AsmPrinter.cpp

    case 2: Kind = SectionKind::getReadOnlyWithRel(); break;
    case 1:
      Kind = SectionKind::getReadOnlyWithRelLocal();
      break;
    case 0:
    switch (TM.getDataLayout()->getTypeAllocSize(CPE.getType())) {
    case 4:  Kind = SectionKind::getMergeableConst4(); break;
    case 8:  Kind = SectionKind::getMergeableConst8(); break;
    case 16: Kind = SectionKind::getMergeableConst16();break;
    default: Kind = SectionKind::getMergeableConst(); break;
    }
    }

    const MCSection *S = getObjFileLowering().getSectionForConstant(Kind);

    // The number of sections are small, just do a linear search from the
    // last section to the first.
    bool Found = false;
    unsigned SecIdx = CPSections.size();
    while (SecIdx != 0) {
      if (CPSections[--SecIdx].S == S) {
        Found = true;
        break;
      }
    }
    if (!Found) {
      SecIdx = CPSections.size();
      CPSections.push_back(SectionCPs(S, Align));
    }

    if (Align > CPSections[SecIdx].Alignment)
      CPSections[SecIdx].Alignment = Align;
    CPSections[SecIdx].CPEs.push_back(i);
  }

  // Now print stuff into the calculated sections.
  for (unsigned i = 0, e = CPSections.size(); i != e; ++i) {
    OutStreamer.SwitchSection(CPSections[i].S);
    EmitAlignment(Log2_32(CPSections[i].Alignment));

    unsigned Offset = 0;
    for (unsigned j = 0, ee = CPSections[i].CPEs.size(); j != ee; ++j) {
      unsigned CPI = CPSections[i].CPEs[j];
      MachineConstantPoolEntry CPE = CP[CPI];

      // Emit inter-object padding for alignment.
      unsigned AlignMask = CPE.getAlignment() - 1;
      unsigned NewOffset = (Offset + AlignMask) & ~AlignMask;
      OutStreamer.EmitZeros(NewOffset - Offset);

      Type *Ty = CPE.getType();
      Offset = NewOffset + TM.getDataLayout()->getTypeAllocSize(Ty);
      OutStreamer.EmitLabel(GetCPISymbol(CPI));

      if (CPE.isMachineConstantPoolEntry())
        EmitMachineConstantPoolValue(CPE.Val.MachineCPVal);
      else
        EmitGlobalConstant(CPE.Val.ConstVal);
    }
  }
}

/// EmitJumpTableInfo - Print assembly representations of the jump tables used
/// by the current function to the current output stream.
///
void AsmPrinter::EmitJumpTableInfo() {
  const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
  if (MJTI == 0) return;
  if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_Inline) return;
  const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
  if (JT.empty()) return;

  // Pick the directive to use to print the jump table entries, and switch to
  // the appropriate section.
  const Function *F = MF->getFunction();
  bool JTInDiffSection = false;
  if (// In PIC mode, we need to emit the jump table to the same section as the
      // function body itself, otherwise the label differences won't make sense.
      // FIXME: Need a better predicate for this: what about custom entries?
      MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 ||
      // We should also do if the section name is NULL or function is declared
      // in discardable section
      // FIXME: this isn't the right predicate, should be based on the MCSection
      // for the function.
      F->isWeakForLinker()) {
    OutStreamer.SwitchSection(getObjFileLowering().SectionForGlobal(F,Mang,TM));
  } else {
    // Otherwise, drop it in the readonly section.
    const MCSection *ReadOnlySection =
      getObjFileLowering().getSectionForConstant(SectionKind::getReadOnly());
    OutStreamer.SwitchSection(ReadOnlySection);
    JTInDiffSection = true;
  }

  EmitAlignment(Log2_32(MJTI->getEntryAlignment(*TM.getDataLayout())));

  // Jump tables in code sections are marked with a data_region directive
  // where that's supported.
  if (!JTInDiffSection)
    OutStreamer.EmitDataRegion(MCDR_DataRegionJT32);

  for (unsigned JTI = 0, e = JT.size(); JTI != e; ++JTI) {
    const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs;

    // If this jump table was deleted, ignore it.
    if (JTBBs.empty()) continue;

    // For the EK_LabelDifference32 entry, if the target supports .set, emit a
    // .set directive for each unique entry.  This reduces the number of
    // relocations the assembler will generate for the jump table.
    if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 &&
        MAI->hasSetDirective()) {
      SmallPtrSet<const MachineBasicBlock*, 16> EmittedSets;
      const TargetLowering *TLI = TM.getTargetLowering();
      const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF,JTI,OutContext);
      for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii) {
        const MachineBasicBlock *MBB = JTBBs[ii];
        if (!EmittedSets.insert(MBB)) continue;

        // .set LJTSet, LBB32-base
        const MCExpr *LHS =
          MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext);
        OutStreamer.EmitAssignment(GetJTSetSymbol(JTI, MBB->getNumber()),
                                MCBinaryExpr::CreateSub(LHS, Base, OutContext));
      }
    }

    // On some targets (e.g. Darwin) we want to emit two consecutive labels
    // before each jump table.  The first label is never referenced, but tells
    // the assembler and linker the extents of the jump table object.  The
    // second label is actually referenced by the code.
    if (JTInDiffSection && MAI->getLinkerPrivateGlobalPrefix()[0])
      // FIXME: This doesn't have to have any specific name, just any randomly
      // named and numbered 'l' label would work.  Simplify GetJTISymbol.
      OutStreamer.EmitLabel(GetJTISymbol(JTI, true));

    OutStreamer.EmitLabel(GetJTISymbol(JTI));

    for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii)
      EmitJumpTableEntry(MJTI, JTBBs[ii], JTI);
  }
  if (!JTInDiffSection)
    OutStreamer.EmitDataRegion(MCDR_DataRegionEnd);
}

/// EmitJumpTableEntry - Emit a jump table entry for the specified MBB to the
/// current stream.
void AsmPrinter::EmitJumpTableEntry(const MachineJumpTableInfo *MJTI,
                                    const MachineBasicBlock *MBB,
                                    unsigned UID) const {
  assert(MBB && MBB->getNumber() >= 0 && "Invalid basic block");
  const MCExpr *Value = 0;
  switch (MJTI->getEntryKind()) {
  case MachineJumpTableInfo::EK_Inline:
    llvm_unreachable("Cannot emit EK_Inline jump table entry");
  case MachineJumpTableInfo::EK_Custom32:
    Value = TM.getTargetLowering()->LowerCustomJumpTableEntry(MJTI, MBB, UID,
                                                              OutContext);
    break;
  case MachineJumpTableInfo::EK_BlockAddress:
    // EK_BlockAddress - Each entry is a plain address of block, e.g.:
    //     .word LBB123
    Value = MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext);
    break;
  case MachineJumpTableInfo::EK_GPRel32BlockAddress: {
    // EK_GPRel32BlockAddress - Each entry is an address of block, encoded
    // with a relocation as gp-relative, e.g.:
    //     .gprel32 LBB123
    MCSymbol *MBBSym = MBB->getSymbol();
    OutStreamer.EmitGPRel32Value(MCSymbolRefExpr::Create(MBBSym, OutContext));
    return;
  }

  case MachineJumpTableInfo::EK_GPRel64BlockAddress: {
    // EK_GPRel64BlockAddress - Each entry is an address of block, encoded
    // with a relocation as gp-relative, e.g.:
    //     .gpdword LBB123
    MCSymbol *MBBSym = MBB->getSymbol();
    OutStreamer.EmitGPRel64Value(MCSymbolRefExpr::Create(MBBSym, OutContext));
    return;
  }

  case MachineJumpTableInfo::EK_LabelDifference32: {
    // EK_LabelDifference32 - Each entry is the address of the block minus
    // the address of the jump table.  This is used for PIC jump tables where
    // gprel32 is not supported.  e.g.:
    //      .word LBB123 - LJTI1_2
    // If the .set directive is supported, this is emitted as:
    //      .set L4_5_set_123, LBB123 - LJTI1_2
    //      .word L4_5_set_123

    // If we have emitted set directives for the jump table entries, print
    // them rather than the entries themselves.  If we're emitting PIC, then
    // emit the table entries as differences between two text section labels.
    if (MAI->hasSetDirective()) {
      // If we used .set, reference the .set's symbol.
      Value = MCSymbolRefExpr::Create(GetJTSetSymbol(UID, MBB->getNumber()),
                                      OutContext);
      break;
    }
    // Otherwise, use the difference as the jump table entry.
    Value = MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext);
    const MCExpr *JTI = MCSymbolRefExpr::Create(GetJTISymbol(UID), OutContext);
    Value = MCBinaryExpr::CreateSub(Value, JTI, OutContext);
    break;
  }
  }

  assert(Value && "Unknown entry kind!");

  unsigned EntrySize = MJTI->getEntrySize(*TM.getDataLayout());
  OutStreamer.EmitValue(Value, EntrySize);
}


/// EmitSpecialLLVMGlobal - Check to see if the specified global is a
/// special global used by LLVM.  If so, emit it and return true, otherwise
/// do nothing and return false.
bool AsmPrinter::EmitSpecialLLVMGlobal(const GlobalVariable *GV) {
  if (GV->getName() == "llvm.used") {
    if (MAI->hasNoDeadStrip())    // No need to emit this at all.
      EmitLLVMUsedList(cast<ConstantArray>(GV->getInitializer()));
    return true;
  }

  // Ignore debug and non-emitted data.  This handles llvm.compiler.used.
  if (GV->getSection() == "llvm.metadata" ||
      GV->hasAvailableExternallyLinkage())
    return true;

  if (!GV->hasAppendingLinkage()) return false;

  assert(GV->hasInitializer() && "Not a special LLVM global!");

  if (GV->getName() == "llvm.global_ctors") {
    EmitXXStructorList(GV->getInitializer(), /* isCtor */ true);

    if (TM.getRelocationModel() == Reloc::Static &&
        MAI->hasStaticCtorDtorReferenceInStaticMode()) {
      StringRef Sym(".constructors_used");
      OutStreamer.EmitSymbolAttribute(OutContext.GetOrCreateSymbol(Sym),
                                      MCSA_Reference);
    }
    return true;
  }

  if (GV->getName() == "llvm.global_dtors") {
    EmitXXStructorList(GV->getInitializer(), /* isCtor */ false);

    if (TM.getRelocationModel() == Reloc::Static &&
        MAI->hasStaticCtorDtorReferenceInStaticMode()) {
      StringRef Sym(".destructors_used");
      OutStreamer.EmitSymbolAttribute(OutContext.GetOrCreateSymbol(Sym),
                                      MCSA_Reference);
    }
    return true;
  }

  if (GV->getName() == "llvm.tls_init_funcs") {
    EmitTLSInitFuncs(cast<ConstantArray>(GV->getInitializer()));
    return true;
  }

  return false;
}

/// EmitLLVMUsedList - For targets that define a MAI::UsedDirective, mark each
/// global in the specified llvm.used list for which emitUsedDirectiveFor
/// is true, as being used with this directive.
void AsmPrinter::EmitLLVMUsedList(const ConstantArray *InitList) {
  // Should be an array of 'i8*'.
  for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
    const GlobalValue *GV =
      dyn_cast<GlobalValue>(InitList->getOperand(i)->stripPointerCasts());
    if (GV && getObjFileLowering().shouldEmitUsedDirectiveFor(GV, Mang))
      OutStreamer.EmitSymbolAttribute(Mang->getSymbol(GV), MCSA_NoDeadStrip);
  }
}

typedef std::pair<unsigned, Constant*> Structor;

static bool priority_order(const Structor& lhs, const Structor& rhs) {
  return lhs.first < rhs.first;
}

/// EmitXXStructorList - Emit the ctor or dtor list taking into account the init
/// priority.
void AsmPrinter::EmitXXStructorList(const Constant *List, bool isCtor) {
  // Should be an array of '{ int, void ()* }' structs.  The first value is the
  // init priority.
  if (!isa<ConstantArray>(List)) return;

  // Sanity check the structors list.
  const ConstantArray *InitList = dyn_cast<ConstantArray>(List);
  if (!InitList) return; // Not an array!
  StructType *ETy = dyn_cast<StructType>(InitList->getType()->getElementType());
  if (!ETy || ETy->getNumElements() != 2) return; // Not an array of pairs!
  if (!isa<IntegerType>(ETy->getTypeAtIndex(0U)) ||
      !isa<PointerType>(ETy->getTypeAtIndex(1U))) return; // Not (int, ptr).

  // Gather the structors in a form that's convenient for sorting by priority.
  SmallVector<Structor, 8> Structors;
  for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
    ConstantStruct *CS = dyn_cast<ConstantStruct>(InitList->getOperand(i));
    if (!CS) continue; // Malformed.
    if (CS->getOperand(1)->isNullValue())
      break;  // Found a null terminator, skip the rest.
    ConstantInt *Priority = dyn_cast<ConstantInt>(CS->getOperand(0));
    if (!Priority) continue; // Malformed.
    Structors.push_back(std::make_pair(Priority->getLimitedValue(65535),
                                       CS->getOperand(1)));
  }

  // Emit the function pointers in the target-specific order
  const DataLayout *TD = TM.getDataLayout();
  unsigned Align = Log2_32(TD->getPointerPrefAlignment());
  std::stable_sort(Structors.begin(), Structors.end(), priority_order);
  for (unsigned i = 0, e = Structors.size(); i != e; ++i) {
    const MCSection *OutputSection =
      (isCtor ?
       getObjFileLowering().getStaticCtorSection(Structors[i].first) :
       getObjFileLowering().getStaticDtorSection(Structors[i].first));
    OutStreamer.SwitchSection(OutputSection);
    if (OutStreamer.getCurrentSection() != OutStreamer.getPreviousSection())
      EmitAlignment(Align);
    EmitXXStructor(Structors[i].second);
  }
}

/// EmitTLSInitFuncs - Emit the TLS initialization functions.
void AsmPrinter::EmitTLSInitFuncs(const ConstantArray *InitList) {
  const DataLayout *TD = TM.getDataLayout();
  OutStreamer.SwitchSection(getObjFileLowering().getTLSThreadInitSection());
  EmitAlignment(Log2_32(TD->getPointerPrefAlignment()));
  for (unsigned I = 0, E = InitList->getNumOperands(); I != E; ++I)
    EmitGlobalConstant(
      dyn_cast<Constant>(InitList->getOperand(I)->stripPointerCasts()));
}

//===--------------------------------------------------------------------===//
// Emission and print routines
//

/// EmitInt8 - Emit a byte directive and value.
///
void AsmPrinter::EmitInt8(int Value) const {
  OutStreamer.EmitIntValue(Value, 1);
}

/// EmitInt16 - Emit a short directive and value.
///
void AsmPrinter::EmitInt16(int Value) const {
  OutStreamer.EmitIntValue(Value, 2);
}

/// EmitInt32 - Emit a long directive and value.
///
void AsmPrinter::EmitInt32(int Value) const {
  OutStreamer.EmitIntValue(Value, 4);
}

/// EmitLabelDifference - Emit something like ".long Hi-Lo" where the size
/// in bytes of the directive is specified by Size and Hi/Lo specify the
/// labels.  This implicitly uses .set if it is available.
void AsmPrinter::EmitLabelDifference(const MCSymbol *Hi, const MCSymbol *Lo,
                                     unsigned Size) const {
  // Get the Hi-Lo expression.
  const MCExpr *Diff =
    MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(Hi, OutContext),
                            MCSymbolRefExpr::Create(Lo, OutContext),
                            OutContext);

  if (!MAI->hasSetDirective()) {
    OutStreamer.EmitValue(Diff, Size);
    return;
  }

  // Otherwise, emit with .set (aka assignment).
  MCSymbol *SetLabel = GetTempSymbol("set", SetCounter++);
  OutStreamer.EmitAssignment(SetLabel, Diff);
  OutStreamer.EmitSymbolValue(SetLabel, Size);
}

/// EmitLabelOffsetDifference - Emit something like ".long Hi+Offset-Lo"
/// where the size in bytes of the directive is specified by Size and Hi/Lo
/// specify the labels.  This implicitly uses .set if it is available.
void AsmPrinter::EmitLabelOffsetDifference(const MCSymbol *Hi, uint64_t Offset,
                                           const MCSymbol *Lo, unsigned Size)
  const {

  // Emit Hi+Offset - Lo
  // Get the Hi+Offset expression.
  const MCExpr *Plus =
    MCBinaryExpr::CreateAdd(MCSymbolRefExpr::Create(Hi, OutContext),
                            MCConstantExpr::Create(Offset, OutContext),
                            OutContext);

  // Get the Hi+Offset-Lo expression.
  const MCExpr *Diff =
    MCBinaryExpr::CreateSub(Plus,
                            MCSymbolRefExpr::Create(Lo, OutContext),
                            OutContext);

  if (!MAI->hasSetDirective())
    OutStreamer.EmitValue(Diff, 4);
  else {
    // Otherwise, emit with .set (aka assignment).
    MCSymbol *SetLabel = GetTempSymbol("set", SetCounter++);
    OutStreamer.EmitAssignment(SetLabel, Diff);
    OutStreamer.EmitSymbolValue(SetLabel, 4);
  }
}

/// EmitLabelPlusOffset - Emit something like ".long Label+Offset"
/// where the size in bytes of the directive is specified by Size and Label
/// specifies the label.  This implicitly uses .set if it is available.
void AsmPrinter::EmitLabelPlusOffset(const MCSymbol *Label, uint64_t Offset,
                                      unsigned Size)
  const {

  // Emit Label+Offset (or just Label if Offset is zero)
  const MCExpr *Expr = MCSymbolRefExpr::Create(Label, OutContext);
  if (Offset)
    Expr = MCBinaryExpr::CreateAdd(Expr,
                                   MCConstantExpr::Create(Offset, OutContext),
                                   OutContext);

  OutStreamer.EmitValue(Expr, Size);
}


//===----------------------------------------------------------------------===//

// EmitAlignment - Emit an alignment directive to the specified power of
// two boundary.  For example, if you pass in 3 here, you will get an 8
// byte alignment.  If a global value is specified, and if that global has
// an explicit alignment requested, it will override the alignment request
// if required for correctness.
//
void AsmPrinter::EmitAlignment(unsigned NumBits, const GlobalValue *GV) const {
  if (GV) NumBits = getGVAlignmentLog2(GV, *TM.getDataLayout(), NumBits);

  if (NumBits == 0) return;   // 1-byte aligned: no need to emit alignment.

  if (getCurrentSection()->getKind().isText())
    OutStreamer.EmitCodeAlignment(1 << NumBits);
  else
    OutStreamer.EmitValueToAlignment(1 << NumBits, 0, 1, 0);
}

//===----------------------------------------------------------------------===//
// Constant emission.
//===----------------------------------------------------------------------===//

/// lowerConstant - Lower the specified LLVM Constant to an MCExpr.
///
static const MCExpr *lowerConstant(const Constant *CV, AsmPrinter &AP) {
  MCContext &Ctx = AP.OutContext;

  if (CV->isNullValue() || isa<UndefValue>(CV))
    return MCConstantExpr::Create(0, Ctx);

  if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV))
    return MCConstantExpr::Create(CI->getZExtValue(), Ctx);

  if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV))
    return MCSymbolRefExpr::Create(AP.Mang->getSymbol(GV), Ctx);

  if (const BlockAddress *BA = dyn_cast<BlockAddress>(CV))
    return MCSymbolRefExpr::Create(AP.GetBlockAddressSymbol(BA), Ctx);

  const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV);
  if (CE == 0) {
    llvm_unreachable("Unknown constant value to lower!");
  }

  switch (CE->getOpcode()) {
  default:
    // If the code isn't optimized, there may be outstanding folding
    // opportunities. Attempt to fold the expression using DataLayout as a
    // last resort before giving up.
    if (Constant *C =
          ConstantFoldConstantExpression(CE, AP.TM.getDataLayout()))
      if (C != CE)
        return lowerConstant(C, AP);

    // Otherwise report the problem to the user.
    {
      std::string S;
      raw_string_ostream OS(S);
      OS << "Unsupported expression in static initializer: ";
      WriteAsOperand(OS, CE, /*PrintType=*/false,
                     !AP.MF ? 0 : AP.MF->getFunction()->getParent());
      report_fatal_error(OS.str());
    }
  case Instruction::GetElementPtr: {
    const DataLayout &TD = *AP.TM.getDataLayout();
    // Generate a symbolic expression for the byte address
    APInt OffsetAI(TD.getPointerSizeInBits(), 0);
    cast<GEPOperator>(CE)->accumulateConstantOffset(TD, OffsetAI);

    const MCExpr *Base = lowerConstant(CE->getOperand(0), AP);
    if (!OffsetAI)
      return Base;

    int64_t Offset = OffsetAI.getSExtValue();
    return MCBinaryExpr::CreateAdd(Base, MCConstantExpr::Create(Offset, Ctx),
                                   Ctx);
  }

  case Instruction::Trunc:
    // We emit the value and depend on the assembler to truncate the generated
    // expression properly.  This is important for differences between
    // blockaddress labels.  Since the two labels are in the same function, it
    // is reasonable to treat their delta as a 32-bit value.
    // FALL THROUGH.
  case Instruction::BitCast:
    return lowerConstant(CE->getOperand(0), AP);

  case Instruction::IntToPtr: {
    const DataLayout &TD = *AP.TM.getDataLayout();
    // Handle casts to pointers by changing them into casts to the appropriate
    // integer type.  This promotes constant folding and simplifies this code.
    Constant *Op = CE->getOperand(0);
    Op = ConstantExpr::getIntegerCast(Op, TD.getIntPtrType(CV->getContext()),
                                      false/*ZExt*/);
    return lowerConstant(Op, AP);
  }

  case Instruction::PtrToInt: {
    const DataLayout &TD = *AP.TM.getDataLayout();
    // Support only foldable casts to/from pointers that can be eliminated by
    // changing the pointer to the appropriately sized integer type.
    Constant *Op = CE->getOperand(0);
    Type *Ty = CE->getType();

    const MCExpr *OpExpr = lowerConstant(Op, AP);

    // We can emit the pointer value into this slot if the slot is an
    // integer slot equal to the size of the pointer.
    if (TD.getTypeAllocSize(Ty) == TD.getTypeAllocSize(Op->getType()))
      return OpExpr;

    // Otherwise the pointer is smaller than the resultant integer, mask off
    // the high bits so we are sure to get a proper truncation if the input is
    // a constant expr.
    unsigned InBits = TD.getTypeAllocSizeInBits(Op->getType());
    const MCExpr *MaskExpr = MCConstantExpr::Create(~0ULL >> (64-InBits), Ctx);
    return MCBinaryExpr::CreateAnd(OpExpr, MaskExpr, Ctx);
  }

  // The MC library also has a right-shift operator, but it isn't consistently
  // signed or unsigned between different targets.
  case Instruction::Add:
  case Instruction::Sub:
  case Instruction::Mul:
  case Instruction::SDiv:
  case Instruction::SRem:
  case Instruction::Shl:
  case Instruction::And:
  case Instruction::Or:
  case Instruction::Xor: {
    const MCExpr *LHS = lowerConstant(CE->getOperand(0), AP);
    const MCExpr *RHS = lowerConstant(CE->getOperand(1), AP);
    switch (CE->getOpcode()) {
    default: llvm_unreachable("Unknown binary operator constant cast expr");
    case Instruction::Add: return MCBinaryExpr::CreateAdd(LHS, RHS, Ctx);
    case Instruction::Sub: return MCBinaryExpr::CreateSub(LHS, RHS, Ctx);
    case Instruction::Mul: return MCBinaryExpr::CreateMul(LHS, RHS, Ctx);
    case Instruction::SDiv: return MCBinaryExpr::CreateDiv(LHS, RHS, Ctx);
    case Instruction::SRem: return MCBinaryExpr::CreateMod(LHS, RHS, Ctx);
    case Instruction::Shl: return MCBinaryExpr::CreateShl(LHS, RHS, Ctx);
    case Instruction::And: return MCBinaryExpr::CreateAnd(LHS, RHS, Ctx);
    case Instruction::Or:  return MCBinaryExpr::CreateOr (LHS, RHS, Ctx);
    case Instruction::Xor: return MCBinaryExpr::CreateXor(LHS, RHS, Ctx);
    }
  }
  }
}

static void emitGlobalConstantImpl(const Constant *C, unsigned AddrSpace,
                                   AsmPrinter &AP);

/// isRepeatedByteSequence - Determine whether the given value is
/// composed of a repeated sequence of identical bytes and return the
/// byte value.  If it is not a repeated sequence, return -1.
static int isRepeatedByteSequence(const ConstantDataSequential *V) {
  StringRef Data = V->getRawDataValues();
  assert(!Data.empty() && "Empty aggregates should be CAZ node");
  char C = Data[0];
  for (unsigned i = 1, e = Data.size(); i != e; ++i)
    if (Data[i] != C) return -1;
  return static_cast<uint8_t>(C); // Ensure 255 is not returned as -1.
}


/// isRepeatedByteSequence - Determine whether the given value is
/// composed of a repeated sequence of identical bytes and return the
/// byte value.  If it is not a repeated sequence, return -1.
static int isRepeatedByteSequence(const Value *V, TargetMachine &TM) {

  if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
    if (CI->getBitWidth() > 64) return -1;

    uint64_t Size = TM.getDataLayout()->getTypeAllocSize(V->getType());
    uint64_t Value = CI->getZExtValue();

    // Make sure the constant is at least 8 bits long and has a power
    // of 2 bit width.  This guarantees the constant bit width is
    // always a multiple of 8 bits, avoiding issues with padding out
    // to Size and other such corner cases.
    if (CI->getBitWidth() < 8 || !isPowerOf2_64(CI->getBitWidth())) return -1;

    uint8_t Byte = static_cast<uint8_t>(Value);

    for (unsigned i = 1; i < Size; ++i) {
      Value >>= 8;
      if (static_cast<uint8_t>(Value) != Byte) return -1;
    }
    return Byte;
  }
  if (const ConstantArray *CA = dyn_cast<ConstantArray>(V)) {
    // Make sure all array elements are sequences of the same repeated
    // byte.
    assert(CA->getNumOperands() != 0 && "Should be a CAZ");
    int Byte = isRepeatedByteSequence(CA->getOperand(0), TM);
    if (Byte == -1) return -1;

    for (unsigned i = 1, e = CA->getNumOperands(); i != e; ++i) {
      int ThisByte = isRepeatedByteSequence(CA->getOperand(i), TM);
      if (ThisByte == -1) return -1;
      if (Byte != ThisByte) return -1;
    }
    return Byte;
  }

  if (const ConstantDataSequential *CDS = dyn_cast<ConstantDataSequential>(V))
    return isRepeatedByteSequence(CDS);

  return -1;
}

static void emitGlobalConstantDataSequential(const ConstantDataSequential *CDS,
                                             unsigned AddrSpace,AsmPrinter &AP){

  // See if we can aggregate this into a .fill, if so, emit it as such.
  int Value = isRepeatedByteSequence(CDS, AP.TM);
  if (Value != -1) {
    uint64_t Bytes = AP.TM.getDataLayout()->getTypeAllocSize(CDS->getType());
    // Don't emit a 1-byte object as a .fill.
    if (Bytes > 1)
      return AP.OutStreamer.EmitFill(Bytes, Value, AddrSpace);
  }

  // If this can be emitted with .ascii/.asciz, emit it as such.
  if (CDS->isString())
    return AP.OutStreamer.EmitBytes(CDS->getAsString(), AddrSpace);

  // Otherwise, emit the values in successive locations.
  unsigned ElementByteSize = CDS->getElementByteSize();
  if (isa<IntegerType>(CDS->getElementType())) {
    for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
      if (AP.isVerbose())
        AP.OutStreamer.GetCommentOS() << format("0x%" PRIx64 "\n",
                                                CDS->getElementAsInteger(i));
      AP.OutStreamer.EmitIntValue(CDS->getElementAsInteger(i),
                                  ElementByteSize, AddrSpace);
    }
  } else if (ElementByteSize == 4) {
    // FP Constants are printed as integer constants to avoid losing
    // precision.
    assert(CDS->getElementType()->isFloatTy());
    for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
      union {
        float F;
        uint32_t I;
      };

      F = CDS->getElementAsFloat(i);
      if (AP.isVerbose())
        AP.OutStreamer.GetCommentOS() << "float " << F << '\n';
      AP.OutStreamer.EmitIntValue(I, 4, AddrSpace);
    }
  } else {
    assert(CDS->getElementType()->isDoubleTy());
    for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
      union {
        double F;
        uint64_t I;
      };

      F = CDS->getElementAsDouble(i);
      if (AP.isVerbose())
        AP.OutStreamer.GetCommentOS() << "double " << F << '\n';
      AP.OutStreamer.EmitIntValue(I, 8, AddrSpace);
    }
  }

  const DataLayout &TD = *AP.TM.getDataLayout();
  unsigned Size = TD.getTypeAllocSize(CDS->getType());
  unsigned EmittedSize = TD.getTypeAllocSize(CDS->getType()->getElementType()) *
                        CDS->getNumElements();
  if (unsigned Padding = Size - EmittedSize)
    AP.OutStreamer.EmitZeros(Padding, AddrSpace);

}

static void emitGlobalConstantArray(const ConstantArray *CA, unsigned AddrSpace,
                                    AsmPrinter &AP) {
  // See if we can aggregate some values.  Make sure it can be
  // represented as a series of bytes of the constant value.
  int Value = isRepeatedByteSequence(CA, AP.TM);

  if (Value != -1) {
    uint64_t Bytes = AP.TM.getDataLayout()->getTypeAllocSize(CA->getType());
    AP.OutStreamer.EmitFill(Bytes, Value, AddrSpace);
  }
  else {
    for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i)
      emitGlobalConstantImpl(CA->getOperand(i), AddrSpace, AP);
  }
}

static void emitGlobalConstantVector(const ConstantVector *CV,
                                     unsigned AddrSpace, AsmPrinter &AP) {
  for (unsigned i = 0, e = CV->getType()->getNumElements(); i != e; ++i)
    emitGlobalConstantImpl(CV->getOperand(i), AddrSpace, AP);

  const DataLayout &TD = *AP.TM.getDataLayout();
  unsigned Size = TD.getTypeAllocSize(CV->getType());
  unsigned EmittedSize = TD.getTypeAllocSize(CV->getType()->getElementType()) *
                         CV->getType()->getNumElements();
  if (unsigned Padding = Size - EmittedSize)
    AP.OutStreamer.EmitZeros(Padding, AddrSpace);
}

static void emitGlobalConstantStruct(const ConstantStruct *CS,
                                     unsigned AddrSpace, AsmPrinter &AP) {
  // Print the fields in successive locations. Pad to align if needed!
  const DataLayout *TD = AP.TM.getDataLayout();
  unsigned Size = TD->getTypeAllocSize(CS->getType());
  const StructLayout *Layout = TD->getStructLayout(CS->getType());
  uint64_t SizeSoFar = 0;
  for (unsigned i = 0, e = CS->getNumOperands(); i != e; ++i) {
    const Constant *Field = CS->getOperand(i);

    // Check if padding is needed and insert one or more 0s.
    uint64_t FieldSize = TD->getTypeAllocSize(Field->getType());
    uint64_t PadSize = ((i == e-1 ? Size : Layout->getElementOffset(i+1))
                        - Layout->getElementOffset(i)) - FieldSize;
    SizeSoFar += FieldSize + PadSize;

    // Now print the actual field value.
    emitGlobalConstantImpl(Field, AddrSpace, AP);

    // Insert padding - this may include padding to increase the size of the
    // current field up to the ABI size (if the struct is not packed) as well
    // as padding to ensure that the next field starts at the right offset.
    AP.OutStreamer.EmitZeros(PadSize, AddrSpace);
  }
  assert(SizeSoFar == Layout->getSizeInBytes() &&
         "Layout of constant struct may be incorrect!");
}

static void emitGlobalConstantFP(const ConstantFP *CFP, unsigned AddrSpace,
                                 AsmPrinter &AP) {
  APInt API = CFP->getValueAPF().bitcastToAPInt();

  // First print a comment with what we think the original floating-point value
  // should have been.
  if (AP.isVerbose()) {
    SmallString<8> StrVal;
    CFP->getValueAPF().toString(StrVal);

    CFP->getType()->print(AP.OutStreamer.GetCommentOS());
    AP.OutStreamer.GetCommentOS() << ' ' << StrVal << '\n';
  }

  // Now iterate through the APInt chunks, emitting them in endian-correct
  // order, possibly with a smaller chunk at beginning/end (e.g. for x87 80-bit
  // floats).
  unsigned NumBytes = API.getBitWidth() / 8;
  unsigned TrailingBytes = NumBytes % sizeof(uint64_t);
  const uint64_t *p = API.getRawData();

  // PPC's long double has odd notions of endianness compared to how LLVM
  // handles it: p[0] goes first for *big* endian on PPC.
  if (AP.TM.getDataLayout()->isBigEndian() != CFP->getType()->isPPC_FP128Ty()) {
    int Chunk = API.getNumWords() - 1;

    if (TrailingBytes)
      AP.OutStreamer.EmitIntValue(p[Chunk--], TrailingBytes, AddrSpace);

    for (; Chunk >= 0; --Chunk)
      AP.OutStreamer.EmitIntValue(p[Chunk], sizeof(uint64_t), AddrSpace);
  } else {
    unsigned Chunk;
    for (Chunk = 0; Chunk < NumBytes / sizeof(uint64_t); ++Chunk)
      AP.OutStreamer.EmitIntValue(p[Chunk], sizeof(uint64_t), AddrSpace);

    if (TrailingBytes)
      AP.OutStreamer.EmitIntValue(p[Chunk], TrailingBytes, AddrSpace);
  }

  // Emit the tail padding for the long double.
  const DataLayout &TD = *AP.TM.getDataLayout();
  AP.OutStreamer.EmitZeros(TD.getTypeAllocSize(CFP->getType()) -
                           TD.getTypeStoreSize(CFP->getType()), AddrSpace);
}

static void emitGlobalConstantLargeInt(const ConstantInt *CI,
                                       unsigned AddrSpace, AsmPrinter &AP) {
  const DataLayout *TD = AP.TM.getDataLayout();
  unsigned BitWidth = CI->getBitWidth();
  assert((BitWidth & 63) == 0 && "only support multiples of 64-bits");

  // We don't expect assemblers to support integer data directives
  // for more than 64 bits, so we emit the data in at most 64-bit
  // quantities at a time.
  const uint64_t *RawData = CI->getValue().getRawData();
  for (unsigned i = 0, e = BitWidth / 64; i != e; ++i) {
    uint64_t Val = TD->isBigEndian() ? RawData[e - i - 1] : RawData[i];
    AP.OutStreamer.EmitIntValue(Val, 8, AddrSpace);
  }
}

static void emitGlobalConstantImpl(const Constant *CV, unsigned AddrSpace,
                                   AsmPrinter &AP) {
  const DataLayout *TD = AP.TM.getDataLayout();
  uint64_t Size = TD->getTypeAllocSize(CV->getType());
  if (isa<ConstantAggregateZero>(CV) || isa<UndefValue>(CV))
    return AP.OutStreamer.EmitZeros(Size, AddrSpace);

  if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) {
    switch (Size) {
    case 1:
    case 2:
    case 4:
    case 8:
      if (AP.isVerbose())
        AP.OutStreamer.GetCommentOS() << format("0x%" PRIx64 "\n",
                                                CI->getZExtValue());
      AP.OutStreamer.EmitIntValue(CI->getZExtValue(), Size, AddrSpace);
      return;
    default:
      emitGlobalConstantLargeInt(CI, AddrSpace, AP);
      return;
    }
  }

  if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV))
    return emitGlobalConstantFP(CFP, AddrSpace, AP);

  if (isa<ConstantPointerNull>(CV)) {
    AP.OutStreamer.EmitIntValue(0, Size, AddrSpace);
    return;
  }

  if (const ConstantDataSequential *CDS = dyn_cast<ConstantDataSequential>(CV))
    return emitGlobalConstantDataSequential(CDS, AddrSpace, AP);

  if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV))
    return emitGlobalConstantArray(CVA, AddrSpace, AP);

  if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV))
    return emitGlobalConstantStruct(CVS, AddrSpace, AP);

  if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV)) {
    // Look through bitcasts, which might not be able to be MCExpr'ized (e.g. of
    // vectors).
    if (CE->getOpcode() == Instruction::BitCast)
      return emitGlobalConstantImpl(CE->getOperand(0), AddrSpace, AP);

    if (Size > 8) {
      // If the constant expression's size is greater than 64-bits, then we have
      // to emit the value in chunks. Try to constant fold the value and emit it
      // that way.
      Constant *New = ConstantFoldConstantExpression(CE, TD);
      if (New && New != CE)
        return emitGlobalConstantImpl(New, AddrSpace, AP);
    }
  }

  if (const ConstantVector *V = dyn_cast<ConstantVector>(CV))
    return emitGlobalConstantVector(V, AddrSpace, AP);

  // Otherwise, it must be a ConstantExpr.  Lower it to an MCExpr, then emit it
  // thread the streamer with EmitValue.
  AP.OutStreamer.EmitValue(lowerConstant(CV, AP), Size, AddrSpace);
}

/// EmitGlobalConstant - Print a general LLVM constant to the .s file.
void AsmPrinter::EmitGlobalConstant(const Constant *CV, unsigned AddrSpace) {
  uint64_t Size = TM.getDataLayout()->getTypeAllocSize(CV->getType());
  if (Size)
    emitGlobalConstantImpl(CV, AddrSpace, *this);
  else if (MAI->hasSubsectionsViaSymbols()) {
    // If the global has zero size, emit a single byte so that two labels don't
    // look like they are at the same location.
    OutStreamer.EmitIntValue(0, 1, AddrSpace);
  }
}

void AsmPrinter::EmitMachineConstantPoolValue(MachineConstantPoolValue *MCPV) {
  // Target doesn't support this yet!
  llvm_unreachable("Target does not support EmitMachineConstantPoolValue");
}

void AsmPrinter::printOffset(int64_t Offset, raw_ostream &OS) const {
  if (Offset > 0)
    OS << '+' << Offset;
  else if (Offset < 0)
    OS << Offset;
}

//===----------------------------------------------------------------------===//
// Symbol Lowering Routines.
//===----------------------------------------------------------------------===//

/// GetTempSymbol - Return the MCSymbol corresponding to the assembler
/// temporary label with the specified stem and unique ID.
MCSymbol *AsmPrinter::GetTempSymbol(StringRef Name, unsigned ID) const {
  return OutContext.GetOrCreateSymbol(Twine(MAI->getPrivateGlobalPrefix()) +
                                      Name + Twine(ID));
}

/// GetTempSymbol - Return an assembler temporary label with the specified
/// stem.
MCSymbol *AsmPrinter::GetTempSymbol(StringRef Name) const {
  return OutContext.GetOrCreateSymbol(Twine(MAI->getPrivateGlobalPrefix())+
                                      Name);
}


MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BlockAddress *BA) const {
  return MMI->getAddrLabelSymbol(BA->getBasicBlock());
}

MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BasicBlock *BB) const {
  return MMI->getAddrLabelSymbol(BB);
}

/// GetCPISymbol - Return the symbol for the specified constant pool entry.
MCSymbol *AsmPrinter::GetCPISymbol(unsigned CPID) const {
  return OutContext.GetOrCreateSymbol
    (Twine(MAI->getPrivateGlobalPrefix()) + "CPI" + Twine(getFunctionNumber())
     + "_" + Twine(CPID));
}

/// GetJTISymbol - Return the symbol for the specified jump table entry.
MCSymbol *AsmPrinter::GetJTISymbol(unsigned JTID, bool isLinkerPrivate) const {
  return MF->getJTISymbol(JTID, OutContext, isLinkerPrivate);
}

/// GetJTSetSymbol - Return the symbol for the specified jump table .set
/// FIXME: privatize to AsmPrinter.
MCSymbol *AsmPrinter::GetJTSetSymbol(unsigned UID, unsigned MBBID) const {
  return OutContext.GetOrCreateSymbol
  (Twine(MAI->getPrivateGlobalPrefix()) + Twine(getFunctionNumber()) + "_" +
   Twine(UID) + "_set_" + Twine(MBBID));
}

/// GetSymbolWithGlobalValueBase - Return the MCSymbol for a symbol with
/// global value name as its base, with the specified suffix, and where the
/// symbol is forced to have private linkage if ForcePrivate is true.
MCSymbol *AsmPrinter::GetSymbolWithGlobalValueBase(const GlobalValue *GV,
                                                   StringRef Suffix,
                                                   bool ForcePrivate) const {
  SmallString<60> NameStr;
  Mang->getNameWithPrefix(NameStr, GV, ForcePrivate);
  NameStr.append(Suffix.begin(), Suffix.end());
  return OutContext.GetOrCreateSymbol(NameStr.str());
}

/// GetExternalSymbolSymbol - Return the MCSymbol for the specified
/// ExternalSymbol.
MCSymbol *AsmPrinter::GetExternalSymbolSymbol(StringRef Sym) const {
  SmallString<60> NameStr;
  Mang->getNameWithPrefix(NameStr, Sym);
  return OutContext.GetOrCreateSymbol(NameStr.str());
}



/// PrintParentLoopComment - Print comments about parent loops of this one.
static void PrintParentLoopComment(raw_ostream &OS, const MachineLoop *Loop,
                                   unsigned FunctionNumber) {
  if (Loop == 0) return;
  PrintParentLoopComment(OS, Loop->getParentLoop(), FunctionNumber);
  OS.indent(Loop->getLoopDepth()*2)
    << "Parent Loop BB" << FunctionNumber << "_"
    << Loop->getHeader()->getNumber()
    << " Depth=" << Loop->getLoopDepth() << '\n';
}


/// PrintChildLoopComment - Print comments about child loops within
/// the loop for this basic block, with nesting.
static void PrintChildLoopComment(raw_ostream &OS, const MachineLoop *Loop,
                                  unsigned FunctionNumber) {