsmInfo();
    132 
    133     OS << "\t.localentry\t";
    134     S->print(OS, MAI);
    135     OS << ", ";
    136     LocalOffset->print(OS, MAI);
    137     OS << '\n';
    138   }
    139 };
    140 
    141 class PPCTargetELFStreamer : public PPCTargetStreamer {
    142 public:
    143   PPCTargetELFStreamer(MCStreamer &S) : PPCTargetStreamer(S) {}
    144   MCELFStreamer &getStreamer() {
    145     return static_cast<MCELFStreamer &>(Streamer);
    146   }
    147   void emitTCEntry(const MCSymbol &S) override {
    148     // Creates a R_PPC64_TOC relocation
    149     Streamer.EmitValueToAlignment(8);
    150     Streamer.EmitSymbolValue(&S, 8);
    151   }
    152   void emitMachine(StringRef CPU) override {
    153     // FIXME: Is there anything to do in here or does this directive only
    154     // limit the parser?
    155   }
    156   void emitAbiVersion(int AbiVersion) override {
    157     MCAssembler &MCA = getStreamer().getAssembler();
    158     unsigned Flags = MCA.getELFHeaderEFlags();
    159     Flags &= ~ELF::EF_PPC64_ABI;
    160     Flags |= (AbiVersion & ELF::EF_PPC64_ABI);
    161     MCA.setELFHeaderEFlags(Flags);
    162   }
    163   void emitLocalEntry(MCSymbolELF *S, const MCExpr *LocalOffset) override {
    164     MCAssembler &MCA = getStreamer().getAssembler();
    165 
    166     int64_t Res;
    167     if (!LocalOffset->evaluateAsAbsolute(Res, MCA))
    168       report_fatal_error(".localentry expression must be absolute.");
    169 
    170     unsigned Encoded = ELF::encodePPC64LocalEntryOffset(Res);
    171     if (Res != ELF::decodePPC64LocalEntryOffset(Encoded))
    172       report_fatal_error(".localentry expression cannot be encoded.");
    173 
    174     unsigned Other = S->getOther();
    175     Other &= ~ELF::STO_PPC64_LOCAL_MASK;
    176     Other |= Encoded;
    177     S->setOther(Other);
    178 
    179     // For GAS compatibility, unless we already saw a .abiversion directive,
    180     // set e_flags to indicate ELFv2 ABI.
    181     unsigned Flags = MCA.getELFHeaderEFlags();
    182     if ((Flags & ELF::EF_PPC64_ABI) == 0)
    183       MCA.setELFHeaderEFlags(Flags | 2);
    184   }
    185   void emitAssignment(MCSymbol *S, const MCExpr *Value) override {
    186     auto *Symbol = cast<MCSymbolELF>(S);
    187     // When encoding an assignment to set symbol A to symbol B, also copy
    188     // the st_other bits encoding the local entry point offset.
    189     if (Value->getKind() != MCExpr::SymbolRef)
    190       return;
    191     const auto &RhsSym = cast<MCSymbolELF>(
    192         static_cast<const MCSymbolRefExpr *>(Value)->getSymbol());
    193     unsigned Other = Symbol->getOther();
    194     Other &= ~ELF::STO_PPC64_LOCAL_MASK;
    195     Other |= RhsSym.getOther() & ELF::STO_PPC64_LOCAL_MASK;
    196     Symbol->setOther(Other);
    197   }
    198 };
    199 
    200 class PPCTargetMachOStreamer : public PPCTargetStreamer {
    201 public:
    202   PPCTargetMachOStreamer(MCStreamer &S) : PPCTargetStreamer(S) {}
    203   void emitTCEntry(const MCSymbol &S) override {
    204     llvm_unreachable("Unknown pseudo-op: .tc");
    205   }
    206   void emitMachine(StringRef CPU) override {
    207     // FIXME: We should update the CPUType, CPUSubType in the Object file if
    208     // the new values are different from the defaults.
    209   }
    210   void emitAbiVersion(int AbiVersion) override {
    211     llvm_unreachable("Unknown pseudo-op: .abiversion");
    212   }
    213   void emitLocalEntry(MCSymbolELF *S, const MCExpr *LocalOffset) override {
    214     llvm_unreachable("Unknown pseudo-op: .localentry");
    215   }
    216 };
    217 }
    218 
    219 static MCTargetStreamer *createAsmTargetStreamer(MCStreamer &S,
    220                                                  formatted_raw_ostream &OS,
    221                                                  MCInstPrinter *InstPrint,
    222                                                  bool isVerboseAsm) {
    223   return new PPCTargetAsmStreamer(S, OS);
    224 }
    225 
    226 static MCTargetStreamer *
    227 createObjectTargetStreamer(MCStreamer &S, const MCSubtargetInfo &STI) {
    228   const Triple &TT = STI.getTargetTriple();
    229   if (TT.isOSBinFormatELF())
    230     return new PPCTargetELFStreamer(S);
    231   return new PPCTargetMachOStreamer(S);
    232 }
    233 
    234 static MCInstPrinter *createPPCMCInstPrinter(const Triple &T,
    235                                              unsigned SyntaxVariant,
    236                                              const MCAsmInfo &MAI,
    237                                              const MCInstrInfo &MII,
    238                                              const MCRegisterInfo &MRI) {
    239   return new PPCInstPrinter(MAI, MII, MRI, T.isOSDarwin());
    240 }
    241 
    242 extern "C" void LLVMInitializePowerPCTargetMC() {
    243   for (Target *T : {&ThePPC32Target, &ThePPC64Target, &ThePPC64LETarget}) {
    244     // Register the MC asm info.
    245     RegisterMCAsmInfoFn C(*T, createPPCMCAsmInfo);
    246 
    247     // Register the MC codegen info.
    248     TargetRegistry::RegisterMCCodeGenInfo(*T, createPPCMCCodeGenInfo);
    249 
    250     // Register the MC instruction info.
    251     TargetRegistry::RegisterMCInstrInfo(*T, createPPCMCInstrInfo);
    252 
    253     // Register the MC register info.
    254     TargetRegistry::RegisterMCRegInfo(*T, createPPCMCRegisterInfo);
    255 
    256     // Register the MC subtarget info.
    257     TargetRegistry::RegisterMCSubtargetInfo(*T, createPPCMCSubtargetInfo);
    258 
    259     // Register the MC Code Emitter
    260     TargetRegistry::RegisterMCCodeEmitter(*T, createPPCMCCodeEmitter);
    261 
    262     // Register the asm backend.
    263     TargetRegistry::RegisterMCAsmBackend(*T, createPPCAsmBackend);
    264 
    265     // Register the object target streamer.
    266     TargetRegistry::RegisterObjectTargetStreamer(*T,
    267                                                  createObjectTargetStreamer);
    268 
    269     // Register the asm target streamer.
    270     TargetRegistry::RegisterAsmTargetStreamer(*T, createAsmTargetStreamer);
    271 
    272     // Register the MCInstPrinter.
    273     TargetRegistry::RegisterMCInstPrinter(*T, createPPCMCInstPrinter);
    274   }
    275 }
    276