diff --git a/include/llvm/Analysis/DebugInfo.h b/include/llvm/Analysis/DebugInfo.h
new file mode 100644
index 0000000..21bbaba
--- /dev/null
+++ b/include/llvm/Analysis/DebugInfo.h
@@ -0,0 +1,394 @@
+//===--- llvm/Analysis/DebugInfo.h - Debug Information Helpers --*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines a bunch of datatypes that are useful for creating and
+// walking debug info in LLVM IR form.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_SUPPORT_DEBUGINFO_H
+#define LLVM_SUPPORT_DEBUGINFO_H
+
+#include "llvm/ADT/StringMap.h"
+#include "llvm/ADT/DenseMap.h"
+
+namespace llvm {
+  class BasicBlock;
+  class Constant;
+  class Function;
+  class GlobalVariable;
+  class Module;
+  class Value;
+  
+  class DIDescriptor {
+  public:
+    enum {
+      Version6    = 6 << 16,     // Current version of debug information.
+      Version5    = 5 << 16,     // Constant for version 5.
+      Version4    = 4 << 16,     // Constant for version 4.
+      VersionMask = 0xffff0000   // Mask for version number.
+    };
+    
+  protected:    
+    GlobalVariable *GV;
+    
+    /// DIDescriptor constructor.  If the specified GV is non-null, this checks
+    /// to make sure that the tag in the descriptor matches 'RequiredTag'.  If
+    /// not, the debug info is corrupt and we ignore it.
+    DIDescriptor(GlobalVariable *GV, unsigned RequiredTag);
+    
+    unsigned getTag() const {
+      return getUnsignedField(0) & ~VersionMask;
+    }
+    unsigned getVersion() const {
+      return getUnsignedField(0) & VersionMask;
+    }
+    
+    std::string getStringField(unsigned Elt) const;
+    unsigned getUnsignedField(unsigned Elt) const {
+      return (unsigned)getUInt64Field(Elt);
+    }
+    uint64_t getUInt64Field(unsigned Elt) const;
+    DIDescriptor getDescriptorField(unsigned Elt) const;
+    
+    template <typename DescTy>
+    DescTy getFieldAs(unsigned Elt) const {
+      return DescTy(getDescriptorField(6).getGV());
+    }
+  
+    GlobalVariable *getGlobalVariableField(unsigned Elt) const;
+    
+  public:
+    explicit DIDescriptor() : GV(0) {}
+    explicit DIDescriptor(GlobalVariable *gv) : GV(gv) {}
+
+    bool isNull() const { return GV == 0; }
+
+    GlobalVariable *getGV() const { return GV; }
+    
+    /// getCastToEmpty - Return this descriptor as a Constant* with type '{}*'.
+    Constant *getCastToEmpty() const;
+  };
+  
+  /// DIAnchor - A wrapper for various anchor descriptors.
+  class DIAnchor : public DIDescriptor {
+  public:
+    explicit DIAnchor(GlobalVariable *GV = 0);
+    
+    unsigned getAnchorTag() const { return getUnsignedField(1); }
+  };
+  
+  /// DIArray - This descriptor holds an array of descriptors.
+  class DIArray : public DIDescriptor {
+  public:
+    explicit DIArray(GlobalVariable *GV = 0) : DIDescriptor(GV) {}
+    
+    unsigned getNumElements() const;
+    DIDescriptor getElement(unsigned Idx) const;
+  };
+  
+  /// DICompileUnit - A wrapper for a compile unit.
+  class DICompileUnit : public DIDescriptor {
+  public:
+    explicit DICompileUnit(GlobalVariable *GV = 0);
+    
+    unsigned getLanguage() const     { return getUnsignedField(2); }
+    std::string getFilename() const  { return getStringField(3); }
+    std::string getDirectory() const { return getStringField(4); }
+    std::string getProducer() const  { return getStringField(5); }
+  };
+
+  /// DIEnumerator - A wrapper for an enumerator (e.g. X and Y in 'enum {X,Y}').
+  /// FIXME: it seems strange that this doesn't have either a reference to the
+  /// type/precision or a file/line pair for location info.
+  class DIEnumerator : public DIDescriptor {
+  public:
+    explicit DIEnumerator(GlobalVariable *GV = 0);
+    
+    std::string getName() const  { return getStringField(1); }
+    uint64_t getLanguage() const { return getUInt64Field(2); }
+  };
+  
+  /// DISubrange - This is used to represent ranges, for array bounds.
+  class DISubrange : public DIDescriptor {
+  public:
+    explicit DISubrange(GlobalVariable *GV = 0);
+    
+    int64_t getLo() const { return (int64_t)getUInt64Field(1); }
+    int64_t getHi() const { return (int64_t)getUInt64Field(2); }
+  };
+  
+  /// DIType - This is a wrapper for a type.
+  /// FIXME: Types should be factored much better so that CV qualifiers and
+  /// others do not require a huge and empty descriptor full of zeros.
+  class DIType : public DIDescriptor {
+  protected:
+    DIType(GlobalVariable *GV, unsigned Tag) : DIDescriptor(GV, Tag) {}
+    // This ctor is used when the Tag has already been validated by a derived
+    // ctor.
+    DIType(GlobalVariable *GV, bool, bool) : DIDescriptor(GV) {}
+  public:
+    explicit DIType(GlobalVariable *GV);
+    explicit DIType() {}
+    
+    DIDescriptor getContext() const     { return getDescriptorField(1); }
+    std::string getName() const         { return getStringField(2); }
+    DICompileUnit getCompileUnit() const{ return getFieldAs<DICompileUnit>(3); }
+    unsigned getLineNumber() const      { return getUnsignedField(4); }
+    uint64_t getSizeInBits() const      { return getUInt64Field(5); }
+    uint64_t getAlignInBits() const     { return getUInt64Field(6); }
+    // FIXME: Offset is only used for DW_TAG_member nodes.  Making every type
+    // carry this is just plain insane.
+    uint64_t getOffsetInBits() const    { return getUInt64Field(7); }
+    unsigned getFlags() const           { return getUnsignedField(8); }
+  };
+  
+  /// DIBasicType - A basic type, like 'int' or 'float'.
+  class DIBasicType : public DIType {
+  public:
+    explicit DIBasicType(GlobalVariable *GV);
+    
+    unsigned getEncoding() const { return getUnsignedField(9); }
+  };
+  
+  /// DIDerivedType - A simple derived type, like a const qualified type,
+  /// a typedef, a pointer or reference, etc.
+  class DIDerivedType : public DIType {
+  protected:
+    explicit DIDerivedType(GlobalVariable *GV, bool, bool)
+      : DIType(GV, true, true) {}
+  public:
+    explicit DIDerivedType(GlobalVariable *GV);
+    
+    DIType getTypeDerivedFrom() const { return getFieldAs<DIType>(9); }
+    
+    /// isDerivedType - Return true if the specified tag is legal for
+    /// DIDerivedType.
+    static bool isDerivedType(unsigned TAG);
+  };
+
+  
+  /// DICompositeType - This descriptor holds a type that can refer to multiple
+  /// other types, like a function or struct.
+  /// FIXME: Why is this a DIDerivedType??
+  class DICompositeType : public DIDerivedType {
+  public:
+    explicit DICompositeType(GlobalVariable *GV);
+    
+    DIArray getTypeArray() const { return getFieldAs<DIArray>(10); }
+    
+    /// isCompositeType - Return true if the specified tag is legal for
+    /// DICompositeType.
+    static bool isCompositeType(unsigned TAG);
+  };
+  
+  /// DIGlobal - This is a common class for global variables and subprograms.
+  class DIGlobal : public DIDescriptor {
+  protected:
+    explicit DIGlobal(GlobalVariable *GV = 0, unsigned RequiredTag)
+      : DIDescriptor(GV, RequiredTag) {}
+  public:
+    
+    DIDescriptor getContext() const     { return getDescriptorField(2); }
+    std::string getName() const         { return getStringField(3); }
+    std::string getDisplayName() const  { return getStringField(4); }
+    std::string getLinkageName() const  { return getStringField(5); }
+    
+    DICompileUnit getCompileUnit() const{ return getFieldAs<DICompileUnit>(6); }
+    unsigned getLineNumber() const      { return getUnsignedField(7); }
+    DIType getType() const              { return getFieldAs<DIType>(8); }
+    
+    /// isLocalToUnit - Return true if this subprogram is local to the current
+    /// compile unit, like 'static' in C.
+    unsigned isLocalToUnit() const      { return getUnsignedField(9); }
+    unsigned isDefinition() const       { return getUnsignedField(10); }
+  };
+  
+  
+  /// DISubprogram - This is a wrapper for a subprogram (e.g. a function).
+  class DISubprogram : public DIGlobal {
+  public:
+    explicit DISubprogram(GlobalVariable *GV = 0);
+
+  };
+  
+  /// DIGlobalVariable - This is a wrapper for a global variable.
+  class DIGlobalVariable : public DIGlobal {
+  public:
+    explicit DIGlobalVariable(GlobalVariable *GV = 0);
+    
+    GlobalVariable *getGlobal() const { return getGlobalVariableField(11); }
+  };
+  
+  
+  /// DIVariable - This is a wrapper for a variable (e.g. parameter, local,
+  /// global etc).
+  class DIVariable : public DIDescriptor {
+  public:
+    explicit DIVariable(GlobalVariable *GV = 0);
+    
+    DIDescriptor getContext() const { return getDescriptorField(1); }
+    std::string getName() const { return getStringField(2); }
+    
+    DICompileUnit getCompileUnit() const{ return getFieldAs<DICompileUnit>(3); }
+    unsigned getLineNumber() const      { return getUnsignedField(4); }
+    DIType getType() const              { return getFieldAs<DIType>(5); }
+    
+    /// isVariable - Return true if the specified tag is legal for DIVariable.
+    static bool isVariable(unsigned Tag);
+  };
+  
+  
+  /// DIBlock - This is a wrapper for a block (e.g. a function, scope, etc).
+  class DIBlock : public DIDescriptor {
+  public:
+    explicit DIBlock(GlobalVariable *GV = 0);
+    
+    DIDescriptor getContext() const { return getDescriptorField(1); }
+  };
+  
+  /// DIFactory - This object assists with the construction of the various
+  /// descriptors.
+  class DIFactory {
+    Module &M;
+    // Cached values for uniquing and faster lookups.
+    DIAnchor CompileUnitAnchor, SubProgramAnchor, GlobalVariableAnchor;
+    Function *StopPointFn;   // llvm.dbg.stoppoint
+    Function *FuncStartFn;   // llvm.dbg.func.start
+    Function *RegionStartFn; // llvm.dbg.region.start
+    Function *RegionEndFn;   // llvm.dbg.region.end
+    Function *DeclareFn;     // llvm.dbg.declare
+    StringMap<Constant*> StringCache;
+    DenseMap<Constant*, DIDescriptor> SimpleConstantCache;
+    
+    DIFactory(const DIFactory &);     // DO NOT IMPLEMENT
+    void operator=(const DIFactory&); // DO NOT IMPLEMENT
+  public:
+    explicit DIFactory(Module &m) : M(m) {
+      StopPointFn = FuncStartFn = RegionStartFn = RegionEndFn = DeclareFn = 0;
+    }
+    
+    /// GetOrCreateCompileUnitAnchor - Return the anchor for compile units,
+    /// creating a new one if there isn't already one in the module.
+    DIAnchor GetOrCreateCompileUnitAnchor();
+
+    /// GetOrCreateSubprogramAnchor - Return the anchor for subprograms,
+    /// creating a new one if there isn't already one in the module.
+    DIAnchor GetOrCreateSubprogramAnchor();
+
+    /// GetOrCreateGlobalVariableAnchor - Return the anchor for globals,
+    /// creating a new one if there isn't already one in the module.
+    DIAnchor GetOrCreateGlobalVariableAnchor();
+
+    /// GetOrCreateArray - Create an descriptor for an array of descriptors. 
+    /// This implicitly uniques the arrays created.
+    DIArray GetOrCreateArray(DIDescriptor *Tys, unsigned NumTys);
+
+    /// GetOrCreateSubrange - Create a descriptor for a value range.  This
+    /// implicitly uniques the values returned.
+    DISubrange GetOrCreateSubrange(int64_t Lo, int64_t Hi);
+    
+    
+    /// CreateCompileUnit - Create a new descriptor for the specified compile
+    /// unit.
+    DICompileUnit CreateCompileUnit(unsigned LangID,
+                                    const std::string &Filename,
+                                    const std::string &Directory,
+                                    const std::string &Producer);
+
+    /// CreateEnumerator - Create a single enumerator value.
+    DIEnumerator CreateEnumerator(const std::string &Name, uint64_t Val);
+    
+    /// CreateBasicType - Create a basic type like int, float, etc.
+    DIBasicType CreateBasicType(DIDescriptor Context, const std::string &Name,
+                                DICompileUnit CompileUnit, unsigned LineNumber,
+                                uint64_t SizeInBits, uint64_t AlignInBits,
+                                uint64_t OffsetInBits, unsigned Flags,
+                                unsigned Encoding);
+ 
+    /// CreateDerivedType - Create a derived type like const qualified type,
+    /// pointer, typedef, etc.
+    DIDerivedType CreateDerivedType(unsigned Tag, DIDescriptor Context,
+                                    const std::string &Name,
+                                    DICompileUnit CompileUnit,
+                                    unsigned LineNumber,
+                                    uint64_t SizeInBits, uint64_t AlignInBits,
+                                    uint64_t OffsetInBits, unsigned Flags,
+                                    DIType DerivedFrom);
+
+    /// CreateCompositeType - Create a composite type like array, struct, etc.
+    DICompositeType CreateCompositeType(unsigned Tag, DIDescriptor Context,
+                                        const std::string &Name,
+                                        DICompileUnit CompileUnit,
+                                        unsigned LineNumber,
+                                        uint64_t SizeInBits,
+                                        uint64_t AlignInBits,
+                                        uint64_t OffsetInBits, unsigned Flags,
+                                        DIType DerivedFrom,
+                                        DIArray Elements);
+    
+    /// CreateSubprogram - Create a new descriptor for the specified subprogram.
+    /// See comments in DISubprogram for descriptions of these fields.
+    DISubprogram CreateSubprogram(DIDescriptor Context, const std::string &Name,
+                                  const std::string &DisplayName,
+                                  const std::string &LinkageName,
+                                  DICompileUnit CompileUnit, unsigned LineNo,
+                                  DIType Type, bool isLocalToUnit,
+                                  bool isDefinition);
+
+    /// CreateGlobalVariable - Create a new descriptor for the specified global.
+    DIGlobalVariable
+    CreateGlobalVariable(DIDescriptor Context, const std::string &Name,
+                         const std::string &DisplayName,
+                         const std::string &LinkageName, 
+                         DICompileUnit CompileUnit,
+                         unsigned LineNo, DIType Type, bool isLocalToUnit,
+                         bool isDefinition, llvm::GlobalVariable *GV);
+    
+    
+    /// CreateVariable - Create a new descriptor for the specified variable.
+    DIVariable CreateVariable(unsigned Tag, DIDescriptor Context,
+                              const std::string &Name,
+                              DICompileUnit CompileUnit, unsigned LineNo,
+                              DIType Type);
+    
+    /// CreateBlock - This creates a descriptor for a lexical block with the
+    /// specified parent context.
+    DIBlock CreateBlock(DIDescriptor Context);
+    
+    /// InsertStopPoint - Create a new llvm.dbg.stoppoint intrinsic invocation,
+    /// inserting it at the end of the specified basic block.
+    void InsertStopPoint(DICompileUnit CU, unsigned LineNo, unsigned ColNo,
+                         BasicBlock *BB);
+    
+    /// InsertSubprogramStart - Create a new llvm.dbg.func.start intrinsic to
+    /// mark the start of the specified subprogram.
+    void InsertSubprogramStart(DISubprogram SP, BasicBlock *BB);
+
+    /// InsertRegionStart - Insert a new llvm.dbg.region.start intrinsic call to
+    /// mark the start of a region for the specified scoping descriptor.
+    void InsertRegionStart(DIDescriptor D, BasicBlock *BB);
+    
+    /// InsertRegionEnd - Insert a new llvm.dbg.region.end intrinsic call to
+    /// mark the end of a region for the specified scoping descriptor.
+    void InsertRegionEnd(DIDescriptor D, BasicBlock *BB);
+    
+    /// InsertDeclare - Insert a new llvm.dbg.declare intrinsic call.
+    void InsertDeclare(llvm::Value *Storage, DIVariable D, BasicBlock *BB);
+    
+  private:
+    Constant *GetTagConstant(unsigned TAG);
+    Constant *GetStringConstant(const std::string &String);
+    DIAnchor GetOrCreateAnchor(unsigned TAG, const char *Name);
+  };
+  
+  
+} // end namespace llvm
+
+#endif
diff --git a/lib/Analysis/DebugInfo.cpp b/lib/Analysis/DebugInfo.cpp
new file mode 100644
index 0000000..7de3c54
--- /dev/null
+++ b/lib/Analysis/DebugInfo.cpp
@@ -0,0 +1,662 @@
+//===--- DebugInfo.cpp - Debug Information Helper Classes -----------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the helper classes used to build and interpret debug
+// information in LLVM IR form.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Analysis/DebugInfo.h"
+#include "llvm/Constants.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/Intrinsics.h"
+#include "llvm/Instructions.h"
+#include "llvm/Module.h"
+#include "llvm/Analysis/ValueTracking.h"
+#include "llvm/Support/Dwarf.h"
+using namespace llvm;
+
+//===----------------------------------------------------------------------===//
+// DIDescriptor
+//===----------------------------------------------------------------------===//
+
+DIDescriptor::DIDescriptor(GlobalVariable *gv, unsigned RequiredTag) {
+  GV = gv;
+  
+  // If this is non-null, check to see if the Tag matches.  If not, set to null.
+  if (GV && getTag() != RequiredTag)
+    GV = 0;
+}
+
+
+std::string DIDescriptor::getStringField(unsigned Elt) const {
+  if (GV == 0) return "";
+  Constant *C = GV->getInitializer();
+  if (C == 0 || Elt >= C->getNumOperands())
+    return "";
+  
+  std::string Result;
+  // Fills in the string if it succeeds
+  if (!GetConstantStringInfo(C->getOperand(Elt), Result))
+    Result.clear();
+  return Result;
+}
+
+uint64_t DIDescriptor::getUInt64Field(unsigned Elt) const {
+  if (GV == 0) return 0;
+  Constant *C = GV->getInitializer();
+  if (C == 0 || Elt >= C->getNumOperands())
+    return 0;
+  if (ConstantInt *CI = dyn_cast<ConstantInt>(C->getOperand(Elt)))
+    return CI->getZExtValue();
+  return 0;
+}
+
+
+DIDescriptor DIDescriptor::getDescriptorField(unsigned Elt) const {
+  if (GV == 0) return DIDescriptor();
+  Constant *C = GV->getInitializer();
+  if (C == 0 || Elt >= C->getNumOperands())
+    return DIDescriptor();
+  C = C->getOperand(Elt);
+  return DIDescriptor(dyn_cast<GlobalVariable>(C->stripPointerCasts()));
+}
+
+GlobalVariable *DIDescriptor::getGlobalVariableField(unsigned Elt) const {
+  if (GV == 0) return 0;
+  Constant *C = GV->getInitializer();
+  if (C == 0 || Elt >= C->getNumOperands())
+    return 0;
+  C = C->getOperand(Elt);
+  
+  return dyn_cast<GlobalVariable>(C->stripPointerCasts());
+}
+
+
+
+/// getCastToEmpty - Return this descriptor as a Constant* with type '{}*'.
+/// This is only valid when the descriptor is non-null.
+Constant *DIDescriptor::getCastToEmpty() const {
+  const Type *DestTy = PointerType::getUnqual(StructType::get(NULL, NULL));
+  if (isNull()) return Constant::getNullValue(DestTy);
+  return ConstantExpr::getBitCast(GV, DestTy);
+}
+
+//===----------------------------------------------------------------------===//
+// Simple Descriptor Constructors and other Methods
+//===----------------------------------------------------------------------===//
+
+DIAnchor::DIAnchor(GlobalVariable *GV)
+  : DIDescriptor(GV, dwarf::DW_TAG_anchor) {}
+DIEnumerator::DIEnumerator(GlobalVariable *GV)
+  : DIDescriptor(GV, dwarf::DW_TAG_enumerator) {}
+DISubrange::DISubrange(GlobalVariable *GV)
+  : DIDescriptor(GV, dwarf::DW_TAG_subrange_type) {}
+DICompileUnit::DICompileUnit(GlobalVariable *GV)
+  : DIDescriptor(GV, dwarf::DW_TAG_compile_unit) {}
+DIBasicType::DIBasicType(GlobalVariable *GV)
+  : DIType(GV, dwarf::DW_TAG_base_type) {}
+DISubprogram::DISubprogram(GlobalVariable *GV)
+  : DIGlobal(GV, dwarf::DW_TAG_subprogram) {}
+DIGlobalVariable::DIGlobalVariable(GlobalVariable *GV)
+  : DIGlobal(GV, dwarf::DW_TAG_variable) {}
+DIBlock::DIBlock(GlobalVariable *GV)
+  : DIDescriptor(GV, dwarf::DW_TAG_lexical_block) {}
+
+/// isDerivedType - Return true if the specified tag is legal for
+/// DIDerivedType.
+bool DIDerivedType::isDerivedType(unsigned Tag) {
+  switch (Tag) {
+  case dwarf::DW_TAG_typedef:
+  case dwarf::DW_TAG_pointer_type:
+  case dwarf::DW_TAG_reference_type:
+  case dwarf::DW_TAG_const_type:
+  case dwarf::DW_TAG_volatile_type:
+  case dwarf::DW_TAG_restrict_type:
+  case dwarf::DW_TAG_member:
+  case dwarf::DW_TAG_inheritance:
+    return true;
+  default:
+    // FIXME: Even though it doesn't make sense, CompositeTypes are current
+    // modelled as DerivedTypes, this should return true for them as well.
+    return false;
+  }
+}
+
+DIDerivedType::DIDerivedType(GlobalVariable *GV) : DIType(GV, true, true) {
+  if (GV && !isDerivedType(getTag()))
+    GV = 0;
+}
+
+/// isCompositeType - Return true if the specified tag is legal for
+/// DICompositeType.
+bool DICompositeType::isCompositeType(unsigned TAG) {
+  switch (TAG) {
+  case dwarf::DW_TAG_array_type:
+  case dwarf::DW_TAG_structure_type:
+  case dwarf::DW_TAG_union_type:
+  case dwarf::DW_TAG_enumeration_type:
+  case dwarf::DW_TAG_vector_type:
+  case dwarf::DW_TAG_subroutine_type:
+    return true;
+  default:
+    return false;
+  }
+}
+
+DICompositeType::DICompositeType(GlobalVariable *GV)
+  : DIDerivedType(GV, true, true) {
+  if (GV && !isCompositeType(getTag()))
+    GV = 0;
+}
+
+/// isVariable - Return true if the specified tag is legal for DIVariable.
+bool DIVariable::isVariable(unsigned Tag) {
+  switch (Tag) {
+  case dwarf::DW_TAG_auto_variable:
+  case dwarf::DW_TAG_arg_variable:
+  case dwarf::DW_TAG_return_variable:
+    return true;
+  default:
+    return false;
+  }
+}
+
+DIVariable::DIVariable(GlobalVariable *GV) : DIDescriptor(GV) {
+  if (GV && !isVariable(getTag()))
+    GV = 0;
+}
+
+
+
+//===----------------------------------------------------------------------===//
+// DIFactory: Basic Helpers
+//===----------------------------------------------------------------------===//
+
+Constant *DIFactory::GetTagConstant(unsigned TAG) {
+  assert((TAG & DIDescriptor::VersionMask) == 0 &&
+         "Tag too large for debug encoding!");
+  return ConstantInt::get(Type::Int32Ty, TAG | DIDescriptor::Version6);
+}
+
+Constant *DIFactory::GetStringConstant(const std::string &String) {
+  // Check string cache for previous edition.
+  Constant *&Slot = StringCache[String];
+  
+  // Return Constant if previously defined.
+  if (Slot) return Slot;
+  
+  const PointerType *DestTy = PointerType::getUnqual(Type::Int8Ty);
+  
+  // If empty string then use a sbyte* null instead.
+  if (String.empty())
+    return Slot = ConstantPointerNull::get(DestTy);
+
+  // Construct string as an llvm constant.
+  Constant *ConstStr = ConstantArray::get(String);
+    
+  // Otherwise create and return a new string global.
+  GlobalVariable *StrGV = new GlobalVariable(ConstStr->getType(), true,
+                                             GlobalVariable::InternalLinkage,
+                                             ConstStr, ".str", &M);
+  StrGV->setSection("llvm.metadata");
+  return Slot = ConstantExpr::getBitCast(StrGV, DestTy);
+}
+
+/// GetOrCreateAnchor - Look up an anchor for the specified tag and name.  If it
+/// already exists, return it.  If not, create a new one and return it.
+DIAnchor DIFactory::GetOrCreateAnchor(unsigned TAG, const char *Name) {
+  const Type *EltTy = StructType::get(Type::Int32Ty,  Type::Int32Ty, NULL);
+  
+  // Otherwise, create the global or return it if already in the module.
+  Constant *C = M.getOrInsertGlobal(Name, EltTy);
+  assert(isa<GlobalVariable>(C) && "Incorrectly typed anchor?");
+  GlobalVariable *GV = cast<GlobalVariable>(C);
+  
+  // If it has an initializer, it is already in the module.
+  if (GV->hasInitializer()) 
+    return SubProgramAnchor = DIAnchor(GV);
+  
+  GV->setLinkage(GlobalValue::LinkOnceLinkage);
+  GV->setSection("llvm.metadata");
+  GV->setConstant(true);
+  M.addTypeName("llvm.dbg.anchor.type", EltTy);
+  
+  // Otherwise, set the initializer.
+  Constant *Elts[] = {
+    GetTagConstant(dwarf::DW_TAG_anchor),
+    ConstantInt::get(Type::Int32Ty, TAG)
+  };
+  
+  GV->setInitializer(ConstantStruct::get(Elts, 2));
+  return DIAnchor(GV);
+}
+
+
+
+//===----------------------------------------------------------------------===//
+// DIFactory: Primary Constructors
+//===----------------------------------------------------------------------===//
+
+/// GetOrCreateCompileUnitAnchor - Return the anchor for compile units,
+/// creating a new one if there isn't already one in the module.
+DIAnchor DIFactory::GetOrCreateCompileUnitAnchor() {
+  // If we already created one, just return it.
+  if (!CompileUnitAnchor.isNull())
+    return CompileUnitAnchor;
+  return CompileUnitAnchor = GetOrCreateAnchor(dwarf::DW_TAG_compile_unit,
+                                               "llvm.dbg.compile_units");
+}
+
+/// GetOrCreateSubprogramAnchor - Return the anchor for subprograms,
+/// creating a new one if there isn't already one in the module.
+DIAnchor DIFactory::GetOrCreateSubprogramAnchor() {
+  // If we already created one, just return it.
+  if (!SubProgramAnchor.isNull())
+    return SubProgramAnchor;
+  return SubProgramAnchor = GetOrCreateAnchor(dwarf::DW_TAG_subprogram,
+                                              "llvm.dbg.subprograms");
+}
+
+/// GetOrCreateGlobalVariableAnchor - Return the anchor for globals,
+/// creating a new one if there isn't already one in the module.
+DIAnchor DIFactory::GetOrCreateGlobalVariableAnchor() {
+  // If we already created one, just return it.
+  if (!GlobalVariableAnchor.isNull())
+    return GlobalVariableAnchor;
+  return GlobalVariableAnchor = GetOrCreateAnchor(dwarf::DW_TAG_variable,
+                                                  "llvm.dbg.global_variables");
+}
+
+/// GetOrCreateArray - Create an descriptor for an array of descriptors. 
+/// This implicitly uniques the arrays created.
+DIArray DIFactory::GetOrCreateArray(DIDescriptor *Tys, unsigned NumTys) {
+  SmallVector<Constant*, 16> Elts;
+  
+  for (unsigned i = 0; i != NumTys; ++i)
+    Elts.push_back(Tys[i].getCastToEmpty());
+  
+  const Type *EltTy = PointerType::getUnqual(StructType::get(NULL,NULL));
+  
+  Constant *Init = ConstantArray::get(ArrayType::get(EltTy, Elts.size()),
+                                      &Elts[0], Elts.size());
+  // If we already have this array, just return the uniqued version.
+  DIDescriptor &Entry = SimpleConstantCache[Init];
+  if (!Entry.isNull()) return DIArray(Entry.getGV());
+  
+  GlobalVariable *GV = new GlobalVariable(Init->getType(), true,
+                                          GlobalValue::InternalLinkage,
+                                          Init, "llvm.dbg.array", &M);
+  GV->setSection("llvm.metadata");
+  Entry = DIDescriptor(GV);
+  return DIArray(GV);
+}
+
+/// GetOrCreateSubrange - Create a descriptor for a value range.  This
+/// implicitly uniques the values returned.
+DISubrange DIFactory::GetOrCreateSubrange(int64_t Lo, int64_t Hi) {
+  Constant *Elts[] = {
+    GetTagConstant(dwarf::DW_TAG_subrange_type),
+    ConstantInt::get(Type::Int64Ty, Lo),
+    ConstantInt::get(Type::Int64Ty, Hi)
+  };
+  
+  Constant *Init = ConstantStruct::get(Elts, sizeof(Elts)/sizeof(Elts[0]));
+
+  // If we already have this range, just return the uniqued version.
+  DIDescriptor &Entry = SimpleConstantCache[Init];
+  if (!Entry.isNull()) return DISubrange(Entry.getGV());
+  
+  M.addTypeName("llvm.dbg.subrange.type", Init->getType());
+
+  GlobalVariable *GV = new GlobalVariable(Init->getType(), true,
+                                          GlobalValue::InternalLinkage,
+                                          Init, "llvm.dbg.subrange", &M);
+  GV->setSection("llvm.metadata");
+  Entry = DIDescriptor(GV);
+  return DISubrange(GV);
+}
+
+
+
+/// CreateCompileUnit - Create a new descriptor for the specified compile
+/// unit.  Note that this does not unique compile units within the module.
+DICompileUnit DIFactory::CreateCompileUnit(unsigned LangID,
+                                           const std::string &Filename,
+                                           const std::string &Directory,
+                                           const std::string &Producer) {
+  Constant *Elts[] = {
+    GetTagConstant(dwarf::DW_TAG_compile_unit),
+    GetOrCreateCompileUnitAnchor().getCastToEmpty(),
+    ConstantInt::get(Type::Int32Ty, LangID),
+    GetStringConstant(Filename),
+    GetStringConstant(Directory),
+    GetStringConstant(Producer)
+  };
+  
+  Constant *Init = ConstantStruct::get(Elts, sizeof(Elts)/sizeof(Elts[0]));
+  
+  M.addTypeName("llvm.dbg.compile_unit.type", Init->getType());
+  GlobalVariable *GV = new GlobalVariable(Init->getType(), true,
+                                          GlobalValue::InternalLinkage,
+                                          Init, "llvm.dbg.compile_unit", &M);
+  GV->setSection("llvm.metadata");
+  return DICompileUnit(GV);
+}
+
+/// CreateEnumerator - Create a single enumerator value.
+DIEnumerator DIFactory::CreateEnumerator(const std::string &Name, uint64_t Val){
+  Constant *Elts[] = {
+    GetTagConstant(dwarf::DW_TAG_enumerator),
+    GetStringConstant(Name),
+    ConstantInt::get(Type::Int64Ty, Val)
+  };
+  
+  Constant *Init = ConstantStruct::get(Elts, sizeof(Elts)/sizeof(Elts[0]));
+  
+  M.addTypeName("llvm.dbg.enumerator.type", Init->getType());
+  GlobalVariable *GV = new GlobalVariable(Init->getType(), true,
+                                          GlobalValue::InternalLinkage,
+                                          Init, "llvm.dbg.enumerator", &M);
+  GV->setSection("llvm.metadata");
+  return DIEnumerator(GV);
+}
+
+
+/// CreateBasicType - Create a basic type like int, float, etc.
+DIBasicType DIFactory::CreateBasicType(DIDescriptor Context,
+                                      const std::string &Name,
+                                       DICompileUnit CompileUnit,
+                                       unsigned LineNumber,
+                                       uint64_t SizeInBits,
+                                       uint64_t AlignInBits,
+                                       uint64_t OffsetInBits, unsigned Flags,
+                                       unsigned Encoding) {
+  Constant *Elts[] = {
+    GetTagConstant(dwarf::DW_TAG_base_type),
+    Context.getCastToEmpty(),
+    GetStringConstant(Name),
+    CompileUnit.getCastToEmpty(),
+    ConstantInt::get(Type::Int32Ty, LineNumber),
+    ConstantInt::get(Type::Int64Ty, SizeInBits),
+    ConstantInt::get(Type::Int64Ty, AlignInBits),
+    ConstantInt::get(Type::Int64Ty, OffsetInBits),
+    ConstantInt::get(Type::Int32Ty, Flags),
+    ConstantInt::get(Type::Int32Ty, Encoding)
+  };
+  
+  Constant *Init = ConstantStruct::get(Elts, sizeof(Elts)/sizeof(Elts[0]));
+  
+  M.addTypeName("llvm.dbg.basictype.type", Init->getType());
+  GlobalVariable *GV = new GlobalVariable(Init->getType(), true,
+                                          GlobalValue::InternalLinkage,
+                                          Init, "llvm.dbg.basictype", &M);
+  GV->setSection("llvm.metadata");
+  return DIBasicType(GV);
+}
+
+/// CreateDerivedType - Create a derived type like const qualified type,
+/// pointer, typedef, etc.
+DIDerivedType DIFactory::CreateDerivedType(unsigned Tag,
+                                           DIDescriptor Context,
+                                           const std::string &Name,
+                                           DICompileUnit CompileUnit,
+                                           unsigned LineNumber,
+                                           uint64_t SizeInBits,
+                                           uint64_t AlignInBits,
+                                           uint64_t OffsetInBits,
+                                           unsigned Flags,
+                                           DIType DerivedFrom) {
+  Constant *Elts[] = {
+    GetTagConstant(Tag),
+    Context.getCastToEmpty(),
+    GetStringConstant(Name),
+    CompileUnit.getCastToEmpty(),
+    ConstantInt::get(Type::Int32Ty, LineNumber),
+    ConstantInt::get(Type::Int64Ty, SizeInBits),
+    ConstantInt::get(Type::Int64Ty, AlignInBits),
+    ConstantInt::get(Type::Int64Ty, OffsetInBits),
+    ConstantInt::get(Type::Int32Ty, Flags),
+    DerivedFrom.getCastToEmpty()
+  };
+  
+  Constant *Init = ConstantStruct::get(Elts, sizeof(Elts)/sizeof(Elts[0]));
+  
+  M.addTypeName("llvm.dbg.derivedtype.type", Init->getType());
+  GlobalVariable *GV = new GlobalVariable(Init->getType(), true,
+                                          GlobalValue::InternalLinkage,
+                                          Init, "llvm.dbg.derivedtype", &M);
+  GV->setSection("llvm.metadata");
+  return DIDerivedType(GV);
+}
+
+/// CreateCompositeType - Create a composite type like array, struct, etc.
+DICompositeType DIFactory::CreateCompositeType(unsigned Tag,
+                                               DIDescriptor Context,
+                                               const std::string &Name,
+                                               DICompileUnit CompileUnit,
+                                               unsigned LineNumber,
+                                               uint64_t SizeInBits,
+                                               uint64_t AlignInBits,
+                                               uint64_t OffsetInBits,
+                                               unsigned Flags,
+                                               DIType DerivedFrom,
+                                               DIArray Elements) {
+  Constant *Elts[] = {
+    GetTagConstant(Tag),
+    Context.getCastToEmpty(),
+    GetStringConstant(Name),
+    CompileUnit.getCastToEmpty(),
+    ConstantInt::get(Type::Int32Ty, LineNumber),
+    ConstantInt::get(Type::Int64Ty, SizeInBits),
+    ConstantInt::get(Type::Int64Ty, AlignInBits),
+    ConstantInt::get(Type::Int64Ty, OffsetInBits),
+    ConstantInt::get(Type::Int32Ty, Flags),
+    DerivedFrom.getCastToEmpty(),
+    Elements.getCastToEmpty()
+  };
+  
+  Constant *Init = ConstantStruct::get(Elts, sizeof(Elts)/sizeof(Elts[0]));
+  
+  M.addTypeName("llvm.dbg.composite.type", Init->getType());
+  GlobalVariable *GV = new GlobalVariable(Init->getType(), true,
+                                          GlobalValue::InternalLinkage,
+                                          Init, "llvm.dbg.composite", &M);
+  GV->setSection("llvm.metadata");
+  return DICompositeType(GV);
+}
+
+
+/// CreateSubprogram - Create a new descriptor for the specified subprogram.
+/// See comments in DISubprogram for descriptions of these fields.  This
+/// method does not unique the generated descriptors.
+DISubprogram DIFactory::CreateSubprogram(DIDescriptor Context, 
+                                         const std::string &Name,
+                                         const std::string &DisplayName,
+                                         const std::string &LinkageName,
+                                         DICompileUnit CompileUnit,
+                                         unsigned LineNo, DIType Type,
+                                         bool isLocalToUnit,
+                                         bool isDefinition) {
+  Constant *Elts[] = {
+    GetTagConstant(dwarf::DW_TAG_subprogram),
+    GetOrCreateSubprogramAnchor().getCastToEmpty(),
+    Context.getCastToEmpty(),
+    GetStringConstant(Name),
+    GetStringConstant(DisplayName),
+    GetStringConstant(LinkageName),
+    CompileUnit.getCastToEmpty(),
+    ConstantInt::get(Type::Int32Ty, LineNo),
+    Type.getCastToEmpty(),
+    ConstantInt::get(Type::Int1Ty, isLocalToUnit),
+    ConstantInt::get(Type::Int1Ty, isDefinition)
+  };
+  
+  Constant *Init = ConstantStruct::get(Elts, sizeof(Elts)/sizeof(Elts[0]));
+  
+  M.addTypeName("llvm.dbg.subprogram.type", Init->getType());
+  GlobalVariable *GV = new GlobalVariable(Init->getType(), true,
+                                          GlobalValue::InternalLinkage,
+                                          Init, "llvm.dbg.subprogram", &M);
+  GV->setSection("llvm.metadata");
+  return DISubprogram(GV);
+}
+
+/// CreateGlobalVariable - Create a new descriptor for the specified global.
+DIGlobalVariable
+DIFactory::CreateGlobalVariable(DIDescriptor Context, const std::string &Name,
+                                const std::string &DisplayName,
+                                const std::string &LinkageName,
+                                DICompileUnit CompileUnit,
+                                unsigned LineNo, DIType Type,bool isLocalToUnit,
+                                bool isDefinition, llvm::GlobalVariable *Val) {
+  
+  Constant *Elts[] = {
+    GetTagConstant(dwarf::DW_TAG_variable),
+    GetOrCreateGlobalVariableAnchor().getCastToEmpty(),
+    Context.getCastToEmpty(),
+    GetStringConstant(Name),
+    GetStringConstant(DisplayName),
+    GetStringConstant(LinkageName),
+    CompileUnit.getCastToEmpty(),
+    ConstantInt::get(Type::Int32Ty, LineNo),
+    Type.getCastToEmpty(),
+    ConstantInt::get(Type::Int1Ty, isLocalToUnit),
+    ConstantInt::get(Type::Int1Ty, isDefinition),
+    ConstantExpr::getBitCast(Val, 
+                             PointerType::getUnqual(StructType::get(NULL,NULL)))
+  };
+  
+  Constant *Init = ConstantStruct::get(Elts, sizeof(Elts)/sizeof(Elts[0]));
+  
+  M.addTypeName("llvm.dbg.global_variable.type", Init->getType());
+  GlobalVariable *GV = new GlobalVariable(Init->getType(), true,
+                                          GlobalValue::InternalLinkage,
+                                          Init, "llvm.dbg.global_variable", &M);
+  GV->setSection("llvm.metadata");
+  return DIGlobalVariable(GV);
+}
+
+
+/// CreateVariable - Create a new descriptor for the specified variable.
+DIVariable DIFactory::CreateVariable(unsigned Tag, DIDescriptor Context,
+                                     const std::string &Name,
+                                     DICompileUnit CompileUnit, unsigned LineNo,
+                                     DIType Type) {
+  
+  Constant *Elts[] = {
+    GetTagConstant(Tag),
+    Context.getCastToEmpty(),
+    GetStringConstant(Name),
+    CompileUnit.getCastToEmpty(),
+    ConstantInt::get(Type::Int32Ty, LineNo),
+    Type.getCastToEmpty(),
+  };
+  
+  Constant *Init = ConstantStruct::get(Elts, sizeof(Elts)/sizeof(Elts[0]));
+  
+  M.addTypeName("llvm.dbg.variable.type", Init->getType());
+  GlobalVariable *GV = new GlobalVariable(Init->getType(), true,
+                                          GlobalValue::InternalLinkage,
+                                          Init, "llvm.dbg.variable", &M);
+  GV->setSection("llvm.metadata");
+  return DIVariable(GV);
+}
+
+
+/// CreateBlock - This creates a descriptor for a lexical block with the
+/// specified parent context.
+DIBlock DIFactory::CreateBlock(DIDescriptor Context) {
+  Constant *Elts[] = {
+    GetTagConstant(dwarf::DW_TAG_lexical_block),
+    Context.getCastToEmpty()
+  };
+  
+  Constant *Init = ConstantStruct::get(Elts, sizeof(Elts)/sizeof(Elts[0]));
+  
+  M.addTypeName("llvm.dbg.block.type", Init->getType());
+  GlobalVariable *GV = new GlobalVariable(Init->getType(), true,
+                                          GlobalValue::InternalLinkage,
+                                          Init, "llvm.dbg.block", &M);
+  GV->setSection("llvm.metadata");
+  return DIBlock(GV);
+}
+
+
+//===----------------------------------------------------------------------===//
+// DIFactory: Routines for inserting code into a function
+//===----------------------------------------------------------------------===//
+
+/// InsertStopPoint - Create a new llvm.dbg.stoppoint intrinsic invocation,
+/// inserting it at the end of the specified basic block.
+void DIFactory::InsertStopPoint(DICompileUnit CU, unsigned LineNo,
+                                unsigned ColNo, BasicBlock *BB) {
+  
+  // Lazily construct llvm.dbg.stoppoint function.
+  if (!StopPointFn)
+    StopPointFn = llvm::Intrinsic::getDeclaration(&M, 
+                                              llvm::Intrinsic::dbg_stoppoint);
+  
+  // Invoke llvm.dbg.stoppoint
+  Value *Args[] = {
+    llvm::ConstantInt::get(llvm::Type::Int32Ty, LineNo),
+    llvm::ConstantInt::get(llvm::Type::Int32Ty, ColNo),
+    CU.getCastToEmpty()
+  };
+  CallInst::Create(StopPointFn, Args, Args+3, "", BB);
+}
+
+/// InsertSubprogramStart - Create a new llvm.dbg.func.start intrinsic to
+/// mark the start of the specified subprogram.
+void DIFactory::InsertSubprogramStart(DISubprogram SP, BasicBlock *BB) {
+  // Lazily construct llvm.dbg.func.start.
+  if (!FuncStartFn)
+    FuncStartFn = llvm::Intrinsic::getDeclaration(&M, 
+                                              llvm::Intrinsic::dbg_func_start);
+  
+  // Call llvm.dbg.func.start which also implicitly sets a stoppoint.
+  CallInst::Create(FuncStartFn, SP.getCastToEmpty(), "", BB);
+}
+
+/// InsertRegionStart - Insert a new llvm.dbg.region.start intrinsic call to
+/// mark the start of a region for the specified scoping descriptor.
+void DIFactory::InsertRegionStart(DIDescriptor D, BasicBlock *BB) {
+  // Lazily construct llvm.dbg.region.start function.
+  if (!RegionStartFn)
+    RegionStartFn = llvm::Intrinsic::getDeclaration(&M, 
+                                            llvm::Intrinsic::dbg_region_start);
+  // Call llvm.dbg.func.start.
+  CallInst::Create(RegionStartFn, D.getCastToEmpty(), "", BB);
+}
+
+
+/// InsertRegionEnd - Insert a new llvm.dbg.region.end intrinsic call to
+/// mark the end of a region for the specified scoping descriptor.
+void DIFactory::InsertRegionEnd(DIDescriptor D, BasicBlock *BB) {
+  // Lazily construct llvm.dbg.region.end function.
+  if (!RegionEndFn)
+    RegionEndFn = llvm::Intrinsic::getDeclaration(&M,
+                                               llvm::Intrinsic::dbg_region_end);
+  
+  CallInst::Create(RegionEndFn, D.getCastToEmpty(), "", BB);
+}
+
+/// InsertDeclare - Insert a new llvm.dbg.declare intrinsic call.
+void DIFactory::InsertDeclare(llvm::Value *Storage, DIVariable D,
+                              BasicBlock *BB) {
+  // Cast the storage to a {}* for the call to llvm.dbg.declare.
+  const Type *DestTy = PointerType::getUnqual(StructType::get(NULL, NULL));
+  Storage = new llvm::BitCastInst(Storage, DestTy, Storage->getName(), BB);
+  
+  if (!DeclareFn)
+    DeclareFn = llvm::Intrinsic::getDeclaration(&M,
+                                                llvm::Intrinsic::dbg_declare);
+  Value *Args[] = { Storage, D.getCastToEmpty() };
+  CallInst::Create(DeclareFn, Args, Args+2, "", BB);
+}