lib/VMCore/AsmWriter.cpp

//===-- AsmWriter.cpp - Printing LLVM as an assembly file -----------------===//
// 
//                     The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
// 
//===----------------------------------------------------------------------===//
//
// This library implements the functionality defined in llvm/Assembly/Writer.h
//
// Note that these routines must be extremely tolerant of various errors in the
// LLVM code, because it can be used for debugging transformations.
//
//===----------------------------------------------------------------------===//

#include "llvm/Assembly/CachedWriter.h"
#include "llvm/Assembly/Writer.h"
#include "llvm/Assembly/PrintModulePass.h"
#include "llvm/Assembly/AsmAnnotationWriter.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Instruction.h"
#include "llvm/iMemory.h"
#include "llvm/iTerminators.h"
#include "llvm/iPHINode.h"
#include "llvm/iOther.h"
#include "llvm/Module.h"
#include "llvm/SymbolTable.h"
#include "llvm/Assembly/Writer.h"
#include "llvm/Support/CFG.h"
#include "Support/StringExtras.h"
#include "Support/STLExtras.h"
#include <algorithm>
using namespace llvm;

namespace llvm {

/// This class provides computation of slot numbers for LLVM Assembly writing.
/// @brief LLVM Assembly Writing Slot Computation.
class SlotMachine {

/// @name Types
/// @{
public:

  /// @brief A mapping of Values to slot numbers
  typedef std::map<const Value*, unsigned> ValueMap;
  typedef std::map<const Type*, unsigned> TypeMap;

  /// @brief A plane with next slot number and ValueMap
  struct ValuePlane { 
    unsigned next_slot;        ///< The next slot number to use
    ValueMap map;              ///< The map of Value* -> unsigned
    ValuePlane() { next_slot = 0; } ///< Make sure we start at 0
  };

  struct TypePlane {
    unsigned next_slot;
    TypeMap map;
    TypePlane() { next_slot = 0; }
    void clear() { map.clear(); next_slot = 0; }
  };

  /// @brief The map of planes by Type
  typedef std::map<const Type*, ValuePlane> TypedPlanes;

/// @}
/// @name Constructors
/// @{
public:
  /// @brief Construct from a module
  SlotMachine(const Module *M );

  /// @brief Construct from a function, starting out in incorp state.
  SlotMachine(const Function *F );

/// @}
/// @name Accessors
/// @{
public:
  /// Return the slot number of the specified value in it's type
  /// plane.  Its an error to ask for something not in the SlotMachine.
  /// Its an error to ask for a Type*
  int getSlot(const Value *V);
  int getSlot(const Type*Ty);

  /// Determine if a Value has a slot or not
  bool hasSlot(const Value* V);
  bool hasSlot(const Type* Ty);

/// @}
/// @name Mutators
/// @{
public:
  /// If you'd like to deal with a function instead of just a module, use 
  /// this method to get its data into the SlotMachine.
  void incorporateFunction(const Function *F) { TheFunction = F; }

  /// After calling incorporateFunction, use this method to remove the 
  /// most recently incorporated function from the SlotMachine. This 
  /// will reset the state of the machine back to just the module contents.
  void purgeFunction();

/// @}
/// @name Implementation Details
/// @{
private:
  /// This function does the actual initialization.
  inline void initialize();

  /// Values can be crammed into here at will. If they haven't 
  /// been inserted already, they get inserted, otherwise they are ignored.
  /// Either way, the slot number for the Value* is returned.
  unsigned createSlot(const Value *V);
  unsigned createSlot(const Type* Ty);

  /// Insert a value into the value table. Return the slot number
  /// that it now occupies.  BadThings(TM) will happen if you insert a
  /// Value that's already been inserted. 
  unsigned insertValue( const Value *V );
  unsigned insertValue( const Type* Ty);

  /// Add all of the module level global variables (and their initializers)
  /// and function declarations, but not the contents of those functions.
  void processModule();

  /// Add all of the functions arguments, basic blocks, and instructions
  void processFunction();

  SlotMachine(const SlotMachine &);  // DO NOT IMPLEMENT
  void operator=(const SlotMachine &);  // DO NOT IMPLEMENT

/// @}
/// @name Data
/// @{
public:

  /// @brief The module for which we are holding slot numbers
  const Module* TheModule;

  /// @brief The function for which we are holding slot numbers
  const Function* TheFunction;

  /// @brief The TypePlanes map for the module level data
  TypedPlanes mMap;
  TypePlane mTypes;

  /// @brief The TypePlanes map for the function level data
  TypedPlanes fMap;
  TypePlane fTypes;

/// @}

};

}  // end namespace llvm

static RegisterPass<PrintModulePass>
X("printm", "Print module to stderr",PassInfo::Analysis|PassInfo::Optimization);
static RegisterPass<PrintFunctionPass>
Y("print","Print function to stderr",PassInfo::Analysis|PassInfo::Optimization);

static void WriteAsOperandInternal(std::ostream &Out, const Value *V, 
                                   bool PrintName,
                                 std::map<const Type *, std::string> &TypeTable,
                                   SlotMachine *Machine);

static void WriteAsOperandInternal(std::ostream &Out, const Type *T, 
                                   bool PrintName,
                                 std::map<const Type *, std::string> &TypeTable,
                                   SlotMachine *Machine);

static const Module *getModuleFromVal(const Value *V) {
  if (const Argument *MA = dyn_cast<Argument>(V))
    return MA->getParent() ? MA->getParent()->getParent() : 0;
  else if (const BasicBlock *BB = dyn_cast<BasicBlock>(V))
    return BB->getParent() ? BB->getParent()->getParent() : 0;
  else if (const Instruction *I = dyn_cast<Instruction>(V)) {
    const Function *M = I->getParent() ? I->getParent()->getParent() : 0;
    return M ? M->getParent() : 0;
  } else if (const GlobalValue *GV = dyn_cast<GlobalValue>(V))
    return GV->getParent();
  return 0;
}

static SlotMachine *createSlotMachine(const Value *V) {
  if (const Argument *FA = dyn_cast<Argument>(V)) {
    return new SlotMachine(FA->getParent());
  } else if (const Instruction *I = dyn_cast<Instruction>(V)) {
    return new SlotMachine(I->getParent()->getParent());
  } else if (const BasicBlock *BB = dyn_cast<BasicBlock>(V)) {
    return new SlotMachine(BB->getParent());
  } else if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(V)){
    return new SlotMachine(GV->getParent());
  } else if (const Function *Func = dyn_cast<Function>(V)) {
    return new SlotMachine(Func);
  }
  return 0;
}

// getLLVMName - Turn the specified string into an 'LLVM name', which is either
// prefixed with % (if the string only contains simple characters) or is
// surrounded with ""'s (if it has special chars in it).
static std::string getLLVMName(const std::string &Name) {
  assert(!Name.empty() && "Cannot get empty name!");

  // First character cannot start with a number...
  if (Name[0] >= '0' && Name[0] <= '9')
    return "\"" + Name + "\"";

  // Scan to see if we have any characters that are not on the "white list"
  for (unsigned i = 0, e = Name.size(); i != e; ++i) {
    char C = Name[i];
    assert(C != '"' && "Illegal character in LLVM value name!");
    if ((C < 'a' || C > 'z') && (C < 'A' || C > 'Z') && (C < '0' || C > '9') &&
        C != '-' && C != '.' && C != '_')
      return "\"" + Name + "\"";
  }
  
  // If we get here, then the identifier is legal to use as a "VarID".
  return "%"+Name;
}


/// fillTypeNameTable - If the module has a symbol table, take all global types
/// and stuff their names into the TypeNames map.
///
static void fillTypeNameTable(const Module *M,
                              std::map<const Type *, std::string> &TypeNames) {
  if (!M) return;
  const SymbolTable &ST = M->getSymbolTable();
  SymbolTable::type_const_iterator TI = ST.type_begin();
  for (; TI != ST.type_end(); ++TI ) {
    // As a heuristic, don't insert pointer to primitive types, because
    // they are used too often to have a single useful name.
    //
    const Type *Ty = cast<Type>(TI->second);
    if (!isa<PointerType>(Ty) ||
        !cast<PointerType>(Ty)->getElementType()->isPrimitiveType() ||
        isa<OpaqueType>(cast<PointerType>(Ty)->getElementType()))
      TypeNames.insert(std::make_pair(Ty, getLLVMName(TI->first)));
  }
}



static void calcTypeName(const Type *Ty, 
                         std::vector<const Type *> &TypeStack,
                         std::map<const Type *, std::string> &TypeNames,
                         std::string & Result){
  if (Ty->isPrimitiveType() && !isa<OpaqueType>(Ty)) {
    Result += Ty->getDescription();  // Base case
    return;
  }

  // Check to see if the type is named.
  std::map<const Type *, std::string>::iterator I = TypeNames.find(Ty);
  if (I != TypeNames.end()) {
    Result += I->second;
    return;
  }

  if (isa<OpaqueType>(Ty)) {
    Result += "opaque";
    return;
  }

  // Check to see if the Type is already on the stack...
  unsigned Slot = 0, CurSize = TypeStack.size();
  while (Slot < CurSize && TypeStack[Slot] != Ty) ++Slot; // Scan for type

  // This is another base case for the recursion.  In this case, we know 
  // that we have looped back to a type that we have previously visited.
  // Generate the appropriate upreference to handle this.
  if (Slot < CurSize) {
    Result += "\\" + utostr(CurSize-Slot);     // Here's the upreference
    return;
  }

  TypeStack.push_back(Ty);    // Recursive case: Add us to the stack..
  
  switch (Ty->getTypeID()) {
  case Type::FunctionTyID: {
    const FunctionType *FTy = cast<FunctionType>(Ty);
    calcTypeName(FTy->getReturnType(), TypeStack, TypeNames, Result);
    Result += " (";
    for (FunctionType::param_iterator I = FTy->param_begin(),
           E = FTy->param_end(); I != E; ++I) {
      if (I != FTy->param_begin())
        Result += ", ";
      calcTypeName(*I, TypeStack, TypeNames, Result);
    }
    if (FTy->isVarArg()) {
      if (FTy->getNumParams()) Result += ", ";
      Result += "...";
    }
    Result += ")";
    break;
  }
  case Type::StructTyID: {
    const StructType *STy = cast<StructType>(Ty);
    Result += "{ ";
    for (StructType::element_iterator I = STy->element_begin(),
           E = STy->element_end(); I != E; ++I) {
      if (I != STy->element_begin())
        Result += ", ";
      calcTypeName(*I, TypeStack, TypeNames, Result);
    }
    Result += " }";
    break;
  }
  case Type::PointerTyID:
    calcTypeName(cast<PointerType>(Ty)->getElementType(), 
                          TypeStack, TypeNames, Result);
    Result += "*";
    break;
  case Type::ArrayTyID: {
    const ArrayType *ATy = cast<ArrayType>(Ty);
    Result += "[" + utostr(ATy->getNumElements()) + " x ";
    calcTypeName(ATy->getElementType(), TypeStack, TypeNames, Result);
    Result += "]";
    break;
  }
  case Type::OpaqueTyID:
    Result += "opaque";
    break;
  default:
    Result += "<unrecognized-type>";
  }

  TypeStack.pop_back();       // Remove self from stack...
  return;
}


/// printTypeInt - The internal guts of printing out a type that has a
/// potentially named portion.
///
static std::ostream &printTypeInt(std::ostream &Out, const Type *Ty,
                              std::map<const Type *, std::string> &TypeNames) {
  // Primitive types always print out their description, regardless of whether
  // they have been named or not.
  //
  if (Ty->isPrimitiveType() && !isa<OpaqueType>(Ty))
    return Out << Ty->getDescription();

  // Check to see if the type is named.
  std::map<const Type *, std::string>::iterator I = TypeNames.find(Ty);
  if (I != TypeNames.end()) return Out << I->second;

  // Otherwise we have a type that has not been named but is a derived type.
  // Carefully recurse the type hierarchy to print out any contained symbolic
  // names.
  //
  std::vector<const Type *> TypeStack;
  std::string TypeName;
  calcTypeName(Ty, TypeStack, TypeNames, TypeName);
  TypeNames.insert(std::make_pair(Ty, TypeName));//Cache type name for later use
  return (Out << TypeName);
}


/// WriteTypeSymbolic - This attempts to write the specified type as a symbolic
/// type, iff there is an entry in the modules symbol table for the specified
/// type or one of it's component types. This is slower than a simple x << Type
///
std::ostream &llvm::WriteTypeSymbolic(std::ostream &Out, const Type *Ty,
                                      const Module *M) {
  Out << ' '; 

  // If they want us to print out a type, attempt to make it symbolic if there
  // is a symbol table in the module...
  if (M) {
    std::map<const Type *, std::string> TypeNames;
    fillTypeNameTable(M, TypeNames);
    
    return printTypeInt(Out, Ty, TypeNames);
  } else {
    return Out << Ty->getDescription();
  }
}

static void WriteConstantInt(std::ostream &Out, const Constant *CV, 
                             bool PrintName,
                             std::map<const Type *, std::string> &TypeTable,
                             SlotMachine *Machine) {
  if (const ConstantBool *CB = dyn_cast<ConstantBool>(CV)) {
    Out << (CB == ConstantBool::True ? "true" : "false");
  } else if (const ConstantSInt *CI = dyn_cast<ConstantSInt>(CV)) {
    Out << CI->getValue();
  } else if (const ConstantUInt *CI = dyn_cast<ConstantUInt>(CV)) {
    Out << CI->getValue();
  } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV)) {
    // We would like to output the FP constant value in exponential notation,
    // but we cannot do this if doing so will lose precision.  Check here to
    // make sure that we only output it in exponential format if we can parse
    // the value back and get the same value.
    //
    std::string StrVal = ftostr(CFP->getValue());

    // Check to make sure that the stringized number is not some string like
    // "Inf" or NaN, that atof will accept, but the lexer will not.  Check that
    // the string matches the "[-+]?[0-9]" regex.
    //
    if ((StrVal[0] >= '0' && StrVal[0] <= '9') ||
        ((StrVal[0] == '-' || StrVal[0] == '+') &&
         (StrVal[1] >= '0' && StrVal[1] <= '9')))
      // Reparse stringized version!
      if (atof(StrVal.c_str()) == CFP->getValue()) {
        Out << StrVal; return;
      }
    
    // Otherwise we could not reparse it to exactly the same value, so we must
    // output the string in hexadecimal format!
    //
    // Behave nicely in the face of C TBAA rules... see:
    // http://www.nullstone.com/htmls/category/aliastyp.htm
    //
    double Val = CFP->getValue();
    char *Ptr = (char*)&Val;
    assert(sizeof(double) == sizeof(uint64_t) && sizeof(double) == 8 &&
           "assuming that double is 64 bits!");
    Out << "0x" << utohexstr(*(uint64_t*)Ptr);

  } else if (isa<ConstantAggregateZero>(CV)) {
    Out << "zeroinitializer";
  } else if (const ConstantArray *CA = dyn_cast<ConstantArray>(CV)) {
    // As a special case, print the array as a string if it is an array of
    // ubytes or an array of sbytes with positive values.
    // 
    const Type *ETy = CA->getType()->getElementType();
    bool isString = (ETy == Type::SByteTy || ETy == Type::UByteTy);

    if (ETy == Type::SByteTy)
      for (unsigned i = 0; i < CA->getNumOperands(); ++i)
        if (cast<ConstantSInt>(CA->getOperand(i))->getValue() < 0) {
          isString = false;
          break;
        }

    if (isString) {
      Out << "c\"";
      for (unsigned i = 0; i < CA->getNumOperands(); ++i) {
        unsigned char C = 
          (unsigned char)cast<ConstantInt>(CA->getOperand(i))->getRawValue();
        
        if (isprint(C) && C != '"' && C != '\\') {
          Out << C;
        } else {
          Out << '\\'
              << (char) ((C/16  < 10) ? ( C/16 +'0') : ( C/16 -10+'A'))
              << (char)(((C&15) < 10) ? ((C&15)+'0') : ((C&15)-10+'A'));
        }
      }
      Out << "\"";

    } else {                // Cannot output in string format...
      Out << '[';
      if (CA->getNumOperands()) {
        Out << ' ';
        printTypeInt(Out, ETy, TypeTable);
        WriteAsOperandInternal(Out, CA->getOperand(0),
                               PrintName, TypeTable, Machine);
        for (unsigned i = 1, e = CA->getNumOperands(); i != e; ++i) {
          Out << ", ";
          printTypeInt(Out, ETy, TypeTable);
          WriteAsOperandInternal(Out, CA->getOperand(i), PrintName,
                                 TypeTable, Machine);
        }
      }
      Out << " ]";
    }
  } else if (const ConstantStruct *CS = dyn_cast<ConstantStruct>(CV)) {
    Out << '{';
    if (CS->getNumOperands()) {
      Out << ' ';
      printTypeInt(Out, CS->getOperand(0)->getType(), TypeTable);

      WriteAsOperandInternal(Out, CS->getOperand(0),
                             PrintName, TypeTable, Machine);

      for (unsigned i = 1; i < CS->getNumOperands(); i++) {
        Out << ", ";
        printTypeInt(Out, CS->getOperand(i)->getType(), TypeTable);

        WriteAsOperandInternal(Out, CS->getOperand(i),
                               PrintName, TypeTable, Machine);
      }
    }

    Out << " }";
  } else if (isa<ConstantPointerNull>(CV)) {
    Out << "null";

  } else if (const ConstantPointerRef *PR = dyn_cast<ConstantPointerRef>(CV)) {
    WriteAsOperandInternal(Out, PR->getValue(), true, TypeTable, Machine);

  } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV)) {
    Out << CE->getOpcodeName() << " (";
    
    for (User::const_op_iterator OI=CE->op_begin(); OI != CE->op_end(); ++OI) {
      printTypeInt(Out, (*OI)->getType(), TypeTable);
      WriteAsOperandInternal(Out, *OI, PrintName, TypeTable, Machine);
      if (OI+1 != CE->op_end())
        Out << ", ";
    }
    
    if (CE->getOpcode() == Instruction::Cast) {
      Out << " to ";
      printTypeInt(Out, CE->getType(), TypeTable);
    }
    Out << ')';

  } else {
    Out << "<placeholder or erroneous Constant>";
  }
}


/// WriteAsOperand - Write the name of the specified value out to the specified
/// ostream.  This can be useful when you just want to print int %reg126, not
/// the whole instruction that generated it.
///
static void WriteAsOperandInternal(std::ostream &Out, const Value *V, 
                                   bool PrintName,
                                  std::map<const Type*, std::string> &TypeTable,
                                   SlotMachine *Machine) {
  Out << ' ';
  if (PrintName && V->hasName()) {
    Out << getLLVMName(V->getName());
  } else {
    if (const Constant *CV = dyn_cast<Constant>(V)) {
      WriteConstantInt(Out, CV, PrintName, TypeTable, Machine);
    } else {
      int Slot;
      if (Machine) {
        Slot = Machine->getSlot(V);
      } else {
        Machine = createSlotMachine(V);
        if (Machine == 0) 
          Slot = Machine->getSlot(V);
        else
          Slot = -1;
        delete Machine;
      }
      if (Slot != -1)
        Out << '%' << Slot;
      else
        Out << "<badref>";
    }
  }
}

/// WriteAsOperand - Write the name of the specified value out to the specified
/// ostream.  This can be useful when you just want to print int %reg126, not
/// the whole instruction that generated it.
///
std::ostream &llvm::WriteAsOperand(std::ostream &Out, const Value *V,
                                   bool PrintType, bool PrintName, 
                                   const Module *Context) {
  std::map<const Type *, std::string> TypeNames;
  if (Context == 0) Context = getModuleFromVal(V);

  if (Context)
    fillTypeNameTable(Context, TypeNames);

  if (PrintType)
    printTypeInt(Out, V->getType(), TypeNames);
  
  WriteAsOperandInternal(Out, V, PrintName, TypeNames, 0);
  return Out;
}

/// WriteAsOperandInternal - Write the name of the specified value out to 
/// the specified ostream.  This can be useful when you just want to print 
/// int %reg126, not the whole instruction that generated it.
///
static void WriteAsOperandInternal(std::ostream &Out, const Type *T, 
                                   bool PrintName,
                                  std::map<const Type*, std::string> &TypeTable,
                                   SlotMachine *Machine) {
  Out << ' ';
  int Slot;
  if (Machine) {
    Slot = Machine->getSlot(T);
    if (Slot != -1)
      Out << '%' << Slot;
    else
      Out << "<badref>";
  } else {
    Out << T->getDescription();
  }
}

/// WriteAsOperand - Write the name of the specified value out to the specified
/// ostream.  This can be useful when you just want to print int %reg126, not
/// the whole instruction that generated it.
///
std::ostream &llvm::WriteAsOperand(std::ostream &Out, const Type *Ty,
                                   bool PrintType, bool PrintName, 
                                   const Module *Context) {
  std::map<const Type *, std::string> TypeNames;
  assert(Context != 0 && "Can't write types as operand without module context");

  fillTypeNameTable(Context, TypeNames);

  // if (PrintType)
    // printTypeInt(Out, V->getType(), TypeNames);
  
  printTypeInt(Out, Ty, TypeNames);

  WriteAsOperandInternal(Out, Ty, PrintName, TypeNames, 0);
  return Out;
}

namespace llvm {

class AssemblyWriter {
  std::ostream &Out;
  SlotMachine &Machine;
  const Module *TheModule;
  std::map<const Type *, std::string> TypeNames;
  AssemblyAnnotationWriter *AnnotationWriter;
public:
  inline AssemblyWriter(std::ostream &o, SlotMachine &Mac, const Module *M,
                        AssemblyAnnotationWriter *AAW)
    : Out(o), Machine(Mac), TheModule(M), AnnotationWriter(AAW) {

    // If the module has a symbol table, take all global types and stuff their
    // names into the TypeNames map.
    //
    fillTypeNameTable(M, TypeNames);
  }

  inline void write(const Module *M)         { printModule(M);      }
  inline void write(const GlobalVariable *G) { printGlobal(G);      }
  inline void write(const Function *F)       { printFunction(F);    }
  inline void write(const BasicBlock *BB)    { printBasicBlock(BB); }
  inline void write(const Instruction *I)    { printInstruction(*I); }
  inline void write(const Constant *CPV)     { printConstant(CPV);  }
  inline void write(const Type *Ty)          { printType(Ty);       }

  void writeOperand(const Value *Op, bool PrintType, bool PrintName = true);

  const Module* getModule() { return TheModule; }

private :
  void printModule(const Module *M);
  void printSymbolTable(const SymbolTable &ST);
  void printConstant(const Constant *CPV);
  void printGlobal(const GlobalVariable *GV);
  void printFunction(const Function *F);
  void printArgument(const Argument *FA);
  void printBasicBlock(const BasicBlock *BB);
  void printInstruction(const Instruction &I);

  // printType - Go to extreme measures to attempt to print out a short,
  // symbolic version of a type name.
  //
  std::ostream &printType(const Type *Ty) {
    return printTypeInt(Out, Ty, TypeNames);
  }

  // printTypeAtLeastOneLevel - Print out one level of the possibly complex type
  // without considering any symbolic types that we may have equal to it.
  //
  std::ostream &printTypeAtLeastOneLevel(const Type *Ty);

  // printInfoComment - Print a little comment after the instruction indicating
  // which slot it occupies.
  void printInfoComment(const Value &V);
};
}  // end of llvm namespace

/// printTypeAtLeastOneLevel - Print out one level of the possibly complex type
/// without considering any symbolic types that we may have equal to it.
///
std::ostream &AssemblyWriter::printTypeAtLeastOneLevel(const Type *Ty) {
  if (const FunctionType *FTy = dyn_cast<FunctionType>(Ty)) {
    printType(FTy->getReturnType()) << " (";
    for (FunctionType::param_iterator I = FTy->param_begin(),
           E = FTy->param_end(); I != E; ++I) {
      if (I != FTy->param_begin())
        Out << ", ";
      printType(*I);
    }
    if (FTy->isVarArg()) {
      if (FTy->getNumParams()) Out << ", ";
      Out << "...";
    }
    Out << ')';
  } else if (const StructType *STy = dyn_cast<StructType>(Ty)) {
    Out << "{ ";
    for (StructType::element_iterator I = STy->element_begin(),
           E = STy->element_end(); I != E; ++I) {
      if (I != STy->element_begin())
        Out << ", ";
      printType(*I);
    }
    Out << " }";
  } else if (const PointerType *PTy = dyn_cast<PointerType>(Ty)) {
    printType(PTy->getElementType()) << '*';
  } else if (const ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
    Out << '[' << ATy->getNumElements() << " x ";
    printType(ATy->getElementType()) << ']';
  } else if (const OpaqueType *OTy = dyn_cast<OpaqueType>(Ty)) {
    Out << "opaque";
  } else {
    if (!Ty->isPrimitiveType())
      Out << "<unknown derived type>";
    printType(Ty);
  }
  return Out;
}


void AssemblyWriter::writeOperand(const Value *Operand, bool PrintType, 
                                  bool PrintName) {
  if (PrintType) { Out << ' '; printType(Operand->getType()); }
  WriteAsOperandInternal(Out, Operand, PrintName, TypeNames, &Machine);
}


void AssemblyWriter::printModule(const Module *M) {
  switch (M->getEndianness()) {
  case Module::LittleEndian: Out << "target endian = little\n"; break;
  case Module::BigEndian:    Out << "target endian = big\n";    break;
  case Module::AnyEndianness: break;
  }
  switch (M->getPointerSize()) {
  case Module::Pointer32:    Out << "target pointersize = 32\n"; break;
  case Module::Pointer64:    Out << "target pointersize = 64\n"; break;
  case Module::AnyPointerSize: break;
  }
  
  // Loop over the symbol table, emitting all named constants...
  printSymbolTable(M->getSymbolTable());
  
  for (Module::const_giterator I = M->gbegin(), E = M->gend(); I != E; ++I)
    printGlobal(I);

  Out << "\nimplementation   ; Functions:\n";
  
  // Output all of the functions...
  for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I)
    printFunction(I);
}

void AssemblyWriter::printGlobal(const GlobalVariable *GV) {
  if (GV->hasName()) Out << getLLVMName(GV->getName()) << " = ";

  if (!GV->hasInitializer()) 
    Out << "external ";
  else
    switch (GV->getLinkage()) {
    case GlobalValue::InternalLinkage:  Out << "internal "; break;
    case GlobalValue::LinkOnceLinkage:  Out << "linkonce "; break;
    case GlobalValue::WeakLinkage:      Out << "weak "; break;
    case GlobalValue::AppendingLinkage: Out << "appending "; break;
    case GlobalValue::ExternalLinkage: break;
    }

  Out << (GV->isConstant() ? "constant " : "global ");
  printType(GV->getType()->getElementType());

  if (GV->hasInitializer())
    writeOperand(GV->getInitializer(), false, false);

  printInfoComment(*GV);
  Out << "\n";
}


// printSymbolTable - Run through symbol table looking for constants
// and types. Emit their declarations.
void AssemblyWriter::printSymbolTable(const SymbolTable &ST) {

  // Print the types.
  for (SymbolTable::type_const_iterator TI = ST.type_begin();
       TI != ST.type_end(); ++TI ) {
    Out << "\t" << getLLVMName(TI->first) << " = type ";

    // Make sure we print out at least one level of the type structure, so
    // that we do not get %FILE = type %FILE
    //
    printTypeAtLeastOneLevel(TI->second) << "\n";
  }
    
  // Print the constants, in type plane order.
  for (SymbolTable::plane_const_iterator PI = ST.plane_begin();
       PI != ST.plane_end(); ++PI ) {
    SymbolTable::value_const_iterator VI = ST.value_begin(PI->first);
    SymbolTable::value_const_iterator VE = ST.value_end(PI->first);

    for (; VI != VE; ++VI) {
      const Value *V = VI->second;
      if (const Constant *CPV = dyn_cast<Constant>(V)) {
        printConstant(CPV);
      }
    }
  }
}


/// printConstant - Print out a constant pool entry...
///
void AssemblyWriter::printConstant(const Constant *CPV) {
  // Don't print out unnamed constants, they will be inlined
  if (!CPV->hasName()) return;

  // Print out name...
  Out << "\t" << getLLVMName(CPV->getName()) << " =";

  // Write the value out now...
  writeOperand(CPV, true, false);

  printInfoComment(*CPV);
  Out << "\n";
}

/// printFunction - Print all aspects of a function.
///
void AssemblyWriter::printFunction(const Function *F) {
  // Print out the return type and name...
  Out << "\n";

  if (AnnotationWriter) AnnotationWriter->emitFunctionAnnot(F, Out);

  if (F->isExternal())
    Out << "declare ";
  else
    switch (F->getLinkage()) {
    case GlobalValue::InternalLinkage:  Out << "internal "; break;
    case GlobalValue::LinkOnceLinkage:  Out << "linkonce "; break;
    case GlobalValue::WeakLinkage:      Out << "weak "; break;
    case GlobalValue::AppendingLinkage: Out << "appending "; break;
    case GlobalValue::ExternalLinkage: break;
    }

  printType(F->getReturnType()) << ' ';
  if (!F->getName().empty())
    Out << getLLVMName(F->getName());
  else
    Out << "\"\"";
  Out << '(';
  Machine.incorporateFunction(F);

  // Loop over the arguments, printing them...
  const FunctionType *FT = F->getFunctionType();

  for(Function::const_aiterator I = F->abegin(), E = F->aend(); I != E; ++I)
    printArgument(I);

  // Finish printing arguments...
  if (FT->isVarArg()) {
    if (FT->getNumParams()) Out << ", ";
    Out << "...";  // Output varargs portion of signature!
  }
  Out << ')';

  if (F->isExternal()) {
    Out << "\n";
  } else {
    Out << " {";
  
    // Output all of its basic blocks... for the function
    for (Function::const_iterator I = F->begin(), E = F->end(); I != E; ++I)
      printBasicBlock(I);

    Out << "}\n";
  }

  Machine.purgeFunction();
}

/// printArgument - This member is called for every argument that is passed into
/// the function.  Simply print it out
///
void AssemblyWriter::printArgument(const Argument *Arg) {
  // Insert commas as we go... the first arg doesn't get a comma
  if (Arg != &Arg->getParent()->afront()) Out << ", ";

  // Output type...
  printType(Arg->getType());
  
  // Output name, if available...
  if (Arg->hasName())
    Out << ' ' << getLLVMName(Arg->getName());
}

/// printBasicBlock - This member is called for each basic block in a method.
///
void AssemblyWriter::printBasicBlock(const BasicBlock *BB) {
  if (BB->hasName()) {              // Print out the label if it exists...
    Out << "\n" << BB->getName() << ':';
  } else if (!BB->use_empty()) {      // Don't print block # of no uses...
    Out << "\n; <label>:";
    int Slot = Machine.getSlot(BB);
    if (Slot != -1)
      Out << Slot;
    else
      Out << "<badref>";
  }

  if (BB->getParent() == 0)
    Out << "\t\t; Error: Block without parent!";
  else {
    if (BB != &BB->getParent()->front()) {  // Not the entry block?
      // Output predecessors for the block...
      Out << "\t\t;";
      pred_const_iterator PI = pred_begin(BB), PE = pred_end(BB);
      
      if (PI == PE) {
        Out << " No predecessors!";
      } else {
        Out << " preds =";
        writeOperand(*PI, false, true);
        for (++PI; PI != PE; ++PI) {
          Out << ',';
          writeOperand(*PI, false, true);
        }
      }
    }
  }
  
  Out << "\n";

  if (AnnotationWriter) AnnotationWriter->emitBasicBlockStartAnnot(BB, Out);

  // Output all of the instructions in the basic block...
  for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I != E; ++I)
    printInstruction(*I);

  if (AnnotationWriter) AnnotationWriter->emitBasicBlockEndAnnot(BB, Out);
}


/// printInfoComment - Print a little comment after the instruction indicating
/// which slot it occupies.
///
void AssemblyWriter::printInfoComment(const Value &V) {
  if (V.getType() != Type::VoidTy) {
    Out << "\t\t; <";
    printType(V.getType()) << '>';

    if (!V.hasName()) {
      int SlotNum = Machine.getSlot(&V);
      if (SlotNum == -1)
        Out << ":<badref>";
      else
        Out << ':' << SlotNum; // Print out the def slot taken.
    }
    Out << " [#uses=" << V.use_size() << ']';  // Output # uses
  }
}

/// printInstruction - This member is called for each Instruction in a function..
///
void AssemblyWriter::printInstruction(const Instruction &I) {
  if (AnnotationWriter) AnnotationWriter->emitInstructionAnnot(&I, Out);

  Out << "\t";

  // Print out name if it exists...
  if (I.hasName())
    Out << getLLVMName(I.getName()) << " = ";

  // If this is a volatile load or store, print out the volatile marker
  if ((isa<LoadInst>(I)  && cast<LoadInst>(I).isVolatile()) ||
      (isa<StoreInst>(I) && cast<StoreInst>(I).isVolatile()))
      Out << "volatile ";

  // Print out the opcode...
  Out << I.getOpcodeName();

  // Print out the type of the operands...
  const Value *Operand = I.getNumOperands() ? I.getOperand(0) : 0;

  // Special case conditional branches to swizzle the condition out to the front
  if (isa<BranchInst>(I) && I.getNumOperands() > 1) {
    writeOperand(I.getOperand(2), true);
    Out << ',';
    writeOperand(Operand, true);
    Out << ',';
    writeOperand(I.getOperand(1), true);

  } else if (isa<SwitchInst>(I)) {
    // Special case switch statement to get formatting nice and correct...
    writeOperand(Operand        , true); Out << ',';
    writeOperand(I.getOperand(1), true); Out << " [";

    for (unsigned op = 2, Eop = I.getNumOperands(); op < Eop; op += 2) {
      Out << "\n\t\t";
      writeOperand(I.getOperand(op  ), true); Out << ',';
      writeOperand(I.getOperand(op+1), true);
    }
    Out << "\n\t]";
  } else if (isa<PHINode>(I)) {
    Out << ' ';
    printType(I.getType());
    Out << ' ';

    for (unsigned op = 0, Eop = I.getNumOperands(); op < Eop; op += 2) {
      if (op) Out << ", ";
      Out << '[';  
      writeOperand(I.getOperand(op  ), false); Out << ',';
      writeOperand(I.getOperand(op+1), false); Out << " ]";
    }
  } else if (isa<ReturnInst>(I) && !Operand) {
    Out << " void";
  } else if (isa<CallInst>(I)) {
    const PointerType  *PTy = cast<PointerType>(Operand->getType());
    const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
    const Type       *RetTy = FTy->getReturnType();

    // If possible, print out the short form of the call instruction.  We can
    // only do this if the first argument is a pointer to a nonvararg function,
    // and if the return type is not a pointer to a function.
    //
    if (!FTy->isVarArg() &&
        (!isa<PointerType>(RetTy) || 
         !isa<FunctionType>(cast<PointerType>(RetTy)->getElementType()))) {
      Out << ' '; printType(RetTy);
      writeOperand(Operand, false);
    } else {
      writeOperand(Operand, true);
    }
    Out << '(';
    if (I.getNumOperands() > 1) writeOperand(I.getOperand(1), true);
    for (unsigned op = 2, Eop = I.getNumOperands(); op < Eop; ++op) {
      Out << ',';
      writeOperand(I.getOperand(op), true);
    }

    Out << " )";
  } else if (const InvokeInst *II = dyn_cast<InvokeInst>(&I)) {
    const PointerType  *PTy = cast<PointerType>(Operand->getType());
    const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
    const Type       *RetTy = FTy->getReturnType();

    // If possible, print out the short form of the invoke instruction. We can
    // only do this if the first argument is a pointer to a nonvararg function,
    // and if the return type is not a pointer to a function.
    //
    if (!FTy->isVarArg() &&
        (!isa<PointerType>(RetTy) || 
         !isa<FunctionType>(cast<PointerType>(RetTy)->getElementType()))) {
      Out << ' '; printType(RetTy);
      writeOperand(Operand, false);
    } else {
      writeOperand(Operand, true);
    }

    Out << '(';
    if (I.getNumOperands() > 3) writeOperand(I.getOperand(3), true);
    for (unsigned op = 4, Eop = I.getNumOperands(); op < Eop; ++op) {
      Out << ',';
      writeOperand(I.getOperand(op), true);
    }

    Out << " )\n\t\t\tto";
    writeOperand(II->getNormalDest(), true);
    Out << " unwind";
    writeOperand(II->getUnwindDest(), true);

  } else if (const AllocationInst *AI = dyn_cast<AllocationInst>(&I)) {
    Out << ' ';
    printType(AI->getType()->getElementType());
    if (AI->isArrayAllocation()) {
      Out << ',';
      writeOperand(AI->getArraySize(), true);
    }
  } else if (isa<CastInst>(I)) {
    if (Operand) writeOperand(Operand, true);   // Work with broken code
    Out << " to ";
    printType(I.getType());
  } else if (isa<VAArgInst>(I)) {
    if (Operand) writeOperand(Operand, true);   // Work with broken code
    Out << ", ";
    printType(I.getType());
  } else if (const VANextInst *VAN = dyn_cast<VANextInst>(&I)) {
    if (Operand) writeOperand(Operand, true);   // Work with broken code
    Out << ", ";
    printType(VAN->getArgType());
  } else if (Operand) {   // Print the normal way...

    // PrintAllTypes - Instructions who have operands of all the same type 
    // omit the type from all but the first operand.  If the instruction has
    // different type operands (for example br), then they are all printed.
    bool PrintAllTypes = false;
    const Type *TheType = Operand->getType();

    // Shift Left & Right print both types even for Ubyte LHS, and select prints
    // types even if all operands are bools.
    if (isa<ShiftInst>(I) || isa<SelectInst>(I)) {
      PrintAllTypes = true;
    } else {
      for (unsigned i = 1, E = I.getNumOperands(); i != E; ++i) {
        Operand = I.getOperand(i);
        if (Operand->getType() != TheType) {
          PrintAllTypes = true;    // We have differing types!  Print them all!
          break;
        }
      }
    }
    
    if (!PrintAllTypes) {
      Out << ' ';
      printType(TheType);
    }

    for (unsigned i = 0, E = I.getNumOperands(); i != E; ++i) {
      if (i) Out << ',';
      writeOperand(I.getOperand(i), PrintAllTypes);
    }
  }

  printInfoComment(I);
  Out << "\n";
}


//===----------------------------------------------------------------------===//
//                       External Interface declarations
//===----------------------------------------------------------------------===//

void Module::print(std::ostream &o, AssemblyAnnotationWriter *AAW) const {
  SlotMachine SlotTable(this);
  AssemblyWriter W(o, SlotTable, this, AAW);
  W.write(this);
}

void GlobalVariable::print(std::ostream &o) const {
  SlotMachine SlotTable(getParent());
  AssemblyWriter W(o, SlotTable, getParent(), 0);
  W.write(this);
}

void Function::print(std::ostream &o, AssemblyAnnotationWriter *AAW) const {
  SlotMachine SlotTable(getParent());
  AssemblyWriter W(o, SlotTable, getParent(), AAW);

  W.write(this);
}

void BasicBlock::print(std::ostream &o, AssemblyAnnotationWriter *AAW) const {
  SlotMachine SlotTable(getParent());
  AssemblyWriter W(o, SlotTable, 
                   getParent() ? getParent()->getParent() : 0, AAW);
  W.write(this);
}

void Instruction::print(std::ostream &o, AssemblyAnnotationWriter *AAW) const {
  const Function *F = getParent() ? getParent()->getParent() : 0;
  SlotMachine SlotTable(F);
  AssemblyWriter W(o, SlotTable, F ? F->getParent() : 0, AAW);

  W.write(this);
}

void Constant::print(std::ostream &o) const {
  if (this == 0) { o << "<null> constant value\n"; return; }

  // Handle CPR's special, because they have context information...
  if (const ConstantPointerRef *CPR = dyn_cast<ConstantPointerRef>(this)) {
    CPR->getValue()->print(o);  // Print as a global value, with context info.
    return;
  }

  o << ' ' << getType()->getDescription() << ' ';

  std::map<const Type *, std::string> TypeTable;
  WriteConstantInt(o, this, false, TypeTable, 0);
}

void Type::print(std::ostream &o) const { 
  if (this == 0)
    o << "<null Type>";
  else
    o << getDescription();
}

void Argument::print(std::ostream &o) const {
  WriteAsOperand(o, this, true, true,
                 getParent() ? getParent()->getParent() : 0);
}

// Value::dump - allow easy printing of  Values from the debugger.
// Located here because so much of the needed functionality is here.
void Value::dump() const { print(std::cerr); }

// Type::dump - allow easy printing of  Values from the debugger.
// Located here because so much of the needed functionality is here.
void Type::dump() const { print(std::cerr); }

//===----------------------------------------------------------------------===//
//  CachedWriter Class Implementation
//===----------------------------------------------------------------------===//

void CachedWriter::setModule(const Module *M) {
  delete SC; delete AW;
  if (M) {
    SC = new SlotMachine(M );
    AW = new AssemblyWriter(Out, *SC, M, 0);
  } else {
    SC = 0; AW = 0;
  }
}

CachedWriter::~CachedWriter() {
  delete AW;
  delete SC;
}

CachedWriter &CachedWriter::operator<<(const Value &V) {
  assert(AW && SC && "CachedWriter does not have a current module!");
  if (const Instruction *I = dyn_cast<Instruction>(&V))
    AW->write(I);
  else if (const BasicBlock *BB = dyn_cast<BasicBlock>(&V))
    AW->write(BB);
  else if (const Function *F = dyn_cast<Function>(&V))
    AW->write(F);
  else if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(&V))
    AW->write(GV);
  else 
    AW->writeOperand(&V, true, true);
  return *this;
}

CachedWriter& CachedWriter::operator<<(const Type &Ty) {
  if (SymbolicTypes) {
    const Module *M = AW->getModule();
    if (M) WriteTypeSymbolic(Out, &Ty, M);
  } else {
    AW->write(&Ty);
  }
  return *this;
}

//===----------------------------------------------------------------------===//
//===--                    SlotMachine Implementation
//===----------------------------------------------------------------------===//

#if 0
#define SC_DEBUG(X) std::cerr << X
#else
#define SC_DEBUG(X)
#endif

// Module level constructor. Causes the contents of the Module (sans functions)
// to be added to the slot table.
SlotMachine::SlotMachine(const Module *M) 
  : TheModule(M)    ///< Saved for lazy initialization.
  , TheFunction(0)
  , mMap()
  , mTypes()
  , fMap()
  , fTypes()
{
}

// Function level constructor. Causes the contents of the Module and the one
// function provided to be added to the slot table.
SlotMachine::SlotMachine(const Function *F ) 
  : TheModule( F ? F->getParent() : 0 ) ///< Saved for lazy initialization
  , TheFunction(F) ///< Saved for lazy initialization
  , mMap()
  , mTypes()
  , fMap()
  , fTypes()
{
}

inline void SlotMachine::initialize(void) {
  if ( TheModule) { 
    processModule(); 
    TheModule = 0; ///< Prevent re-processing next time we're called.
  }
  if ( TheFunction ) { 
    processFunction(); 
  }
}

// Iterate through all the global variables, functions, and global
// variable initializers and create slots for them. 
void SlotMachine::processModule() {
  SC_DEBUG("begin processModule!\n");

  // Add all of the global variables to the value table...
  for (Module::const_giterator I = TheModule->gbegin(), E = TheModule->gend();
       I != E; ++I)
    createSlot(I);

  // Add all the functions to the table
  for (Module::const_iterator I = TheModule->begin(), E = TheModule->end();
       I != E; ++I)
    createSlot(I);

  SC_DEBUG("end processModule!\n");
}


// Process the arguments, basic blocks, and instructions  of a function.
void SlotMachine::processFunction() {
  SC_DEBUG("begin processFunction!\n");

  // Add all the function arguments
  for(Function::const_aiterator AI = TheFunction->abegin(), 
      AE = TheFunction->aend(); AI != AE; ++AI)
    createSlot(AI);

  SC_DEBUG("Inserting Instructions:\n");

  // Add all of the basic blocks and instructions
  for (Function::const_iterator BB = TheFunction->begin(), 
       E = TheFunction->end(); BB != E; ++BB) {
    createSlot(BB);
    for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I!=E; ++I) {
      createSlot(I);
    }
  }

  SC_DEBUG("end processFunction!\n");
}

// Clean up after incorporating a function. This is the only way
// to get out of the function incorporation state that affects the
// getSlot/createSlot lock. Function incorporation state is indicated
// by TheFunction != 0.
void SlotMachine::purgeFunction() {
  SC_DEBUG("begin purgeFunction!\n");
  fMap.clear(); // Simply discard the function level map
  fTypes.clear();
  TheFunction = 0;
  SC_DEBUG("end purgeFunction!\n");
}

/// Get the slot number for a value. This function will assert if you
/// ask for a Value that hasn't previously been inserted with createSlot.
/// Types are forbidden because Type does not inherit from Value (any more).
int SlotMachine::getSlot(const Value *V) {
  assert( V && "Can't get slot for null Value" );
  assert(!isa<Constant>(V) || isa<GlobalValue>(V) && 
    "Can't insert a non-GlobalValue Constant into SlotMachine"); 

  // Check for uninitialized state and do lazy initialization
  this->initialize();

  // Do not number CPR's at all. They are an abomination
  if ( const ConstantPointerRef* CPR = dyn_cast<ConstantPointerRef>(V) )
    V = CPR->getValue() ;

  // Get the type of the value
  const Type* VTy = V->getType();

  // Find the type plane in the module map
  TypedPlanes::const_iterator MI = mMap.find(VTy);

  if ( TheFunction ) {
    // Lookup the type in the function map too
    TypedPlanes::const_iterator FI = fMap.find(VTy);
    // If there is a corresponding type plane in the function map
    if ( FI != fMap.end() ) {
      // Lookup the Value in the function map
      ValueMap::const_iterator FVI = FI->second.map.find(V);
      // If the value doesn't exist in the function map
      if ( FVI == FI->second.map.end() ) {
        // Look up the value in the module map.
        if (MI == mMap.end()) return -1;
        ValueMap::const_iterator MVI = MI->second.map.find(V);
        // If we didn't find it, it wasn't inserted
        if (MVI == MI->second.map.end()) return -1;
        assert( MVI != MI->second.map.end() && "Value not found");
        // We found it only at the module level
        return MVI->second; 

      // else the value exists in the function map
      } else {
        // Return the slot number as the module's contribution to
        // the type plane plus the index in the function's contribution
        // to the type plane.
        if (MI != mMap.end())
          return MI->second.next_slot + FVI->second;
        else
          return FVI->second;
      }
    }
  }

  // N.B. Can get here only if either !TheFunction or the function doesn't
  // have a corresponding type plane for the Value

  // Make sure the type plane exists
  if (MI == mMap.end()) return -1;
  // Lookup the value in the module's map
  ValueMap::const_iterator MVI = MI->second.map.find(V);
  // Make sure we found it.
  if (MVI == MI->second.map.end()) return -1;
  // Return it.
  return MVI->second;
}

/// Get the slot number for a value. This function will assert if you
/// ask for a Value that hasn't previously been inserted with createSlot.
/// Types are forbidden because Type does not inherit from Value (any more).
int SlotMachine::getSlot(const Type *Ty) {
  assert( Ty && "Can't get slot for null Type" );

  // Check for uninitialized state and do lazy initialization
  this->initialize();

  if ( TheFunction ) {
    // Lookup the Type in the function map
    TypeMap::const_iterator FTI = fTypes.map.find(Ty);
    // If the Type doesn't exist in the function map
    if ( FTI == fTypes.map.end() ) {
      TypeMap::const_iterator MTI = mTypes.map.find(Ty);
      // If we didn't find it, it wasn't inserted
      if (MTI == mTypes.map.end()) 
        return -1;
      // We found it only at the module level
      return MTI->second; 

    // else the value exists in the function map
    } else {
      // Return the slot number as the module's contribution to
      // the type plane plus the index in the function's contribution
      // to the type plane.
      return mTypes.next_slot + FTI->second;
    }
  }

  // N.B. Can get here only if either !TheFunction

  // Lookup the value in the module's map
  TypeMap::const_iterator MTI = mTypes.map.find(Ty);
  // Make sure we found it.
  if (MTI == mTypes.map.end()) return -1;
  // Return it.
  return MTI->second;
}

// Create a new slot, or return the existing slot if it is already
// inserted. Note that the logic here parallels getSlot but instead
// of asserting when the Value* isn't found, it inserts the value.
unsigned SlotMachine::createSlot(const Value *V) {
  assert( V && "Can't insert a null Value to SlotMachine");
  assert(!isa<Constant>(V) || isa<GlobalValue>(V) && 
    "Can't insert a non-GlobalValue Constant into SlotMachine"); 

  const Type* VTy = V->getType();

  // Just ignore void typed things
  if (VTy == Type::VoidTy) return 0; // FIXME: Wrong return value!

  // Look up the type plane for the Value's type from the module map
  TypedPlanes::const_iterator MI = mMap.find(VTy);

  if ( TheFunction ) {
    // Get the type plane for the Value's type from the function map
    TypedPlanes::const_iterator FI = fMap.find(VTy);
    // If there is a corresponding type plane in the function map
    if ( FI != fMap.end() ) {
      // Lookup the Value in the function map
      ValueMap::const_iterator FVI = FI->second.map.find(V);
      // If the value doesn't exist in the function map
      if ( FVI == FI->second.map.end() ) {
        // If there is no corresponding type plane in the module map
        if ( MI == mMap.end() )
          return insertValue(V);
        // Look up the value in the module map
        ValueMap::const_iterator MVI = MI->second.map.find(V);
        // If we didn't find it, it wasn't inserted
        if ( MVI == MI->second.map.end() )
          return insertValue(V);
        else
          // We found it only at the module level
          return MVI->second;

      // else the value exists in the function map
      } else {
        if ( MI == mMap.end() )
          return FVI->second;
        else
          // Return the slot number as the module's contribution to
          // the type plane plus the index in the function's contribution
          // to the type plane.
          return MI->second.next_slot + FVI->second;
      }

    // else there is not a corresponding type plane in the function map
    } else {
      // If the type plane doesn't exists at the module level
      if ( MI == mMap.end() ) {
        return insertValue(V);
      // else type plane exists at the module level, examine it
      } else {
        // Look up the value in the module's map
        ValueMap::const_iterator MVI = MI->second.map.find(V);
        // If we didn't find it there either
        if ( MVI == MI->second.map.end() )
          // Return the slot number as the module's contribution to
          // the type plane plus the index of the function map insertion.
          return MI->second.next_slot + insertValue(V);
        else
          return MVI->second;
      }
    }
  }

  // N.B. Can only get here if !TheFunction

  // If the module map's type plane is not for the Value's type
  if ( MI != mMap.end() ) {
    // Lookup the value in the module's map
    ValueMap::const_iterator MVI = MI->second.map.find(V);
    if ( MVI != MI->second.map.end() ) 
      return MVI->second;
  }

  return insertValue(V);
}

// Create a new slot, or return the existing slot if it is already
// inserted. Note that the logic here parallels getSlot but instead
// of asserting when the Value* isn't found, it inserts the value.
unsigned SlotMachine::createSlot(const Type *Ty) {
  assert( Ty && "Can't insert a null Type to SlotMachine");

  if ( TheFunction ) {
    // Lookup the Type in the function map
    TypeMap::const_iterator FTI = fTypes.map.find(Ty);
    // If the type doesn't exist in the function map
    if ( FTI == fTypes.map.end() ) {
      // Look up the type in the module map
      TypeMap::const_iterator MTI = mTypes.map.find(Ty);
      // If we didn't find it, it wasn't inserted
      if ( MTI == mTypes.map.end() )
        return insertValue(Ty);
      else
        // We found it only at the module level
        return MTI->second;

    // else the value exists in the function map
    } else {
      // Return the slot number as the module's contribution to
      // the type plane plus the index in the function's contribution
      // to the type plane.
      return mTypes.next_slot + FTI->second;
    }
  }

  // N.B. Can only get here if !TheFunction

  // Lookup the type in the module's map
  TypeMap::const_iterator MTI = mTypes.map.find(Ty);
  if ( MTI != mTypes.map.end() ) 
    return MTI->second;

  return insertValue(Ty);
}

// Low level insert function. Minimal checking is done. This
// function is just for the convenience of createSlot (above).
unsigned SlotMachine::insertValue(const Value *V ) {
  assert(V && "Can't insert a null Value into SlotMachine!");
  assert(!isa<Constant>(V) || isa<GlobalValue>(V) && 
    "Can't insert a non-GlobalValue Constant into SlotMachine"); 

  // If this value does not contribute to a plane (is void)
  // or if the value already has a name then ignore it. 
  if (V->getType() == Type::VoidTy || V->hasName() ) {
      SC_DEBUG("ignored value " << *V << "\n");
      return 0;   // FIXME: Wrong return value
  }

  const Type *VTy = V->getType();
  unsigned DestSlot = 0;

  if ( TheFunction ) {
    TypedPlanes::iterator I = fMap.find( VTy );
    if ( I == fMap.end() ) 
      I = fMap.insert(std::make_pair(VTy,ValuePlane())).first;
    DestSlot = I->second.map[V] = I->second.next_slot++;
  } else {
    TypedPlanes::iterator I = mMap.find( VTy );
    if ( I == mMap.end() )
      I = mMap.insert(std::make_pair(VTy,ValuePlane())).first;
    DestSlot = I->second.map[V] = I->second.next_slot++;
  }

  SC_DEBUG("  Inserting value [" << VTy << "] = " << V << " slot=" << 
           DestSlot << " [");
  // G = Global, C = Constant, T = Type, F = Function, o = other
  SC_DEBUG((isa<GlobalVariable>(V) ? 'G' : (isa<Constant>(V) ? 'C' : 
           (isa<Function>(V) ? 'F' : 'o'))));
  SC_DEBUG("]\n");
  return DestSlot;
}

// Low level insert function. Minimal checking is done. This
// function is just for the convenience of createSlot (above).
unsigned SlotMachine::insertValue(const Type *Ty ) {
  assert(Ty && "Can't insert a null Type into SlotMachine!");

  unsigned DestSlot = 0;

  if ( TheFunction ) {
    DestSlot = fTypes.map[Ty] = fTypes.next_slot++;
  } else {
    DestSlot = fTypes.map[Ty] = fTypes.next_slot++;
  }
  SC_DEBUG("  Inserting type [" << DestSlot << "] = " << Ty << "\n");
  return DestSlot;
}

// vim: sw=2