AsmPrinter.cpp

//===-- AsmPrinter.cpp - Common AsmPrinter code ---------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the AsmPrinter class.
//
//===----------------------------------------------------------------------===//

#include "llvm/CodeGen/AsmPrinter.h"
#include "llvm/Assembly/Writer.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Constants.h"
#include "llvm/Module.h"
#include "llvm/CodeGen/GCMetadataPrinter.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineJumpTableInfo.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/DwarfWriter.h"
#include "llvm/Support/Mangler.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetAsmInfo.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetLowering.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringExtras.h"
#include <cerrno>
using namespace llvm;

char AsmPrinter::ID = 0;
AsmPrinter::AsmPrinter(raw_ostream &o, TargetMachine &tm,
                       const TargetAsmInfo *T, bool F)
  : MachineFunctionPass(&ID), FunctionNumber(0), Fast(F), O(o),
    TM(tm), TAI(T), TRI(tm.getRegisterInfo()),
    IsInTextSection(false)
{}

AsmPrinter::~AsmPrinter() {
  for (gcp_iterator I = GCMetadataPrinters.begin(),
                    E = GCMetadataPrinters.end(); I != E; ++I)
    delete I->second;
}

/// SwitchToTextSection - Switch to the specified text section of the executable
/// if we are not already in it!
///
void AsmPrinter::SwitchToTextSection(const char *NewSection,
                                     const GlobalValue *GV) {
  std::string NS;
  if (GV && GV->hasSection())
    NS = TAI->getSwitchToSectionDirective() + GV->getSection();
  else
    NS = NewSection;
  
  // If we're already in this section, we're done.
  if (CurrentSection == NS) return;

  // Close the current section, if applicable.
  if (TAI->getSectionEndDirectiveSuffix() && !CurrentSection.empty())
    O << CurrentSection << TAI->getSectionEndDirectiveSuffix() << '\n';

  CurrentSection = NS;

  if (!CurrentSection.empty())
    O << CurrentSection << TAI->getTextSectionStartSuffix() << '\n';

  IsInTextSection = true;
}

/// SwitchToDataSection - Switch to the specified data section of the executable
/// if we are not already in it!
///
void AsmPrinter::SwitchToDataSection(const char *NewSection,
                                     const GlobalValue *GV) {
  std::string NS;
  if (GV && GV->hasSection())
    NS = TAI->getSwitchToSectionDirective() + GV->getSection();
  else
    NS = NewSection;
  
  // If we're already in this section, we're done.
  if (CurrentSection == NS) return;

  // Close the current section, if applicable.
  if (TAI->getSectionEndDirectiveSuffix() && !CurrentSection.empty())
    O << CurrentSection << TAI->getSectionEndDirectiveSuffix() << '\n';

  CurrentSection = NS;
  
  if (!CurrentSection.empty())
    O << CurrentSection << TAI->getDataSectionStartSuffix() << '\n';

  IsInTextSection = false;
}

/// SwitchToSection - Switch to the specified section of the executable if we
/// are not already in it!
void AsmPrinter::SwitchToSection(const Section* NS) {
  const std::string& NewSection = NS->getName();

  // If we're already in this section, we're done.
  if (CurrentSection == NewSection) return;

  // Close the current section, if applicable.
  if (TAI->getSectionEndDirectiveSuffix() && !CurrentSection.empty())
    O << CurrentSection << TAI->getSectionEndDirectiveSuffix() << '\n';

  // FIXME: Make CurrentSection a Section* in the future
  CurrentSection = NewSection;
  CurrentSection_ = NS;

  if (!CurrentSection.empty()) {
    // If section is named we need to switch into it via special '.section'
    // directive and also append funky flags. Otherwise - section name is just
    // some magic assembler directive.
    if (NS->isNamed())
      O << TAI->getSwitchToSectionDirective()
        << CurrentSection
        << TAI->getSectionFlags(NS->getFlags());
    else
      O << CurrentSection;
    O << TAI->getDataSectionStartSuffix() << '\n';
  }

  IsInTextSection = (NS->getFlags() & SectionFlags::Code);
}

void AsmPrinter::getAnalysisUsage(AnalysisUsage &AU) const {
  MachineFunctionPass::getAnalysisUsage(AU);
  AU.addRequired<GCModuleInfo>();
}

bool AsmPrinter::doInitialization(Module &M) {
  Mang = new Mangler(M, TAI->getGlobalPrefix(), TAI->getPrivateGlobalPrefix());
  
  GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
  assert(MI && "AsmPrinter didn't require GCModuleInfo?");

  if (TAI->hasSingleParameterDotFile()) {
    /* Very minimal debug info. It is ignored if we emit actual
       debug info. If we don't, this at helps the user find where
       a function came from. */
    O << "\t.file\t\"" << M.getModuleIdentifier() << "\"\n";
  }

  for (GCModuleInfo::iterator I = MI->begin(), E = MI->end(); I != E; ++I)
    if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*I))
      MP->beginAssembly(O, *this, *TAI);
  
  if (!M.getModuleInlineAsm().empty())
    O << TAI->getCommentString() << " Start of file scope inline assembly\n"
      << M.getModuleInlineAsm()
      << '\n' << TAI->getCommentString()
      << " End of file scope inline assembly\n";

  SwitchToDataSection("");   // Reset back to no section.
  
  MachineModuleInfo *MMI = getAnalysisIfAvailable<MachineModuleInfo>();
  if (MMI) MMI->AnalyzeModule(M);
  DW = getAnalysisIfAvailable<DwarfWriter>();
  return false;
}

bool AsmPrinter::doFinalization(Module &M) {
  if (TAI->getWeakRefDirective()) {
    if (!ExtWeakSymbols.empty())
      SwitchToDataSection("");

    for (std::set<const GlobalValue*>::iterator i = ExtWeakSymbols.begin(),
         e = ExtWeakSymbols.end(); i != e; ++i) {
      const GlobalValue *GV = *i;
      std::string Name = Mang->getValueName(GV);
      O << TAI->getWeakRefDirective() << Name << '\n';
    }
  }

  if (TAI->getSetDirective()) {
    if (!M.alias_empty())
      SwitchToSection(TAI->getTextSection());

    O << '\n';
    for (Module::const_alias_iterator I = M.alias_begin(), E = M.alias_end();
         I!=E; ++I) {
      std::string Name = Mang->getValueName(I);
      std::string Target;

      const GlobalValue *GV = cast<GlobalValue>(I->getAliasedGlobal());
      Target = Mang->getValueName(GV);

      if (I->hasExternalLinkage() || !TAI->getWeakRefDirective())
        O << "\t.globl\t" << Name << '\n';
      else if (I->hasWeakLinkage())
        O << TAI->getWeakRefDirective() << Name << '\n';
      else if (!I->hasLocalLinkage())
        assert(0 && "Invalid alias linkage");

      printVisibility(Name, I->getVisibility());

      O << TAI->getSetDirective() << ' ' << Name << ", " << Target << '\n';
    }
  }

  GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
  assert(MI && "AsmPrinter didn't require GCModuleInfo?");
  for (GCModuleInfo::iterator I = MI->end(), E = MI->begin(); I != E; )
    if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*--I))
      MP->finishAssembly(O, *this, *TAI);

  // If we don't have any trampolines, then we don't require stack memory
  // to be executable. Some targets have a directive to declare this.
  Function* InitTrampolineIntrinsic = M.getFunction("llvm.init.trampoline");
  if (!InitTrampolineIntrinsic || InitTrampolineIntrinsic->use_empty())
    if (TAI->getNonexecutableStackDirective())
      O << TAI->getNonexecutableStackDirective() << '\n';

  delete Mang; Mang = 0;
  return false;
}

std::string AsmPrinter::getCurrentFunctionEHName(const MachineFunction *MF) {
  assert(MF && "No machine function?");
  std::string Name = MF->getFunction()->getName();
  if (Name.empty())
    Name = Mang->getValueName(MF->getFunction());
  return Mang->makeNameProper(TAI->getEHGlobalPrefix() +
                              Name + ".eh", TAI->getGlobalPrefix());
}

void AsmPrinter::SetupMachineFunction(MachineFunction &MF) {
  // What's my mangled name?
  CurrentFnName = Mang->getValueName(MF.getFunction());
  IncrementFunctionNumber();
}

/// EmitConstantPool - Print to the current output stream assembly
/// representations of the constants in the constant pool MCP. This is
/// used to print out constants which have been "spilled to memory" by
/// the code generator.
///
void AsmPrinter::EmitConstantPool(MachineConstantPool *MCP) {
  const std::vector<MachineConstantPoolEntry> &CP = MCP->getConstants();
  if (CP.empty()) return;

  // Calculate sections for constant pool entries. We collect entries to go into
  // the same section together to reduce amount of section switch statements.
  typedef
    std::multimap<const Section*,
                  std::pair<MachineConstantPoolEntry, unsigned> > CPMap;
  CPMap  CPs;
  SmallPtrSet<const Section*, 5> Sections;

  for (unsigned i = 0, e = CP.size(); i != e; ++i) {
    MachineConstantPoolEntry CPE = CP[i];
    const Section* S = TAI->SelectSectionForMachineConst(CPE.getType());
    CPs.insert(std::make_pair(S, std::make_pair(CPE, i)));
    Sections.insert(S);
  }

  // Now print stuff into the calculated sections.
  for (SmallPtrSet<const Section*, 5>::iterator IS = Sections.begin(),
         ES = Sections.end(); IS != ES; ++IS) {
    SwitchToSection(*IS);
    EmitAlignment(MCP->getConstantPoolAlignment());

    std::pair<CPMap::iterator, CPMap::iterator> II = CPs.equal_range(*IS);
    for (CPMap::iterator I = II.first, E = II.second; I != E; ++I) {
      CPMap::iterator J = next(I);
      MachineConstantPoolEntry Entry = I->second.first;
      unsigned index = I->second.second;

      O << TAI->getPrivateGlobalPrefix() << "CPI" << getFunctionNumber() << '_'
        << index << ":\t\t\t\t\t";
    // O << TAI->getCommentString() << ' ' << 
    //      WriteTypeSymbolic(O, CP[i].first.getType(), 0);
      O << '\n';
      if (Entry.isMachineConstantPoolEntry())
        EmitMachineConstantPoolValue(Entry.Val.MachineCPVal);
      else
        EmitGlobalConstant(Entry.Val.ConstVal);

      // Emit inter-object padding for alignment.
      if (J != E) {
        const Type *Ty = Entry.getType();
        unsigned EntSize = TM.getTargetData()->getTypePaddedSize(Ty);
        unsigned ValEnd = Entry.getOffset() + EntSize;
        EmitZeros(J->second.first.getOffset()-ValEnd);
      }
    }
  }
}

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

  bool IsPic = TM.getRelocationModel() == Reloc::PIC_;
  
  // Pick the directive to use to print the jump table entries, and switch to 
  // the appropriate section.
  TargetLowering *LoweringInfo = TM.getTargetLowering();

  const char* JumpTableDataSection = TAI->getJumpTableDataSection();
  const Function *F = MF.getFunction();
  unsigned SectionFlags = TAI->SectionFlagsForGlobal(F);
  if ((IsPic && !(LoweringInfo && LoweringInfo->usesGlobalOffsetTable())) ||
     !JumpTableDataSection ||
      SectionFlags & SectionFlags::Linkonce) {
    // 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.
    // We should also do if the section name is NULL or function is declared in
    // discardable section.
    SwitchToSection(TAI->SectionForGlobal(F));
  } else {
    SwitchToDataSection(JumpTableDataSection);
  }
  
  EmitAlignment(Log2_32(MJTI->getAlignment()));
  
  for (unsigned i = 0, e = JT.size(); i != e; ++i) {
    const std::vector<MachineBasicBlock*> &JTBBs = JT[i].MBBs;
    
    // If this jump table was deleted, ignore it. 
    if (JTBBs.empty()) continue;

    // For PIC codegen, if possible we want to use the SetDirective to reduce
    // the number of relocations the assembler will generate for the jump table.
    // Set directives are all printed before the jump table itself.
    SmallPtrSet<MachineBasicBlock*, 16> EmittedSets;
    if (TAI->getSetDirective() && IsPic)
      for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii)
        if (EmittedSets.insert(JTBBs[ii]))
          printPICJumpTableSetLabel(i, JTBBs[ii]);
    
    // On some targets (e.g. darwin) we want to emit two consequtive 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 (const char *JTLabelPrefix = TAI->getJumpTableSpecialLabelPrefix())
      O << JTLabelPrefix << "JTI" << getFunctionNumber() << '_' << i << ":\n";
    
    O << TAI->getPrivateGlobalPrefix() << "JTI" << getFunctionNumber() 
      << '_' << i << ":\n";
    
    for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii) {
      printPICJumpTableEntry(MJTI, JTBBs[ii], i);
      O << '\n';
    }
  }
}

void AsmPrinter::printPICJumpTableEntry(const MachineJumpTableInfo *MJTI,
                                        const MachineBasicBlock *MBB,
                                        unsigned uid)  const {
  bool IsPic = TM.getRelocationModel() == Reloc::PIC_;
  
  // Use JumpTableDirective otherwise honor the entry size from the jump table
  // info.
  const char *JTEntryDirective = TAI->getJumpTableDirective();
  bool HadJTEntryDirective = JTEntryDirective != NULL;
  if (!HadJTEntryDirective) {
    JTEntryDirective = MJTI->getEntrySize() == 4 ?
      TAI->getData32bitsDirective() : TAI->getData64bitsDirective();
  }

  O << JTEntryDirective << ' ';

  // 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 we're emitting non-PIC code, then emit the entries as direct
  // references to the target basic blocks.
  if (IsPic) {
    if (TAI->getSetDirective()) {
      O << TAI->getPrivateGlobalPrefix() << getFunctionNumber()
        << '_' << uid << "_set_" << MBB->getNumber();
    } else {
      printBasicBlockLabel(MBB, false, false, false);
      // If the arch uses custom Jump Table directives, don't calc relative to
      // JT
      if (!HadJTEntryDirective) 
        O << '-' << TAI->getPrivateGlobalPrefix() << "JTI"
          << getFunctionNumber() << '_' << uid;
    }
  } else {
    printBasicBlockLabel(MBB, false, false, false);
  }
}


/// 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 (TAI->getUsedDirective() != 0)    // No need to emit this at all.
      EmitLLVMUsedList(GV->getInitializer());
    return true;
  }

  // Ignore debug and non-emitted data.
  if (GV->getSection() == "llvm.metadata") return true;
  
  if (!GV->hasAppendingLinkage()) return false;

  assert(GV->hasInitializer() && "Not a special LLVM global!");
  
  const TargetData *TD = TM.getTargetData();
  unsigned Align = Log2_32(TD->getPointerPrefAlignment());
  if (GV->getName() == "llvm.global_ctors" && GV->use_empty()) {
    SwitchToDataSection(TAI->getStaticCtorsSection());
    EmitAlignment(Align, 0);
    EmitXXStructorList(GV->getInitializer());
    return true;
  } 
  
  if (GV->getName() == "llvm.global_dtors" && GV->use_empty()) {
    SwitchToDataSection(TAI->getStaticDtorsSection());
    EmitAlignment(Align, 0);
    EmitXXStructorList(GV->getInitializer());
    return true;
  }
  
  return false;
}

/// findGlobalValue - if CV is an expression equivalent to a single
/// global value, return that value.
const GlobalValue * AsmPrinter::findGlobalValue(const Constant *CV) {
  if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV))
    return GV;
  else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV)) {
    const TargetData *TD = TM.getTargetData();
    unsigned Opcode = CE->getOpcode();    
    switch (Opcode) {
    case Instruction::GetElementPtr: {
      const Constant *ptrVal = CE->getOperand(0);
      SmallVector<Value*, 8> idxVec(CE->op_begin()+1, CE->op_end());
      if (TD->getIndexedOffset(ptrVal->getType(), &idxVec[0], idxVec.size()))
        return 0;
      return findGlobalValue(ptrVal);
    }
    case Instruction::BitCast:
      return findGlobalValue(CE->getOperand(0));
    default:
      return 0;
    }
  }
  return 0;
}

/// EmitLLVMUsedList - For targets that define a TAI::UsedDirective, mark each
/// global in the specified llvm.used list for which emitUsedDirectiveFor
/// is true, as being used with this directive.

void AsmPrinter::EmitLLVMUsedList(Constant *List) {
  const char *Directive = TAI->getUsedDirective();

  // Should be an array of 'sbyte*'.
  ConstantArray *InitList = dyn_cast<ConstantArray>(List);
  if (InitList == 0) return;
  
  for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
    const GlobalValue *GV = findGlobalValue(InitList->getOperand(i));
    if (TAI->emitUsedDirectiveFor(GV, Mang)) {
      O << Directive;
      EmitConstantValueOnly(InitList->getOperand(i));
      O << '\n';
    }
  }
}

/// EmitXXStructorList - Emit the ctor or dtor list.  This just prints out the 
/// function pointers, ignoring the init priority.
void AsmPrinter::EmitXXStructorList(Constant *List) {
  // Should be an array of '{ int, void ()* }' structs.  The first value is the
  // init priority, which we ignore.
  if (!isa<ConstantArray>(List)) return;
  ConstantArray *InitList = cast<ConstantArray>(List);
  for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i)
    if (ConstantStruct *CS = dyn_cast<ConstantStruct>(InitList->getOperand(i))){
      if (CS->getNumOperands() != 2) return;  // Not array of 2-element structs.

      if (CS->getOperand(1)->isNullValue())
        return;  // Found a null terminator, exit printing.
      // Emit the function pointer.
      EmitGlobalConstant(CS->getOperand(1));
    }
}

/// getGlobalLinkName - Returns the asm/link name of of the specified
/// global variable.  Should be overridden by each target asm printer to
/// generate the appropriate value.
const std::string AsmPrinter::getGlobalLinkName(const GlobalVariable *GV) const{
  std::string LinkName;
  
  if (isa<Function>(GV)) {
    LinkName += TAI->getFunctionAddrPrefix();
    LinkName += Mang->getValueName(GV);
    LinkName += TAI->getFunctionAddrSuffix();
  } else {
    LinkName += TAI->getGlobalVarAddrPrefix();
    LinkName += Mang->getValueName(GV);
    LinkName += TAI->getGlobalVarAddrSuffix();
  }  
  
  return LinkName;
}

/// EmitExternalGlobal - Emit the external reference to a global variable.
/// Should be overridden if an indirect reference should be used.
void AsmPrinter::EmitExternalGlobal(const GlobalVariable *GV) {
  O << getGlobalLinkName(GV);
}



//===----------------------------------------------------------------------===//
/// LEB 128 number encoding.

/// PrintULEB128 - Print a series of hexidecimal values (separated by commas)
/// representing an unsigned leb128 value.
void AsmPrinter::PrintULEB128(unsigned Value) const {
  char Buffer[20];
  do {
    unsigned char Byte = static_cast<unsigned char>(Value & 0x7f);
    Value >>= 7;
    if (Value) Byte |= 0x80;
    O << "0x" << utohex_buffer(Byte, Buffer+20);
    if (Value) O << ", ";
  } while (Value);
}

/// PrintSLEB128 - Print a series of hexidecimal values (separated by commas)
/// representing a signed leb128 value.
void AsmPrinter::PrintSLEB128(int Value) const {
  int Sign = Value >> (8 * sizeof(Value) - 1);
  bool IsMore;
  char Buffer[20];

  do {
    unsigned char Byte = static_cast<unsigned char>(Value & 0x7f);
    Value >>= 7;
    IsMore = Value != Sign || ((Byte ^ Sign) & 0x40) != 0;
    if (IsMore) Byte |= 0x80;
    O << "0x" << utohex_buffer(Byte, Buffer+20);
    if (IsMore) O << ", ";
  } while (IsMore);
}

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

/// PrintHex - Print a value as a hexidecimal value.
///
void AsmPrinter::PrintHex(int Value) const { 
  char Buffer[20];
  O << "0x" << utohex_buffer(static_cast<unsigned>(Value), Buffer+20);
}

/// EOL - Print a newline character to asm stream.  If a comment is present
/// then it will be printed first.  Comments should not contain '\n'.
void AsmPrinter::EOL() const {
  O << '\n';
}

void AsmPrinter::EOL(const std::string &Comment) const {
  if (VerboseAsm && !Comment.empty()) {
    O << '\t'
      << TAI->getCommentString()
      << ' '
      << Comment;
  }
  O << '\n';
}

void AsmPrinter::EOL(const char* Comment) const {
  if (VerboseAsm && *Comment) {
    O << '\t'
      << TAI->getCommentString()
      << ' '
      << Comment;
  }
  O << '\n';
}

/// EmitULEB128Bytes - Emit an assembler byte data directive to compose an
/// unsigned leb128 value.
void AsmPrinter::EmitULEB128Bytes(unsigned Value) const {
  if (TAI->hasLEB128()) {
    O << "\t.uleb128\t"
      << Value;
  } else {
    O << TAI->getData8bitsDirective();
    PrintULEB128(Value);
  }
}

/// EmitSLEB128Bytes - print an assembler byte data directive to compose a
/// signed leb128 value.
void AsmPrinter::EmitSLEB128Bytes(int Value) const {
  if (TAI->hasLEB128()) {
    O << "\t.sleb128\t"
      << Value;
  } else {
    O << TAI->getData8bitsDirective();
    PrintSLEB128(Value);
  }
}

/// EmitInt8 - Emit a byte directive and value.
///
void AsmPrinter::EmitInt8(int Value) const {
  O << TAI->getData8bitsDirective();
  PrintHex(Value & 0xFF);
}

/// EmitInt16 - Emit a short directive and value.
///
void AsmPrinter::EmitInt16(int Value) const {
  O << TAI->getData16bitsDirective();
  PrintHex(Value & 0xFFFF);
}

/// EmitInt32 - Emit a long directive and value.
///
void AsmPrinter::EmitInt32(int Value) const {
  O << TAI->getData32bitsDirective();
  PrintHex(Value);
}

/// EmitInt64 - Emit a long long directive and value.
///
void AsmPrinter::EmitInt64(uint64_t Value) const {
  if (TAI->getData64bitsDirective()) {
    O << TAI->getData64bitsDirective();
    PrintHex(Value);
  } else {
    if (TM.getTargetData()->isBigEndian()) {
      EmitInt32(unsigned(Value >> 32)); O << '\n';
      EmitInt32(unsigned(Value));
    } else {
      EmitInt32(unsigned(Value)); O << '\n';
      EmitInt32(unsigned(Value >> 32));
    }
  }
}

/// toOctal - Convert the low order bits of X into an octal digit.
///
static inline char toOctal(int X) {
  return (X&7)+'0';
}

/// printStringChar - Print a char, escaped if necessary.
///
static void printStringChar(raw_ostream &O, char C) {
  if (C == '"') {
    O << "\\\"";
  } else if (C == '\\') {
    O << "\\\\";
  } else if (isprint((unsigned char)C)) {
    O << C;
  } else {
    switch(C) {
    case '\b': O << "\\b"; break;
    case '\f': O << "\\f"; break;
    case '\n': O << "\\n"; break;
    case '\r': O << "\\r"; break;
    case '\t': O << "\\t"; break;
    default:
      O << '\\';
      O << toOctal(C >> 6);
      O << toOctal(C >> 3);
      O << toOctal(C >> 0);
      break;
    }
  }
}

/// EmitString - Emit a string with quotes and a null terminator.
/// Special characters are emitted properly.
/// \literal (Eg. '\t') \endliteral
void AsmPrinter::EmitString(const std::string &String) const {
  const char* AscizDirective = TAI->getAscizDirective();
  if (AscizDirective)
    O << AscizDirective;
  else
    O << TAI->getAsciiDirective();
  O << '\"';
  for (unsigned i = 0, N = String.size(); i < N; ++i) {
    unsigned char C = String[i];
    printStringChar(O, C);
  }
  if (AscizDirective)
    O << '\"';
  else
    O << "\\0\"";
}


/// EmitFile - Emit a .file directive.
void AsmPrinter::EmitFile(unsigned Number, const std::string &Name) const {
  O << "\t.file\t" << Number << " \"";
  for (unsigned i = 0, N = Name.size(); i < N; ++i) {
    unsigned char C = Name[i];
    printStringChar(O, C);
  }
  O << '\"';
}


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

// 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 unconditionally override the
// alignment request.  However, if ForcedAlignBits is specified, this value
// has final say: the ultimate alignment will be the max of ForcedAlignBits
// and the alignment computed with NumBits and the global.
//
// The algorithm is:
//     Align = NumBits;
//     if (GV && GV->hasalignment) Align = GV->getalignment();
//     Align = std::max(Align, ForcedAlignBits);
//
void AsmPrinter::EmitAlignment(unsigned NumBits, const GlobalValue *GV,
                               unsigned ForcedAlignBits,
                               bool UseFillExpr) const {
  if (GV && GV->getAlignment())
    NumBits = Log2_32(GV->getAlignment());
  NumBits = std::max(NumBits, ForcedAlignBits);
  
  if (NumBits == 0) return;   // No need to emit alignment.
  if (TAI->getAlignmentIsInBytes()) NumBits = 1 << NumBits;
  O << TAI->getAlignDirective() << NumBits;

  unsigned FillValue = TAI->getTextAlignFillValue();
  UseFillExpr &= IsInTextSection && FillValue;
  if (UseFillExpr) {
    O << ',';
    PrintHex(FillValue);
  }
  O << '\n';
}

    
/// EmitZeros - Emit a block of zeros.
///
void AsmPrinter::EmitZeros(uint64_t NumZeros, unsigned AddrSpace) const {
  if (NumZeros) {
    if (TAI->getZeroDirective()) {
      O << TAI->getZeroDirective() << NumZeros;
      if (TAI->getZeroDirectiveSuffix())
        O << TAI->getZeroDirectiveSuffix();
      O << '\n';
    } else {
      for (; NumZeros; --NumZeros)
        O << TAI->getData8bitsDirective(AddrSpace) << "0\n";
    }
  }
}

// Print out the specified constant, without a storage class.  Only the
// constants valid in constant expressions can occur here.
void AsmPrinter::EmitConstantValueOnly(const Constant *CV) {
  if (CV->isNullValue() || isa<UndefValue>(CV))
    O << '0';
  else if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) {
    O << CI->getZExtValue();
  } else if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV)) {
    // This is a constant address for a global variable or function. Use the
    // name of the variable or function as the address value, possibly
    // decorating it with GlobalVarAddrPrefix/Suffix or
    // FunctionAddrPrefix/Suffix (these all default to "" )
    if (isa<Function>(GV)) {
      O << TAI->getFunctionAddrPrefix()
        << Mang->getValueName(GV)
        << TAI->getFunctionAddrSuffix();
    } else {
      O << TAI->getGlobalVarAddrPrefix()
        << Mang->getValueName(GV)
        << TAI->getGlobalVarAddrSuffix();
    }
  } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV)) {
    const TargetData *TD = TM.getTargetData();
    unsigned Opcode = CE->getOpcode();    
    switch (Opcode) {
    case Instruction::GetElementPtr: {
      // generate a symbolic expression for the byte address
      const Constant *ptrVal = CE->getOperand(0);
      SmallVector<Value*, 8> idxVec(CE->op_begin()+1, CE->op_end());
      if (int64_t Offset = TD->getIndexedOffset(ptrVal->getType(), &idxVec[0],
                                                idxVec.size())) {
        // Truncate/sext the offset to the pointer size.
        if (TD->getPointerSizeInBits() != 64) {
          int SExtAmount = 64-TD->getPointerSizeInBits();
          Offset = (Offset << SExtAmount) >> SExtAmount;
        }
        
        if (Offset)
          O << '(';
        EmitConstantValueOnly(ptrVal);
        if (Offset > 0)
          O << ") + " << Offset;
        else if (Offset < 0)
          O << ") - " << -Offset;
      } else {
        EmitConstantValueOnly(ptrVal);
      }
      break;
    }
    case Instruction::Trunc:
    case Instruction::ZExt:
    case Instruction::SExt:
    case Instruction::FPTrunc:
    case Instruction::FPExt:
    case Instruction::UIToFP:
    case Instruction::SIToFP:
    case Instruction::FPToUI:
    case Instruction::FPToSI:
      assert(0 && "FIXME: Don't yet support this kind of constant cast expr");
      break;
    case Instruction::BitCast:
      return EmitConstantValueOnly(CE->getOperand(0));

    case Instruction::IntToPtr: {
      // 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(), false/*ZExt*/);
      return EmitConstantValueOnly(Op);
    }
      
      
    case Instruction::PtrToInt: {
      // 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);
      const Type *Ty = CE->getType();

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

      O << "((";
      EmitConstantValueOnly(Op);
      APInt ptrMask = APInt::getAllOnesValue(TD->getTypePaddedSizeInBits(Ty));
      
      SmallString<40> S;
      ptrMask.toStringUnsigned(S);
      O << ") & " << S.c_str() << ')';
      break;
    }
    case Instruction::Add:
    case Instruction::Sub:
    case Instruction::And:
    case Instruction::Or:
    case Instruction::Xor:
      O << '(';
      EmitConstantValueOnly(CE->getOperand(0));
      O << ')';
      switch (Opcode) {
      case Instruction::Add:
       O << " + ";
       break;
      case Instruction::Sub:
       O << " - ";
       break;
      case Instruction::And:
       O << " & ";
       break;
      case Instruction::Or:
       O << " | ";
       break;
      case Instruction::Xor:
       O << " ^ ";
       break;
      default:
       break;
      }
      O << '(';
      EmitConstantValueOnly(CE->getOperand(1));
      O << ')';
      break;
    default:
      assert(0 && "Unsupported operator!");
    }
  } else {
    assert(0 && "Unknown constant value!");
  }
}

/// printAsCString - Print the specified array as a C compatible string, only if
/// the predicate isString is true.
///
static void printAsCString(raw_ostream &O, const ConstantArray *CVA,
                           unsigned LastElt) {
  assert(CVA->isString() && "Array is not string compatible!");

  O << '\"';
  for (unsigned i = 0; i != LastElt; ++i) {
    unsigned char C =
        (unsigned char)cast<ConstantInt>(CVA->getOperand(i))->getZExtValue();
    printStringChar(O, C);
  }
  O << '\"';
}

/// EmitString - Emit a zero-byte-terminated string constant.
///
void AsmPrinter::EmitString(const ConstantArray *CVA) const {
  unsigned NumElts = CVA->getNumOperands();
  if (TAI->getAscizDirective() && NumElts && 
      cast<ConstantInt>(CVA->getOperand(NumElts-1))->getZExtValue() == 0) {
    O << TAI->getAscizDirective();
    printAsCString(O, CVA, NumElts-1);
  } else {
    O << TAI->getAsciiDirective();
    printAsCString(O, CVA, NumElts);
  }
  O << '\n';
}

void AsmPrinter::EmitGlobalConstantArray(const ConstantArray *CVA) {
  if (CVA->isString()) {
    EmitString(CVA);
  } else { // Not a string.  Print the values in successive locations
    for (unsigned i = 0, e = CVA->getNumOperands(); i != e; ++i)
      EmitGlobalConstant(CVA->getOperand(i));
  }
}

void AsmPrinter::EmitGlobalConstantVector(const ConstantVector *CP) {
  const VectorType *PTy = CP->getType();
  
  for (unsigned I = 0, E = PTy->getNumElements(); I < E; ++I)
    EmitGlobalConstant(CP->getOperand(I));
}

void AsmPrinter::EmitGlobalConstantStruct(const ConstantStruct *CVS,
                                          unsigned AddrSpace) {
  // Print the fields in successive locations. Pad to align if needed!
  const TargetData *TD = TM.getTargetData();
  unsigned Size = TD->getTypePaddedSize(CVS->getType());
  const StructLayout *cvsLayout = TD->getStructLayout(CVS->getType());
  uint64_t sizeSoFar = 0;
  for (unsigned i = 0, e = CVS->getNumOperands(); i != e; ++i) {
    const Constant* field = CVS->getOperand(i);

    // Check if padding is needed and insert one or more 0s.
    uint64_t fieldSize = TD->getTypePaddedSize(field->getType());
    uint64_t padSize = ((i == e-1 ? Size : cvsLayout->getElementOffset(i+1))
                        - cvsLayout->getElementOffset(i)) - fieldSize;
    sizeSoFar += fieldSize + padSize;

    // Now print the actual field value.
    EmitGlobalConstant(field, AddrSpace);

    // 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.
    EmitZeros(padSize, AddrSpace);
  }
  assert(sizeSoFar == cvsLayout->getSizeInBytes() &&
         "Layout of constant struct may be incorrect!");
}

void AsmPrinter::EmitGlobalConstantFP(const ConstantFP *CFP, 
                                      unsigned AddrSpace) {
  // FP Constants are printed as integer constants to avoid losing
  // precision...
  const TargetData *TD = TM.getTargetData();
  if (CFP->getType() == Type::DoubleTy) {
    double Val = CFP->getValueAPF().convertToDouble();  // for comment only
    uint64_t i = CFP->getValueAPF().bitcastToAPInt().getZExtValue();
    if (TAI->getData64bitsDirective(AddrSpace))
      O << TAI->getData64bitsDirective(AddrSpace) << i << '\t'
        << TAI->getCommentString() << " double value: " << Val << '\n';
    else if (TD->isBigEndian()) {
      O << TAI->getData32bitsDirective(AddrSpace) << unsigned(i >> 32)
        << '\t' << TAI->getCommentString()
        << " double most significant word " << Val << '\n';
      O << TAI->getData32bitsDirective(AddrSpace) << unsigned(i)
        << '\t' << TAI->getCommentString()
        << " double least significant word " << Val << '\n';