AsmPrinter.cpp

  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);
  }
}

/// EmitGlobalConstant - Print a general LLVM constant to the .s file.
void AsmPrinter::EmitGlobalConstant(const Constant *CV, unsigned AddrSpace) {
  if (isa<ConstantAggregateZero>(CV) || isa<UndefValue>(CV)) {
    uint64_t Size = TM.getTargetData()->getTypeAllocSize(CV->getType());
    return OutStreamer.EmitZeros(Size, AddrSpace);
  }

  if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) {
    unsigned Size = TM.getTargetData()->getTypeAllocSize(CV->getType());
    switch (Size) {
    case 1:
    case 2:
    case 4:
    case 8:
      if (VerboseAsm)
        OutStreamer.GetCommentOS() << format("0x%llx\n", CI->getZExtValue());
      OutStreamer.EmitIntValue(CI->getZExtValue(), Size, AddrSpace);
      return;
    default:
      EmitGlobalConstantLargeInt(CI, AddrSpace, *this);
      return;
    }
  }
  
  if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV))
    return EmitGlobalConstantArray(CVA, AddrSpace, *this);
  
  if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV))
    return EmitGlobalConstantStruct(CVS, AddrSpace, *this);

  if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV))
    return EmitGlobalConstantFP(CFP, AddrSpace, *this);
  
  if (const ConstantVector *V = dyn_cast<ConstantVector>(CV))
    return EmitGlobalConstantVector(V, AddrSpace, *this);

  if (isa<ConstantPointerNull>(CV)) {
    unsigned Size = TM.getTargetData()->getTypeAllocSize(CV->getType());
    OutStreamer.EmitIntValue(0, Size, AddrSpace);
    return;
  }
  
  // Otherwise, it must be a ConstantExpr.  Lower it to an MCExpr, then emit it
  // thread the streamer with EmitValue.
  OutStreamer.EmitValue(LowerConstant(CV, *this),
                        TM.getTargetData()->getTypeAllocSize(CV->getType()),
                        AddrSpace);
}

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

/// PrintSpecial - Print information related to the specified machine instr
/// that is independent of the operand, and may be independent of the instr
/// itself.  This can be useful for portably encoding the comment character
/// or other bits of target-specific knowledge into the asmstrings.  The
/// syntax used is ${:comment}.  Targets can override this to add support
/// for their own strange codes.
void AsmPrinter::PrintSpecial(const MachineInstr *MI, const char *Code) const {
  if (!strcmp(Code, "private")) {
    O << MAI->getPrivateGlobalPrefix();
  } else if (!strcmp(Code, "comment")) {
    if (VerboseAsm)
      O << MAI->getCommentString();
  } else if (!strcmp(Code, "uid")) {
    // Comparing the address of MI isn't sufficient, because machineinstrs may
    // be allocated to the same address across functions.
    const Function *ThisF = MI->getParent()->getParent()->getFunction();
    
    // If this is a new LastFn instruction, bump the counter.
    if (LastMI != MI || LastFn != ThisF) {
      ++Counter;
      LastMI = MI;
      LastFn = ThisF;
    }
    O << Counter;
  } else {
    std::string msg;
    raw_string_ostream Msg(msg);
    Msg << "Unknown special formatter '" << Code
         << "' for machine instr: " << *MI;
    llvm_report_error(Msg.str());
  }    
}

/// processDebugLoc - Processes the debug information of each machine
/// instruction's DebugLoc.
void AsmPrinter::processDebugLoc(const MachineInstr *MI, 
                                 bool BeforePrintingInsn) {
  if (!MAI || !DW || !MAI->doesSupportDebugInformation()
      || !DW->ShouldEmitDwarfDebug())
    return;
  DebugLoc DL = MI->getDebugLoc();
  if (DL.isUnknown())
    return;
  DILocation CurDLT = MF->getDILocation(DL);
  if (CurDLT.getScope().isNull())
    return;

  if (!BeforePrintingInsn) {
    // After printing instruction
    DW->EndScope(MI);
  } else if (CurDLT.getNode() != PrevDLT) {
    unsigned L = DW->RecordSourceLine(CurDLT.getLineNumber(), 
                                      CurDLT.getColumnNumber(),
                                      CurDLT.getScope().getNode());
    printLabel(L);
    O << '\n';
    DW->BeginScope(MI, L);
    PrevDLT = CurDLT.getNode();
  }
}


/// printInlineAsm - This method formats and prints the specified machine
/// instruction that is an inline asm.
void AsmPrinter::printInlineAsm(const MachineInstr *MI) const {
  unsigned NumOperands = MI->getNumOperands();
  
  // Count the number of register definitions.
  unsigned NumDefs = 0;
  for (; MI->getOperand(NumDefs).isReg() && MI->getOperand(NumDefs).isDef();
       ++NumDefs)
    assert(NumDefs != NumOperands-1 && "No asm string?");
  
  assert(MI->getOperand(NumDefs).isSymbol() && "No asm string?");

  // Disassemble the AsmStr, printing out the literal pieces, the operands, etc.
  const char *AsmStr = MI->getOperand(NumDefs).getSymbolName();

  O << '\t';

  // If this asmstr is empty, just print the #APP/#NOAPP markers.
  // These are useful to see where empty asm's wound up.
  if (AsmStr[0] == 0) {
    O << MAI->getCommentString() << MAI->getInlineAsmStart() << "\n\t";
    O << MAI->getCommentString() << MAI->getInlineAsmEnd() << '\n';
    return;
  }
  
  O << MAI->getCommentString() << MAI->getInlineAsmStart() << "\n\t";

  // The variant of the current asmprinter.
  int AsmPrinterVariant = MAI->getAssemblerDialect();

  int CurVariant = -1;            // The number of the {.|.|.} region we are in.
  const char *LastEmitted = AsmStr; // One past the last character emitted.
  
  while (*LastEmitted) {
    switch (*LastEmitted) {
    default: {
      // Not a special case, emit the string section literally.
      const char *LiteralEnd = LastEmitted+1;
      while (*LiteralEnd && *LiteralEnd != '{' && *LiteralEnd != '|' &&
             *LiteralEnd != '}' && *LiteralEnd != '$' && *LiteralEnd != '\n')
        ++LiteralEnd;
      if (CurVariant == -1 || CurVariant == AsmPrinterVariant)
        O.write(LastEmitted, LiteralEnd-LastEmitted);
      LastEmitted = LiteralEnd;
      break;
    }
    case '\n':
      ++LastEmitted;   // Consume newline character.
      O << '\n';       // Indent code with newline.
      break;
    case '$': {
      ++LastEmitted;   // Consume '$' character.
      bool Done = true;

      // Handle escapes.
      switch (*LastEmitted) {
      default: Done = false; break;
      case '$':     // $$ -> $
        if (CurVariant == -1 || CurVariant == AsmPrinterVariant)
          O << '$';
        ++LastEmitted;  // Consume second '$' character.
        break;
      case '(':             // $( -> same as GCC's { character.
        ++LastEmitted;      // Consume '(' character.
        if (CurVariant != -1) {
          llvm_report_error("Nested variants found in inline asm string: '"
                            + std::string(AsmStr) + "'");
        }
        CurVariant = 0;     // We're in the first variant now.
        break;
      case '|':
        ++LastEmitted;  // consume '|' character.
        if (CurVariant == -1)
          O << '|';       // this is gcc's behavior for | outside a variant
        else
          ++CurVariant;   // We're in the next variant.
        break;
      case ')':         // $) -> same as GCC's } char.
        ++LastEmitted;  // consume ')' character.
        if (CurVariant == -1)
          O << '}';     // this is gcc's behavior for } outside a variant
        else 
          CurVariant = -1;
        break;
      }
      if (Done) break;
      
      bool HasCurlyBraces = false;
      if (*LastEmitted == '{') {     // ${variable}
        ++LastEmitted;               // Consume '{' character.
        HasCurlyBraces = true;
      }
      
      // If we have ${:foo}, then this is not a real operand reference, it is a
      // "magic" string reference, just like in .td files.  Arrange to call
      // PrintSpecial.
      if (HasCurlyBraces && *LastEmitted == ':') {
        ++LastEmitted;
        const char *StrStart = LastEmitted;
        const char *StrEnd = strchr(StrStart, '}');
        if (StrEnd == 0) {
          llvm_report_error("Unterminated ${:foo} operand in inline asm string: '" 
                            + std::string(AsmStr) + "'");
        }
        
        std::string Val(StrStart, StrEnd);
        PrintSpecial(MI, Val.c_str());
        LastEmitted = StrEnd+1;
        break;
      }
            
      const char *IDStart = LastEmitted;
      char *IDEnd;
      errno = 0;
      long Val = strtol(IDStart, &IDEnd, 10); // We only accept numbers for IDs.
      if (!isdigit(*IDStart) || (Val == 0 && errno == EINVAL)) {
        llvm_report_error("Bad $ operand number in inline asm string: '" 
                          + std::string(AsmStr) + "'");
      }
      LastEmitted = IDEnd;
      
      char Modifier[2] = { 0, 0 };
      
      if (HasCurlyBraces) {
        // If we have curly braces, check for a modifier character.  This
        // supports syntax like ${0:u}, which correspond to "%u0" in GCC asm.
        if (*LastEmitted == ':') {
          ++LastEmitted;    // Consume ':' character.
          if (*LastEmitted == 0) {
            llvm_report_error("Bad ${:} expression in inline asm string: '" 
                              + std::string(AsmStr) + "'");
          }
          
          Modifier[0] = *LastEmitted;
          ++LastEmitted;    // Consume modifier character.
        }
        
        if (*LastEmitted != '}') {
          llvm_report_error("Bad ${} expression in inline asm string: '" 
                            + std::string(AsmStr) + "'");
        }
        ++LastEmitted;    // Consume '}' character.
      }
      
      if ((unsigned)Val >= NumOperands-1) {
        llvm_report_error("Invalid $ operand number in inline asm string: '" 
                          + std::string(AsmStr) + "'");
      }
      
      // Okay, we finally have a value number.  Ask the target to print this
      // operand!
      if (CurVariant == -1 || CurVariant == AsmPrinterVariant) {
        unsigned OpNo = 1;

        bool Error = false;

        // Scan to find the machine operand number for the operand.
        for (; Val; --Val) {
          if (OpNo >= MI->getNumOperands()) break;
          unsigned OpFlags = MI->getOperand(OpNo).getImm();
          OpNo += InlineAsm::getNumOperandRegisters(OpFlags) + 1;
        }

        if (OpNo >= MI->getNumOperands()) {
          Error = true;
        } else {
          unsigned OpFlags = MI->getOperand(OpNo).getImm();
          ++OpNo;  // Skip over the ID number.

          if (Modifier[0] == 'l')  // labels are target independent
            O << *GetMBBSymbol(MI->getOperand(OpNo).getMBB()->getNumber());
          else {
            AsmPrinter *AP = const_cast<AsmPrinter*>(this);
            if ((OpFlags & 7) == 4) {
              Error = AP->PrintAsmMemoryOperand(MI, OpNo, AsmPrinterVariant,
                                                Modifier[0] ? Modifier : 0);
            } else {
              Error = AP->PrintAsmOperand(MI, OpNo, AsmPrinterVariant,
                                          Modifier[0] ? Modifier : 0);
            }
          }
        }
        if (Error) {
          std::string msg;
          raw_string_ostream Msg(msg);
          Msg << "Invalid operand found in inline asm: '" << AsmStr << "'\n";
          MI->print(Msg);
          llvm_report_error(Msg.str());
        }
      }
      break;
    }
    }
  }
  O << "\n\t" << MAI->getCommentString() << MAI->getInlineAsmEnd();
}

/// printImplicitDef - This method prints the specified machine instruction
/// that is an implicit def.
void AsmPrinter::printImplicitDef(const MachineInstr *MI) const {
  if (!VerboseAsm) return;
  O.PadToColumn(MAI->getCommentColumn());
  O << MAI->getCommentString() << " implicit-def: "
    << TRI->getName(MI->getOperand(0).getReg());
}

void AsmPrinter::printKill(const MachineInstr *MI) const {
  if (!VerboseAsm) return;
  O.PadToColumn(MAI->getCommentColumn());
  O << MAI->getCommentString() << " kill:";
  for (unsigned n = 0, e = MI->getNumOperands(); n != e; ++n) {
    const MachineOperand &op = MI->getOperand(n);
    assert(op.isReg() && "KILL instruction must have only register operands");
    O << ' ' << TRI->getName(op.getReg()) << (op.isDef() ? "<def>" : "<kill>");
  }
}

/// printLabel - This method prints a local label used by debug and
/// exception handling tables.
void AsmPrinter::printLabel(const MachineInstr *MI) const {
  printLabel(MI->getOperand(0).getImm());
}

void AsmPrinter::printLabel(unsigned Id) const {
  O << MAI->getPrivateGlobalPrefix() << "label" << Id << ':';
}

/// PrintAsmOperand - Print the specified operand of MI, an INLINEASM
/// instruction, using the specified assembler variant.  Targets should
/// override this to format as appropriate.
bool AsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
                                 unsigned AsmVariant, const char *ExtraCode) {
  // Target doesn't support this yet!
  return true;
}

bool AsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo,
                                       unsigned AsmVariant,
                                       const char *ExtraCode) {
  // Target doesn't support this yet!
  return true;
}

MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BlockAddress *BA,
                                            const char *Suffix) const {
  return GetBlockAddressSymbol(BA->getFunction(), BA->getBasicBlock(), Suffix);
}

MCSymbol *AsmPrinter::GetBlockAddressSymbol(const Function *F,
                                            const BasicBlock *BB,
                                            const char *Suffix) const {
  assert(BB->hasName() &&
         "Address of anonymous basic block not supported yet!");

  // This code must use the function name itself, and not the function number,
  // since it must be possible to generate the label name from within other
  // functions.
  SmallString<60> FnName;
  Mang->getNameWithPrefix(FnName, F, false);

  // FIXME: THIS IS BROKEN IF THE LLVM BASIC BLOCK DOESN'T HAVE A NAME!
  SmallString<60> NameResult;
  Mang->getNameWithPrefix(NameResult,
                          StringRef("BA") + Twine((unsigned)FnName.size()) + 
                          "_" + FnName.str() + "_" + BB->getName() + Suffix, 
                          Mangler::Private);

  return OutContext.GetOrCreateSymbol(NameResult.str());
}

MCSymbol *AsmPrinter::GetMBBSymbol(unsigned MBBID) const {
  SmallString<60> Name;
  raw_svector_ostream(Name) << MAI->getPrivateGlobalPrefix() << "BB"
    << getFunctionNumber() << '_' << MBBID;
  return OutContext.GetOrCreateSymbol(Name.str());
}

/// GetCPISymbol - Return the symbol for the specified constant pool entry.
MCSymbol *AsmPrinter::GetCPISymbol(unsigned CPID) const {
  SmallString<60> Name;
  raw_svector_ostream(Name) << MAI->getPrivateGlobalPrefix() << "CPI"
    << getFunctionNumber() << '_' << CPID;
  return OutContext.GetOrCreateSymbol(Name.str());
}

/// GetJTISymbol - Return the symbol for the specified jump table entry.
MCSymbol *AsmPrinter::GetJTISymbol(unsigned JTID, bool isLinkerPrivate) const {
  const char *Prefix = isLinkerPrivate ? MAI->getLinkerPrivateGlobalPrefix() :
                                         MAI->getPrivateGlobalPrefix();
  SmallString<60> Name;
  raw_svector_ostream(Name) << Prefix << "JTI" << getFunctionNumber() << '_'
    << JTID;
  return OutContext.GetOrCreateSymbol(Name.str());
}

/// GetGlobalValueSymbol - Return the MCSymbol for the specified global
/// value.
MCSymbol *AsmPrinter::GetGlobalValueSymbol(const GlobalValue *GV) const {
  SmallString<60> NameStr;
  Mang->getNameWithPrefix(NameStr, GV, false);
  return OutContext.GetOrCreateSymbol(NameStr.str());
}

/// 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) {
  // Add child loop information
  for (MachineLoop::iterator CL = Loop->begin(), E = Loop->end();CL != E; ++CL){
    OS.indent((*CL)->getLoopDepth()*2)
      << "Child Loop BB" << FunctionNumber << "_"
      << (*CL)->getHeader()->getNumber() << " Depth " << (*CL)->getLoopDepth()
      << '\n';
    PrintChildLoopComment(OS, *CL, FunctionNumber);
  }
}

/// EmitComments - Pretty-print comments for basic blocks.
static void PrintBasicBlockLoopComments(const MachineBasicBlock &MBB,
                                        const MachineLoopInfo *LI,
                                        const AsmPrinter &AP) {
  // Add loop depth information
  const MachineLoop *Loop = LI->getLoopFor(&MBB);
  if (Loop == 0) return;
  
  MachineBasicBlock *Header = Loop->getHeader();
  assert(Header && "No header for loop");
  
  // If this block is not a loop header, just print out what is the loop header
  // and return.
  if (Header != &MBB) {
    AP.OutStreamer.AddComment("  in Loop: Header=BB" +
                              Twine(AP.getFunctionNumber())+"_" +
                              Twine(Loop->getHeader()->getNumber())+
                              " Depth="+Twine(Loop->getLoopDepth()));
    return;
  }
  
  // Otherwise, it is a loop header.  Print out information about child and
  // parent loops.
  raw_ostream &OS = AP.OutStreamer.GetCommentOS();
  
  PrintParentLoopComment(OS, Loop->getParentLoop(), AP.getFunctionNumber()); 
  
  OS << "=>";
  OS.indent(Loop->getLoopDepth()*2-2);
  
  OS << "This ";
  if (Loop->empty())
    OS << "Inner ";
  OS << "Loop Header: Depth=" + Twine(Loop->getLoopDepth()) << '\n';
  
  PrintChildLoopComment(OS, Loop, AP.getFunctionNumber());
}


/// EmitBasicBlockStart - This method prints the label for the specified
/// MachineBasicBlock, an alignment (if present) and a comment describing
/// it if appropriate.
void AsmPrinter::EmitBasicBlockStart(const MachineBasicBlock *MBB) const {
  // Emit an alignment directive for this block, if needed.
  if (unsigned Align = MBB->getAlignment())
    EmitAlignment(Log2_32(Align));

  // If the block has its address taken, emit a special label to satisfy
  // references to the block. This is done so that we don't need to
  // remember the number of this label, and so that we can make
  // forward references to labels without knowing what their numbers
  // will be.
  if (MBB->hasAddressTaken()) {
    const BasicBlock *BB = MBB->getBasicBlock();
    if (VerboseAsm)
      OutStreamer.AddComment("Address Taken");
    OutStreamer.EmitLabel(GetBlockAddressSymbol(BB->getParent(), BB));
  }

  // Print the main label for the block.
  if (MBB->pred_empty() || MBB->isOnlyReachableByFallthrough()) {
    if (VerboseAsm) {
      // NOTE: Want this comment at start of line.
      O << MAI->getCommentString() << " BB#" << MBB->getNumber() << ':';
      if (const BasicBlock *BB = MBB->getBasicBlock())
        if (BB->hasName())
          OutStreamer.AddComment("%" + BB->getName());
      
      PrintBasicBlockLoopComments(*MBB, LI, *this);
      OutStreamer.AddBlankLine();
    }
  } else {
    if (VerboseAsm) {
      if (const BasicBlock *BB = MBB->getBasicBlock())
        if (BB->hasName())
          OutStreamer.AddComment("%" + BB->getName());
      PrintBasicBlockLoopComments(*MBB, LI, *this);
    }

    OutStreamer.EmitLabel(GetMBBSymbol(MBB->getNumber()));
  }
}

/// printPICJumpTableSetLabel - This method prints a set label for the
/// specified MachineBasicBlock for a jumptable entry.
void AsmPrinter::printPICJumpTableSetLabel(unsigned uid, 
                                           const MachineBasicBlock *MBB) const {
  if (!MAI->getSetDirective())
    return;
  
  O << MAI->getSetDirective() << ' ' << MAI->getPrivateGlobalPrefix()
    << getFunctionNumber() << '_' << uid << "_set_" << MBB->getNumber() << ','
    << *GetMBBSymbol(MBB->getNumber())
    << '-' << *GetJTISymbol(uid) << '\n';
}

void AsmPrinter::printPICJumpTableSetLabel(unsigned uid, unsigned uid2,
                                           const MachineBasicBlock *MBB) const {
  if (!MAI->getSetDirective())
    return;
  
  O << MAI->getSetDirective() << ' ' << MAI->getPrivateGlobalPrefix()
    << getFunctionNumber() << '_' << uid << '_' << uid2
    << "_set_" << MBB->getNumber() << ','
    << *GetMBBSymbol(MBB->getNumber())
    << '-' << MAI->getPrivateGlobalPrefix() << "JTI" << getFunctionNumber() 
    << '_' << uid << '_' << uid2 << '\n';
}

void AsmPrinter::printVisibility(MCSymbol *Sym, unsigned Visibility) const {
  MCSymbolAttr Attr = MCSA_Invalid;
  
  switch (Visibility) {
  default: break;
  case GlobalValue::HiddenVisibility:
    Attr = MAI->getHiddenVisibilityAttr();
    break;
  case GlobalValue::ProtectedVisibility:
    Attr = MAI->getProtectedVisibilityAttr();
    break;
  }

  if (Attr != MCSA_Invalid)
    OutStreamer.EmitSymbolAttribute(Sym, Attr);
}

void AsmPrinter::printOffset(int64_t Offset) const {
  if (Offset > 0)
    O << '+' << Offset;
  else if (Offset < 0)
    O << Offset;
}

GCMetadataPrinter *AsmPrinter::GetOrCreateGCPrinter(GCStrategy *S) {
  if (!S->usesMetadata())
    return 0;
  
  gcp_iterator GCPI = GCMetadataPrinters.find(S);
  if (GCPI != GCMetadataPrinters.end())
    return GCPI->second;
  
  const char *Name = S->getName().c_str();
  
  for (GCMetadataPrinterRegistry::iterator
         I = GCMetadataPrinterRegistry::begin(),
         E = GCMetadataPrinterRegistry::end(); I != E; ++I)
    if (strcmp(Name, I->getName()) == 0) {
      GCMetadataPrinter *GMP = I->instantiate();
      GMP->S = S;
      GCMetadataPrinters.insert(std::make_pair(S, GMP));
      return GMP;
    }
  
  llvm_report_error("no GCMetadataPrinter registered for GC: " + Twine(Name));
  return 0;
}

/// EmitComments - Pretty-print comments for instructions
void AsmPrinter::EmitComments(const MachineInstr &MI) const {
  if (!VerboseAsm)
    return;

  bool Newline = false;

  if (!MI.getDebugLoc().isUnknown()) {
    DILocation DLT = MF->getDILocation(MI.getDebugLoc());

    // Print source line info.
    O.PadToColumn(MAI->getCommentColumn());
    O << MAI->getCommentString() << ' ';
    DIScope Scope = DLT.getScope();
    // Omit the directory, because it's likely to be long and uninteresting.
    if (!Scope.isNull())
      O << Scope.getFilename();
    else
      O << "<unknown>";
    O << ':' << DLT.getLineNumber();
    if (DLT.getColumnNumber() != 0)
      O << ':' << DLT.getColumnNumber();
    Newline = true;
  }

  // Check for spills and reloads
  int FI;

  const MachineFrameInfo *FrameInfo =
    MI.getParent()->getParent()->getFrameInfo();

  // We assume a single instruction only has a spill or reload, not
  // both.
  const MachineMemOperand *MMO;
  if (TM.getInstrInfo()->isLoadFromStackSlotPostFE(&MI, FI)) {
    if (FrameInfo->isSpillSlotObjectIndex(FI)) {
      MMO = *MI.memoperands_begin();
      if (Newline) O << '\n';
      O.PadToColumn(MAI->getCommentColumn());
      O << MAI->getCommentString() << ' ' << MMO->getSize() << "-byte Reload";
      Newline = true;
    }
  }
  else if (TM.getInstrInfo()->hasLoadFromStackSlot(&MI, MMO, FI)) {
    if (FrameInfo->isSpillSlotObjectIndex(FI)) {
      if (Newline) O << '\n';
      O.PadToColumn(MAI->getCommentColumn());
      O << MAI->getCommentString() << ' '
        << MMO->getSize() << "-byte Folded Reload";
      Newline = true;
    }
  }
  else if (TM.getInstrInfo()->isStoreToStackSlotPostFE(&MI, FI)) {
    if (FrameInfo->isSpillSlotObjectIndex(FI)) {
      MMO = *MI.memoperands_begin();
      if (Newline) O << '\n';
      O.PadToColumn(MAI->getCommentColumn());
      O << MAI->getCommentString() << ' ' << MMO->getSize() << "-byte Spill";
      Newline = true;
    }
  }
  else if (TM.getInstrInfo()->hasStoreToStackSlot(&MI, MMO, FI)) {
    if (FrameInfo->isSpillSlotObjectIndex(FI)) {
      if (Newline) O << '\n';
      O.PadToColumn(MAI->getCommentColumn());
      O << MAI->getCommentString() << ' '
        << MMO->getSize() << "-byte Folded Spill";
      Newline = true;
    }
  }

  // Check for spill-induced copies
  unsigned SrcReg, DstReg, SrcSubIdx, DstSubIdx;
  if (TM.getInstrInfo()->isMoveInstr(MI, SrcReg, DstReg,
                                      SrcSubIdx, DstSubIdx)) {
    if (MI.getAsmPrinterFlag(ReloadReuse)) {
      if (Newline) O << '\n';
      O.PadToColumn(MAI->getCommentColumn());
      O << MAI->getCommentString() << " Reload Reuse";
    }
  }
}