CBackend now lives here

llvm-svn: 11415

4 files changed, 1438 insertions, 1 deletions

diff --git a/llvm/lib/Target/CBackend/CTargetMachine.h b/llvm/lib/Target/CBackend/CTargetMachine.h
new file mode 100644
index 00000000000..53e01471ea3
--- /dev/null
+++ b/llvm/lib/Target/CBackend/CTargetMachine.h
@@ -0,0 +1,39 @@
+//===-- CTargetMachine.h - TargetMachine for the C backend ------*- C++ -*-===//
+// 
+//                     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 file declares the TargetMachine that is used by the C backend.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef CTARGETMACHINE_H
+#define CTARGETMACHINE_H
+
+#include "llvm/Target/TargetMachine.h"
+
+namespace llvm {
+class IntrinsicLowering;
+
+struct CTargetMachine : public TargetMachine {
+  CTargetMachine(const Module &M, IntrinsicLowering *IL) :
+    TargetMachine("CBackend", IL) {}
+
+  virtual const TargetInstrInfo &getInstrInfo() const { abort(); }
+  virtual const TargetFrameInfo &getFrameInfo() const { abort(); }
+  virtual const TargetSchedInfo &getSchedInfo() const { abort(); }
+  virtual const TargetRegInfo   &getRegInfo()   const { abort(); }
+  virtual const TargetCacheInfo &getCacheInfo() const { abort(); }
+
+  // This is the only thing that actually does anything here.
+  virtual bool addPassesToEmitAssembly(PassManager &PM, std::ostream &Out);
+};
+
+} // End llvm namespace
+
+
+#endif
diff --git a/llvm/lib/Target/CBackend/Makefile b/llvm/lib/Target/CBackend/Makefile
new file mode 100644
index 00000000000..2e13bf7c99a
--- /dev/null
+++ b/llvm/lib/Target/CBackend/Makefile
@@ -0,0 +1,15 @@
+##===- lib/CWriter/Makefile --------------------------------*- Makefile -*-===##
+# 
+#                     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.
+# 
+##===----------------------------------------------------------------------===##
+
+LEVEL = ../..
+
+LIBRARYNAME = cwriter
+
+include $(LEVEL)/Makefile.common
+
diff --git a/llvm/lib/Target/CBackend/Writer.cpp b/llvm/lib/Target/CBackend/Writer.cpp
new file mode 100644
index 00000000000..25c940a6e1b
--- /dev/null
+++ b/llvm/lib/Target/CBackend/Writer.cpp
@@ -0,0 +1,1383 @@
+//===-- Writer.cpp - Library for converting LLVM code to C ----------------===//
+// 
+//                     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 converts LLVM code to C code, compilable by GCC and other C
+// compilers.
+//
+//===----------------------------------------------------------------------===//
+
+#include "CTargetMachine.h"
+#include "llvm/Target/TargetMachineImpls.h"
+#include "llvm/Constants.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/Module.h"
+#include "llvm/Instructions.h"
+#include "llvm/Pass.h"
+#include "llvm/PassManager.h"
+#include "llvm/SymbolTable.h"
+#include "llvm/Intrinsics.h"
+#include "llvm/Analysis/FindUsedTypes.h"
+#include "llvm/Analysis/ConstantsScanner.h"
+#include "llvm/Transforms/Scalar.h"
+#include "llvm/Support/CallSite.h"
+#include "llvm/Support/GetElementPtrTypeIterator.h"
+#include "llvm/Support/InstVisitor.h"
+#include "llvm/Support/Mangler.h"
+#include "Support/StringExtras.h"
+#include <algorithm>
+#include <sstream>
+using namespace llvm;
+
+namespace {
+  class CWriter : public Pass, public InstVisitor<CWriter> {
+    std::ostream &Out; 
+    Mangler *Mang;
+    const Module *TheModule;
+    FindUsedTypes *FUT;
+
+    std::map<const Type *, std::string> TypeNames;
+    std::set<const Value*> MangledGlobals;
+
+    std::map<const ConstantFP *, unsigned> FPConstantMap;
+  public:
+    CWriter(std::ostream &o) : Out(o) {}
+
+    void getAnalysisUsage(AnalysisUsage &AU) const {
+      AU.addRequired<FindUsedTypes>();
+    }
+
+    virtual const char *getPassName() const { return "C backend"; }
+
+    bool doInitialization(Module &M);
+    bool run(Module &M) {
+      doInitialization(M);
+
+      for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
+        if (!I->isExternal())
+          printFunction(*I);
+
+      // Free memory...
+      delete Mang;
+      TypeNames.clear();
+      MangledGlobals.clear();
+      return true;
+    }
+
+    std::ostream &printType(std::ostream &Out, const Type *Ty,
+                            const std::string &VariableName = "",
+                            bool IgnoreName = false);
+
+    void writeOperand(Value *Operand);
+    void writeOperandInternal(Value *Operand);
+
+  private :
+    bool nameAllUsedStructureTypes(Module &M);
+    void printModule(Module *M);
+    void printFloatingPointConstants(Module &M);
+    void printSymbolTable(const SymbolTable &ST);
+    void printContainedStructs(const Type *Ty, std::set<const StructType *> &);
+    void printFunctionSignature(const Function *F, bool Prototype);
+
+    void printFunction(Function &);
+
+    void printConstant(Constant *CPV);
+    void printConstantArray(ConstantArray *CPA);
+
+    // isInlinableInst - Attempt to inline instructions into their uses to build
+    // trees as much as possible.  To do this, we have to consistently decide
+    // what is acceptable to inline, so that variable declarations don't get
+    // printed and an extra copy of the expr is not emitted.
+    //
+    static bool isInlinableInst(const Instruction &I) {
+      // Must be an expression, must be used exactly once.  If it is dead, we
+      // emit it inline where it would go.
+      if (I.getType() == Type::VoidTy || !I.hasOneUse() ||
+          isa<TerminatorInst>(I) || isa<CallInst>(I) || isa<PHINode>(I) || 
+          isa<LoadInst>(I) || isa<VAArgInst>(I) || isa<VANextInst>(I))
+        // Don't inline a load across a store or other bad things!
+        return false;
+
+      // Only inline instruction it it's use is in the same BB as the inst.
+      return I.getParent() == cast<Instruction>(I.use_back())->getParent();
+    }
+
+    // isDirectAlloca - Define fixed sized allocas in the entry block as direct
+    // variables which are accessed with the & operator.  This causes GCC to
+    // generate significantly better code than to emit alloca calls directly.
+    //
+    static const AllocaInst *isDirectAlloca(const Value *V) {
+      const AllocaInst *AI = dyn_cast<AllocaInst>(V);
+      if (!AI) return false;
+      if (AI->isArrayAllocation())
+        return 0;   // FIXME: we can also inline fixed size array allocas!
+      if (AI->getParent() != &AI->getParent()->getParent()->getEntryBlock())
+        return 0;
+      return AI;
+    }
+
+    // Instruction visitation functions
+    friend class InstVisitor<CWriter>;
+
+    void visitReturnInst(ReturnInst &I);
+    void visitBranchInst(BranchInst &I);
+    void visitSwitchInst(SwitchInst &I);
+    void visitInvokeInst(InvokeInst &I);
+    void visitUnwindInst(UnwindInst &I);
+
+    void visitPHINode(PHINode &I);
+    void visitBinaryOperator(Instruction &I);
+
+    void visitCastInst (CastInst &I);
+    void visitCallInst (CallInst &I);
+    void visitCallSite (CallSite CS);
+    void visitShiftInst(ShiftInst &I) { visitBinaryOperator(I); }
+
+    void visitMallocInst(MallocInst &I);
+    void visitAllocaInst(AllocaInst &I);
+    void visitFreeInst  (FreeInst   &I);
+    void visitLoadInst  (LoadInst   &I);
+    void visitStoreInst (StoreInst  &I);
+    void visitGetElementPtrInst(GetElementPtrInst &I);
+    void visitVANextInst(VANextInst &I);
+    void visitVAArgInst (VAArgInst &I);
+
+    void visitInstruction(Instruction &I) {
+      std::cerr << "C Writer does not know about " << I;
+      abort();
+    }
+
+    void outputLValue(Instruction *I) {
+      Out << "  " << Mang->getValueName(I) << " = ";
+    }
+    void printBranchToBlock(BasicBlock *CurBlock, BasicBlock *SuccBlock,
+                            unsigned Indent);
+    void printIndexingExpression(Value *Ptr, gep_type_iterator I,
+                                 gep_type_iterator E);
+  };
+
+// Pass the Type* and the variable name and this prints out the variable
+// declaration.
+//
+std::ostream &CWriter::printType(std::ostream &Out, const Type *Ty,
+                                 const std::string &NameSoFar,
+                                 bool IgnoreName) {
+  if (Ty->isPrimitiveType())
+    switch (Ty->getPrimitiveID()) {
+    case Type::VoidTyID:   return Out << "void "               << NameSoFar;
+    case Type::BoolTyID:   return Out << "bool "               << NameSoFar;
+    case Type::UByteTyID:  return Out << "unsigned char "      << NameSoFar;
+    case Type::SByteTyID:  return Out << "signed char "        << NameSoFar;
+    case Type::UShortTyID: return Out << "unsigned short "     << NameSoFar;
+    case Type::ShortTyID:  return Out << "short "              << NameSoFar;
+    case Type::UIntTyID:   return Out << "unsigned "           << NameSoFar;
+    case Type::IntTyID:    return Out << "int "                << NameSoFar;
+    case Type::ULongTyID:  return Out << "unsigned long long " << NameSoFar;
+    case Type::LongTyID:   return Out << "signed long long "   << NameSoFar;
+    case Type::FloatTyID:  return Out << "float "              << NameSoFar;
+    case Type::DoubleTyID: return Out << "double "             << NameSoFar;
+    default :
+      std::cerr << "Unknown primitive type: " << Ty << "\n";
+      abort();
+    }
+  
+  // Check to see if the type is named.
+  if (!IgnoreName || isa<OpaqueType>(Ty)) {
+    std::map<const Type *, std::string>::iterator I = TypeNames.find(Ty);
+    if (I != TypeNames.end()) return Out << I->second << " " << NameSoFar;
+  }
+
+  switch (Ty->getPrimitiveID()) {
+  case Type::FunctionTyID: {
+    const FunctionType *MTy = cast<FunctionType>(Ty);
+    std::stringstream FunctionInnards; 
+    FunctionInnards << " (" << NameSoFar << ") (";
+    for (FunctionType::param_iterator I = MTy->param_begin(),
+           E = MTy->param_end(); I != E; ++I) {
+      if (I != MTy->param_begin())
+        FunctionInnards << ", ";
+      printType(FunctionInnards, *I, "");
+    }
+    if (MTy->isVarArg()) {
+      if (MTy->getNumParams()) 
+    	FunctionInnards << ", ...";
+    } else if (!MTy->getNumParams()) {
+      FunctionInnards << "void";
+    }
+    FunctionInnards << ")";
+    std::string tstr = FunctionInnards.str();
+    printType(Out, MTy->getReturnType(), tstr);
+    return Out;
+  }
+  case Type::StructTyID: {
+    const StructType *STy = cast<StructType>(Ty);
+    Out << NameSoFar + " {\n";
+    unsigned Idx = 0;
+    for (StructType::element_iterator I = STy->element_begin(),
+           E = STy->element_end(); I != E; ++I) {
+      Out << "  ";
+      printType(Out, *I, "field" + utostr(Idx++));
+      Out << ";\n";
+    }
+    return Out << "}";
+  }  
+
+  case Type::PointerTyID: {
+    const PointerType *PTy = cast<PointerType>(Ty);
+    std::string ptrName = "*" + NameSoFar;
+
+    if (isa<ArrayType>(PTy->getElementType()))
+      ptrName = "(" + ptrName + ")";
+
+    return printType(Out, PTy->getElementType(), ptrName);
+  }
+
+  case Type::ArrayTyID: {
+    const ArrayType *ATy = cast<ArrayType>(Ty);
+    unsigned NumElements = ATy->getNumElements();
+    return printType(Out, ATy->getElementType(),
+                     NameSoFar + "[" + utostr(NumElements) + "]");
+  }
+
+  case Type::OpaqueTyID: {
+    static int Count = 0;
+    std::string TyName = "struct opaque_" + itostr(Count++);
+    assert(TypeNames.find(Ty) == TypeNames.end());
+    TypeNames[Ty] = TyName;
+    return Out << TyName << " " << NameSoFar;
+  }
+  default:
+    assert(0 && "Unhandled case in getTypeProps!");
+    abort();
+  }
+
+  return Out;
+}
+
+void CWriter::printConstantArray(ConstantArray *CPA) {
+
+  // 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 = CPA->getType()->getElementType();
+  bool isString = (ETy == Type::SByteTy || ETy == Type::UByteTy);
+
+  // Make sure the last character is a null char, as automatically added by C
+  if (isString && (CPA->getNumOperands() == 0 ||
+                   !cast<Constant>(*(CPA->op_end()-1))->isNullValue()))
+    isString = false;
+  
+  if (isString) {
+    Out << "\"";
+    // Keep track of whether the last number was a hexadecimal escape
+    bool LastWasHex = false;
+
+    // Do not include the last character, which we know is null
+    for (unsigned i = 0, e = CPA->getNumOperands()-1; i != e; ++i) {
+      unsigned char C = cast<ConstantInt>(CPA->getOperand(i))->getRawValue();
+      
+      // Print it out literally if it is a printable character.  The only thing
+      // to be careful about is when the last letter output was a hex escape
+      // code, in which case we have to be careful not to print out hex digits
+      // explicitly (the C compiler thinks it is a continuation of the previous
+      // character, sheesh...)
+      //
+      if (isprint(C) && (!LastWasHex || !isxdigit(C))) {
+        LastWasHex = false;
+        if (C == '"' || C == '\\')
+          Out << "\\" << C;
+        else
+          Out << C;
+      } else {
+        LastWasHex = false;
+        switch (C) {
+        case '\n': Out << "\\n"; break;
+        case '\t': Out << "\\t"; break;
+        case '\r': Out << "\\r"; break;
+        case '\v': Out << "\\v"; break;
+        case '\a': Out << "\\a"; break;
+        case '\"': Out << "\\\""; break;
+        case '\'': Out << "\\\'"; break;           
+        default:
+          Out << "\\x";
+          Out << (char)(( C/16  < 10) ? ( C/16 +'0') : ( C/16 -10+'A'));
+          Out << (char)(((C&15) < 10) ? ((C&15)+'0') : ((C&15)-10+'A'));
+          LastWasHex = true;
+          break;
+        }
+      }
+    }
+    Out << "\"";
+  } else {
+    Out << "{";
+    if (CPA->getNumOperands()) {
+      Out << " ";
+      printConstant(cast<Constant>(CPA->getOperand(0)));
+      for (unsigned i = 1, e = CPA->getNumOperands(); i != e; ++i) {
+        Out << ", ";
+        printConstant(cast<Constant>(CPA->getOperand(i)));
+      }
+    }
+    Out << " }";
+  }
+}
+
+// isFPCSafeToPrint - Returns true if we may assume that CFP may be written out
+// textually as a double (rather than as a reference to a stack-allocated
+// variable). We decide this by converting CFP to a string and back into a
+// double, and then checking whether the conversion results in a bit-equal
+// double to the original value of CFP. This depends on us and the target C
+// compiler agreeing on the conversion process (which is pretty likely since we
+// only deal in IEEE FP).
+//
+bool isFPCSafeToPrint(const ConstantFP *CFP) {
+#if HAVE_PRINTF_A
+  char Buffer[100];
+  sprintf(Buffer, "%a", CFP->getValue());
+
+  if (!strncmp(Buffer, "0x", 2) ||
+      !strncmp(Buffer, "-0x", 3) ||
+      !strncmp(Buffer, "+0x", 3))
+    return atof(Buffer) == CFP->getValue();
+  return false;
+#else
+  std::string StrVal = ftostr(CFP->getValue());
+
+  while (StrVal[0] == ' ')
+    StrVal.erase(StrVal.begin());
+
+  // Check to make sure that the stringized number is not some string like "Inf"
+  // or NaN.  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!
+    return atof(StrVal.c_str()) == CFP->getValue();
+  return false;
+#endif
+}
+
+// printConstant - The LLVM Constant to C Constant converter.
+void CWriter::printConstant(Constant *CPV) {
+  if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) {
+    switch (CE->getOpcode()) {
+    case Instruction::Cast:
+      Out << "((";
+      printType(Out, CPV->getType());
+      Out << ")";
+      printConstant(CE->getOperand(0));
+      Out << ")";
+      return;
+
+    case Instruction::GetElementPtr:
+      Out << "(&(";
+      printIndexingExpression(CE->getOperand(0), gep_type_begin(CPV),
+                              gep_type_end(CPV));
+      Out << "))";
+      return;
+    case Instruction::Add:
+    case Instruction::Sub:
+    case Instruction::Mul:
+    case Instruction::Div:
+    case Instruction::Rem:
+    case Instruction::SetEQ:
+    case Instruction::SetNE:
+    case Instruction::SetLT:
+    case Instruction::SetLE:
+    case Instruction::SetGT:
+    case Instruction::SetGE:
+    case Instruction::Shl:
+    case Instruction::Shr:
+      Out << "(";
+      printConstant(CE->getOperand(0));
+      switch (CE->getOpcode()) {
+      case Instruction::Add: Out << " + "; break;
+      case Instruction::Sub: Out << " - "; break;
+      case Instruction::Mul: Out << " * "; break;
+      case Instruction::Div: Out << " / "; break;
+      case Instruction::Rem: Out << " % "; break;
+      case Instruction::SetEQ: Out << " == "; break;
+      case Instruction::SetNE: Out << " != "; break;
+      case Instruction::SetLT: Out << " < "; break;
+      case Instruction::SetLE: Out << " <= "; break;
+      case Instruction::SetGT: Out << " > "; break;
+      case Instruction::SetGE: Out << " >= "; break;
+      case Instruction::Shl: Out << " << "; break;
+      case Instruction::Shr: Out << " >> "; break;
+      default: assert(0 && "Illegal opcode here!");
+      }
+      printConstant(CE->getOperand(1));
+      Out << ")";
+      return;
+
+    default:
+      std::cerr << "CWriter Error: Unhandled constant expression: "
+                << CE << "\n";
+      abort();
+    }
+  }
+
+  switch (CPV->getType()->getPrimitiveID()) {
+  case Type::BoolTyID:
+    Out << (CPV == ConstantBool::False ? "0" : "1"); break;
+  case Type::SByteTyID:
+  case Type::ShortTyID:
+    Out << cast<ConstantSInt>(CPV)->getValue(); break;
+  case Type::IntTyID:
+    if ((int)cast<ConstantSInt>(CPV)->getValue() == (int)0x80000000)
+      Out << "((int)0x80000000)";   // Handle MININT specially to avoid warning
+    else
+      Out << cast<ConstantSInt>(CPV)->getValue();
+    break;
+
+  case Type::LongTyID:
+    Out << cast<ConstantSInt>(CPV)->getValue() << "ll"; break;
+
+  case Type::UByteTyID:
+  case Type::UShortTyID:
+    Out << cast<ConstantUInt>(CPV)->getValue(); break;
+  case Type::UIntTyID:
+    Out << cast<ConstantUInt>(CPV)->getValue() << "u"; break;
+  case Type::ULongTyID:
+    Out << cast<ConstantUInt>(CPV)->getValue() << "ull"; break;
+
+  case Type::FloatTyID:
+  case Type::DoubleTyID: {
+    ConstantFP *FPC = cast<ConstantFP>(CPV);
+    std::map<const ConstantFP*, unsigned>::iterator I = FPConstantMap.find(FPC);
+    if (I != FPConstantMap.end()) {
+      // Because of FP precision problems we must load from a stack allocated
+      // value that holds the value in hex.
+      Out << "(*(" << (FPC->getType() == Type::FloatTy ? "float" : "double")
+          << "*)&FPConstant" << I->second << ")";
+    } else {
+#if HAVE_PRINTF_A
+      // Print out the constant as a floating point number.
+      char Buffer[100];
+      sprintf(Buffer, "%a", FPC->getValue());
+      Out << Buffer << " /*" << FPC->getValue() << "*/ ";
+#else
+      Out << ftostr(FPC->getValue());
+#endif
+    }
+    break;
+  }
+
+  case Type::ArrayTyID:
+    printConstantArray(cast<ConstantArray>(CPV));
+    break;
+
+  case Type::StructTyID: {
+    Out << "{";
+    if (CPV->getNumOperands()) {
+      Out << " ";
+      printConstant(cast<Constant>(CPV->getOperand(0)));
+      for (unsigned i = 1, e = CPV->getNumOperands(); i != e; ++i) {
+        Out << ", ";
+        printConstant(cast<Constant>(CPV->getOperand(i)));
+      }
+    }
+    Out << " }";
+    break;
+  }
+
+  case Type::PointerTyID:
+    if (isa<ConstantPointerNull>(CPV)) {
+      Out << "((";
+      printType(Out, CPV->getType());
+      Out << ")/*NULL*/0)";
+      break;
+    } else if (ConstantPointerRef *CPR = dyn_cast<ConstantPointerRef>(CPV)) {
+      writeOperand(CPR->getValue());
+      break;
+    }
+    // FALL THROUGH
+  default:
+    std::cerr << "Unknown constant type: " << CPV << "\n";
+    abort();
+  }
+}
+
+void CWriter::writeOperandInternal(Value *Operand) {
+  if (Instruction *I = dyn_cast<Instruction>(Operand))
+    if (isInlinableInst(*I) && !isDirectAlloca(I)) {
+      // Should we inline this instruction to build a tree?
+      Out << "(";
+      visit(*I);
+      Out << ")";    
+      return;
+    }
+  
+  if (Constant *CPV = dyn_cast<Constant>(Operand)) {
+    printConstant(CPV); 
+  } else {
+    Out << Mang->getValueName(Operand);
+  }
+}
+
+void CWriter::writeOperand(Value *Operand) {
+  if (isa<GlobalVariable>(Operand) || isDirectAlloca(Operand))
+    Out << "(&";  // Global variables are references as their addresses by llvm
+
+  writeOperandInternal(Operand);
+
+  if (isa<GlobalVariable>(Operand) || isDirectAlloca(Operand))
+    Out << ")";
+}
+
+// nameAllUsedStructureTypes - If there are structure types in the module that
+// are used but do not have names assigned to them in the symbol table yet then
+// we assign them names now.
+//
+bool CWriter::nameAllUsedStructureTypes(Module &M) {
+  // Get a set of types that are used by the program...
+  std::set<const Type *> UT = FUT->getTypes();
+
+  // Loop over the module symbol table, removing types from UT that are already
+  // named.
+  //
+  SymbolTable &MST = M.getSymbolTable();
+  if (MST.find(Type::TypeTy) != MST.end())
+    for (SymbolTable::type_iterator I = MST.type_begin(Type::TypeTy),
+           E = MST.type_end(Type::TypeTy); I != E; ++I)
+      UT.erase(cast<Type>(I->second));
+
+  // UT now contains types that are not named.  Loop over it, naming structure
+  // types.
+  //
+  bool Changed = false;
+  for (std::set<const Type *>::const_iterator I = UT.begin(), E = UT.end();
+       I != E; ++I)
+    if (const StructType *ST = dyn_cast<StructType>(*I)) {
+      ((Value*)ST)->setName("unnamed", &MST);
+      Changed = true;
+    }
+  return Changed;
+}
+
+// generateCompilerSpecificCode - This is where we add conditional compilation
+// directives to cater to specific compilers as need be.
+//
+static void generateCompilerSpecificCode(std::ostream& Out) {
+  // Alloca is hard to get, and we don't want to include stdlib.h here...
+  Out << "/* get a declaration for alloca */\n"
+      << "#ifdef sun\n"
+      << "extern void *__builtin_alloca(unsigned long);\n"
+      << "#define alloca(x) __builtin_alloca(x)\n"
+      << "#else\n"
+      << "#ifndef __FreeBSD__\n"
+      << "#include <alloca.h>\n"
+      << "#endif\n"
+      << "#endif\n\n";
+
+  // We output GCC specific attributes to preserve 'linkonce'ness on globals.
+  // If we aren't being compiled with GCC, just drop these attributes.
+  Out << "#ifndef __GNUC__  /* Can only support \"linkonce\" vars with GCC */\n"
+      << "#define __attribute__(X)\n"
+      << "#endif\n\n";
+
+#if 0
+  // At some point, we should support "external weak" vs. "weak" linkages.
+  // On Mac OS X, "external weak" is spelled "__attribute__((weak_import))".
+  Out << "#if defined(__GNUC__) && defined(__APPLE_CC__)\n"
+      << "#define __EXTERNAL_WEAK__ __attribute__((weak_import))\n"
+      << "#elif defined(__GNUC__)\n"
+      << "#define __EXTERNAL_WEAK__ __attribute__((weak))\n"
+      << "#else\n"
+      << "#define __EXTERNAL_WEAK__\n"
+      << "#endif\n\n";
+#endif
+
+  // For now, turn off the weak linkage attribute on Mac OS X. (See above.)
+  Out << "#if defined(__GNUC__) && defined(__APPLE_CC__)\n"
+      << "#define __ATTRIBUTE_WEAK__\n"
+      << "#elif defined(__GNUC__)\n"
+      << "#define __ATTRIBUTE_WEAK__ __attribute__((weak))\n"
+      << "#else\n"
+      << "#define __ATTRIBUTE_WEAK__\n"
+      << "#endif\n\n";
+}
+
+bool CWriter::doInitialization(Module &M) {
+  // Initialize
+  TheModule = &M;
+  FUT = &getAnalysis<FindUsedTypes>();
+  
+  // Ensure that all structure types have names...
+  bool Changed = nameAllUsedStructureTypes(M);
+  Mang = new Mangler(M);
+
+  // Calculate which global values have names that will collide when we throw
+  // away type information.
+  {  // Scope to delete the FoundNames set when we are done with it...
+    std::set<std::string> FoundNames;
+    for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
+      if (I->hasName())                      // If the global has a name...
+        if (FoundNames.count(I->getName()))  // And the name is already used
+          MangledGlobals.insert(I);          // Mangle the name
+        else
+          FoundNames.insert(I->getName());   // Otherwise, keep track of name
+
+    for (Module::giterator I = M.gbegin(), E = M.gend(); I != E; ++I)
+      if (I->hasName())                      // If the global has a name...
+        if (FoundNames.count(I->getName()))  // And the name is already used
+          MangledGlobals.insert(I);          // Mangle the name
+        else
+          FoundNames.insert(I->getName());   // Otherwise, keep track of name
+  }
+
+  // get declaration for alloca
+  Out << "/* Provide Declarations */\n";
+  Out << "#include <stdarg.h>\n";      // Varargs support
+  Out << "#include <setjmp.h>\n";      // Unwind support
+  generateCompilerSpecificCode(Out);
+
+  // Provide a definition for `bool' if not compiling with a C++ compiler.
+  Out << "\n"
+      << "#ifndef __cplusplus\ntypedef unsigned char bool;\n#endif\n"
+    
+      << "\n\n/* Support for floating point constants */\n"
+      << "typedef unsigned long long ConstantDoubleTy;\n"
+      << "typedef unsigned int        ConstantFloatTy;\n"
+    
+      << "\n\n/* Global Declarations */\n";
+
+  // First output all the declarations for the program, because C requires
+  // Functions & globals to be declared before they are used.
+  //
+
+  // Loop over the symbol table, emitting all named constants...
+  printSymbolTable(M.getSymbolTable());
+
+  // Global variable declarations...
+  if (!M.gempty()) {
+    Out << "\n/* External Global Variable Declarations */\n";
+    for (Module::giterator I = M.gbegin(), E = M.gend(); I != E; ++I) {
+      if (I->hasExternalLinkage()) {
+        Out << "extern ";
+        printType(Out, I->getType()->getElementType(), Mang->getValueName(I));
+        Out << ";\n";
+      }
+    }
+  }
+
+  // Function declarations
+  if (!M.empty()) {
+    Out << "\n/* Function Declarations */\n";
+    for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) {
+      // If the function is external and the name collides don't print it.
+      // Sometimes the bytecode likes to have multiple "declarations" for
+      // external functions
+      if ((I->hasInternalLinkage() || !MangledGlobals.count(I)) &&
+          !I->getIntrinsicID() &&
+          I->getName() != "setjmp" && I->getName() != "longjmp") {
+        printFunctionSignature(I, true);
+        if (I->hasWeakLinkage()) Out << " __ATTRIBUTE_WEAK__";
+        Out << ";\n";
+      }
+    }
+  }
+
+  // Output the global variable declarations
+  if (!M.gempty()) {
+    Out << "\n\n/* Global Variable Declarations */\n";
+    for (Module::giterator I = M.gbegin(), E = M.gend(); I != E; ++I)
+      if (!I->isExternal()) {
+        Out << "extern ";
+        printType(Out, I->getType()->getElementType(), Mang->getValueName(I));
+
+        if (I->hasLinkOnceLinkage())
+          Out << " __attribute__((common))";
+        else if (I->hasWeakLinkage())
+          Out << " __ATTRIBUTE_WEAK__";
+        Out << ";\n";
+      }
+  }
+
+  // Output the global variable definitions and contents...
+  if (!M.gempty()) {
+    Out << "\n\n/* Global Variable Definitions and Initialization */\n";
+    for (Module::giterator I = M.gbegin(), E = M.gend(); I != E; ++I)
+      if (!I->isExternal()) {
+        if (I->hasInternalLinkage())
+          Out << "static ";
+        printType(Out, I->getType()->getElementType(), Mang->getValueName(I));
+        if (I->hasLinkOnceLinkage())
+          Out << " __attribute__((common))";
+        else if (I->hasWeakLinkage())
+          Out << " __ATTRIBUTE_WEAK__";
+
+        // If the initializer is not null, emit the initializer.  If it is null,
+        // we try to avoid emitting large amounts of zeros.  The problem with
+        // this, however, occurs when the variable has weak linkage.  In this
+        // case, the assembler will complain about the variable being both weak
+        // and common, so we disable this optimization.
+        if (!I->getInitializer()->isNullValue() ||
+            I->hasWeakLinkage()) {
+          Out << " = " ;
+          writeOperand(I->getInitializer());
+        }
+        Out << ";\n";
+      }
+  }
+
+  // Output all floating point constants that cannot be printed accurately...
+  printFloatingPointConstants(M);
+  
+  if (!M.empty())
+    Out << "\n\n/* Function Bodies */\n";
+  return false;
+}
+
+
+/// Output all floating point constants that cannot be printed accurately...
+void CWriter::printFloatingPointConstants(Module &M) {
+  union {
+    double D;
+    unsigned long long U;
+  } DBLUnion;
+
+  union {
+    float F;
+    unsigned U;
+  } FLTUnion;
+
+  // Scan the module for floating point constants.  If any FP constant is used
+  // in the function, we want to redirect it here so that we do not depend on
+  // the precision of the printed form, unless the printed form preserves
+  // precision.
+  //
+  unsigned FPCounter = 0;
+  for (Module::iterator F = M.begin(), E = M.end(); F != E; ++F)
+    for (constant_iterator I = constant_begin(F), E = constant_end(F);
+         I != E; ++I)
+      if (const ConstantFP *FPC = dyn_cast<ConstantFP>(*I))
+        if (!isFPCSafeToPrint(FPC) && // Do not put in FPConstantMap if safe.
+            !FPConstantMap.count(FPC)) {
+          double Val = FPC->getValue();
+          
+          FPConstantMap[FPC] = FPCounter;  // Number the FP constants
+          
+          if (FPC->getType() == Type::DoubleTy) {
+            DBLUnion.D = Val;
+            Out << "const ConstantDoubleTy FPConstant" << FPCounter++
+                << " = 0x" << std::hex << DBLUnion.U << std::dec
+                << "ULL;    /* " << Val << " */\n";
+          } else if (FPC->getType() == Type::FloatTy) {
+            FLTUnion.F = Val;
+            Out << "const ConstantFloatTy FPConstant" << FPCounter++
+                << " = 0x" << std::hex << FLTUnion.U << std::dec
+                << "U;    /* " << Val << " */\n";
+          } else
+            assert(0 && "Unknown float type!");
+        }
+  
+  Out << "\n";
+ }
+
+
+/// printSymbolTable - Run through symbol table looking for type names.  If a
+/// type name is found, emit it's declaration...
+///
+void CWriter::printSymbolTable(const SymbolTable &ST) {
+  // If there are no type names, exit early.
+  if (ST.find(Type::TypeTy) == ST.end())
+    return;
+
+  // We are only interested in the type plane of the symbol table...
+  SymbolTable::type_const_iterator I   = ST.type_begin(Type::TypeTy);
+  SymbolTable::type_const_iterator End = ST.type_end(Type::TypeTy);
+  
+  // Print out forward declarations for structure types before anything else!
+  Out << "/* Structure forward decls */\n";
+  for (; I != End; ++I)
+    if (const Type *STy = dyn_cast<StructType>(I->second))
+      // Only print out used types!
+      if (FUT->getTypes().count(STy)) {
+        std::string Name = "struct l_" + Mangler::makeNameProper(I->first);
+        Out << Name << ";\n";
+        TypeNames.insert(std::make_pair(STy, Name));
+      }
+
+  Out << "\n";
+
+  // Now we can print out typedefs...
+  Out << "/* Typedefs */\n";
+  for (I = ST.type_begin(Type::TypeTy); I != End; ++I)
+    // Only print out used types!
+    if (FUT->getTypes().count(cast<Type>(I->second))) {
+      const Type *Ty = cast<Type>(I->second);
+      std::string Name = "l_" + Mangler::makeNameProper(I->first);
+      Out << "typedef ";
+      printType(Out, Ty, Name);
+      Out << ";\n";
+    }
+  
+  Out << "\n";
+
+  // Keep track of which structures have been printed so far...
+  std::set<const StructType *> StructPrinted;
+
+  // Loop over all structures then push them into the stack so they are
+  // printed in the correct order.
+  //
+  Out << "/* Structure contents */\n";
+  for (I = ST.type_begin(Type::TypeTy); I != End; ++I)
+    if (const StructType *STy = dyn_cast<StructType>(I->second))
+      // Only print out used types!
+      if (FUT->getTypes().count(STy))
+        printContainedStructs(STy, StructPrinted);
+}
+
+// Push the struct onto the stack and recursively push all structs
+// this one depends on.
+void CWriter::printContainedStructs(const Type *Ty,
+                                    std::set<const StructType*> &StructPrinted){
+  if (const StructType *STy = dyn_cast<StructType>(Ty)) {
+    //Check to see if we have already printed this struct
+    if (StructPrinted.count(STy) == 0) {
+      // Print all contained types first...
+      for (StructType::element_iterator I = STy->element_begin(),
+             E = STy->element_end(); I != E; ++I) {
+        const Type *Ty1 = I->get();
+        if (isa<StructType>(Ty1) || isa<ArrayType>(Ty1))
+          printContainedStructs(*I, StructPrinted);
+      }
+      
+      //Print structure type out..
+      StructPrinted.insert(STy);
+      std::string Name = TypeNames[STy];  
+      printType(Out, STy, Name, true);
+      Out << ";\n\n";
+    }
+
+    // If it is an array, check contained types and continue
+  } else if (const ArrayType *ATy = dyn_cast<ArrayType>(Ty)){
+    const Type *Ty1 = ATy->getElementType();
+    if (isa<StructType>(Ty1) || isa<ArrayType>(Ty1))
+      printContainedStructs(Ty1, StructPrinted);
+  }
+}
+
+
+void CWriter::printFunctionSignature(const Function *F, bool Prototype) {
+  if (F->hasInternalLinkage()) Out << "static ";
+  if (F->hasLinkOnceLinkage()) Out << "inline ";
+  
+  // Loop over the arguments, printing them...
+  const FunctionType *FT = cast<FunctionType>(F->getFunctionType());
+  
+  std::stringstream FunctionInnards; 
+    
+  // Print out the name...
+  FunctionInnards << Mang->getValueName(F) << "(";
+    
+  if (!F->isExternal()) {
+    if (!F->aempty()) {
+      std::string ArgName;
+      if (F->abegin()->hasName() || !Prototype)
+        ArgName = Mang->getValueName(F->abegin());
+      printType(FunctionInnards, F->afront().getType(), ArgName);
+      for (Function::const_aiterator I = ++F->abegin(), E = F->aend();
+           I != E; ++I) {
+        FunctionInnards << ", ";
+        if (I->hasName() || !Prototype)
+          ArgName = Mang->getValueName(I);
+        else 
+          ArgName = "";
+        printType(FunctionInnards, I->getType(), ArgName);
+      }
+    }
+  } else {
+    // Loop over the arguments, printing them...
+    for (FunctionType::param_iterator I = FT->param_begin(),
+	   E = FT->param_end(); I != E; ++I) {
+      if (I != FT->param_begin()) FunctionInnards << ", ";
+      printType(FunctionInnards, *I);
+    }
+  }
+
+  // Finish printing arguments... if this is a vararg function, print the ...,
+  // unless there are no known types, in which case, we just emit ().
+  //
+  if (FT->isVarArg() && FT->getNumParams()) {
+    if (FT->getNumParams()) FunctionInnards << ", ";
+    FunctionInnards << "...";  // Output varargs portion of signature!
+  } else if (!FT->isVarArg() && FT->getNumParams() == 0) {
+    FunctionInnards << "void"; // ret() -> ret(void) in C.
+  }
+  FunctionInnards << ")";
+  // Print out the return type and the entire signature for that matter
+  printType(Out, F->getReturnType(), FunctionInnards.str());
+}
+
+void CWriter::printFunction(Function &F) {
+  printFunctionSignature(&F, false);
+  Out << " {\n";
+
+  // print local variable information for the function
+  for (inst_iterator I = inst_begin(&F), E = inst_end(&F); I != E; ++I)
+    if (const AllocaInst *AI = isDirectAlloca(*I)) {
+      Out << "  ";
+      printType(Out, AI->getAllocatedType(), Mang->getValueName(AI));
+      Out << ";    /* Address exposed local */\n";
+    } else if ((*I)->getType() != Type::VoidTy && !isInlinableInst(**I)) {
+      Out << "  ";
+      printType(Out, (*I)->getType(), Mang->getValueName(*I));
+      Out << ";\n";
+      
+      if (isa<PHINode>(*I)) {  // Print out PHI node temporaries as well...
+        Out << "  ";
+        printType(Out, (*I)->getType(),
+                  Mang->getValueName(*I)+"__PHI_TEMPORARY");
+        Out << ";\n";
+      }
+    }
+
+  Out << "\n";
+
+  // print the basic blocks
+  for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
+    BasicBlock *Prev = BB->getPrev();
+
+    // Don't print the label for the basic block if there are no uses, or if the
+    // only terminator use is the predecessor basic block's terminator.  We have
+    // to scan the use list because PHI nodes use basic blocks too but do not
+    // require a label to be generated.
+    //
+    bool NeedsLabel = false;
+    for (Value::use_iterator UI = BB->use_begin(), UE = BB->use_end();
+         UI != UE; ++UI)
+      if (TerminatorInst *TI = dyn_cast<TerminatorInst>(*UI))
+        if (TI != Prev->getTerminator() ||
+            isa<SwitchInst>(Prev->getTerminator()) ||
+            isa<InvokeInst>(Prev->getTerminator())) {
+          NeedsLabel = true;
+          break;        
+        }
+
+    if (NeedsLabel) Out << Mang->getValueName(BB) << ":\n";
+
+    // Output all of the instructions in the basic block...
+    for (BasicBlock::iterator II = BB->begin(), E = --BB->end(); II != E; ++II){
+      if (!isInlinableInst(*II) && !isDirectAlloca(II)) {
+        if (II->getType() != Type::VoidTy)
+          outputLValue(II);
+        else
+          Out << "  ";
+        visit(*II);
+        Out << ";\n";
+      }
+    }
+
+    // Don't emit prefix or suffix for the terminator...
+    visit(*BB->getTerminator());
+  }
+  
+  Out << "}\n\n";
+}
+
+// Specific Instruction type classes... note that all of the casts are
+// necessary because we use the instruction classes as opaque types...
+//
+void CWriter::visitReturnInst(ReturnInst &I) {
+  // Don't output a void return if this is the last basic block in the function
+  if (I.getNumOperands() == 0 && 
+      &*--I.getParent()->getParent()->end() == I.getParent() &&
+      !I.getParent()->size() == 1) {
+    return;
+  }
+
+  Out << "  return";
+  if (I.getNumOperands()) {
+    Out << " ";
+    writeOperand(I.getOperand(0));
+  }
+  Out << ";\n";
+}
+
+void CWriter::visitSwitchInst(SwitchInst &SI) {
+  Out << "  switch (";
+  writeOperand(SI.getOperand(0));
+  Out << ") {\n  default:\n";
+  printBranchToBlock(SI.getParent(), SI.getDefaultDest(), 2);
+  Out << ";\n";
+  for (unsigned i = 2, e = SI.getNumOperands(); i != e; i += 2) {
+    Out << "  case ";
+    writeOperand(SI.getOperand(i));
+    Out << ":\n";
+    BasicBlock *Succ = cast<BasicBlock>(SI.getOperand(i+1));
+    printBranchToBlock(SI.getParent(), Succ, 2);
+    if (Succ == SI.getParent()->getNext())
+      Out << "    break;\n";
+  }
+  Out << "  }\n";
+}
+
+void CWriter::visitInvokeInst(InvokeInst &II) {
+  assert(0 && "Lowerinvoke pass didn't work!");
+}
+
+
+void CWriter::visitUnwindInst(UnwindInst &I) {
+  assert(0 && "Lowerinvoke pass didn't work!");
+}
+
+bool isGotoCodeNecessary(BasicBlock *From, BasicBlock *To) {
+  // If PHI nodes need copies, we need the copy code...
+  if (isa<PHINode>(To->front()) ||
+      From->getNext() != To)      // Not directly successor, need goto
+    return true;
+
+  // Otherwise we don't need the code.
+  return false;
+}
+
+void CWriter::printBranchToBlock(BasicBlock *CurBB, BasicBlock *Succ,
+                                 unsigned Indent) {
+  for (BasicBlock::iterator I = Succ->begin();
+       PHINode *PN = dyn_cast<PHINode>(I); ++I) {
+    //  now we have to do the printing
+    Out << std::string(Indent, ' ');
+    Out << "  " << Mang->getValueName(I) << "__PHI_TEMPORARY = ";
+    writeOperand(PN->getIncomingValue(PN->getBasicBlockIndex(CurBB)));
+    Out << ";   /* for PHI node */\n";
+  }
+
+  if (CurBB->getNext() != Succ ||
+      isa<InvokeInst>(CurBB->getTerminator()) ||
+      isa<SwitchInst>(CurBB->getTerminator())) {
+    Out << std::string(Indent, ' ') << "  goto ";
+    writeOperand(Succ);
+    Out << ";\n";
+  }
+}
+
+// Branch instruction printing - Avoid printing out a branch to a basic block
+// that immediately succeeds the current one.
+//
+void CWriter::visitBranchInst(BranchInst &I) {
+  if (I.isConditional()) {
+    if (isGotoCodeNecessary(I.getParent(), I.getSuccessor(0))) {
+      Out << "  if (";
+      writeOperand(I.getCondition());
+      Out << ") {\n";
+      
+      printBranchToBlock(I.getParent(), I.getSuccessor(0), 2);
+      
+      if (isGotoCodeNecessary(I.getParent(), I.getSuccessor(1))) {
+        Out << "  } else {\n";
+        printBranchToBlock(I.getParent(), I.getSuccessor(1), 2);
+      }
+    } else {
+      // First goto not necessary, assume second one is...
+      Out << "  if (!";
+      writeOperand(I.getCondition());
+      Out << ") {\n";
+
+      printBranchToBlock(I.getParent(), I.getSuccessor(1), 2);
+    }
+
+    Out << "  }\n";
+  } else {
+    printBranchToBlock(I.getParent(), I.getSuccessor(0), 0);
+  }
+  Out << "\n";
+}
+
+// PHI nodes get copied into temporary values at the end of predecessor basic
+// blocks.  We now need to copy these temporary values into the REAL value for
+// the PHI.
+void CWriter::visitPHINode(PHINode &I) {
+  writeOperand(&I);
+  Out << "__PHI_TEMPORARY";
+}
+
+
+void CWriter::visitBinaryOperator(Instruction &I) {
+  // binary instructions, shift instructions, setCond instructions.
+  assert(!isa<PointerType>(I.getType()));
+
+  // We must cast the results of binary operations which might be promoted.
+  bool needsCast = false;
+  if ((I.getType() == Type::UByteTy) || (I.getType() == Type::SByteTy)
+      || (I.getType() == Type::UShortTy) || (I.getType() == Type::ShortTy)
+      || (I.getType() == Type::FloatTy)) {
+    needsCast = true;
+    Out << "((";
+    printType(Out, I.getType());
+    Out << ")(";
+  }
+      
+  writeOperand(I.getOperand(0));
+
+  switch (I.getOpcode()) {
+  case Instruction::Add: Out << " + "; break;
+  case Instruction::Sub: Out << " - "; break;
+  case Instruction::Mul: Out << "*"; break;
+  case Instruction::Div: Out << "/"; break;
+  case Instruction::Rem: Out << "%"; break;
+  case Instruction::And: Out << " & "; break;
+  case Instruction::Or: Out << " | "; break;
+  case Instruction::Xor: Out << " ^ "; break;
+  case Instruction::SetEQ: Out << " == "; break;
+  case Instruction::SetNE: Out << " != "; break;
+  case Instruction::SetLE: Out << " <= "; break;
+  case Instruction::SetGE: Out << " >= "; break;
+  case Instruction::SetLT: Out << " < "; break;
+  case Instruction::SetGT: Out << " > "; break;
+  case Instruction::Shl : Out << " << "; break;
+  case Instruction::Shr : Out << " >> "; break;
+  default: std::cerr << "Invalid operator type!" << I; abort();
+  }
+
+  writeOperand(I.getOperand(1));
+
+  if (needsCast) {
+    Out << "))";
+  }
+}
+
+void CWriter::visitCastInst(CastInst &I) {
+  if (I.getType() == Type::BoolTy) {
+    Out << "(";
+    writeOperand(I.getOperand(0));
+    Out << " != 0)";
+    return;
+  }
+  Out << "(";
+  printType(Out, I.getType());
+  Out << ")";
+  if (isa<PointerType>(I.getType())&&I.getOperand(0)->getType()->isIntegral() ||
+      isa<PointerType>(I.getOperand(0)->getType())&&I.getType()->isIntegral()) {
+    // Avoid "cast to pointer from integer of different size" warnings
+    Out << "(long)";  
+  }
+  
+  writeOperand(I.getOperand(0));
+}
+
+void CWriter::visitCallInst(CallInst &I) {
+  // Handle intrinsic function calls first...
+  if (Function *F = I.getCalledFunction())
+    if (Intrinsic::ID ID = (Intrinsic::ID)F->getIntrinsicID()) {
+      switch (ID) {
+      default:  assert(0 && "Unknown LLVM intrinsic!");
+      case Intrinsic::va_start: 
+        Out << "0; ";
+        
+        Out << "va_start(*(va_list*)&" << Mang->getValueName(&I) << ", ";
+        // Output the last argument to the enclosing function...
+        if (I.getParent()->getParent()->aempty()) {
+          std::cerr << "The C backend does not currently support zero "
+                    << "argument varargs functions, such as '"
+                    << I.getParent()->getParent()->getName() << "'!\n";
+          abort();
+        }
+        writeOperand(&I.getParent()->getParent()->aback());
+        Out << ")";
+        return;
+      case Intrinsic::va_end:
+        Out << "va_end(*(va_list*)&";
+        writeOperand(I.getOperand(1));
+        Out << ")";
+        return;
+      case Intrinsic::va_copy:
+        Out << "0;";
+        Out << "va_copy(*(va_list*)&" << Mang->getValueName(&I) << ", ";
+        Out << "*(va_list*)&";
+        writeOperand(I.getOperand(1));
+        Out << ")";
+        return;
+      case Intrinsic::setjmp:
+      case Intrinsic::sigsetjmp:
+        // This intrinsic should never exist in the program, but until we get
+        // setjmp/longjmp transformations going on, we should codegen it to
+        // something reasonable.  This will allow code that never calls longjmp
+        // to work.
+        Out << "0";
+        return;
+      case Intrinsic::longjmp:
+      case Intrinsic::siglongjmp:
+        // Longjmp is not implemented, and never will be.  It would cause an
+        // exception throw.
+        Out << "abort()";
+        return;
+      case Intrinsic::memcpy:
+        Out << "memcpy(";
+        writeOperand(I.getOperand(1));
+        Out << ", ";
+        writeOperand(I.getOperand(2));
+        Out << ", ";
+        writeOperand(I.getOperand(3));
+        Out << ")";
+        return;
+      case Intrinsic::memmove:
+        Out << "memmove(";
+        writeOperand(I.getOperand(1));
+        Out << ", ";
+        writeOperand(I.getOperand(2));
+        Out << ", ";
+        writeOperand(I.getOperand(3));
+        Out << ")";
+        return;
+      }
+    }
+  visitCallSite(&I);
+}
+
+void CWriter::visitCallSite(CallSite CS) {
+  const PointerType  *PTy   = cast<PointerType>(CS.getCalledValue()->getType());
+  const FunctionType *FTy   = cast<FunctionType>(PTy->getElementType());
+  const Type         *RetTy = FTy->getReturnType();
+  
+  writeOperand(CS.getCalledValue());
+  Out << "(";
+
+  if (CS.arg_begin() != CS.arg_end()) {
+    CallSite::arg_iterator AI = CS.arg_begin(), AE = CS.arg_end();
+    writeOperand(*AI);
+
+    for (++AI; AI != AE; ++AI) {
+      Out << ", ";
+      writeOperand(*AI);
+    }
+  }
+  Out << ")";
+}  
+
+void CWriter::visitMallocInst(MallocInst &I) {
+  assert(0 && "lowerallocations pass didn't work!");
+}
+
+void CWriter::visitAllocaInst(AllocaInst &I) {
+  Out << "(";
+  printType(Out, I.getType());
+  Out << ") alloca(sizeof(";
+  printType(Out, I.getType()->getElementType());
+  Out << ")";
+  if (I.isArrayAllocation()) {
+    Out << " * " ;
+    writeOperand(I.getOperand(0));
+  }
+  Out << ")";
+}
+
+void CWriter::visitFreeInst(FreeInst &I) {
+  assert(0 && "lowerallocations pass didn't work!");
+}
+
+void CWriter::printIndexingExpression(Value *Ptr, gep_type_iterator I,
+                                      gep_type_iterator E) {
+  bool HasImplicitAddress = false;
+  // If accessing a global value with no indexing, avoid *(&GV) syndrome
+  if (GlobalValue *V = dyn_cast<GlobalValue>(Ptr)) {
+    HasImplicitAddress = true;
+  } else if (ConstantPointerRef *CPR = dyn_cast<ConstantPointerRef>(Ptr)) {
+    HasImplicitAddress = true;
+    Ptr = CPR->getValue();         // Get to the global...
+  } else if (isDirectAlloca(Ptr)) {
+    HasImplicitAddress = true;
+  }
+
+  if (I == E) {
+    if (!HasImplicitAddress)
+      Out << "*";  // Implicit zero first argument: '*x' is equivalent to 'x[0]'
+
+    writeOperandInternal(Ptr);
+    return;
+  }
+
+  const Constant *CI = dyn_cast<Constant>(I.getOperand());
+  if (HasImplicitAddress && (!CI || !CI->isNullValue()))
+    Out << "(&";
+
+  writeOperandInternal(Ptr);
+
+  if (HasImplicitAddress && (!CI || !CI->isNullValue())) {
+    Out << ")";
+    HasImplicitAddress = false;  // HIA is only true if we haven't addressed yet
+  }
+
+  assert(!HasImplicitAddress || (CI && CI->isNullValue()) &&
+         "Can only have implicit address with direct accessing");
+
+  if (HasImplicitAddress) {
+    ++I;
+  } else if (CI && CI->isNullValue()) {
+    gep_type_iterator TmpI = I; ++TmpI;
+
+    // Print out the -> operator if possible...
+    if (TmpI != E && isa<StructType>(*TmpI)) {
+      Out << (HasImplicitAddress ? "." : "->");
+      Out << "field" << cast<ConstantUInt>(TmpI.getOperand())->getValue();
+      I = ++TmpI;
+    }
+  }
+
+  for (; I != E; ++I)
+    if (isa<StructType>(*I)) {
+      Out << ".field" << cast<ConstantUInt>(I.getOperand())->getValue();
+    } else {
+      Out << "[";
+      writeOperand(I.getOperand());
+      Out << "]";
+    }
+}
+
+void CWriter::visitLoadInst(LoadInst &I) {
+  Out << "*";
+  writeOperand(I.getOperand(0));
+}
+
+void CWriter::visitStoreInst(StoreInst &I) {
+  Out << "*";
+  writeOperand(I.getPointerOperand());
+  Out << " = ";
+  writeOperand(I.getOperand(0));
+}
+
+void CWriter::visitGetElementPtrInst(GetElementPtrInst &I) {
+  Out << "&";
+  printIndexingExpression(I.getPointerOperand(), gep_type_begin(I),
+                          gep_type_end(I));
+}
+
+void CWriter::visitVANextInst(VANextInst &I) {
+  Out << Mang->getValueName(I.getOperand(0));
+  Out << ";  va_arg(*(va_list*)&" << Mang->getValueName(&I) << ", ";
+  printType(Out, I.getArgType());
+  Out << ")";  
+}
+
+void CWriter::visitVAArgInst(VAArgInst &I) {
+  Out << "0;\n";
+  Out << "{ va_list Tmp; va_copy(Tmp, *(va_list*)&";
+  writeOperand(I.getOperand(0));
+  Out << ");\n  " << Mang->getValueName(&I) << " = va_arg(Tmp, ";
+  printType(Out, I.getType());
+  Out << ");\n  va_end(Tmp); }";
+}
+
+}
+
+//===----------------------------------------------------------------------===//
+//                       External Interface declaration
+//===----------------------------------------------------------------------===//
+
+bool CTargetMachine::addPassesToEmitAssembly(PassManager &PM, std::ostream &o) {
+  PM.add(createLowerAllocationsPass());
+  PM.add(createLowerInvokePass());
+  PM.add(new CWriter(o));
+  return false;
+}
+
+TargetMachine *llvm::allocateCTargetMachine(const Module &M,
+                                            IntrinsicLowering *IL) {
+  return new CTargetMachine(M, IL);
+}
diff --git a/llvm/lib/Target/Makefile b/llvm/lib/Target/Makefile
index 01ad71116b5..89ed3e975d7 100644
--- a/llvm/lib/Target/Makefile
+++ b/llvm/lib/Target/Makefile
@@ -7,7 +7,7 @@
 # 
 ##===----------------------------------------------------------------------===##
 LEVEL = ../..
-DIRS = Sparc X86 PowerPC
+DIRS = CBackend X86 Sparc PowerPC
 LIBRARYNAME = target
 BUILD_ARCHIVE = 1