Initial revision


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@2 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Bytecode/Makefile b/lib/Bytecode/Makefile
new file mode 100644
index 0000000..75d4f7c
--- /dev/null
+++ b/lib/Bytecode/Makefile
@@ -0,0 +1,5 @@
+LEVEL = ../..
+DIRS = Reader Writer
+
+include $(LEVEL)/Makefile.common
+
diff --git a/lib/Bytecode/Reader/ConstantReader.cpp b/lib/Bytecode/Reader/ConstantReader.cpp
new file mode 100644
index 0000000..b85bd88
--- /dev/null
+++ b/lib/Bytecode/Reader/ConstantReader.cpp
@@ -0,0 +1,218 @@
+//===- ReadConst.cpp - Code to constants and constant pools -----------------===
+//
+// This file implements functionality to deserialize constants and entire 
+// constant pools.
+// 
+// Note that this library should be as fast as possible, reentrant, and 
+// threadsafe!!
+//
+//===------------------------------------------------------------------------===
+
+#include "llvm/Module.h"
+#include "llvm/BasicBlock.h"
+#include "llvm/ConstPoolVals.h"
+#include "llvm/DerivedTypes.h"
+#include "ReaderInternals.h"
+
+bool BytecodeParser::parseTypeConstant(const uchar *&Buf, const uchar *EndBuf,
+				       ConstPoolVal *&V) {
+  const Type *Val = 0;
+
+  unsigned PrimType;
+  if (read_vbr(Buf, EndBuf, PrimType)) return true;
+
+  if ((Val = Type::getPrimitiveType((Type::PrimitiveID)PrimType))) {
+    V = new ConstPoolType(Val);    // It's just a primitive ID.
+    return false;
+  }
+  
+  switch (PrimType) {
+  case Type::MethodTyID: {
+    unsigned Typ;
+    if (read_vbr(Buf, EndBuf, Typ)) return true;
+    const Type *RetType = getType(Typ);
+    if (RetType == 0) return true;
+
+    MethodType::ParamTypes Params;
+
+    if (read_vbr(Buf, EndBuf, Typ)) return true;
+    while (Typ) {
+      const Type *Ty = getType(Typ);
+      if (Ty == 0) return true;
+      Params.push_back(Ty);
+      
+      if (read_vbr(Buf, EndBuf, Typ)) return true;
+    }
+
+    Val = MethodType::getMethodType(RetType, Params);
+    break;
+  }
+  case Type::ArrayTyID: {
+    unsigned ElTyp;
+    if (read_vbr(Buf, EndBuf, ElTyp)) return true;
+    const Type *ElementType = getType(ElTyp);
+    if (ElementType == 0) return true;
+
+    int NumElements;
+    if (read_vbr(Buf, EndBuf, NumElements)) return true;
+    Val = ArrayType::getArrayType(ElementType, NumElements);
+    break;
+  }
+  case Type::StructTyID: {
+    unsigned Typ;
+    StructType::ElementTypes Elements;
+
+    if (read_vbr(Buf, EndBuf, Typ)) return true;
+    while (Typ) {         // List is terminated by void/0 typeid
+      const Type *Ty = getType(Typ);
+      if (Ty == 0) return true;
+      Elements.push_back(Ty);
+      
+      if (read_vbr(Buf, EndBuf, Typ)) return true;
+    }
+
+    Val = StructType::getStructType(Elements);
+    break;
+  }
+  case Type::PointerTyID: {
+    unsigned ElTyp;
+    if (read_vbr(Buf, EndBuf, ElTyp)) return true;
+    const Type *ElementType = getType(ElTyp);
+    if (ElementType == 0) return true;
+    Val = PointerType::getPointerType(ElementType);
+    break;
+  }
+
+  default:
+    cerr << __FILE__ << ":" << __LINE__ << ": Don't know how to deserialize"
+	 << " primitive Type " << PrimType << "\n";
+    return true;
+  }
+
+  V = new ConstPoolType(Val);
+  return false;
+}
+
+bool BytecodeParser::parseConstPoolValue(const uchar *&Buf, 
+					 const uchar *EndBuf,
+					 const Type *Ty, ConstPoolVal *&V) {
+  switch (Ty->getPrimitiveID()) {
+  case Type::BoolTyID: {
+    unsigned Val;
+    if (read_vbr(Buf, EndBuf, Val)) return true;
+    if (Val != 0 && Val != 1) return true;
+    V = new ConstPoolBool(Val == 1);
+    break;
+  }
+
+  case Type::UByteTyID:   // Unsigned integer types...
+  case Type::UShortTyID:
+  case Type::UIntTyID: {
+    unsigned Val;
+    if (read_vbr(Buf, EndBuf, Val)) return true;
+    if (!ConstPoolUInt::isValueValidForType(Ty, Val)) return true;
+    V = new ConstPoolUInt(Ty, Val);
+    break;
+  }
+
+  case Type::ULongTyID: {
+    uint64_t Val;
+    if (read_vbr(Buf, EndBuf, Val)) return true;
+    V = new ConstPoolUInt(Ty, Val);
+    break;
+  }
+
+  case Type::SByteTyID:   // Unsigned integer types...
+  case Type::ShortTyID:
+  case Type::IntTyID: {
+    int Val;
+    if (read_vbr(Buf, EndBuf, Val)) return true;
+    if (!ConstPoolSInt::isValueValidForType(Ty, Val)) return 0;
+    V = new ConstPoolSInt(Ty, Val);
+    break;
+  }
+
+  case Type::LongTyID: {
+    int64_t Val;
+    if (read_vbr(Buf, EndBuf, Val)) return true;
+    V = new ConstPoolSInt(Ty, Val);
+    break;
+  }
+
+  case Type::TypeTyID:
+    if (parseTypeConstant(Buf, EndBuf, V)) return true;
+    break;
+
+  case Type::ArrayTyID: {
+    const ArrayType *AT = (const ArrayType*)Ty;
+    unsigned NumElements;
+    if (AT->isSized())          // Sized array, # elements stored in type!
+      NumElements = (unsigned)AT->getNumElements();
+    else                        // Unsized array, # elements stored in stream!
+      if (read_vbr(Buf, EndBuf, NumElements)) return true;
+
+    vector<ConstPoolVal *> Elements;
+    while (NumElements--) {   // Read all of the elements of the constant.
+      unsigned Slot;
+      if (read_vbr(Buf, EndBuf, Slot)) return true;
+      Value *V = getValue(AT->getElementType(), Slot, false);
+      if (!V || V->getValueType() != Value::ConstantVal)
+	return true;
+      Elements.push_back((ConstPoolVal*)V);
+    }
+    V = new ConstPoolArray(AT, Elements);
+    break;
+  }
+
+  case Type::StructTyID: {
+    const StructType *ST = (const StructType*)Ty;
+    const StructType::ElementTypes &ET = ST->getElementTypes();
+
+    vector<ConstPoolVal *> Elements;
+    for (unsigned i = 0; i < ET.size(); ++i) {
+      unsigned Slot;
+      if (read_vbr(Buf, EndBuf, Slot)) return true;
+      Value *V = getValue(ET[i], Slot, false);
+      if (!V || V->getValueType() != Value::ConstantVal)
+	return true;
+      Elements.push_back((ConstPoolVal*)V);      
+    }
+
+    V = new ConstPoolStruct(ST, Elements);
+    break;
+  }    
+
+  default:
+    cerr << __FILE__ << ":" << __LINE__ 
+	 << ": Don't know how to deserialize constant value of type '"
+	 << Ty->getName() << "'\n";
+    return true;
+  }
+  return false;
+}
+
+bool BytecodeParser::ParseConstantPool(const uchar *&Buf, const uchar *EndBuf,
+				       SymTabValue::ConstantPoolType &CP, 
+				       ValueTable &Tab) {
+  while (Buf < EndBuf) {
+    unsigned NumEntries, Typ;
+
+    if (read_vbr(Buf, EndBuf, NumEntries) ||
+        read_vbr(Buf, EndBuf, Typ)) return true;
+    const Type *Ty = getType(Typ);
+    if (Ty == 0) return true;
+
+    for (unsigned i = 0; i < NumEntries; i++) {
+      ConstPoolVal *I;
+      if (parseConstPoolValue(Buf, EndBuf, Ty, I)) return true;
+#if 0
+      cerr << "  Read const value: <" << I->getType()->getName() 
+	   << ">: " << I->getStrValue() << endl;
+#endif
+      insertValue(I, Tab);
+      CP.insert(I);
+    }
+  }
+  
+  return Buf > EndBuf;
+}
diff --git a/lib/Bytecode/Reader/InstructionReader.cpp b/lib/Bytecode/Reader/InstructionReader.cpp
new file mode 100644
index 0000000..667e144
--- /dev/null
+++ b/lib/Bytecode/Reader/InstructionReader.cpp
@@ -0,0 +1,213 @@
+//===- ReadInst.cpp - Code to read an instruction from bytecode -------------===
+//
+// This file defines the mechanism to read an instruction from a bytecode 
+// stream.
+//
+// Note that this library should be as fast as possible, reentrant, and 
+// threadsafe!!
+//
+// TODO: Change from getValue(Raw.Arg1) etc, to getArg(Raw, 1)
+//       Make it check type, so that casts are checked.
+//
+//===------------------------------------------------------------------------===
+
+#include "llvm/iOther.h"
+#include "llvm/iTerminators.h"
+#include "llvm/iMemory.h"
+#include "llvm/DerivedTypes.h"
+#include "ReaderInternals.h"
+
+bool BytecodeParser::ParseRawInst(const uchar *&Buf, const uchar *EndBuf, 
+				  RawInst &Result) {
+  unsigned Op, Typ;
+  if (read(Buf, EndBuf, Op)) return true;
+
+  Result.NumOperands =  Op >> 30;
+  Result.Opcode      = (Op >> 24) & 63;
+
+  switch (Result.NumOperands) {
+  case 1:
+    Result.Ty   = getType((Op >> 12) & 4095);
+    Result.Arg1 = Op & 4095;
+    if (Result.Arg1 == 4095)    // Handle special encoding for 0 operands...
+      Result.NumOperands = 0;
+    break;
+  case 2:
+    Result.Ty   = getType((Op >> 16) & 255);
+    Result.Arg1 = (Op >> 8 ) & 255;
+    Result.Arg2 = (Op >> 0 ) & 255;
+    break;
+  case 3:
+    Result.Ty   = getType((Op >> 18) & 63);
+    Result.Arg1 = (Op >> 12) & 63;
+    Result.Arg2 = (Op >> 6 ) & 63;
+    Result.Arg3 = (Op >> 0 ) & 63;
+    break;
+  case 0:
+    Buf -= 4;  // Hrm, try this again...
+    if (read_vbr(Buf, EndBuf, Result.Opcode)) return true;
+    if (read_vbr(Buf, EndBuf, Typ)) return true;
+    Result.Ty = getType(Typ);
+    if (read_vbr(Buf, EndBuf, Result.NumOperands)) return true;
+
+    switch (Result.NumOperands) {
+    case 0: 
+      cerr << "Zero Arg instr found!\n"; 
+      return true;  // This encoding is invalid!
+    case 1: 
+      if (read_vbr(Buf, EndBuf, Result.Arg1)) return true;
+      break;
+    case 2:
+      if (read_vbr(Buf, EndBuf, Result.Arg1) || 
+	  read_vbr(Buf, EndBuf, Result.Arg2)) return true;
+      break;
+    case 3:
+      if (read_vbr(Buf, EndBuf, Result.Arg1) || 
+	  read_vbr(Buf, EndBuf, Result.Arg2) ||
+	  read_vbr(Buf, EndBuf, Result.Arg3)) return true;
+      break;
+    default:
+      if (read_vbr(Buf, EndBuf, Result.Arg1) || 
+	  read_vbr(Buf, EndBuf, Result.Arg2)) return true;
+
+      // Allocate a vector to hold arguments 3, 4, 5, 6 ...
+      Result.VarArgs = new vector<unsigned>(Result.NumOperands-2);
+      for (unsigned a = 0; a < Result.NumOperands-2; a++)
+	if (read_vbr(Buf, EndBuf, (*Result.VarArgs)[a])) return true;
+      break;
+    }
+    if (align32(Buf, EndBuf)) return true;
+    break;
+  }
+
+  //cerr << "NO: "  << Result.NumOperands   << " opcode: " << Result.Opcode 
+  //   << " Ty: " << Result.Ty->getName() << " arg1: "   << Result.Arg1 << endl;
+  return false;
+}
+
+
+bool BytecodeParser::ParseInstruction(const uchar *&Buf, const uchar *EndBuf,
+				      Instruction *&Res) {
+  RawInst Raw;
+  if (ParseRawInst(Buf, EndBuf, Raw)) return true;;
+
+  if (Raw.Opcode >= Instruction::FirstUnaryOp && 
+      Raw.Opcode <  Instruction::NumUnaryOps  && Raw.NumOperands == 1) {
+    Res = Instruction::getUnaryOperator(Raw.Opcode, getValue(Raw.Ty, Raw.Arg1));
+    return false;
+  } else if (Raw.Opcode >= Instruction::FirstBinaryOp &&
+	     Raw.Opcode <  Instruction::NumBinaryOps  && Raw.NumOperands == 2) {
+    Res = Instruction::getBinaryOperator(Raw.Opcode, getValue(Raw.Ty, Raw.Arg1),
+					 getValue(Raw.Ty, Raw.Arg2));
+    return false;
+  } else if (Raw.Opcode == Instruction::PHINode) {
+    PHINode *PN = new PHINode(Raw.Ty);
+    switch (Raw.NumOperands) {
+    case 0: cerr << "Invalid phi node encountered!\n"; 
+            delete PN; 
+	    return true;
+    case 1: PN->addIncoming(getValue(Raw.Ty, Raw.Arg1)); break;
+    case 2: PN->addIncoming(getValue(Raw.Ty, Raw.Arg1)); 
+            PN->addIncoming(getValue(Raw.Ty, Raw.Arg2)); break;
+    case 3: PN->addIncoming(getValue(Raw.Ty, Raw.Arg1)); 
+            PN->addIncoming(getValue(Raw.Ty, Raw.Arg2)); 
+            PN->addIncoming(getValue(Raw.Ty, Raw.Arg3)); break;
+    default:
+      PN->addIncoming(getValue(Raw.Ty, Raw.Arg1)); 
+      PN->addIncoming(getValue(Raw.Ty, Raw.Arg2));
+      {
+        vector<unsigned> &args = *Raw.VarArgs;
+        for (unsigned i = 0; i < args.size(); i++)
+          PN->addIncoming(getValue(Raw.Ty, args[i]));
+      }
+      delete Raw.VarArgs;
+    }
+    Res = PN;
+    return false;
+  } else if (Raw.Opcode == Instruction::Ret) {
+    if (Raw.NumOperands == 0) {
+      Res = new ReturnInst(); return false; 
+    } else if (Raw.NumOperands == 1) {
+      Res = new ReturnInst(getValue(Raw.Ty, Raw.Arg1)); return false; 
+    }
+  } else if (Raw.Opcode == Instruction::Br) {
+    if (Raw.NumOperands == 1) {
+      Res = new BranchInst((BasicBlock*)getValue(Type::LabelTy, Raw.Arg1));
+      return false;
+    } else if (Raw.NumOperands == 3) {
+      Res = new BranchInst((BasicBlock*)getValue(Type::LabelTy, Raw.Arg1),
+			   (BasicBlock*)getValue(Type::LabelTy, Raw.Arg2),
+			                getValue(Type::BoolTy , Raw.Arg3));
+      return false;
+    }
+  } else if (Raw.Opcode == Instruction::Switch) {
+    SwitchInst *I = 
+      new SwitchInst(getValue(Raw.Ty, Raw.Arg1), 
+                     (BasicBlock*)getValue(Type::LabelTy, Raw.Arg2));
+    Res = I;
+    if (Raw.NumOperands < 3) return false;  // No destinations?  Wierd.
+
+    if (Raw.NumOperands == 3 || Raw.VarArgs->size() & 1) {
+      cerr << "Switch statement with odd number of arguments!\n";
+      delete I;
+      return true;
+    }      
+    
+    vector<unsigned> &args = *Raw.VarArgs;
+    for (unsigned i = 0; i < args.size(); i += 2)
+      I->dest_push_back((ConstPoolVal*)getValue(Raw.Ty, args[i]),
+                        (BasicBlock*)getValue(Type::LabelTy, args[i+1]));
+
+    delete Raw.VarArgs;
+    return false;
+  } else if (Raw.Opcode == Instruction::Call) {
+    Method *M = (Method*)getValue(Raw.Ty, Raw.Arg1);
+    if (M == 0) return true;
+
+    const MethodType::ParamTypes &PL = M->getMethodType()->getParamTypes();
+    MethodType::ParamTypes::const_iterator It = PL.begin();
+
+    vector<Value *> Params;
+    switch (Raw.NumOperands) {
+    case 0: cerr << "Invalid call instruction encountered!\n";
+	    return true;
+    case 1: break;
+    case 2: Params.push_back(getValue(*It++, Raw.Arg2)); break;
+    case 3: Params.push_back(getValue(*It++, Raw.Arg2)); 
+            if (It == PL.end()) return true;
+            Params.push_back(getValue(*It++, Raw.Arg3)); break;
+    default:
+      Params.push_back(getValue(*It++, Raw.Arg2));
+      {
+        vector<unsigned> &args = *Raw.VarArgs;
+        for (unsigned i = 0; i < args.size(); i++) {
+	  if (It == PL.end()) return true;
+          Params.push_back(getValue(*It++, args[i]));
+	}
+      }
+      delete Raw.VarArgs;
+    }
+    if (It != PL.end()) return true;
+
+    Res = new CallInst(M, Params);
+    return false;
+  } else if (Raw.Opcode == Instruction::Malloc) {
+    if (Raw.NumOperands > 2) return true;
+    Value *Sz = (Raw.NumOperands == 2) ? getValue(Type::UIntTy, Raw.Arg2) : 0;
+    Res = new MallocInst((ConstPoolType*)getValue(Type::TypeTy, Raw.Arg1), Sz);
+    return false;
+  } else if (Raw.Opcode == Instruction::Alloca) {
+    if (Raw.NumOperands > 2) return true;
+    Value *Sz = (Raw.NumOperands == 2) ? getValue(Type::UIntTy, Raw.Arg2) : 0;
+    Res = new AllocaInst((ConstPoolType*)getValue(Type::TypeTy, Raw.Arg1), Sz);
+    return false;
+  } else if (Raw.Opcode == Instruction::Free) {
+    Value *Val = getValue(Raw.Ty, Raw.Arg1);
+    if (!Val->getType()->isPointerType()) return true;
+    Res = new FreeInst(Val);
+    return false;
+  }
+
+  cerr << "Unrecognized instruction! " << Raw.Opcode << endl;
+  return true;
+}
diff --git a/lib/Bytecode/Reader/Makefile b/lib/Bytecode/Reader/Makefile
new file mode 100644
index 0000000..2c79d15
--- /dev/null
+++ b/lib/Bytecode/Reader/Makefile
@@ -0,0 +1,7 @@
+
+LEVEL = ../../..
+
+LIBRARYNAME = bcreader
+
+include $(LEVEL)/Makefile.common
+
diff --git a/lib/Bytecode/Reader/Reader.cpp b/lib/Bytecode/Reader/Reader.cpp
new file mode 100644
index 0000000..c3f4c90
--- /dev/null
+++ b/lib/Bytecode/Reader/Reader.cpp
@@ -0,0 +1,478 @@
+//===- Reader.cpp - Code to read bytecode files -----------------------------===
+//
+// This library implements the functionality defined in llvm/Bytecode/Reader.h
+//
+// Note that this library should be as fast as possible, reentrant, and 
+// threadsafe!!
+//
+// TODO: Make error message outputs be configurable depending on an option?
+// TODO: Allow passing in an option to ignore the symbol table
+//
+//===------------------------------------------------------------------------===
+
+#include "llvm/Bytecode/Reader.h"
+#include "llvm/Bytecode/Format.h"
+#include "llvm/Module.h"
+#include "llvm/BasicBlock.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/ConstPoolVals.h"
+#include "llvm/iOther.h"
+#include "ReaderInternals.h"
+#include <sys/types.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <algorithm>
+
+bool BytecodeParser::getTypeSlot(const Type *Ty, unsigned &Slot) {
+  if (Ty->isPrimitiveType()) {
+    Slot = Ty->getPrimitiveID();
+  } else {
+    TypeMapType::iterator I = TypeMap.find(Ty);
+    if (I == TypeMap.end()) return true;   // Didn't find type!
+    Slot = I->second;
+  }
+  //cerr << "getTypeSlot '" << Ty->getName() << "' = " << Slot << endl;
+  return false;
+}
+
+const Type *BytecodeParser::getType(unsigned ID) {
+  const Type *T = Type::getPrimitiveType((Type::PrimitiveID)ID);
+  if (T) return T;
+  
+  //cerr << "Looking up Type ID: " << ID << endl;
+
+  const Value *D = getValue(Type::TypeTy, ID, false);
+  if (D == 0) return 0;
+
+  assert(D->getType() == Type::TypeTy &&
+	 D->getValueType() == Value::ConstantVal);
+
+
+  return ((const ConstPoolType*)D)->getValue();;
+}
+
+bool BytecodeParser::insertValue(Value *Def, vector<ValueList> &ValueTab) {
+  unsigned type;
+  if (getTypeSlot(Def->getType(), type)) return true;
+ 
+  if (ValueTab.size() <= type)
+    ValueTab.resize(type+1, ValueList());
+
+  //cerr << "insertValue Values[" << type << "][" << ValueTab[type].size() 
+  //     << "] = " << Def << endl;
+
+  if (type == Type::TypeTyID && Def->getValueType() == Value::ConstantVal) {
+    const Type *Ty = ((const ConstPoolType*)Def)->getValue();
+    unsigned ValueOffset = FirstDerivedTyID;
+
+    if (&ValueTab == &Values)    // Take into consideration module level types
+      ValueOffset += ModuleValues[type].size();
+
+    if (TypeMap.find(Ty) == TypeMap.end())
+      TypeMap[Ty] = ValueTab[type].size()+ValueOffset;
+  }
+
+  ValueTab[type].push_back(Def);
+
+  return false;
+}
+
+Value *BytecodeParser::getValue(const Type *Ty, unsigned oNum, bool Create) {
+  unsigned Num = oNum;
+  unsigned type;   // The type plane it lives in...
+
+  if (getTypeSlot(Ty, type)) return 0; // TODO: true
+
+  if (type == Type::TypeTyID) {  // The 'type' plane has implicit values
+    const Type *T = Type::getPrimitiveType((Type::PrimitiveID)Num);
+    if (T) return (Value*)T;   // Asked for a primitive type...
+
+    // Otherwise, derived types need offset...
+    Num -= FirstDerivedTyID;
+  }
+
+  if (ModuleValues.size() > type) {
+    if (ModuleValues[type].size() > Num)
+      return ModuleValues[type][Num];
+    Num -= ModuleValues[type].size();
+  }
+
+  if (Values.size() > type && Values[type].size() > Num)
+    return Values[type][Num];
+
+  if (!Create) return 0;  // Do not create a placeholder?
+
+  Value *d = 0;
+  switch (Ty->getPrimitiveID()) {
+  case Type::LabelTyID: d = new    BBPHolder(Ty, oNum); break;
+  case Type::MethodTyID:
+    cerr << "Creating method pholder! : " << type << ":" << oNum << " " 
+	 << Ty->getName() << endl;
+    d = new MethPHolder(Ty, oNum);
+    insertValue(d, LateResolveModuleValues);
+    return d;
+  default:                   d = new   DefPHolder(Ty, oNum); break;
+  }
+
+  assert(d != 0 && "How did we not make something?");
+  if (insertValue(d, LateResolveValues)) return 0;
+  return d;
+}
+
+bool BytecodeParser::postResolveValues(ValueTable &ValTab) {
+  bool Error = false;
+  for (unsigned ty = 0; ty < ValTab.size(); ty++) {
+    ValueList &DL = ValTab[ty];
+    unsigned Size;
+    while ((Size = DL.size())) {
+      unsigned IDNumber = getValueIDNumberFromPlaceHolder(DL[Size-1]);
+
+      Value *D = DL[Size-1];
+      DL.pop_back();
+
+      Value *NewDef = getValue(D->getType(), IDNumber, false);
+      if (NewDef == 0) {
+	Error = true;  // Unresolved thinger
+	cerr << "Unresolvable reference found: <" << D->getType()->getName()
+	     << ">:" << IDNumber << "!\n";
+      } else {
+	// Fixup all of the uses of this placeholder def...
+        D->replaceAllUsesWith(NewDef);
+
+        // Now that all the uses are gone, delete the placeholder...
+        // If we couldn't find a def (error case), then leak a little
+	delete D;  // memory, 'cause otherwise we can't remove all uses!
+      }
+    }
+  }
+
+  return Error;
+}
+
+bool BytecodeParser::ParseBasicBlock(const uchar *&Buf, const uchar *EndBuf, 
+				     BasicBlock *&BB) {
+  BB = new BasicBlock();
+
+  while (Buf < EndBuf) {
+    Instruction *Def;
+    if (ParseInstruction(Buf, EndBuf, Def)) {
+      delete BB;
+      return true;
+    }
+
+    if (Def == 0) { delete BB; return true; }
+    if (insertValue(Def, Values)) { delete BB; return true; }
+
+    BB->getInstList().push_back(Def);
+  }
+
+  return false;
+}
+
+bool BytecodeParser::ParseSymbolTable(const uchar *&Buf, const uchar *EndBuf) {
+  while (Buf < EndBuf) {
+    // Symtab block header: [num entries][type id number]
+    unsigned NumEntries, Typ;
+    if (read_vbr(Buf, EndBuf, NumEntries) ||
+        read_vbr(Buf, EndBuf, Typ)) return true;
+    const Type *Ty = getType(Typ);
+    if (Ty == 0) return true;
+
+    for (unsigned i = 0; i < NumEntries; i++) {
+      // Symtab entry: [def slot #][name]
+      unsigned slot;
+      if (read_vbr(Buf, EndBuf, slot)) return true;
+      string Name;
+      if (read(Buf, EndBuf, Name, false))  // Not aligned...
+	return true;
+
+      Value *D = getValue(Ty, slot, false); // Find mapping...
+      if (D == 0) return true;
+      D->setName(Name);
+    }
+  }
+
+  return Buf > EndBuf;
+}
+
+
+bool BytecodeParser::ParseMethod(const uchar *&Buf, const uchar *EndBuf, 
+				 Module *C) {
+  // Clear out the local values table...
+  Values.clear();
+  if (MethodSignatureList.empty()) return true;  // Unexpected method!
+
+  const MethodType *MTy = MethodSignatureList.front().first;
+  unsigned MethSlot = MethodSignatureList.front().second;
+  MethodSignatureList.pop_front();
+  Method *M = new Method(MTy);
+
+  const MethodType::ParamTypes &Params = MTy->getParamTypes();
+  for (MethodType::ParamTypes::const_iterator It = Params.begin();
+       It != Params.end(); It++) {
+    MethodArgument *MA = new MethodArgument(*It);
+    if (insertValue(MA, Values)) { delete M; return true; }
+    M->getArgumentList().push_back(MA);
+  }
+
+  while (Buf < EndBuf) {
+    unsigned Type, Size;
+    const uchar *OldBuf = Buf;
+    if (readBlock(Buf, EndBuf, Type, Size)) { delete M; return true; }
+
+    switch (Type) {
+    case BytecodeFormat::ConstantPool:
+      if (ParseConstantPool(Buf, Buf+Size, M->getConstantPool(), Values)) {
+	cerr << "Error reading constant pool!\n";
+	delete M; return true;
+      }
+      break;
+
+    case BytecodeFormat::BasicBlock: {
+      BasicBlock *BB;
+      if (ParseBasicBlock(Buf, Buf+Size, BB) ||
+	  insertValue(BB, Values)) {
+	cerr << "Error parsing basic block!\n";
+	delete M; return true;                       // Parse error... :(
+      }
+
+      M->getBasicBlocks().push_back(BB);
+      break;
+    }
+
+    case BytecodeFormat::SymbolTable:
+      if (ParseSymbolTable(Buf, Buf+Size)) {
+	cerr << "Error reading method symbol table!\n";
+	delete M; return true;
+      }
+      break;
+
+    default:
+      Buf += Size;
+      if (OldBuf > Buf) return true; // Wrap around!
+      break;
+    }
+    if (align32(Buf, EndBuf)) {
+      delete M;    // Malformed bc file, read past end of block.
+      return true;
+    }
+  }
+
+  if (postResolveValues(LateResolveValues) ||
+      postResolveValues(LateResolveModuleValues)) {
+    delete M; return true;     // Unresolvable references!
+  }
+
+  Value *MethPHolder = getValue(MTy, MethSlot, false);
+  assert(MethPHolder && "Something is broken no placeholder found!");
+  assert(MethPHolder->getValueType() == Value::MethodVal && "Not a method?");
+
+  unsigned type;  // Type slot
+  assert(!getTypeSlot(MTy, type) && "How can meth type not exist?");
+  getTypeSlot(MTy, type);
+
+  C->getMethodList().push_back(M);
+
+  // Replace placeholder with the real method pointer...
+  ModuleValues[type][MethSlot] = M;
+
+  // If anyone is using the placeholder make them use the real method instead
+  MethPHolder->replaceAllUsesWith(M);
+
+  // We don't need the placeholder anymore!
+  delete MethPHolder;
+
+  return false;
+}
+
+bool BytecodeParser::ParseModuleGlobalInfo(const uchar *&Buf, const uchar *End,
+					  Module *C) {
+
+  if (!MethodSignatureList.empty()) return true;  // Two ModuleGlobal blocks?
+
+  // Read the method signatures for all of the methods that are coming, and 
+  // create fillers in the Value tables.
+  unsigned MethSignature;
+  if (read_vbr(Buf, End, MethSignature)) return true;
+  while (MethSignature != Type::VoidTyID) { // List is terminated by Void
+    const Type *Ty = getType(MethSignature);
+    if (!Ty || !Ty->isMethodType()) { 
+      cerr << "Method not meth type! ";
+      if (Ty) cerr << Ty->getName(); else cerr << MethSignature; cerr << endl; 
+      return true; 
+    }
+
+    // When the ModuleGlobalInfo section is read, we load the type of each method
+    // and the 'ModuleValues' slot that it lands in.  We then load a placeholder
+    // into its slot to reserve it.  When the method is loaded, this placeholder
+    // is replaced.
+
+    // Insert the placeholder...
+    Value *Def = new MethPHolder(Ty, 0);
+    insertValue(Def, ModuleValues);
+
+    // Figure out which entry of its typeslot it went into...
+    unsigned TypeSlot;
+    if (getTypeSlot(Def->getType(), TypeSlot)) return true;
+
+    unsigned SlotNo = ModuleValues[TypeSlot].size()-1;
+    
+    // Keep track of this information in a linked list that is emptied as 
+    // methods are loaded...
+    //
+    MethodSignatureList.push_back(make_pair((const MethodType*)Ty, SlotNo));
+    if (read_vbr(Buf, End, MethSignature)) return true;
+  }
+
+  if (align32(Buf, End)) return true;
+
+  // This is for future proofing... in the future extra fields may be added that
+  // we don't understand, so we transparently ignore them.
+  //
+  Buf = End;
+  return false;
+}
+
+bool BytecodeParser::ParseModule(const uchar *Buf, const uchar *EndBuf, 
+				Module *&C) {
+
+  unsigned Type, Size;
+  if (readBlock(Buf, EndBuf, Type, Size)) return true;
+  if (Type != BytecodeFormat::Module || Buf+Size != EndBuf)
+    return true;                               // Hrm, not a class?
+
+  MethodSignatureList.clear();                 // Just in case...
+
+  // Read into instance variables...
+  if (read_vbr(Buf, EndBuf, FirstDerivedTyID)) return true;
+  if (align32(Buf, EndBuf)) return true;
+
+  C = new Module();
+
+  while (Buf < EndBuf) {
+    const uchar *OldBuf = Buf;
+    if (readBlock(Buf, EndBuf, Type, Size)) { delete C; return true; }
+    switch (Type) {
+    case BytecodeFormat::ModuleGlobalInfo:
+      if (ParseModuleGlobalInfo(Buf, Buf+Size, C)) {
+	cerr << "Error reading class global info section!\n";
+	delete C; return true;
+      }
+      break;
+
+    case BytecodeFormat::ConstantPool:
+      if (ParseConstantPool(Buf, Buf+Size, C->getConstantPool(), ModuleValues)) {
+	cerr << "Error reading class constant pool!\n";
+	delete C; return true;
+      }
+      break;
+
+    case BytecodeFormat::Method: {
+      if (ParseMethod(Buf, Buf+Size, C)) {
+	delete C; return true;               // Error parsing method
+      }
+      break;
+    }
+
+    case BytecodeFormat::SymbolTable:
+      if (ParseSymbolTable(Buf, Buf+Size)) {
+	cerr << "Error reading class symbol table!\n";
+	delete C; return true;
+      }
+      break;
+
+    default:
+      cerr << "Unknown class block: " << Type << endl;
+      Buf += Size;
+      if (OldBuf > Buf) return true; // Wrap around!
+      break;
+    }
+    if (align32(Buf, EndBuf)) { delete C; return true; }
+  }
+
+  if (!MethodSignatureList.empty())      // Expected more methods!
+    return true;
+  return false;
+}
+
+Module *BytecodeParser::ParseBytecode(const uchar *Buf, const uchar *EndBuf) {
+  LateResolveValues.clear();
+  unsigned Sig;
+  // Read and check signature...
+  if (read(Buf, EndBuf, Sig) ||
+      Sig != ('l' | ('l' << 8) | ('v' << 16) | 'm' << 24))
+    return 0;                                         // Invalid signature!
+
+  Module *Result;
+  if (ParseModule(Buf, EndBuf, Result)) return 0;
+  return Result;
+}
+
+
+Module *ParseBytecodeBuffer(const uchar *Buffer, unsigned Length) {
+  BytecodeParser Parser;
+  return Parser.ParseBytecode(Buffer, Buffer+Length);
+}
+
+// Parse and return a class file...
+//
+Module *ParseBytecodeFile(const string &Filename) {
+  struct stat StatBuf;
+  Module *Result = 0;
+
+  if (Filename != string("-")) {        // Read from a file...
+    int FD = open(Filename.data(), O_RDONLY);
+    if (FD == -1) return 0;
+
+    if (fstat(FD, &StatBuf) == -1) { close(FD); return 0; }
+
+    int Length = StatBuf.st_size;
+    if (Length == 0) { close(FD); return 0; }
+    uchar *Buffer = (uchar*)mmap(0, Length, PROT_READ, 
+				MAP_PRIVATE, FD, 0);
+    if (Buffer == (uchar*)-1) { close(FD); return 0; }
+
+    BytecodeParser Parser;
+    Result  = Parser.ParseBytecode(Buffer, Buffer+Length);
+
+    munmap((char*)Buffer, Length);
+    close(FD);
+  } else {                              // Read from stdin
+    size_t FileSize = 0;
+    int BlockSize;
+    uchar Buffer[4096], *FileData = 0;
+    while ((BlockSize = read(0, Buffer, 4))) {
+      if (BlockSize == -1) { free(FileData); return 0; }
+
+      FileData = (uchar*)realloc(FileData, FileSize+BlockSize);
+      memcpy(FileData+FileSize, Buffer, BlockSize);
+      FileSize += BlockSize;
+    }
+
+    if (FileSize == 0) { free(FileData); return 0; }
+
+#define ALIGN_PTRS 1
+#if ALIGN_PTRS
+    uchar *Buf = (uchar*)mmap(0, FileSize, PROT_READ|PROT_WRITE, 
+			      MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
+    assert((Buf != (uchar*)-1) && "mmap returned error!");
+    free(FileData);
+    memcpy(Buf, FileData, FileSize);
+#else
+    uchar *Buf = FileData;
+#endif
+
+    BytecodeParser Parser;
+    Result = Parser.ParseBytecode(Buf, Buf+FileSize);
+
+#if ALIGN_PTRS
+    munmap((char*)Buf, FileSize);   // Free mmap'd data area
+#else
+    free(FileData);          // Free realloc'd block of memory
+#endif
+  }
+
+  return Result;
+}
diff --git a/lib/Bytecode/Reader/ReaderInternals.h b/lib/Bytecode/Reader/ReaderInternals.h
new file mode 100644
index 0000000..3bb0472
--- /dev/null
+++ b/lib/Bytecode/Reader/ReaderInternals.h
@@ -0,0 +1,146 @@
+//===-- ReaderInternals.h - Definitions internal to the reader ---*- C++ -*--=//
+//
+//  This header file defines various stuff that is used by the bytecode reader.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef READER_INTERNALS_H
+#define READER_INTERNALS_H
+
+#include "llvm/Bytecode/Primitives.h"
+#include "llvm/SymTabValue.h"
+#include "llvm/Method.h"
+#include "llvm/Instruction.h"
+#include <map>
+#include <utility>
+
+class BasicBlock;
+class Method;
+class Module;
+class Type;
+
+typedef unsigned char uchar;
+
+struct RawInst {       // The raw fields out of the bytecode stream...
+  unsigned NumOperands;
+  unsigned Opcode;
+  const Type *Ty;
+  unsigned Arg1, Arg2;
+  union {
+    unsigned Arg3;
+    vector<unsigned> *VarArgs;   // Contains arg #3,4,5... if NumOperands > 3
+  };
+};
+
+class BytecodeParser {
+public:
+  BytecodeParser() {
+    // Define this in case we don't see a ModuleGlobalInfo block.
+    FirstDerivedTyID = Type::FirstDerivedTyID;
+  }
+
+  Module *ParseBytecode(const uchar *Buf, const uchar *EndBuf);
+private:          // All of this data is transient across calls to ParseBytecode
+  typedef vector<Value *> ValueList;
+  typedef vector<ValueList> ValueTable;
+  typedef map<const Type *, unsigned> TypeMapType;
+  ValueTable Values, LateResolveValues;
+  ValueTable ModuleValues, LateResolveModuleValues;
+  TypeMapType TypeMap;
+
+  // Information read from the ModuleGlobalInfo section of the file...
+  unsigned FirstDerivedTyID;
+
+  // When the ModuleGlobalInfo section is read, we load the type of each method
+  // and the 'ModuleValues' slot that it lands in.  We then load a placeholder
+  // into its slot to reserve it.  When the method is loaded, this placeholder
+  // is replaced.
+  //
+  list<pair<const MethodType *, unsigned> > MethodSignatureList;
+
+private:
+  bool ParseModule            (const uchar * Buf, const uchar *End, Module *&);
+  bool ParseModuleGlobalInfo  (const uchar *&Buf, const uchar *End, Module *);
+  bool ParseSymbolTable       (const uchar *&Buf, const uchar *End);
+  bool ParseMethod            (const uchar *&Buf, const uchar *End, Module *);
+  bool ParseBasicBlock    (const uchar *&Buf, const uchar *End, BasicBlock *&);
+  bool ParseInstruction   (const uchar *&Buf, const uchar *End, Instruction *&);
+  bool ParseRawInst       (const uchar *&Buf, const uchar *End, RawInst &);
+
+  bool ParseConstantPool(const uchar *&Buf, const uchar *EndBuf,
+			 SymTabValue::ConstantPoolType &CP, ValueTable &Tab);
+
+
+  bool parseConstPoolValue(const uchar *&Buf, const uchar *End,
+			   const Type *Ty, ConstPoolVal *&V);
+  bool parseTypeConstant  (const uchar *&Buf, const uchar *, ConstPoolVal *&);
+
+  Value      *getValue(const Type *Ty, unsigned num, bool Create = true);
+  const Type *getType(unsigned ID);
+
+  bool insertValue(Value *D, vector<ValueList> &D);
+  bool postResolveValues(ValueTable &ValTab);
+
+  bool getTypeSlot(const Type *Ty, unsigned &Slot);
+};
+
+template<class SuperType>
+class PlaceholderDef : public SuperType {
+  unsigned ID;
+public:
+  PlaceholderDef(const Type *Ty, unsigned id) : SuperType(Ty), ID(id) {}
+  unsigned getID() { return ID; }
+};
+
+struct InstPlaceHolderHelper : public Instruction {
+  InstPlaceHolderHelper(const Type *Ty) : Instruction(Ty, UserOp1, "") {}
+  inline virtual void dropAllReferences() {}
+  virtual string getOpcode() const { return "placeholder"; }
+
+  virtual Instruction *clone() const { abort(); return 0; }
+
+  // No "operands"...
+  virtual Value *getOperand(unsigned i) { return 0; }
+  virtual const Value *getOperand(unsigned i) const { return 0; }
+  virtual bool setOperand(unsigned i, Value *Val) { return false; }
+  virtual unsigned getNumOperands() const { return 0; }
+};
+
+struct BBPlaceHolderHelper : public BasicBlock {
+  BBPlaceHolderHelper(const Type *Ty) : BasicBlock() {
+    assert(Ty->isLabelType());
+  }
+};
+
+struct MethPlaceHolderHelper : public Method {
+  MethPlaceHolderHelper(const Type *Ty) 
+    : Method((const MethodType*)Ty) {
+    assert(Ty->isMethodType() && "Method placeholders must be method types!");
+  }
+};
+
+typedef PlaceholderDef<InstPlaceHolderHelper>  DefPHolder;
+typedef PlaceholderDef<BBPlaceHolderHelper>    BBPHolder;
+typedef PlaceholderDef<MethPlaceHolderHelper>  MethPHolder;
+
+static inline unsigned getValueIDNumberFromPlaceHolder(Value *Def) {
+  switch (Def->getType()->getPrimitiveID()) {
+  case Type::LabelTyID:  return ((BBPHolder*)Def)->getID();
+  case Type::MethodTyID: return ((MethPHolder*)Def)->getID();
+  default:               return ((DefPHolder*)Def)->getID();
+  }
+}
+
+static inline bool readBlock(const uchar *&Buf, const uchar *EndBuf, 
+			     unsigned &Type, unsigned &Size) {
+#if DEBUG_OUTPUT
+  bool Result = read(Buf, EndBuf, Type) || read(Buf, EndBuf, Size);
+  cerr << "StartLoc = " << ((unsigned)Buf & 4095)
+       << " Type = " << Type << " Size = " << Size << endl;
+  return Result;
+#else
+  return read(Buf, EndBuf, Type) || read(Buf, EndBuf, Size);
+#endif
+}
+
+#endif
diff --git a/lib/Bytecode/Writer/ConstantWriter.cpp b/lib/Bytecode/Writer/ConstantWriter.cpp
new file mode 100644
index 0000000..e0504a5
--- /dev/null
+++ b/lib/Bytecode/Writer/ConstantWriter.cpp
@@ -0,0 +1,154 @@
+//===-- WriteConst.cpp - Functions for writing constants ---------*- C++ -*--=//
+//
+// This file implements the routines for encoding constants to a bytecode 
+// stream.
+//
+// Note that the performance of this library is not terribly important, because
+// it shouldn't be used by JIT type applications... so it is not a huge focus
+// at least.  :)
+//
+//===----------------------------------------------------------------------===//
+
+#include "WriterInternals.h"
+#include "llvm/ConstPoolVals.h"
+#include "llvm/SymbolTable.h"
+#include "llvm/DerivedTypes.h"
+
+void BytecodeWriter::outputType(const Type *T) {
+  output_vbr((unsigned)T->getPrimitiveID(), Out);
+  
+  // That's all there is to handling primitive types...
+  if (T->isPrimitiveType())
+    return;     // We might do this if we alias a prim type: %x = type int
+  
+  switch (T->getPrimitiveID()) {   // Handle derived types now.
+  case Type::MethodTyID: {
+    const MethodType *MT = (const MethodType*)T;
+    int Slot = Table.getValSlot(MT->getReturnType());
+    assert(Slot != -1 && "Type used but not available!!");
+    output_vbr((unsigned)Slot, Out);
+
+    // Output all of the arguments...
+    MethodType::ParamTypes::const_iterator I = MT->getParamTypes().begin();
+    for (; I != MT->getParamTypes().end(); I++) {
+      Slot = Table.getValSlot(*I);
+      assert(Slot != -1 && "Type used but not available!!");
+      output_vbr((unsigned)Slot, Out);
+    }
+
+    // Terminate list with VoidTy
+    output_vbr((unsigned)Type::VoidTy->getPrimitiveID(), Out);
+    break;
+  }
+
+  case Type::ArrayTyID: {
+    const ArrayType *AT = (const ArrayType*)T;
+    int Slot = Table.getValSlot(AT->getElementType());
+    assert(Slot != -1 && "Type used but not available!!");
+    output_vbr((unsigned)Slot, Out);
+    //cerr << "Type slot = " << Slot << " Type = " << T->getName() << endl;
+
+    output_vbr(AT->getNumElements(), Out);
+    break;
+  }
+
+  case Type::StructTyID: {
+    const StructType *ST = (const StructType*)T;
+
+    // Output all of the element types...
+    StructType::ElementTypes::const_iterator I = ST->getElementTypes().begin();
+    for (; I != ST->getElementTypes().end(); I++) {
+      int Slot = Table.getValSlot(*I);
+      assert(Slot != -1 && "Type used but not available!!");
+      output_vbr((unsigned)Slot, Out);
+    }
+
+    // Terminate list with VoidTy
+    output_vbr((unsigned)Type::VoidTy->getPrimitiveID(), Out);
+    break;
+  }
+
+  case Type::PointerTyID: {
+    const PointerType *PT = (const PointerType*)T;
+    int Slot = Table.getValSlot(PT->getValueType());
+    assert(Slot != -1 && "Type used but not available!!");
+    output_vbr((unsigned)Slot, Out);
+    break;
+  }
+
+  case Type::ModuleTyID:
+  case Type::PackedTyID:
+  default:
+    cerr << __FILE__ << ":" << __LINE__ << ": Don't know how to serialize"
+	 << " Type '" << T->getName() << "'\n";
+    break;
+  }
+}
+
+bool BytecodeWriter::outputConstant(const ConstPoolVal *CPV) {
+  switch (CPV->getType()->getPrimitiveID()) {
+  case Type::BoolTyID:    // Boolean Types
+    if (((const ConstPoolBool*)CPV)->getValue())
+      output_vbr((unsigned)1, Out);
+    else
+      output_vbr((unsigned)0, Out);
+    break;
+
+  case Type::UByteTyID:   // Unsigned integer types...
+  case Type::UShortTyID:
+  case Type::UIntTyID:
+  case Type::ULongTyID:
+    output_vbr(((const ConstPoolUInt*)CPV)->getValue(), Out);
+    break;
+
+  case Type::SByteTyID:   // Signed integer types...
+  case Type::ShortTyID:
+  case Type::IntTyID:
+  case Type::LongTyID:
+    output_vbr(((const ConstPoolSInt*)CPV)->getValue(), Out);
+    break;
+
+  case Type::TypeTyID:     // Serialize type type
+    outputType(((const ConstPoolType*)CPV)->getValue());
+    break;
+
+  case Type::ArrayTyID: {
+    const ConstPoolArray *CPA = (const ConstPoolArray *)CPV;
+    unsigned size = CPA->getValues().size();
+    if (!((const ArrayType *)CPA->getType())->isSized())
+      output_vbr(size, Out);            // Not for sized arrays!!!
+
+    for (unsigned i = 0; i < size; i++) {
+      int Slot = Table.getValSlot(CPA->getValues()[i]);
+      assert(Slot != -1 && "Constant used but not available!!");
+      output_vbr((unsigned)Slot, Out);
+    }
+    break;
+  }
+
+  case Type::StructTyID: {
+    const ConstPoolStruct *CPS = (const ConstPoolStruct*)CPV;
+    const vector<ConstPoolUse> &Vals = CPS->getValues();
+
+    for (unsigned i = 0; i < Vals.size(); ++i) {
+      int Slot = Table.getValSlot(Vals[i]);
+      assert(Slot != -1 && "Constant used but not available!!");
+      output_vbr((unsigned)Slot, Out);
+    }      
+    break;
+  }
+
+  case Type::FloatTyID:    // Floating point types...
+  case Type::DoubleTyID:
+    // TODO: Floating point type serialization
+
+
+  case Type::VoidTyID: 
+  case Type::LabelTyID:
+  default:
+    cerr << __FILE__ << ":" << __LINE__ << ": Don't know how to serialize"
+	 << " type '" << CPV->getType()->getName() << "'\n";
+    break;
+  }
+  return false;
+}
diff --git a/lib/Bytecode/Writer/InstructionWriter.cpp b/lib/Bytecode/Writer/InstructionWriter.cpp
new file mode 100644
index 0000000..c7c04ef
--- /dev/null
+++ b/lib/Bytecode/Writer/InstructionWriter.cpp
@@ -0,0 +1,184 @@
+//===-- WriteInst.cpp - Functions for writing instructions -------*- C++ -*--=//
+//
+// This file implements the routines for encoding instruction opcodes to a 
+// bytecode stream.
+//
+// Note that the performance of this library is not terribly important, because
+// it shouldn't be used by JIT type applications... so it is not a huge focus
+// at least.  :)
+//
+//===----------------------------------------------------------------------===//
+
+#include "WriterInternals.h"
+#include "llvm/Module.h"
+#include "llvm/Method.h"
+#include "llvm/BasicBlock.h"
+#include "llvm/Instruction.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/Tools/DataTypes.h"
+#include <algorithm>
+
+typedef unsigned char uchar;
+
+// outputInstructionFormat0 - Output those wierd instructions that have a large
+// number of operands or have large operands themselves...
+//
+// Format: [opcode] [type] [numargs] [arg0] [arg1] ... [arg<numargs-1>]
+//
+static void outputInstructionFormat0(const Instruction *I,
+				     const SlotCalculator &Table,
+				     unsigned Type, vector<uchar> &Out) {
+  // Opcode must have top two bits clear...
+  output_vbr(I->getInstType(), Out);             // Instruction Opcode ID
+  output_vbr(Type, Out);                         // Result type
+
+  unsigned NumArgs;  // Count the number of arguments to the instruction
+  for (NumArgs = 0; I->getOperand(NumArgs); NumArgs++) /*empty*/;
+  output_vbr(NumArgs, Out);
+
+  for (unsigned i = 0; const Value *N = I->getOperand(i); i++) {
+    assert(i < NumArgs && "Count of arguments failed!");
+
+    int Slot = Table.getValSlot(N);
+    output_vbr((unsigned)Slot, Out);
+  }
+  align32(Out);    // We must maintain correct alignment!
+}
+
+
+// outputInstructionFormat1 - Output one operand instructions, knowing that no
+// operand index is >= 2^12.
+//
+static void outputInstructionFormat1(const Instruction *I, 
+				     const SlotCalculator &Table, int *Slots,
+				     unsigned Type, vector<uchar> &Out) {
+  unsigned IType = I->getInstType();      // Instruction Opcode ID
+  
+  // bits   Instruction format:
+  // --------------------------
+  // 31-30: Opcode type, fixed to 1.
+  // 29-24: Opcode
+  // 23-12: Resulting type plane
+  // 11- 0: Operand #1 (if set to (2^12-1), then zero operands)
+  //
+  unsigned Opcode = (1 << 30) | (IType << 24) | (Type << 12) | Slots[0];
+  //  cerr << "1 " << IType << " " << Type << " " << Slots[0] << endl;
+  output(Opcode, Out);
+}
+
+
+// outputInstructionFormat2 - Output two operand instructions, knowing that no
+// operand index is >= 2^8.
+//
+static void outputInstructionFormat2(const Instruction *I, 
+				     const SlotCalculator &Table, int *Slots,
+				     unsigned Type, vector<uchar> &Out) {
+  unsigned IType = I->getInstType();      // Instruction Opcode ID
+
+  // bits   Instruction format:
+  // --------------------------
+  // 31-30: Opcode type, fixed to 2.
+  // 29-24: Opcode
+  // 23-16: Resulting type plane
+  // 15- 8: Operand #1
+  //  7- 0: Operand #2  
+  //
+  unsigned Opcode = (2 << 30) | (IType << 24) | (Type << 16) |
+                    (Slots[0] << 8) | (Slots[1] << 0);
+  //  cerr << "2 " << IType << " " << Type << " " << Slots[0] << " " 
+  //       << Slots[1] << endl;
+  output(Opcode, Out);
+}
+
+
+// outputInstructionFormat3 - Output three operand instructions, knowing that no
+// operand index is >= 2^6.
+//
+static void outputInstructionFormat3(const Instruction *I, 
+				     const SlotCalculator &Table, int *Slots,
+				     unsigned Type, vector<uchar> &Out) {
+  unsigned IType = I->getInstType();      // Instruction Opcode ID
+
+  // bits   Instruction format:
+  // --------------------------
+  // 31-30: Opcode type, fixed to 3
+  // 29-24: Opcode
+  // 23-18: Resulting type plane
+  // 17-12: Operand #1
+  // 11- 6: Operand #2
+  //  5- 0: Operand #3
+  //
+  unsigned Opcode = (3 << 30) | (IType << 24) | (Type << 18) |
+                    (Slots[0] << 12) | (Slots[1] << 6) | (Slots[2] << 0);
+  //  cerr << "3 " << IType << " " << Type << " " << Slots[0] << " " 
+  //       << Slots[1] << " " << Slots[2] << endl;
+  output(Opcode, Out);
+}
+
+bool BytecodeWriter::processInstruction(const Instruction *I) {
+  assert(I->getInstType() < 64 && "Opcode too big???");
+
+  unsigned NumOperands = 0;
+  int MaxOpSlot = 0;
+  int Slots[3]; Slots[0] = (1 << 12)-1;
+
+  const Value *Def;
+  while ((Def = I->getOperand(NumOperands))) {
+    int slot = Table.getValSlot(Def);
+    assert(slot != -1 && "Broken bytecode!");
+    if (slot > MaxOpSlot) MaxOpSlot = slot;
+    if (NumOperands < 3) Slots[NumOperands] = slot;
+    NumOperands++;
+  }
+
+  // Figure out which type to encode with the instruction.  Typically we want
+  // the type of the first parameter, as opposed to the type of the instruction
+  // (for example, with setcc, we always know it returns bool, but the type of
+  // the first param is actually interesting).  But if we have no arguments
+  // we take the type of the instruction itself.  
+  //
+
+  const Type *Ty;
+  if (NumOperands)
+    Ty = I->getOperand(0)->getType();
+  else
+    Ty = I->getType();
+
+  unsigned Type;
+  int Slot = Table.getValSlot(Ty);
+  assert(Slot != -1 && "Type not available!!?!");
+  Type = (unsigned)Slot;
+
+
+  // Decide which instruction encoding to use.  This is determined primarily by
+  // the number of operands, and secondarily by whether or not the max operand
+  // will fit into the instruction encoding.  More operands == fewer bits per
+  // operand.
+  //
+  switch (NumOperands) {
+  case 0:
+  case 1:
+    if (MaxOpSlot < (1 << 12)-1) { // -1 because we use 4095 to indicate 0 ops
+      outputInstructionFormat1(I, Table, Slots, Type, Out);
+      return false;
+    }
+    break;
+
+  case 2:
+    if (MaxOpSlot < (1 << 8)) {
+      outputInstructionFormat2(I, Table, Slots, Type, Out);
+      return false;
+    }
+    break;
+
+  case 3:
+    if (MaxOpSlot < (1 << 6)) {
+      outputInstructionFormat3(I, Table, Slots, Type, Out);
+      return false;
+    }
+    break;
+  }
+
+  outputInstructionFormat0(I, Table, Type, Out);
+  return false;
+}
diff --git a/lib/Bytecode/Writer/Makefile b/lib/Bytecode/Writer/Makefile
new file mode 100644
index 0000000..c03db56
--- /dev/null
+++ b/lib/Bytecode/Writer/Makefile
@@ -0,0 +1,7 @@
+
+LEVEL = ../../..
+
+LIBRARYNAME = bcwriter
+
+include $(LEVEL)/Makefile.common
+
diff --git a/lib/Bytecode/Writer/SlotCalculator.cpp b/lib/Bytecode/Writer/SlotCalculator.cpp
new file mode 100644
index 0000000..01fae37
--- /dev/null
+++ b/lib/Bytecode/Writer/SlotCalculator.cpp
@@ -0,0 +1,195 @@
+//===-- SlotCalculator.cpp - Calculate what slots values land in ------------=//
+//
+// This file implements a useful analysis step to figure out what numbered 
+// slots values in a program will land in (keeping track of per plane
+// information as required.
+//
+// This is used primarily for when writing a file to disk, either in bytecode
+// or source format.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Analysis/SlotCalculator.h"
+#include "llvm/ConstantPool.h"
+#include "llvm/Method.h"
+#include "llvm/Module.h"
+#include "llvm/BasicBlock.h"
+#include "llvm/ConstPoolVals.h"
+#include "llvm/iOther.h"
+#include "llvm/DerivedTypes.h"
+
+SlotCalculator::SlotCalculator(const Module *M, bool IgnoreNamed) {
+  IgnoreNamedNodes = IgnoreNamed;
+  TheModule = M;
+
+  // Preload table... Make sure that all of the primitive types are in the table
+  // and that their Primitive ID is equal to their slot #
+  //
+  for (unsigned i = 0; i < Type::FirstDerivedTyID; ++i) {
+    assert(Type::getPrimitiveType((Type::PrimitiveID)i));
+    insertVal(Type::getPrimitiveType((Type::PrimitiveID)i));
+  }
+
+  if (M == 0) return;   // Empty table...
+
+  bool Result = processModule(M);
+  assert(Result == false && "Error in processModule!");
+}
+
+SlotCalculator::SlotCalculator(const Method *M, bool IgnoreNamed) {
+  IgnoreNamedNodes = IgnoreNamed;
+  TheModule = M ? M->getParent() : 0;
+
+  // Preload table... Make sure that all of the primitive types are in the table
+  // and that their Primitive ID is equal to their slot #
+  //
+  for (unsigned i = 0; i < Type::FirstDerivedTyID; ++i) {
+    assert(Type::getPrimitiveType((Type::PrimitiveID)i));
+    insertVal(Type::getPrimitiveType((Type::PrimitiveID)i));
+  }
+
+  if (TheModule == 0) return;   // Empty table...
+
+  bool Result = processModule(TheModule);
+  assert(Result == false && "Error in processModule!");
+
+  incorporateMethod(M);
+}
+
+void SlotCalculator::incorporateMethod(const Method *M) {
+  assert(ModuleLevel.size() == 0 && "Module already incorporated!");
+
+  // Save the Table state before we process the method...
+  for (unsigned i = 0; i < Table.size(); ++i) {
+    ModuleLevel.push_back(Table[i].size());
+  }
+
+  // Process the method to incorporate its values into our table
+  processMethod(M);
+}
+
+void SlotCalculator::purgeMethod() {
+  assert(ModuleLevel.size() != 0 && "Module not incorporated!");
+  unsigned NumModuleTypes = ModuleLevel.size();
+
+  // First, remove values from existing type planes
+  for (unsigned i = 0; i < NumModuleTypes; ++i) {
+    unsigned ModuleSize = ModuleLevel[i];  // Size of plane before method came
+    while (Table[i].size() != ModuleSize) {
+      NodeMap.erase(NodeMap.find(Table[i].back()));   // Erase from nodemap
+      Table[i].pop_back();                            // Shrink plane
+    }
+  }
+
+  // We don't need this state anymore, free it up.
+  ModuleLevel.clear();
+
+  // Next, remove any type planes defined by the method...
+  while (NumModuleTypes != Table.size()) {
+    TypePlane &Plane = Table.back();
+    while (Plane.size()) {
+      NodeMap.erase(NodeMap.find(Plane.back()));   // Erase from nodemap
+      Plane.pop_back();                            // Shrink plane
+    }
+
+    Table.pop_back();                      // Nuke the plane, we don't like it.
+  }
+}
+
+bool SlotCalculator::processConstant(const ConstPoolVal *CPV) { 
+  //cerr << "Inserting constant: '" << CPV->getStrValue() << endl;
+  insertVal(CPV);
+  return false;
+}
+
+// processType - This callback occurs when an derived type is discovered
+// at the class level. This activity occurs when processing a constant pool.
+//
+bool SlotCalculator::processType(const Type *Ty) { 
+  //cerr << "processType: " << Ty->getName() << endl;
+  // TODO: Don't leak memory!!!  Free this in the dtor!
+  insertVal(new ConstPoolType(Ty));
+  return false; 
+}
+
+bool SlotCalculator::visitMethod(const Method *M) {
+  //cerr << "visitMethod: '" << M->getType()->getName() << "'\n";
+  insertVal(M);
+  return false; 
+}
+
+bool SlotCalculator::processMethodArgument(const MethodArgument *MA) {
+  insertVal(MA);
+  return false;
+}
+
+bool SlotCalculator::processBasicBlock(const BasicBlock *BB) {
+  insertVal(BB);
+  ModuleAnalyzer::processBasicBlock(BB);  // Lets visit the instructions too!
+  return false;
+}
+
+bool SlotCalculator::processInstruction(const Instruction *I) {
+  insertVal(I);
+  return false;
+}
+
+int SlotCalculator::getValSlot(const Value *D) const {
+  map<const Value*, unsigned>::const_iterator I = NodeMap.find(D);
+  if (I == NodeMap.end()) return -1;
+ 
+  return (int)I->second;
+}
+
+void SlotCalculator::insertVal(const Value *D) {
+  if (D == 0) return;
+
+  // If this node does not contribute to a plane, or if the node has a 
+  // name and we don't want names, then ignore the silly node...
+  //
+  if (D->getType() == Type::VoidTy || (IgnoreNamedNodes && D->hasName())) 
+    return;
+
+  const Type *Typ = D->getType();
+  unsigned Ty = Typ->getPrimitiveID();
+  if (Typ->isDerivedType()) {
+    int DefSlot = getValSlot(Typ);
+    if (DefSlot == -1) {                // Have we already entered this type?
+      // This can happen if a type is first seen in an instruction.  For 
+      // example, if you say 'malloc uint', this defines a type 'uint*' that
+      // may be undefined at this point.
+      //
+      cerr << "SHOULDNT HAPPEN Adding Type ba: " << Typ->getName() << endl;
+      assert(0 && "SHouldn't this be taken care of by processType!?!?!");
+      // Nope... add this to the Type plane now!
+      insertVal(Typ);
+
+      DefSlot = getValSlot(Typ);
+      assert(DefSlot >= 0 && "Type didn't get inserted correctly!");
+    }
+    Ty = (unsigned)DefSlot;
+  }
+  
+  if (Table.size() <= Ty)    // Make sure we have the type plane allocated...
+    Table.resize(Ty+1, TypePlane());
+  
+  // Insert node into table and NodeMap...
+  NodeMap[D] = Table[Ty].size();
+
+  if (Typ == Type::TypeTy &&      // If it's a type constant, add the Type also
+      D->getValueType() != Value::TypeVal) {
+    assert(D->getValueType() == Value::ConstantVal && 
+           "All Type instances should be constant types!");
+
+    const ConstPoolType *CPT = (const ConstPoolType*)D;
+    int Slot = getValSlot(CPT->getValue());
+    if (Slot == -1) {
+      // Only add if it's not already here!
+      NodeMap[CPT->getValue()] = Table[Ty].size();
+    } else if (!CPT->hasName()) {    // If the type has no name...
+      NodeMap[D] = (unsigned)Slot;   // Don't readd type, merge.
+      return;
+    }
+  }
+  Table[Ty].push_back(D);
+}
diff --git a/lib/Bytecode/Writer/SlotCalculator.h b/lib/Bytecode/Writer/SlotCalculator.h
new file mode 100644
index 0000000..99e40cb
--- /dev/null
+++ b/lib/Bytecode/Writer/SlotCalculator.h
@@ -0,0 +1,96 @@
+//===-- llvm/Analysis/SlotCalculator.h - Calculate value slots ---*- C++ -*-==//
+//
+// This ModuleAnalyzer subclass calculates the slots that values will land in.
+// This is useful for when writing bytecode or assembly out, because you have 
+// to know these things.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_ANALYSIS_SLOTCALCULATOR_H
+#define LLVM_ANALYSIS_SLOTCALCULATOR_H
+
+#include "llvm/Analysis/ModuleAnalyzer.h"
+#include "llvm/SymTabValue.h"
+#include <vector>
+#include <map>
+
+class SlotCalculator : public ModuleAnalyzer {
+  const Module *TheModule;
+  bool IgnoreNamedNodes;     // Shall we not count named nodes?
+
+  typedef vector<const Value*> TypePlane;
+  vector <TypePlane> Table;
+  map<const Value *, unsigned> NodeMap;
+
+  // ModuleLevel - Used to keep track of which values belong to the module,
+  // and which values belong to the currently incorporated method.
+  //
+  vector <unsigned> ModuleLevel;
+
+public:
+  SlotCalculator(const Module *M, bool IgnoreNamed);
+  SlotCalculator(const Method *M, bool IgnoreNamed);// Start out in incorp state
+  inline ~SlotCalculator() {}
+  
+  // getValSlot returns < 0 on error!
+  int getValSlot(const Value *D) const;
+
+  inline unsigned getNumPlanes() const { return Table.size(); }
+  inline unsigned getModuleLevel(unsigned Plane) const { 
+    return Plane < ModuleLevel.size() ? ModuleLevel[Plane] : 0; 
+  }
+
+  inline const TypePlane &getPlane(unsigned Plane) const { 
+    return Table[Plane]; 
+  }
+
+  // If you'd like to deal with a method, use these two methods to get its data
+  // into the SlotCalculator!
+  //
+  void incorporateMethod(const Method *M);
+  void purgeMethod();
+
+protected:
+  // insertVal - Insert a value into the value table...
+  //
+  void insertVal(const Value *D);
+
+  // visitMethod - This member is called after the constant pool has been 
+  // processed.  The default implementation of this is a noop.
+  //
+  virtual bool visitMethod(const Method *M);
+
+  // processConstant is called once per each constant in the constant pool.  It
+  // traverses the constant pool such that it visits each constant in the
+  // order of its type.  Thus, all 'int' typed constants shall be visited 
+  // sequentially, etc...
+  //
+  virtual bool processConstant(const ConstPoolVal *CPV);
+
+  // processType - This callback occurs when an derived type is discovered
+  // at the class level. This activity occurs when processing a constant pool.
+  //
+  virtual bool processType(const Type *Ty);
+
+  // processMethods - The default implementation of this method loops through 
+  // all of the methods in the module and processModule's them.  We don't want
+  // this (we want to explicitly visit them with incorporateMethod), so we 
+  // disable it.
+  //
+  virtual bool processMethods(const Module *M) { return false; }
+
+  // processMethodArgument - This member is called for every argument that 
+  // is passed into the method.
+  //
+  virtual bool processMethodArgument(const MethodArgument *MA);
+
+  // processBasicBlock - This member is called for each basic block in a methd.
+  //
+  virtual bool processBasicBlock(const BasicBlock *BB);
+
+  // processInstruction - This member is called for each Instruction in a methd.
+  //
+  virtual bool processInstruction(const Instruction *I);
+};
+
+#endif
diff --git a/lib/Bytecode/Writer/Writer.cpp b/lib/Bytecode/Writer/Writer.cpp
new file mode 100644
index 0000000..d03c945
--- /dev/null
+++ b/lib/Bytecode/Writer/Writer.cpp
@@ -0,0 +1,182 @@
+//===-- Writer.cpp - Library for writing VM bytecode files -------*- C++ -*--=//
+//
+// This library implements the functionality defined in llvm/Bytecode/Writer.h
+//
+// This library uses the Analysis library to figure out offsets for
+// variables in the method tables...
+//
+// Note that this file uses an unusual technique of outputting all the bytecode
+// to a vector of unsigned char's, then copies the vector to an ostream.  The
+// reason for this is that we must do "seeking" in the stream to do back-
+// patching, and some very important ostreams that we want to support (like
+// pipes) do not support seeking.  :( :( :(
+//
+// The choice of the vector data structure is influenced by the extremely fast
+// "append" speed, plus the free "seek"/replace in the middle of the stream.
+//
+// Note that the performance of this library is not terribly important, because
+// it shouldn't be used by JIT type applications... so it is not a huge focus
+// at least.  :)
+//
+//===----------------------------------------------------------------------===//
+
+#include "WriterInternals.h"
+#include "llvm/Module.h"
+#include "llvm/Method.h"
+#include "llvm/BasicBlock.h"
+#include "llvm/ConstPoolVals.h"
+#include "llvm/SymbolTable.h"
+#include "llvm/DerivedTypes.h"
+#include <string.h>
+#include <algorithm>
+
+BytecodeWriter::BytecodeWriter(vector<unsigned char> &o, const Module *M) 
+  : Out(o), Table(M, false) {
+
+  outputSignature();
+
+  // Emit the top level CLASS block.
+  BytecodeBlock ModuleBlock(BytecodeFormat::Module, Out);
+
+  // Output largest ID of first "primitive" type:
+  output_vbr((unsigned)Type::FirstDerivedTyID, Out);
+  align32(Out);
+
+  // Do the whole module now!
+  processModule(M);
+
+  // If needed, output the symbol table for the class...
+  if (M->hasSymbolTable())
+    outputSymbolTable(*M->getSymbolTable());
+}
+
+// TODO: REMOVE
+#include "llvm/Assembly/Writer.h"
+
+bool BytecodeWriter::processConstPool(const ConstantPool &CP, bool isMethod) {
+  BytecodeBlock *CPool = new BytecodeBlock(BytecodeFormat::ConstantPool, Out);
+
+  unsigned NumPlanes = Table.getNumPlanes();
+
+  for (unsigned pno = 0; pno < NumPlanes; pno++) {
+    const vector<const Value*> &Plane = Table.getPlane(pno);
+    if (Plane.empty()) continue;          // Skip empty type planes...
+
+    unsigned ValNo = 0;   // Don't reemit module constants
+    if (isMethod) ValNo = Table.getModuleLevel(pno);
+    
+    unsigned NumConstants = 0;
+    for (unsigned vn = ValNo; vn < Plane.size(); vn++)
+      if (Plane[vn]->getValueType() == Value::ConstantVal)
+	NumConstants++;
+
+    if (NumConstants == 0) continue;  // Skip empty type planes...
+
+    // Output type header: [num entries][type id number]
+    //
+    output_vbr(NumConstants, Out);
+
+    // Output the Type ID Number...
+    int Slot = Table.getValSlot(Plane.front()->getType());
+    assert (Slot != -1 && "Type in constant pool but not in method!!");
+    output_vbr((unsigned)Slot, Out);
+
+    //cerr << "NC: " << NumConstants << " Slot = " << hex << Slot << endl;
+
+    for (; ValNo < Plane.size(); ValNo++) {
+      const Value *V = Plane[ValNo];
+      if (V->getValueType() == Value::ConstantVal) {
+	//cerr << "Serializing value: <" << V->getType() << ">: " 
+	//     << ((const ConstPoolVal*)V)->getStrValue() << ":" 
+	//     << Out.size() << "\n";
+	outputConstant((const ConstPoolVal*)V);
+      }
+    }
+  }
+
+  delete CPool;  // End bytecode block section!
+
+  if (!isMethod) { // The ModuleInfoBlock follows directly after the c-pool
+    assert(CP.getParent()->getValueType() == Value::ModuleVal);
+    outputModuleInfoBlock((const Module*)CP.getParent());
+  }
+
+  return false;
+}
+
+void BytecodeWriter::outputModuleInfoBlock(const Module *M) {
+  BytecodeBlock ModuleInfoBlock(BytecodeFormat::ModuleGlobalInfo, Out);
+  
+  // Output the types of the methods in this class
+  Module::MethodListType::const_iterator I = M->getMethodList().begin();
+  while (I != M->getMethodList().end()) {
+    int Slot = Table.getValSlot((*I)->getType());
+    assert(Slot != -1 && "Module const pool is broken!");
+    assert(Slot >= Type::FirstDerivedTyID && "Derived type not in range!");
+    output_vbr((unsigned)Slot, Out);
+    I++;
+  }
+  output_vbr((unsigned)Table.getValSlot(Type::VoidTy), Out);
+  align32(Out);
+}
+
+bool BytecodeWriter::processMethod(const Method *M) {
+  BytecodeBlock MethodBlock(BytecodeFormat::Method, Out);
+
+  Table.incorporateMethod(M);
+
+  if (ModuleAnalyzer::processMethod(M)) return true;
+  
+  // If needed, output the symbol table for the method...
+  if (M->hasSymbolTable())
+    outputSymbolTable(*M->getSymbolTable());
+
+  Table.purgeMethod();
+  return false;
+}
+
+
+bool BytecodeWriter::processBasicBlock(const BasicBlock *BB) {
+  BytecodeBlock MethodBlock(BytecodeFormat::BasicBlock, Out);
+  return ModuleAnalyzer::processBasicBlock(BB);
+}
+
+void BytecodeWriter::outputSymbolTable(const SymbolTable &MST) {
+  BytecodeBlock MethodBlock(BytecodeFormat::SymbolTable, Out);
+
+  for (SymbolTable::const_iterator TI = MST.begin(); TI != MST.end(); TI++) {
+    SymbolTable::type_const_iterator I = MST.type_begin(TI->first);
+    SymbolTable::type_const_iterator End = MST.type_end(TI->first);
+    int Slot;
+    
+    if (I == End) continue;  // Don't mess with an absent type...
+
+    // Symtab block header: [num entries][type id number]
+    output_vbr(MST.type_size(TI->first), Out);
+
+    Slot = Table.getValSlot(TI->first);
+    assert(Slot != -1 && "Type in symtab, but not in table!");
+    output_vbr((unsigned)Slot, Out);
+
+    for (; I != End; I++) {
+      // Symtab entry: [def slot #][name]
+      Slot = Table.getValSlot(I->second);
+      assert (Slot != -1 && "Value in symtab but not in method!!");
+      output_vbr((unsigned)Slot, Out);
+      output(I->first, Out, false); // Don't force alignment...
+    }
+  }
+}
+
+void WriteBytecodeToFile(const Module *C, ostream &Out) {
+  assert(C && "You can't write a null class!!");
+
+  vector<unsigned char> Buffer;
+
+  // This object populates buffer for us...
+  BytecodeWriter BCW(Buffer, C);
+
+  // Okay, write the vector out to the ostream now...
+  Out.write(&Buffer[0], Buffer.size());
+  Out.flush();
+}
diff --git a/lib/Bytecode/Writer/WriterInternals.h b/lib/Bytecode/Writer/WriterInternals.h
new file mode 100644
index 0000000..be9ccf9
--- /dev/null
+++ b/lib/Bytecode/Writer/WriterInternals.h
@@ -0,0 +1,74 @@
+//===-- WriterInternals.h - Data structures shared by the Writer -*- C++ -*--=//
+//
+// This header defines the interface used between components of the bytecode
+// writer.
+//
+// Note that the performance of this library is not terribly important, because
+// it shouldn't be used by JIT type applications... so it is not a huge focus
+// at least.  :)
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIB_BYTECODE_WRITER_WRITERINTERNALS_H
+#define LLVM_LIB_BYTECODE_WRITER_WRITERINTERNALS_H
+
+#include "llvm/Bytecode/Writer.h"
+#include "llvm/Bytecode/Format.h"
+#include "llvm/Bytecode/Primitives.h"
+#include "llvm/Analysis/SlotCalculator.h"
+#include "llvm/Tools/DataTypes.h"
+#include "llvm/Instruction.h"
+
+class BytecodeWriter : public ModuleAnalyzer {
+  vector<unsigned char> &Out;
+  SlotCalculator Table;
+public:
+  BytecodeWriter(vector<unsigned char> &o, const Module *M);
+
+protected:
+  virtual bool processConstPool(const ConstantPool &CP, bool isMethod);
+  virtual bool processMethod(const Method *M);
+  virtual bool processBasicBlock(const BasicBlock *BB);
+  virtual bool processInstruction(const Instruction *I);
+
+private :
+  inline void outputSignature() {
+    static const unsigned char *Sig =  (const unsigned char*)"llvm";
+    Out.insert(Out.end(), Sig, Sig+4); // output the bytecode signature...
+  }
+
+  void outputModuleInfoBlock(const Module *C);
+  void outputSymbolTable(const SymbolTable &ST);
+  bool outputConstant(const ConstPoolVal *CPV);
+  void outputType(const Type *T);
+};
+
+
+
+
+// BytecodeBlock - Little helper class that helps us do backpatching of bytecode
+// block sizes really easily.  It backpatches when it goes out of scope.
+//
+class BytecodeBlock {
+  unsigned Loc;
+  vector<unsigned char> &Out;
+
+  BytecodeBlock(const BytecodeBlock &);   // do not implement
+  void operator=(const BytecodeBlock &);  // do not implement
+public:
+  inline BytecodeBlock(unsigned ID, vector<unsigned char> &o) : Out(o) {
+    output(ID, Out);
+    output((unsigned)0, Out);         // Reserve the space for the block size...
+    Loc = Out.size();
+  }
+
+  inline ~BytecodeBlock() {           // Do backpatch when block goes out
+                                      // of scope...
+    //    cerr << "OldLoc = " << Loc << " NewLoc = " << NewLoc << " diff = " << (NewLoc-Loc) << endl;
+    output((unsigned)(Out.size()-Loc), Out, (int)Loc-4);
+    align32(Out);  // Blocks must ALWAYS be aligned
+  }
+};
+
+
+#endif