Esempio n. 1
0
//
// runMCDesc - Print out MC register descriptions.
//
void
RegisterInfoEmitter::runMCDesc(raw_ostream &OS, CodeGenTarget &Target,
                               CodeGenRegBank &RegBank) {
  emitSourceFileHeader("MC Register Information", OS);

  OS << "\n#ifdef GET_REGINFO_MC_DESC\n";
  OS << "#undef GET_REGINFO_MC_DESC\n";

  const std::vector<CodeGenRegister*> &Regs = RegBank.getRegisters();

  // The lists of sub-registers, super-registers, and overlaps all go in the
  // same array. That allows us to share suffixes.
  typedef std::vector<const CodeGenRegister*> RegVec;

  // Differentially encoded lists.
  SequenceToOffsetTable<DiffVec> DiffSeqs;
  SmallVector<DiffVec, 4> SubRegLists(Regs.size());
  SmallVector<DiffVec, 4> SuperRegLists(Regs.size());
  SmallVector<DiffVec, 4> OverlapLists(Regs.size());
  SmallVector<DiffVec, 4> RegUnitLists(Regs.size());
  SmallVector<unsigned, 4> RegUnitInitScale(Regs.size());

  // Keep track of sub-register names as well. These are not differentially
  // encoded.
  typedef SmallVector<const CodeGenSubRegIndex*, 4> SubRegIdxVec;
  SequenceToOffsetTable<SubRegIdxVec> SubRegIdxSeqs;
  SmallVector<SubRegIdxVec, 4> SubRegIdxLists(Regs.size());

  SequenceToOffsetTable<std::string> RegStrings;

  // Precompute register lists for the SequenceToOffsetTable.
  for (unsigned i = 0, e = Regs.size(); i != e; ++i) {
    const CodeGenRegister *Reg = Regs[i];

    RegStrings.add(Reg->getName());

    // Compute the ordered sub-register list.
    SetVector<const CodeGenRegister*> SR;
    Reg->addSubRegsPreOrder(SR, RegBank);
    diffEncode(SubRegLists[i], Reg->EnumValue, SR.begin(), SR.end());
    DiffSeqs.add(SubRegLists[i]);

    // Compute the corresponding sub-register indexes.
    SubRegIdxVec &SRIs = SubRegIdxLists[i];
    for (unsigned j = 0, je = SR.size(); j != je; ++j)
      SRIs.push_back(Reg->getSubRegIndex(SR[j]));
    SubRegIdxSeqs.add(SRIs);

    // Super-registers are already computed.
    const RegVec &SuperRegList = Reg->getSuperRegs();
    diffEncode(SuperRegLists[i], Reg->EnumValue,
               SuperRegList.begin(), SuperRegList.end());
    DiffSeqs.add(SuperRegLists[i]);

    // The list of overlaps doesn't need to have any particular order, and Reg
    // itself must be omitted.
    DiffVec &OverlapList = OverlapLists[i];
    CodeGenRegister::Set OSet;
    Reg->computeOverlaps(OSet, RegBank);
    OSet.erase(Reg);
    diffEncode(OverlapList, Reg->EnumValue, OSet.begin(), OSet.end());
    DiffSeqs.add(OverlapList);

    // Differentially encode the register unit list, seeded by register number.
    // First compute a scale factor that allows more diff-lists to be reused:
    //
    //   D0 -> (S0, S1)
    //   D1 -> (S2, S3)
    //
    // A scale factor of 2 allows D0 and D1 to share a diff-list. The initial
    // value for the differential decoder is the register number multiplied by
    // the scale.
    //
    // Check the neighboring registers for arithmetic progressions.
    unsigned ScaleA = ~0u, ScaleB = ~0u;
    ArrayRef<unsigned> RUs = Reg->getNativeRegUnits();
    if (i > 0 && Regs[i-1]->getNativeRegUnits().size() == RUs.size())
      ScaleB = RUs.front() - Regs[i-1]->getNativeRegUnits().front();
    if (i+1 != Regs.size() &&
        Regs[i+1]->getNativeRegUnits().size() == RUs.size())
      ScaleA = Regs[i+1]->getNativeRegUnits().front() - RUs.front();
    unsigned Scale = std::min(ScaleB, ScaleA);
    // Default the scale to 0 if it can't be encoded in 4 bits.
    if (Scale >= 16)
      Scale = 0;
    RegUnitInitScale[i] = Scale;
    DiffSeqs.add(diffEncode(RegUnitLists[i], Scale * Reg->EnumValue, RUs));
  }

  // Compute the final layout of the sequence table.
  DiffSeqs.layout();
  SubRegIdxSeqs.layout();

  OS << "namespace llvm {\n\n";

  const std::string &TargetName = Target.getName();

  // Emit the shared table of differential lists.
  OS << "extern const MCPhysReg " << TargetName << "RegDiffLists[] = {\n";
  DiffSeqs.emit(OS, printDiff16);
  OS << "};\n\n";

  // Emit the table of sub-register indexes.
  OS << "extern const uint16_t " << TargetName << "SubRegIdxLists[] = {\n";
  SubRegIdxSeqs.emit(OS, printSubRegIndex);
  OS << "};\n\n";

  // Emit the string table.
  RegStrings.layout();
  OS << "extern const char " << TargetName << "RegStrings[] = {\n";
  RegStrings.emit(OS, printChar);
  OS << "};\n\n";

  OS << "extern const MCRegisterDesc " << TargetName
     << "RegDesc[] = { // Descriptors\n";
  OS << "  { " << RegStrings.get("") << ", 0, 0, 0, 0, 0 },\n";

  // Emit the register descriptors now.
  for (unsigned i = 0, e = Regs.size(); i != e; ++i) {
    const CodeGenRegister *Reg = Regs[i];
    OS << "  { " << RegStrings.get(Reg->getName()) << ", "
       << DiffSeqs.get(OverlapLists[i]) << ", "
       << DiffSeqs.get(SubRegLists[i]) << ", "
       << DiffSeqs.get(SuperRegLists[i]) << ", "
       << SubRegIdxSeqs.get(SubRegIdxLists[i]) << ", "
       << (DiffSeqs.get(RegUnitLists[i])*16 + RegUnitInitScale[i]) << " },\n";
  }
  OS << "};\n\n";      // End of register descriptors...

  // Emit the table of register unit roots. Each regunit has one or two root
  // registers.
  OS << "extern const uint16_t " << TargetName << "RegUnitRoots[][2] = {\n";
  for (unsigned i = 0, e = RegBank.getNumNativeRegUnits(); i != e; ++i) {
    ArrayRef<const CodeGenRegister*> Roots = RegBank.getRegUnit(i).getRoots();
    assert(!Roots.empty() && "All regunits must have a root register.");
    assert(Roots.size() <= 2 && "More than two roots not supported yet.");
    OS << "  { " << getQualifiedName(Roots.front()->TheDef);
    for (unsigned r = 1; r != Roots.size(); ++r)
      OS << ", " << getQualifiedName(Roots[r]->TheDef);
    OS << " },\n";
  }
  OS << "};\n\n";

  ArrayRef<CodeGenRegisterClass*> RegisterClasses = RegBank.getRegClasses();

  // Loop over all of the register classes... emitting each one.
  OS << "namespace {     // Register classes...\n";

  // Emit the register enum value arrays for each RegisterClass
  for (unsigned rc = 0, e = RegisterClasses.size(); rc != e; ++rc) {
    const CodeGenRegisterClass &RC = *RegisterClasses[rc];
    ArrayRef<Record*> Order = RC.getOrder();

    // Give the register class a legal C name if it's anonymous.
    std::string Name = RC.getName();

    // Emit the register list now.
    OS << "  // " << Name << " Register Class...\n"
       << "  const uint16_t " << Name
       << "[] = {\n    ";
    for (unsigned i = 0, e = Order.size(); i != e; ++i) {
      Record *Reg = Order[i];
      OS << getQualifiedName(Reg) << ", ";
    }
    OS << "\n  };\n\n";

    OS << "  // " << Name << " Bit set.\n"
       << "  const uint8_t " << Name
       << "Bits[] = {\n    ";
    BitVectorEmitter BVE;
    for (unsigned i = 0, e = Order.size(); i != e; ++i) {
      Record *Reg = Order[i];
      BVE.add(Target.getRegBank().getReg(Reg)->EnumValue);
    }
    BVE.print(OS);
    OS << "\n  };\n\n";

  }
  OS << "}\n\n";

  OS << "extern const MCRegisterClass " << TargetName
     << "MCRegisterClasses[] = {\n";

  for (unsigned rc = 0, e = RegisterClasses.size(); rc != e; ++rc) {
    const CodeGenRegisterClass &RC = *RegisterClasses[rc];

    // Asserts to make sure values will fit in table assuming types from
    // MCRegisterInfo.h
    assert((RC.SpillSize/8) <= 0xffff && "SpillSize too large.");
    assert((RC.SpillAlignment/8) <= 0xffff && "SpillAlignment too large.");
    assert(RC.CopyCost >= -128 && RC.CopyCost <= 127 && "Copy cost too large.");

    OS << "  { " << '\"' << RC.getName() << "\", "
       << RC.getName() << ", " << RC.getName() << "Bits, "
       << RC.getOrder().size() << ", sizeof(" << RC.getName() << "Bits), "
       << RC.getQualifiedName() + "RegClassID" << ", "
       << RC.SpillSize/8 << ", "
       << RC.SpillAlignment/8 << ", "
       << RC.CopyCost << ", "
       << RC.Allocatable << " },\n";
  }

  OS << "};\n\n";

  ArrayRef<CodeGenSubRegIndex*> SubRegIndices = RegBank.getSubRegIndices();

  EmitRegMappingTables(OS, Regs, false);

  // Emit Reg encoding table
  OS << "extern const uint16_t " << TargetName;
  OS << "RegEncodingTable[] = {\n";
  // Add entry for NoRegister
  OS << "  0,\n";
  for (unsigned i = 0, e = Regs.size(); i != e; ++i) {
    Record *Reg = Regs[i]->TheDef;
    BitsInit *BI = Reg->getValueAsBitsInit("HWEncoding");
    uint64_t Value = 0;
    for (unsigned b = 0, be = BI->getNumBits(); b != be; ++b) {
      if (BitInit *B = dyn_cast<BitInit>(BI->getBit(b)))
      Value |= (uint64_t)B->getValue() << b;
    }
    OS << "  " << Value << ",\n";
  }
  OS << "};\n";       // End of HW encoding table

  // MCRegisterInfo initialization routine.
  OS << "static inline void Init" << TargetName
     << "MCRegisterInfo(MCRegisterInfo *RI, unsigned RA, "
     << "unsigned DwarfFlavour = 0, unsigned EHFlavour = 0, unsigned PC = 0) {\n"
     << "  RI->InitMCRegisterInfo(" << TargetName << "RegDesc, "
     << Regs.size()+1 << ", RA, PC, " << TargetName << "MCRegisterClasses, "
     << RegisterClasses.size() << ", "
     << TargetName << "RegUnitRoots, "
     << RegBank.getNumNativeRegUnits() << ", "
     << TargetName << "RegDiffLists, "
     << TargetName << "RegStrings, "
     << TargetName << "SubRegIdxLists, "
     << (SubRegIndices.size() + 1) << ",\n"
     << "  " << TargetName << "RegEncodingTable);\n\n";

  EmitRegMapping(OS, Regs, false);

  OS << "}\n\n";

  OS << "} // End llvm namespace \n";
  OS << "#endif // GET_REGINFO_MC_DESC\n\n";
}