diff --git a/include/clang-c/Index.h b/include/clang-c/Index.h
index c8af349..76297f4 100644
--- a/include/clang-c/Index.h
+++ b/include/clang-c/Index.h
@@ -63,7 +63,10 @@
 /**
  * \brief A single translation unit, which resides in an index.
  */
-typedef void *CXTranslationUnit;  /* A translation unit instance. */
+typedef struct CXTranslationUnitImpl {
+  void *TUData;
+  void *StringPool;
+} *CXTranslationUnit;  /* A translation unit instance. */
 
 /**
  * \brief Opaque pointer representing client data that will be passed through
@@ -133,7 +136,7 @@
  * with the string data, call \c clang_disposeString() to free the string.
  */
 typedef struct {
-  const char *Spelling;
+  void *data;
   unsigned private_flags;
 } CXString;
 
diff --git a/tools/c-index-test/c-index-test.c b/tools/c-index-test/c-index-test.c
index c0c7a29..c13f031 100644
--- a/tools/c-index-test/c-index-test.c
+++ b/tools/c-index-test/c-index-test.c
@@ -1305,7 +1305,7 @@
             return not_usr("<class USR>", I[2]);
           else {
             CXString x;
-            x.Spelling = I[2];
+            x.data = (void*) I[2];
             x.private_flags = 0;
             print_usr(clang_constructUSR_ObjCIvar(I[1], x));
           }
@@ -1332,7 +1332,7 @@
             return not_usr("<class USR>", I[3]);
           else {
             CXString x;
-            x.Spelling = I[3];
+            x.data = (void*) I[3];
             x.private_flags = 0;
             print_usr(clang_constructUSR_ObjCMethod(I[1], atoi(I[2]), x));
           }
@@ -1362,7 +1362,7 @@
             return not_usr("<class USR>", I[2]);
           else {
             CXString x;
-            x.Spelling = I[2];
+            x.data = (void*) I[2];
             x.private_flags = 0;
             print_usr(clang_constructUSR_ObjCProperty(I[1], x));
           }
diff --git a/tools/libclang/CIndex.cpp b/tools/libclang/CIndex.cpp
index a25570e..f344009 100644
--- a/tools/libclang/CIndex.cpp
+++ b/tools/libclang/CIndex.cpp
@@ -49,6 +49,15 @@
 using namespace clang::cxcursor;
 using namespace clang::cxstring;
 
+static CXTranslationUnit MakeCXTranslationUnit(ASTUnit *TU) {
+  if (!TU)
+    return 0;
+  CXTranslationUnit D = new CXTranslationUnitImpl();
+  D->TUData = TU;
+  D->StringPool = createCXStringPool();
+  return D;
+}
+
 /// \brief The result of comparing two source ranges.
 enum RangeComparisonResult {
   /// \brief Either the ranges overlap or one of the ranges is invalid.
@@ -149,7 +158,8 @@
                       public StmtVisitor<CursorVisitor, bool>
 {
   /// \brief The translation unit we are traversing.
-  ASTUnit *TU;
+  CXTranslationUnit TU;
+  ASTUnit *AU;
 
   /// \brief The parent cursor whose children we are traversing.
   CXCursor Parent;
@@ -214,10 +224,12 @@
   };
 
 public:
-  CursorVisitor(ASTUnit *TU, CXCursorVisitor Visitor, CXClientData ClientData,
+  CursorVisitor(CXTranslationUnit TU, CXCursorVisitor Visitor,
+                CXClientData ClientData,
                 unsigned MaxPCHLevel,
                 SourceRange RegionOfInterest = SourceRange())
-    : TU(TU), Visitor(Visitor), ClientData(ClientData),
+    : TU(TU), AU(static_cast<ASTUnit*>(TU->TUData)),
+      Visitor(Visitor), ClientData(ClientData),
       MaxPCHLevel(MaxPCHLevel), RegionOfInterest(RegionOfInterest), 
       DI_current(0)
   {
@@ -236,7 +248,8 @@
     }
   }
 
-  ASTUnit *getASTUnit() const { return TU; }
+  ASTUnit *getASTUnit() const { return static_cast<ASTUnit*>(TU->TUData); }
+  CXTranslationUnit getTU() const { return TU; }
 
   bool Visit(CXCursor Cursor, bool CheckedRegionOfInterest = false);
   
@@ -350,7 +363,7 @@
 static SourceRange getRawCursorExtent(CXCursor C);
 
 RangeComparisonResult CursorVisitor::CompareRegionOfInterest(SourceRange R) {
-  return RangeCompare(TU->getSourceManager(), R, RegionOfInterest);
+  return RangeCompare(AU->getSourceManager(), R, RegionOfInterest);
 }
 
 /// \brief Visit the given cursor and, if requested by the visitor,
@@ -402,10 +415,10 @@
 std::pair<PreprocessingRecord::iterator, PreprocessingRecord::iterator>
 CursorVisitor::getPreprocessedEntities() {
   PreprocessingRecord &PPRec
-    = *TU->getPreprocessor().getPreprocessingRecord();
+    = *AU->getPreprocessor().getPreprocessingRecord();
   
   bool OnlyLocalDecls
-    = !TU->isMainFileAST() && TU->getOnlyLocalDecls();
+    = !AU->isMainFileAST() && AU->getOnlyLocalDecls();
   
   // There is no region of interest; we have to walk everything.
   if (RegionOfInterest.isInvalid())
@@ -413,7 +426,7 @@
                           PPRec.end(OnlyLocalDecls));
 
   // Find the file in which the region of interest lands.
-  SourceManager &SM = TU->getSourceManager();
+  SourceManager &SM = AU->getSourceManager();
   std::pair<FileID, unsigned> Begin
     = SM.getDecomposedInstantiationLoc(RegionOfInterest.getBegin());
   std::pair<FileID, unsigned> End
@@ -425,7 +438,7 @@
                           PPRec.end(OnlyLocalDecls));
     
   ASTUnit::PreprocessedEntitiesByFileMap &ByFileMap
-    = TU->getPreprocessedEntitiesByFile();
+    = AU->getPreprocessedEntitiesByFile();
   if (ByFileMap.empty()) {
     // Build the mapping from files to sets of preprocessed entities.
     for (PreprocessingRecord::iterator E = PPRec.begin(OnlyLocalDecls),
@@ -442,7 +455,7 @@
 }
 
 /// \brief Visit the children of the given cursor.
-///
+/// 
 /// \returns true if the visitation should be aborted, false if it
 /// should continue.
 bool CursorVisitor::VisitChildren(CXCursor Cursor) {
@@ -467,13 +480,14 @@
     return Visit(getCursorExpr(Cursor));
 
   if (clang_isTranslationUnit(Cursor.kind)) {
-    ASTUnit *CXXUnit = getCursorASTUnit(Cursor);
+    CXTranslationUnit tu = getCursorTU(Cursor);
+    ASTUnit *CXXUnit = static_cast<ASTUnit*>(tu->TUData);
     if (!CXXUnit->isMainFileAST() && CXXUnit->getOnlyLocalDecls() &&
         RegionOfInterest.isInvalid()) {
       for (ASTUnit::top_level_iterator TL = CXXUnit->top_level_begin(),
                                     TLEnd = CXXUnit->top_level_end();
            TL != TLEnd; ++TL) {
-        if (Visit(MakeCXCursor(*TL, CXXUnit), true))
+        if (Visit(MakeCXCursor(*TL, tu), true))
           return true;
       }
     } else if (VisitDeclContext(
@@ -487,21 +501,21 @@
       PreprocessingRecord::iterator E, EEnd;
       for (llvm::tie(E, EEnd) = getPreprocessedEntities(); E != EEnd; ++E) {
         if (MacroInstantiation *MI = dyn_cast<MacroInstantiation>(*E)) {
-          if (Visit(MakeMacroInstantiationCursor(MI, CXXUnit)))
+          if (Visit(MakeMacroInstantiationCursor(MI, tu)))
             return true;
           
           continue;
         }
         
         if (MacroDefinition *MD = dyn_cast<MacroDefinition>(*E)) {
-          if (Visit(MakeMacroDefinitionCursor(MD, CXXUnit)))
+          if (Visit(MakeMacroDefinitionCursor(MD, tu)))
             return true;
           
           continue;
         }
         
         if (InclusionDirective *ID = dyn_cast<InclusionDirective>(*E)) {
-          if (Visit(MakeInclusionDirectiveCursor(ID, CXXUnit)))
+          if (Visit(MakeInclusionDirectiveCursor(ID, tu)))
             return true;
           
           continue;
@@ -859,7 +873,7 @@
   // for later processing.
   llvm::SmallVector<Decl *, 24> DeclsInContainer;
   SourceLocation EndLoc = D->getSourceRange().getEnd();
-  SourceManager &SM = TU->getSourceManager();
+  SourceManager &SM = AU->getSourceManager();
   if (EndLoc.isValid()) {
     DeclContext::decl_iterator next = *DI_current;
     while (++next != DE_current) {
@@ -1243,7 +1257,7 @@
 }
 
 bool CursorVisitor::VisitBuiltinTypeLoc(BuiltinTypeLoc TL) {
-  ASTContext &Context = TU->getASTContext();
+  ASTContext &Context = AU->getASTContext();
 
   // Some builtin types (such as Objective-C's "id", "sel", and
   // "Class") have associated declarations. Create cursors for those.
@@ -2098,9 +2112,10 @@
   FileSystemOpts.WorkingDir = CXXIdx->getWorkingDirectory();
 
   llvm::IntrusiveRefCntPtr<Diagnostic> Diags;
-  return ASTUnit::LoadFromASTFile(ast_filename, Diags, FileSystemOpts,
+  ASTUnit *TU = ASTUnit::LoadFromASTFile(ast_filename, Diags, FileSystemOpts,
                                   CXXIdx->getOnlyLocalDecls(),
                                   0, 0, true);
+  return MakeCXTranslationUnit(TU);
 }
 
 unsigned clang_defaultEditingTranslationUnitOptions() {
@@ -2242,7 +2257,7 @@
     }
   }
 
-  PTUI->result = Unit.take();
+  PTUI->result = MakeCXTranslationUnit(Unit.take());
 }
 CXTranslationUnit clang_parseTranslationUnit(CXIndex CIdx,
                                              const char *source_filename,
@@ -2292,17 +2307,19 @@
   if (!TU)
     return 1;
   
-  return static_cast<ASTUnit *>(TU)->Save(FileName);
+  return static_cast<ASTUnit *>(TU->TUData)->Save(FileName);
 }
 
 void clang_disposeTranslationUnit(CXTranslationUnit CTUnit) {
   if (CTUnit) {
     // If the translation unit has been marked as unsafe to free, just discard
     // it.
-    if (static_cast<ASTUnit *>(CTUnit)->isUnsafeToFree())
+    if (static_cast<ASTUnit *>(CTUnit->TUData)->isUnsafeToFree())
       return;
 
-    delete static_cast<ASTUnit *>(CTUnit);
+    delete static_cast<ASTUnit *>(CTUnit->TUData);
+    disposeCXStringPool(CTUnit->StringPool);
+    delete CTUnit;
   }
 }
 
@@ -2331,7 +2348,7 @@
   if (!TU)
     return;
 
-  ASTUnit *CXXUnit = static_cast<ASTUnit *>(TU);
+  ASTUnit *CXXUnit = static_cast<ASTUnit *>(TU->TUData);
   ASTUnit::ConcurrencyCheck Check(*CXXUnit);
   
   llvm::SmallVector<ASTUnit::RemappedFile, 4> RemappedFiles;
@@ -2357,7 +2374,7 @@
 
   if (!RunSafely(CRC, clang_reparseTranslationUnit_Impl, &RTUI)) {
     fprintf(stderr, "libclang: crash detected during reparsing\n");
-    static_cast<ASTUnit *>(TU)->setUnsafeToFree(true);
+    static_cast<ASTUnit *>(TU->TUData)->setUnsafeToFree(true);
     return 1;
   }
 
@@ -2370,7 +2387,7 @@
   if (!CTUnit)
     return createCXString("");
 
-  ASTUnit *CXXUnit = static_cast<ASTUnit *>(CTUnit);
+  ASTUnit *CXXUnit = static_cast<ASTUnit *>(CTUnit->TUData);
   return createCXString(CXXUnit->getOriginalSourceFileName(), true);
 }
 
@@ -2404,7 +2421,7 @@
   if (!tu || !file)
     return clang_getNullLocation();
   
-  ASTUnit *CXXUnit = static_cast<ASTUnit *>(tu);
+  ASTUnit *CXXUnit = static_cast<ASTUnit *>(tu->TUData);
   SourceLocation SLoc
     = CXXUnit->getSourceManager().getLocation(
                                         static_cast<const FileEntry *>(file),
@@ -2420,7 +2437,7 @@
   if (!tu || !file)
     return clang_getNullLocation();
   
-  ASTUnit *CXXUnit = static_cast<ASTUnit *>(tu);
+  ASTUnit *CXXUnit = static_cast<ASTUnit *>(tu->TUData);
   SourceLocation Start 
     = CXXUnit->getSourceManager().getLocation(
                                         static_cast<const FileEntry *>(file),
@@ -2548,7 +2565,7 @@
 extern "C" {
 CXString clang_getFileName(CXFile SFile) {
   if (!SFile)
-    return createCXString(NULL);
+    return createCXString((const char*)NULL);
 
   FileEntry *FEnt = static_cast<FileEntry *>(SFile);
   return createCXString(FEnt->getName());
@@ -2566,7 +2583,7 @@
   if (!tu)
     return 0;
 
-  ASTUnit *CXXUnit = static_cast<ASTUnit *>(tu);
+  ASTUnit *CXXUnit = static_cast<ASTUnit *>(tu->TUData);
 
   FileManager &FMgr = CXXUnit->getFileManager();
   const FileEntry *File = FMgr.getFile(file_name, file_name+strlen(file_name),
@@ -2628,10 +2645,8 @@
 unsigned clang_visitChildren(CXCursor parent,
                              CXCursorVisitor visitor,
                              CXClientData client_data) {
-  ASTUnit *CXXUnit = getCursorASTUnit(parent);
-
-  CursorVisitor CursorVis(CXXUnit, visitor, client_data, 
-                          CXXUnit->getMaxPCHLevel());
+  CursorVisitor CursorVis(getCursorTU(parent), visitor, client_data, 
+                          getCursorASTUnit(parent)->getMaxPCHLevel());
   return CursorVis.VisitChildren(parent);
 }
 
@@ -2698,7 +2713,8 @@
 
 CXString clang_getCursorSpelling(CXCursor C) {
   if (clang_isTranslationUnit(C.kind))
-    return clang_getTranslationUnitSpelling(C.data[2]);
+    return clang_getTranslationUnitSpelling(
+                            static_cast<CXTranslationUnit>(C.data[2]));
 
   if (clang_isReference(C.kind)) {
     switch (C.kind) {
@@ -3028,7 +3044,7 @@
   }
 
   llvm_unreachable("Unhandled CXCursorKind");
-  return createCXString(NULL);
+  return createCXString((const char*) 0);
 }
 
 enum CXChildVisitResult GetCursorVisitor(CXCursor cursor,
@@ -3052,7 +3068,7 @@
   if (!TU)
     return clang_getNullCursor();
 
-  ASTUnit *CXXUnit = static_cast<ASTUnit *>(TU);
+  ASTUnit *CXXUnit = static_cast<ASTUnit *>(TU->TUData);
   ASTUnit::ConcurrencyCheck Check(*CXXUnit);
 
   // Translate the given source location to make it point at the beginning of
@@ -3073,8 +3089,8 @@
     // FIXME: Would be great to have a "hint" cursor, then walk from that
     // hint cursor upward until we find a cursor whose source range encloses
     // the region of interest, rather than starting from the translation unit.
-    CXCursor Parent = clang_getTranslationUnitCursor(CXXUnit);
-    CursorVisitor CursorVis(CXXUnit, GetCursorVisitor, &Result,
+    CXCursor Parent = clang_getTranslationUnitCursor(TU);
+    CursorVisitor CursorVis(TU, GetCursorVisitor, &Result,
                             Decl::MaxPCHLevel, SourceLocation(SLoc));
     CursorVis.VisitChildren(Parent);
   }
@@ -3366,16 +3382,16 @@
   if (clang_isInvalid(C.kind))
     return clang_getNullCursor();
 
-  ASTUnit *CXXUnit = getCursorASTUnit(C);
+  CXTranslationUnit tu = getCursorTU(C);
   if (clang_isDeclaration(C.kind)) {
     Decl *D = getCursorDecl(C);
     if (UsingDecl *Using = dyn_cast<UsingDecl>(D))
-      return MakeCursorOverloadedDeclRef(Using, D->getLocation(), CXXUnit);
+      return MakeCursorOverloadedDeclRef(Using, D->getLocation(), tu);
     if (ObjCClassDecl *Classes = dyn_cast<ObjCClassDecl>(D))
-      return MakeCursorOverloadedDeclRef(Classes, D->getLocation(), CXXUnit);
+      return MakeCursorOverloadedDeclRef(Classes, D->getLocation(), tu);
     if (ObjCForwardProtocolDecl *Protocols
                                         = dyn_cast<ObjCForwardProtocolDecl>(D))
-      return MakeCursorOverloadedDeclRef(Protocols, D->getLocation(), CXXUnit);
+      return MakeCursorOverloadedDeclRef(Protocols, D->getLocation(), tu);
       
     return C;
   }
@@ -3384,10 +3400,10 @@
     Expr *E = getCursorExpr(C);
     Decl *D = getDeclFromExpr(E);
     if (D)
-      return MakeCXCursor(D, CXXUnit);
+      return MakeCXCursor(D, tu);
     
     if (OverloadExpr *Ovl = dyn_cast_or_null<OverloadExpr>(E))
-      return MakeCursorOverloadedDeclRef(Ovl, CXXUnit);
+      return MakeCursorOverloadedDeclRef(Ovl, tu);
         
     return clang_getNullCursor();
   }
@@ -3395,15 +3411,14 @@
   if (clang_isStatement(C.kind)) {
     Stmt *S = getCursorStmt(C);
     if (GotoStmt *Goto = dyn_cast_or_null<GotoStmt>(S))
-      return MakeCXCursor(Goto->getLabel(), getCursorDecl(C), 
-                          getCursorASTUnit(C));
+      return MakeCXCursor(Goto->getLabel(), getCursorDecl(C), tu);
 
     return clang_getNullCursor();
   }
   
   if (C.kind == CXCursor_MacroInstantiation) {
     if (MacroDefinition *Def = getCursorMacroInstantiation(C)->getDefinition())
-      return MakeMacroDefinitionCursor(Def, CXXUnit);
+      return MakeMacroDefinitionCursor(Def, tu);
   }
 
   if (!clang_isReference(C.kind))
@@ -3411,38 +3426,39 @@
 
   switch (C.kind) {
     case CXCursor_ObjCSuperClassRef:
-      return MakeCXCursor(getCursorObjCSuperClassRef(C).first, CXXUnit);
+      return MakeCXCursor(getCursorObjCSuperClassRef(C).first, tu);
 
     case CXCursor_ObjCProtocolRef: {
-      return MakeCXCursor(getCursorObjCProtocolRef(C).first, CXXUnit);
+      return MakeCXCursor(getCursorObjCProtocolRef(C).first, tu);
 
     case CXCursor_ObjCClassRef:
-      return MakeCXCursor(getCursorObjCClassRef(C).first, CXXUnit);
+      return MakeCXCursor(getCursorObjCClassRef(C).first, tu );
 
     case CXCursor_TypeRef:
-      return MakeCXCursor(getCursorTypeRef(C).first, CXXUnit);
+      return MakeCXCursor(getCursorTypeRef(C).first, tu );
 
     case CXCursor_TemplateRef:
-      return MakeCXCursor(getCursorTemplateRef(C).first, CXXUnit);
+      return MakeCXCursor(getCursorTemplateRef(C).first, tu );
 
     case CXCursor_NamespaceRef:
-      return MakeCXCursor(getCursorNamespaceRef(C).first, CXXUnit);
+      return MakeCXCursor(getCursorNamespaceRef(C).first, tu );
 
     case CXCursor_MemberRef:
-      return MakeCXCursor(getCursorMemberRef(C).first, CXXUnit);
+      return MakeCXCursor(getCursorMemberRef(C).first, tu );
 
     case CXCursor_CXXBaseSpecifier: {
       CXXBaseSpecifier *B = cxcursor::getCursorCXXBaseSpecifier(C);
       return clang_getTypeDeclaration(cxtype::MakeCXType(B->getType(),
-                                                         CXXUnit));
+                                                         tu ));
     }
 
     case CXCursor_LabelRef:
       // FIXME: We end up faking the "parent" declaration here because we
       // don't want to make CXCursor larger.
       return MakeCXCursor(getCursorLabelRef(C).first, 
-                          CXXUnit->getASTContext().getTranslationUnitDecl(),
-                          CXXUnit);
+               static_cast<ASTUnit*>(tu->TUData)->getASTContext()
+                          .getTranslationUnitDecl(),
+                          tu);
 
     case CXCursor_OverloadedDeclRef:
       return C;
@@ -3461,7 +3477,7 @@
   if (clang_isInvalid(C.kind))
     return clang_getNullCursor();
 
-  ASTUnit *CXXUnit = getCursorASTUnit(C);
+  CXTranslationUnit TU = getCursorTU(C);
 
   bool WasReference = false;
   if (clang_isReference(C.kind) || clang_isExpression(C.kind)) {
@@ -3515,10 +3531,10 @@
 
   case Decl::UsingDirective:
     return MakeCXCursor(cast<UsingDirectiveDecl>(D)->getNominatedNamespace(),
-                        CXXUnit);
+                        TU);
 
   case Decl::NamespaceAlias:
-    return MakeCXCursor(cast<NamespaceAliasDecl>(D)->getNamespace(), CXXUnit);
+    return MakeCXCursor(cast<NamespaceAliasDecl>(D)->getNamespace(), TU);
 
   case Decl::Enum:
   case Decl::Record:
@@ -3526,7 +3542,7 @@
   case Decl::ClassTemplateSpecialization:
   case Decl::ClassTemplatePartialSpecialization:
     if (TagDecl *Def = cast<TagDecl>(D)->getDefinition())
-      return MakeCXCursor(Def, CXXUnit);
+      return MakeCXCursor(Def, TU);
     return clang_getNullCursor();
 
   case Decl::Function:
@@ -3536,21 +3552,21 @@
   case Decl::CXXConversion: {
     const FunctionDecl *Def = 0;
     if (cast<FunctionDecl>(D)->getBody(Def))
-      return MakeCXCursor(const_cast<FunctionDecl *>(Def), CXXUnit);
+      return MakeCXCursor(const_cast<FunctionDecl *>(Def), TU);
     return clang_getNullCursor();
   }
 
   case Decl::Var: {
     // Ask the variable if it has a definition.
     if (VarDecl *Def = cast<VarDecl>(D)->getDefinition())
-      return MakeCXCursor(Def, CXXUnit);
+      return MakeCXCursor(Def, TU);
     return clang_getNullCursor();
   }
 
   case Decl::FunctionTemplate: {
     const FunctionDecl *Def = 0;
     if (cast<FunctionTemplateDecl>(D)->getTemplatedDecl()->getBody(Def))
-      return MakeCXCursor(Def->getDescribedFunctionTemplate(), CXXUnit);
+      return MakeCXCursor(Def->getDescribedFunctionTemplate(), TU);
     return clang_getNullCursor();
   }
 
@@ -3558,18 +3574,18 @@
     if (RecordDecl *Def = cast<ClassTemplateDecl>(D)->getTemplatedDecl()
                                                             ->getDefinition())
       return MakeCXCursor(cast<CXXRecordDecl>(Def)->getDescribedClassTemplate(),
-                          CXXUnit);
+                          TU);
     return clang_getNullCursor();
   }
 
   case Decl::Using:
     return MakeCursorOverloadedDeclRef(cast<UsingDecl>(D), 
-                                       D->getLocation(), CXXUnit);
+                                       D->getLocation(), TU);
 
   case Decl::UsingShadow:
     return clang_getCursorDefinition(
                        MakeCXCursor(cast<UsingShadowDecl>(D)->getTargetDecl(),
-                                    CXXUnit));
+                                    TU));
 
   case Decl::ObjCMethod: {
     ObjCMethodDecl *Method = cast<ObjCMethodDecl>(D);
@@ -3585,7 +3601,7 @@
         if (ObjCMethodDecl *Def = ClassImpl->getMethod(Method->getSelector(),
                                                   Method->isInstanceMethod()))
           if (Def->isThisDeclarationADefinition())
-            return MakeCXCursor(Def, CXXUnit);
+            return MakeCXCursor(Def, TU);
 
     return clang_getNullCursor();
   }
@@ -3593,7 +3609,7 @@
   case Decl::ObjCCategory:
     if (ObjCCategoryImplDecl *Impl
                                = cast<ObjCCategoryDecl>(D)->getImplementation())
-      return MakeCXCursor(Impl, CXXUnit);
+      return MakeCXCursor(Impl, TU);
     return clang_getNullCursor();
 
   case Decl::ObjCProtocol:
@@ -3612,7 +3628,7 @@
         return C;
     } else if (ObjCImplementationDecl *Impl
                               = cast<ObjCInterfaceDecl>(D)->getImplementation())
-      return MakeCXCursor(Impl, CXXUnit);
+      return MakeCXCursor(Impl, TU);
     return clang_getNullCursor();
 
   case Decl::ObjCProperty:
@@ -3624,26 +3640,26 @@
     if (ObjCInterfaceDecl *Class
           = cast<ObjCCompatibleAliasDecl>(D)->getClassInterface())
       if (!Class->isForwardDecl())
-        return MakeCXCursor(Class, CXXUnit);
+        return MakeCXCursor(Class, TU);
 
     return clang_getNullCursor();
 
   case Decl::ObjCForwardProtocol:
     return MakeCursorOverloadedDeclRef(cast<ObjCForwardProtocolDecl>(D), 
-                                       D->getLocation(), CXXUnit);
+                                       D->getLocation(), TU);
 
   case Decl::ObjCClass:
     return MakeCursorOverloadedDeclRef(cast<ObjCClassDecl>(D), D->getLocation(),
-                                       CXXUnit);
+                                       TU);
 
   case Decl::Friend:
     if (NamedDecl *Friend = cast<FriendDecl>(D)->getFriendDecl())
-      return clang_getCursorDefinition(MakeCXCursor(Friend, CXXUnit));
+      return clang_getCursorDefinition(MakeCXCursor(Friend, TU));
     return clang_getNullCursor();
 
   case Decl::FriendTemplate:
     if (NamedDecl *Friend = cast<FriendTemplateDecl>(D)->getFriendDecl())
-      return clang_getCursorDefinition(MakeCXCursor(Friend, CXXUnit));
+      return clang_getCursorDefinition(MakeCXCursor(Friend, TU));
     return clang_getNullCursor();
   }
 
@@ -3687,28 +3703,28 @@
   if (index >= clang_getNumOverloadedDecls(cursor))
     return clang_getNullCursor();
   
-  ASTUnit *Unit = getCursorASTUnit(cursor);
+  CXTranslationUnit TU = getCursorTU(cursor);
   OverloadedDeclRefStorage Storage = getCursorOverloadedDeclRef(cursor).first;
   if (OverloadExpr *E = Storage.dyn_cast<OverloadExpr *>())
-    return MakeCXCursor(E->decls_begin()[index], Unit);
+    return MakeCXCursor(E->decls_begin()[index], TU);
   
   if (OverloadedTemplateStorage *S
                               = Storage.dyn_cast<OverloadedTemplateStorage*>())
-    return MakeCXCursor(S->begin()[index], Unit);
+    return MakeCXCursor(S->begin()[index], TU);
   
   Decl *D = Storage.get<Decl*>();
   if (UsingDecl *Using = dyn_cast<UsingDecl>(D)) {
     // FIXME: This is, unfortunately, linear time.
     UsingDecl::shadow_iterator Pos = Using->shadow_begin();
     std::advance(Pos, index);
-    return MakeCXCursor(cast<UsingShadowDecl>(*Pos)->getTargetDecl(), Unit);
+    return MakeCXCursor(cast<UsingShadowDecl>(*Pos)->getTargetDecl(), TU);
   }
   
   if (ObjCClassDecl *Classes = dyn_cast<ObjCClassDecl>(D))
-    return MakeCXCursor(Classes->begin()[index].getInterface(), Unit);
+    return MakeCXCursor(Classes->begin()[index].getInterface(), TU);
   
   if (ObjCForwardProtocolDecl *Protocols = dyn_cast<ObjCForwardProtocolDecl>(D))
-    return MakeCXCursor(Protocols->protocol_begin()[index], Unit);
+    return MakeCXCursor(Protocols->protocol_begin()[index], TU);
   
   return clang_getNullCursor();
 }
@@ -3784,7 +3800,7 @@
 
   // We have to find the starting buffer pointer the hard way, by
   // deconstructing the source location.
-  ASTUnit *CXXUnit = static_cast<ASTUnit *>(TU);
+  ASTUnit *CXXUnit = static_cast<ASTUnit *>(TU->TUData);
   if (!CXXUnit)
     return createCXString("");
 
@@ -3801,7 +3817,7 @@
 }
 
 CXSourceLocation clang_getTokenLocation(CXTranslationUnit TU, CXToken CXTok) {
-  ASTUnit *CXXUnit = static_cast<ASTUnit *>(TU);
+  ASTUnit *CXXUnit = static_cast<ASTUnit *>(TU->TUData);
   if (!CXXUnit)
     return clang_getNullLocation();
 
@@ -3810,7 +3826,7 @@
 }
 
 CXSourceRange clang_getTokenExtent(CXTranslationUnit TU, CXToken CXTok) {
-  ASTUnit *CXXUnit = static_cast<ASTUnit *>(TU);
+  ASTUnit *CXXUnit = static_cast<ASTUnit *>(TU->TUData);
   if (!CXXUnit)
     return clang_getNullRange();
 
@@ -3825,7 +3841,7 @@
   if (NumTokens)
     *NumTokens = 0;
 
-  ASTUnit *CXXUnit = static_cast<ASTUnit *>(TU);
+  ASTUnit *CXXUnit = static_cast<ASTUnit *>(TU->TUData);
   if (!CXXUnit || !Tokens || !NumTokens)
     return;
 
@@ -3958,18 +3974,19 @@
 public:
   AnnotateTokensWorker(AnnotateTokensData &annotated,
                        CXToken *tokens, CXCursor *cursors, unsigned numTokens,
-                       ASTUnit *CXXUnit, SourceRange RegionOfInterest)
+                       CXTranslationUnit tu, SourceRange RegionOfInterest)
     : Annotated(annotated), Tokens(tokens), Cursors(cursors),
       NumTokens(numTokens), TokIdx(0), PreprocessingTokIdx(0),
-      AnnotateVis(CXXUnit, AnnotateTokensVisitor, this,
+      AnnotateVis(tu,
+                  AnnotateTokensVisitor, this,
                   Decl::MaxPCHLevel, RegionOfInterest),
-      SrcMgr(CXXUnit->getSourceManager()) {}
+      SrcMgr(static_cast<ASTUnit*>(tu->TUData)->getSourceManager()) {}
 
   void VisitChildren(CXCursor C) { AnnotateVis.VisitChildren(C); }
   enum CXChildVisitResult Visit(CXCursor cursor, CXCursor parent);
   void AnnotateTokens(CXCursor parent);
   void AnnotateTokens() {
-    AnnotateTokens(clang_getTranslationUnitCursor(AnnotateVis.getASTUnit()));
+    AnnotateTokens(clang_getTranslationUnitCursor(AnnotateVis.getTU()));
   }
 };
 }
@@ -4194,7 +4211,7 @@
   for (unsigned I = 0; I != NumTokens; ++I)
     Cursors[I] = C;
 
-  ASTUnit *CXXUnit = static_cast<ASTUnit *>(TU);
+  ASTUnit *CXXUnit = static_cast<ASTUnit *>(TU->TUData);
   if (!CXXUnit)
     return;
 
@@ -4256,7 +4273,7 @@
         CXCursor Cursor
           = MakePreprocessingDirectiveCursor(SourceRange(Locations.front(),
                                                          Locations.back()),
-                                           CXXUnit);
+                                           TU);
         for (unsigned I = 0, N = Locations.size(); I != N; ++I) {
           Annotated[Locations[I].getRawEncoding()] = Cursor;
         }
@@ -4275,7 +4292,7 @@
   // Annotate all of the source locations in the region of interest that map to
   // a specific cursor.
   AnnotateTokensWorker W(Annotated, Tokens, Cursors, NumTokens,
-                         CXXUnit, RegionOfInterest);
+                         TU, RegionOfInterest);
 
   // Run the worker within a CrashRecoveryContext.
   // FIXME: We use a ridiculous stack size here because the data-recursion
@@ -4392,13 +4409,13 @@
   if (clang_isDeclaration(cursor.kind)) {
     if (Decl *D = getCursorDecl(cursor)) {
       DeclContext *DC = D->getDeclContext();
-      return MakeCXCursor(cast<Decl>(DC), getCursorASTUnit(cursor));
+      return MakeCXCursor(cast<Decl>(DC), getCursorTU(cursor));
     }
   }
   
   if (clang_isStatement(cursor.kind) || clang_isExpression(cursor.kind)) {
     if (Decl *D = getCursorDecl(cursor))
-      return MakeCXCursor(D, getCursorASTUnit(cursor));
+      return MakeCXCursor(D, getCursorTU(cursor));
   }
   
   return clang_getNullCursor();
@@ -4408,7 +4425,7 @@
   if (clang_isDeclaration(cursor.kind)) {
     if (Decl *D = getCursorDecl(cursor)) {
       DeclContext *DC = D->getLexicalDeclContext();
-      return MakeCXCursor(cast<Decl>(DC), getCursorASTUnit(cursor));
+      return MakeCXCursor(cast<Decl>(DC), getCursorTU(cursor));
     }
   }
 
@@ -4491,7 +4508,7 @@
     return;
 
   // Handle C++ member functions.
-  ASTUnit *CXXUnit = getCursorASTUnit(cursor);
+  CXTranslationUnit TU = getCursorTU(cursor);
   if (CXXMethodDecl *CXXMethod = dyn_cast<CXXMethodDecl>(D)) {
     *num_overridden = CXXMethod->size_overridden_methods();
     if (!*num_overridden)
@@ -4503,7 +4520,7 @@
               M = CXXMethod->begin_overridden_methods(),
            MEnd = CXXMethod->end_overridden_methods();
          M != MEnd; (void)++M, ++I)
-      (*overridden)[I] = MakeCXCursor(const_cast<CXXMethodDecl*>(*M), CXXUnit);
+      (*overridden)[I] = MakeCXCursor(const_cast<CXXMethodDecl*>(*M), TU);
     return;
   }
 
@@ -4521,7 +4538,7 @@
   *num_overridden = Methods.size();
   *overridden = new CXCursor [Methods.size()];
   for (unsigned I = 0, N = Methods.size(); I != N; ++I)
-    (*overridden)[I] = MakeCXCursor(Methods[I], CXXUnit);  
+    (*overridden)[I] = MakeCXCursor(Methods[I], TU); 
 }
 
 void clang_disposeOverriddenCursors(CXCursor *overridden) {
@@ -4566,12 +4583,12 @@
 extern "C" {
 CXType clang_getIBOutletCollectionType(CXCursor C) {
   if (C.kind != CXCursor_IBOutletCollectionAttr)
-    return cxtype::MakeCXType(QualType(), cxcursor::getCursorASTUnit(C));
+    return cxtype::MakeCXType(QualType(), cxcursor::getCursorTU(C));
   
   IBOutletCollectionAttr *A =
     cast<IBOutletCollectionAttr>(cxcursor::getCursorAttr(C));
   
-  return cxtype::MakeCXType(A->getInterface(), cxcursor::getCursorASTUnit(C));  
+  return cxtype::MakeCXType(A->getInterface(), cxcursor::getCursorTU(C));  
 }
 } // end: extern "C"
 
diff --git a/tools/libclang/CIndexCXX.cpp b/tools/libclang/CIndexCXX.cpp
index fca89ed..0f49f65 100644
--- a/tools/libclang/CIndexCXX.cpp
+++ b/tools/libclang/CIndexCXX.cpp
@@ -55,7 +55,7 @@
     if (TemplateDecl *Template
                            = dyn_cast_or_null<TemplateDecl>(getCursorDecl(C)))
       return MakeCXCursor(Template->getTemplatedDecl(), 
-                          getCursorASTUnit(C)).kind;
+                          static_cast<CXTranslationUnit>(C.data[2])).kind;
     break;
       
   case CXCursor_ClassTemplatePartialSpecialization:
@@ -117,7 +117,7 @@
   if (!Template)
     return clang_getNullCursor();
   
-  return MakeCXCursor(Template, getCursorASTUnit(C));
+  return MakeCXCursor(Template, static_cast<CXTranslationUnit>(C.data[2]));
 }
   
 } // end extern "C"
diff --git a/tools/libclang/CIndexCodeCompletion.cpp b/tools/libclang/CIndexCodeCompletion.cpp
index 7e8cdb2..d0eb5cc 100644
--- a/tools/libclang/CIndexCodeCompletion.cpp
+++ b/tools/libclang/CIndexCodeCompletion.cpp
@@ -125,7 +125,7 @@
   CXStoredCodeCompletionString *CCStr
     = (CXStoredCodeCompletionString *)completion_string;
   if (!CCStr || chunk_number >= CCStr->size())
-    return createCXString(0);
+    return createCXString((const char*)0);
 
   switch ((*CCStr)[chunk_number].Kind) {
   case CodeCompletionString::CK_TypedText:
@@ -156,7 +156,7 @@
   }
 
   // Should be unreachable, but let's be careful.
-  return createCXString(0);
+  return createCXString((const char*)0);
 }
 
 
@@ -355,7 +355,7 @@
 
   bool EnableLogging = getenv("LIBCLANG_CODE_COMPLETION_LOGGING") != 0;
   
-  ASTUnit *AST = static_cast<ASTUnit *>(TU);
+  ASTUnit *AST = static_cast<ASTUnit *>(TU->TUData);
   if (!AST)
     return;
 
@@ -483,7 +483,7 @@
 
   if (!RunSafely(CRC, clang_codeCompleteAt_Impl, &CCAI)) {
     fprintf(stderr, "libclang: crash detected in code completion\n");
-    static_cast<ASTUnit *>(TU)->setUnsafeToFree(true);
+    static_cast<ASTUnit *>(TU->TUData)->setUnsafeToFree(true);
     return 0;
   }
 
diff --git a/tools/libclang/CIndexDiagnostic.cpp b/tools/libclang/CIndexDiagnostic.cpp
index 84f39e3..31ca679 100644
--- a/tools/libclang/CIndexDiagnostic.cpp
+++ b/tools/libclang/CIndexDiagnostic.cpp
@@ -33,12 +33,12 @@
 extern "C" {
 
 unsigned clang_getNumDiagnostics(CXTranslationUnit Unit) {
-  ASTUnit *CXXUnit = static_cast<ASTUnit *>(Unit);
+  ASTUnit *CXXUnit = static_cast<ASTUnit *>(Unit->TUData);
   return CXXUnit? CXXUnit->stored_diag_size() : 0;
 }
 
 CXDiagnostic clang_getDiagnostic(CXTranslationUnit Unit, unsigned Index) {
-  ASTUnit *CXXUnit = static_cast<ASTUnit *>(Unit);
+  ASTUnit *CXXUnit = static_cast<ASTUnit *>(Unit->TUData);
   if (!CXXUnit || Index >= CXXUnit->stored_diag_size())
     return 0;
 
diff --git a/tools/libclang/CIndexInclusionStack.cpp b/tools/libclang/CIndexInclusionStack.cpp
index 55edc1e..b93bb6f 100644
--- a/tools/libclang/CIndexInclusionStack.cpp
+++ b/tools/libclang/CIndexInclusionStack.cpp
@@ -24,7 +24,7 @@
 void clang_getInclusions(CXTranslationUnit TU, CXInclusionVisitor CB,
                          CXClientData clientData) {
   
-  ASTUnit *CXXUnit = static_cast<ASTUnit *>(TU);
+  ASTUnit *CXXUnit = static_cast<ASTUnit *>(TU->TUData);
   SourceManager &SM = CXXUnit->getSourceManager();
   ASTContext &Ctx = CXXUnit->getASTContext();
 
diff --git a/tools/libclang/CXCursor.cpp b/tools/libclang/CXCursor.cpp
index a8cbca5..ea9cfdf 100644
--- a/tools/libclang/CXCursor.cpp
+++ b/tools/libclang/CXCursor.cpp
@@ -45,13 +45,14 @@
   return CXCursor_UnexposedAttr;
 }
 
-CXCursor cxcursor::MakeCXCursor(const Attr *A, Decl *Parent, ASTUnit *TU) {
+CXCursor cxcursor::MakeCXCursor(const Attr *A, Decl *Parent,
+                                CXTranslationUnit TU) {
   assert(A && Parent && TU && "Invalid arguments!");
   CXCursor C = { GetCursorKind(A), { Parent, (void*)A, TU } };
   return C;
 }
 
-CXCursor cxcursor::MakeCXCursor(Decl *D, ASTUnit *TU,
+CXCursor cxcursor::MakeCXCursor(Decl *D, CXTranslationUnit TU,
                                 bool FirstInDeclGroup) {
   assert(D && TU && "Invalid arguments!");
   CXCursor C = { getCursorKindForDecl(D),
@@ -60,7 +61,8 @@
   return C;
 }
 
-CXCursor cxcursor::MakeCXCursor(Stmt *S, Decl *Parent, ASTUnit *TU) {
+CXCursor cxcursor::MakeCXCursor(Stmt *S, Decl *Parent,
+                                CXTranslationUnit TU) {
   assert(S && TU && "Invalid arguments!");
   CXCursorKind K = CXCursor_NotImplemented;
   
@@ -201,7 +203,7 @@
 
 CXCursor cxcursor::MakeCursorObjCSuperClassRef(ObjCInterfaceDecl *Super, 
                                                SourceLocation Loc, 
-                                               ASTUnit *TU) {
+                                               CXTranslationUnit TU) {
   assert(Super && TU && "Invalid arguments!");
   void *RawLoc = reinterpret_cast<void *>(Loc.getRawEncoding());
   CXCursor C = { CXCursor_ObjCSuperClassRef, { Super, RawLoc, TU } };
@@ -218,7 +220,7 @@
 
 CXCursor cxcursor::MakeCursorObjCProtocolRef(ObjCProtocolDecl *Super, 
                                              SourceLocation Loc, 
-                                             ASTUnit *TU) {
+                                             CXTranslationUnit TU) {
   assert(Super && TU && "Invalid arguments!");
   void *RawLoc = reinterpret_cast<void *>(Loc.getRawEncoding());
   CXCursor C = { CXCursor_ObjCProtocolRef, { Super, RawLoc, TU } };
@@ -235,7 +237,7 @@
 
 CXCursor cxcursor::MakeCursorObjCClassRef(ObjCInterfaceDecl *Class, 
                                           SourceLocation Loc, 
-                                          ASTUnit *TU) {
+                                          CXTranslationUnit TU) {
   // 'Class' can be null for invalid code.
   if (!Class)
     return MakeCXCursorInvalid(CXCursor_InvalidCode);
@@ -254,7 +256,7 @@
 }
 
 CXCursor cxcursor::MakeCursorTypeRef(TypeDecl *Type, SourceLocation Loc, 
-                                     ASTUnit *TU) {
+                                     CXTranslationUnit TU) {
   assert(Type && TU && "Invalid arguments!");
   void *RawLoc = reinterpret_cast<void *>(Loc.getRawEncoding());
   CXCursor C = { CXCursor_TypeRef, { Type, RawLoc, TU } };
@@ -270,7 +272,8 @@
 }
 
 CXCursor cxcursor::MakeCursorTemplateRef(TemplateDecl *Template, 
-                                         SourceLocation Loc, ASTUnit *TU) {
+                                         SourceLocation Loc,
+                                         CXTranslationUnit TU) {
   assert(Template && TU && "Invalid arguments!");
   void *RawLoc = reinterpret_cast<void *>(Loc.getRawEncoding());
   CXCursor C = { CXCursor_TemplateRef, { Template, RawLoc, TU } };
@@ -286,7 +289,7 @@
 }
 
 CXCursor cxcursor::MakeCursorNamespaceRef(NamedDecl *NS, SourceLocation Loc, 
-                                          ASTUnit *TU) {
+                                          CXTranslationUnit TU) {
   
   assert(NS && (isa<NamespaceDecl>(NS) || isa<NamespaceAliasDecl>(NS)) && TU &&
          "Invalid arguments!");
@@ -304,7 +307,7 @@
 }
 
 CXCursor cxcursor::MakeCursorMemberRef(FieldDecl *Field, SourceLocation Loc, 
-                                       ASTUnit *TU) {
+                                       CXTranslationUnit TU) {
   
   assert(Field && TU && "Invalid arguments!");
   void *RawLoc = reinterpret_cast<void *>(Loc.getRawEncoding());
@@ -320,7 +323,8 @@
                                        reinterpret_cast<uintptr_t>(C.data[1])));  
 }
 
-CXCursor cxcursor::MakeCursorCXXBaseSpecifier(CXXBaseSpecifier *B, ASTUnit *TU){
+CXCursor cxcursor::MakeCursorCXXBaseSpecifier(CXXBaseSpecifier *B,
+                                              CXTranslationUnit TU){
   CXCursor C = { CXCursor_CXXBaseSpecifier, { B, 0, TU } };
   return C;  
 }
@@ -331,7 +335,7 @@
 }
 
 CXCursor cxcursor::MakePreprocessingDirectiveCursor(SourceRange Range, 
-                                                    ASTUnit *TU) {
+                                                    CXTranslationUnit TU) {
   CXCursor C = { CXCursor_PreprocessingDirective, 
                  { reinterpret_cast<void *>(Range.getBegin().getRawEncoding()),
                    reinterpret_cast<void *>(Range.getEnd().getRawEncoding()),
@@ -348,7 +352,8 @@
                                       reinterpret_cast<uintptr_t> (C.data[1])));
 }
 
-CXCursor cxcursor::MakeMacroDefinitionCursor(MacroDefinition *MI, ASTUnit *TU) {
+CXCursor cxcursor::MakeMacroDefinitionCursor(MacroDefinition *MI,
+                                             CXTranslationUnit TU) {
   CXCursor C = { CXCursor_MacroDefinition, { MI, 0, TU } };
   return C;
 }
@@ -359,7 +364,7 @@
 }
 
 CXCursor cxcursor::MakeMacroInstantiationCursor(MacroInstantiation *MI, 
-                                                ASTUnit *TU) {
+                                                CXTranslationUnit TU) {
   CXCursor C = { CXCursor_MacroInstantiation, { MI, 0, TU } };
   return C;
 }
@@ -370,7 +375,7 @@
 }
 
 CXCursor cxcursor::MakeInclusionDirectiveCursor(InclusionDirective *ID, 
-                                                ASTUnit *TU) {
+                                                CXTranslationUnit TU) {
   CXCursor C = { CXCursor_InclusionDirective, { ID, 0, TU } };
   return C;
 }
@@ -381,7 +386,7 @@
 }
 
 CXCursor cxcursor::MakeCursorLabelRef(LabelStmt *Label, SourceLocation Loc, 
-                                      ASTUnit *TU) {
+                                      CXTranslationUnit TU) {
   
   assert(Label && TU && "Invalid arguments!");
   void *RawLoc = reinterpret_cast<void *>(Loc.getRawEncoding());
@@ -398,7 +403,7 @@
 }
 
 CXCursor cxcursor::MakeCursorOverloadedDeclRef(OverloadExpr *E, 
-                                               ASTUnit *TU) {
+                                               CXTranslationUnit TU) {
   assert(E && TU && "Invalid arguments!");
   OverloadedDeclRefStorage Storage(E);
   void *RawLoc = reinterpret_cast<void *>(E->getNameLoc().getRawEncoding());
@@ -411,7 +416,7 @@
 
 CXCursor cxcursor::MakeCursorOverloadedDeclRef(Decl *D, 
                                                SourceLocation Loc,
-                                               ASTUnit *TU) {
+                                               CXTranslationUnit TU) {
   assert(D && TU && "Invalid arguments!");
   void *RawLoc = reinterpret_cast<void *>(Loc.getRawEncoding());
   OverloadedDeclRefStorage Storage(D);
@@ -424,7 +429,7 @@
 
 CXCursor cxcursor::MakeCursorOverloadedDeclRef(TemplateName Name, 
                                                SourceLocation Loc,
-                                               ASTUnit *TU) {
+                                               CXTranslationUnit TU) {
   assert(Name.getAsOverloadedTemplate() && TU && "Invalid arguments!");
   void *RawLoc = reinterpret_cast<void *>(Loc.getRawEncoding());
   OverloadedDeclRefStorage Storage(Name.getAsOverloadedTemplate());
@@ -469,7 +474,12 @@
 }
 
 ASTUnit *cxcursor::getCursorASTUnit(CXCursor Cursor) {
-  return static_cast<ASTUnit *>(Cursor.data[2]);
+  return static_cast<ASTUnit *>(static_cast<CXTranslationUnit>(Cursor.data[2])
+                                  ->TUData);
+}
+
+CXTranslationUnit cxcursor::getCursorTU(CXCursor Cursor) {
+  return static_cast<CXTranslationUnit>(Cursor.data[2]);
 }
 
 bool cxcursor::operator==(CXCursor X, CXCursor Y) {
diff --git a/tools/libclang/CXCursor.h b/tools/libclang/CXCursor.h
index 7e518ed..11f2500 100644
--- a/tools/libclang/CXCursor.h
+++ b/tools/libclang/CXCursor.h
@@ -44,16 +44,18 @@
   
 namespace cxcursor {
   
-CXCursor MakeCXCursor(const clang::Attr *A, clang::Decl *Parent, ASTUnit *TU);
-CXCursor MakeCXCursor(clang::Decl *D, ASTUnit *TU,
+CXCursor MakeCXCursor(const clang::Attr *A, clang::Decl *Parent,
+                      CXTranslationUnit TU);
+CXCursor MakeCXCursor(clang::Decl *D, CXTranslationUnit TU,
                       bool FirstInDeclGroup = true);
-CXCursor MakeCXCursor(clang::Stmt *S, clang::Decl *Parent, ASTUnit *TU);
+CXCursor MakeCXCursor(clang::Stmt *S, clang::Decl *Parent,
+                      CXTranslationUnit TU);
 CXCursor MakeCXCursorInvalid(CXCursorKind K);
 
 /// \brief Create an Objective-C superclass reference at the given location.
 CXCursor MakeCursorObjCSuperClassRef(ObjCInterfaceDecl *Super, 
                                      SourceLocation Loc, 
-                                     ASTUnit *TU);
+                                     CXTranslationUnit TU);
 
 /// \brief Unpack an ObjCSuperClassRef cursor into the interface it references
 /// and optionally the location where the reference occurred.
@@ -62,7 +64,7 @@
 
 /// \brief Create an Objective-C protocol reference at the given location.
 CXCursor MakeCursorObjCProtocolRef(ObjCProtocolDecl *Proto, SourceLocation Loc, 
-                                   ASTUnit *TU);
+                                   CXTranslationUnit TU);
 
 /// \brief Unpack an ObjCProtocolRef cursor into the protocol it references
 /// and optionally the location where the reference occurred.
@@ -71,7 +73,7 @@
 
 /// \brief Create an Objective-C class reference at the given location.
 CXCursor MakeCursorObjCClassRef(ObjCInterfaceDecl *Class, SourceLocation Loc, 
-                                ASTUnit *TU);
+                                CXTranslationUnit TU);
 
 /// \brief Unpack an ObjCClassRef cursor into the class it references
 /// and optionally the location where the reference occurred.
@@ -79,7 +81,8 @@
   getCursorObjCClassRef(CXCursor C);
 
 /// \brief Create a type reference at the given location.
-CXCursor MakeCursorTypeRef(TypeDecl *Type, SourceLocation Loc, ASTUnit *TU);
+CXCursor MakeCursorTypeRef(TypeDecl *Type, SourceLocation Loc,
+                           CXTranslationUnit TU);
                                
 /// \brief Unpack a TypeRef cursor into the class it references
 /// and optionally the location where the reference occurred.
@@ -87,7 +90,7 @@
 
 /// \brief Create a reference to a template at the given location.
 CXCursor MakeCursorTemplateRef(TemplateDecl *Template, SourceLocation Loc,
-                               ASTUnit *TU);
+                               CXTranslationUnit TU);
 
 /// \brief Unpack a TemplateRef cursor into the template it references and
 /// the location where the reference occurred.
@@ -95,7 +98,8 @@
 
 /// \brief Create a reference to a namespace or namespace alias at the given 
 /// location.
-CXCursor MakeCursorNamespaceRef(NamedDecl *NS, SourceLocation Loc, ASTUnit *TU);
+CXCursor MakeCursorNamespaceRef(NamedDecl *NS, SourceLocation Loc,
+                                CXTranslationUnit TU);
 
 /// \brief Unpack a NamespaceRef cursor into the namespace or namespace alias
 /// it references and the location where the reference occurred.
@@ -103,62 +107,68 @@
 
 /// \brief Create a reference to a field at the given location.
 CXCursor MakeCursorMemberRef(FieldDecl *Field, SourceLocation Loc, 
-                             ASTUnit *TU);
+                             CXTranslationUnit TU);
   
 /// \brief Unpack a MemberRef cursor into the field it references and the 
 /// location where the reference occurred.
 std::pair<FieldDecl *, SourceLocation> getCursorMemberRef(CXCursor C);
 
 /// \brief Create a CXX base specifier cursor.
-CXCursor MakeCursorCXXBaseSpecifier(CXXBaseSpecifier *B, ASTUnit *TU);
+CXCursor MakeCursorCXXBaseSpecifier(CXXBaseSpecifier *B,
+                                    CXTranslationUnit TU);
 
 /// \brief Unpack a CXXBaseSpecifier cursor into a CXXBaseSpecifier.
 CXXBaseSpecifier *getCursorCXXBaseSpecifier(CXCursor C);
 
 /// \brief Create a preprocessing directive cursor.
-CXCursor MakePreprocessingDirectiveCursor(SourceRange Range, ASTUnit *TU);
+CXCursor MakePreprocessingDirectiveCursor(SourceRange Range,
+                                          CXTranslationUnit TU);
 
 /// \brief Unpack a given preprocessing directive to retrieve its source range.
 SourceRange getCursorPreprocessingDirective(CXCursor C);
 
 /// \brief Create a macro definition cursor.
-CXCursor MakeMacroDefinitionCursor(MacroDefinition *, ASTUnit *TU);
+CXCursor MakeMacroDefinitionCursor(MacroDefinition *, CXTranslationUnit TU);
 
 /// \brief Unpack a given macro definition cursor to retrieve its
 /// source range.
 MacroDefinition *getCursorMacroDefinition(CXCursor C);
 
 /// \brief Create a macro instantiation cursor.
-CXCursor MakeMacroInstantiationCursor(MacroInstantiation *, ASTUnit *TU);
+CXCursor MakeMacroInstantiationCursor(MacroInstantiation *,
+                                      CXTranslationUnit TU);
 
 /// \brief Unpack a given macro instantiation cursor to retrieve its
 /// source range.
 MacroInstantiation *getCursorMacroInstantiation(CXCursor C);
 
 /// \brief Create an inclusion directive cursor.
-CXCursor MakeInclusionDirectiveCursor(InclusionDirective *, ASTUnit *TU);
+CXCursor MakeInclusionDirectiveCursor(InclusionDirective *,
+                                      CXTranslationUnit TU);
 
 /// \brief Unpack a given inclusion directive cursor to retrieve its
 /// source range.
 InclusionDirective *getCursorInclusionDirective(CXCursor C);
 
 /// \brief Create a label reference at the given location.
-CXCursor MakeCursorLabelRef(LabelStmt *Label, SourceLocation Loc, ASTUnit *TU);
+CXCursor MakeCursorLabelRef(LabelStmt *Label, SourceLocation Loc,
+                            CXTranslationUnit TU);
 
 /// \brief Unpack a label reference into the label statement it refers to and
 /// the location of the reference.
 std::pair<LabelStmt *, SourceLocation> getCursorLabelRef(CXCursor C);
 
 /// \brief Create a overloaded declaration reference cursor for an expression.
-CXCursor MakeCursorOverloadedDeclRef(OverloadExpr *E, ASTUnit *TU);
+CXCursor MakeCursorOverloadedDeclRef(OverloadExpr *E, CXTranslationUnit TU);
 
 /// \brief Create a overloaded declaration reference cursor for a declaration.
 CXCursor MakeCursorOverloadedDeclRef(Decl *D, SourceLocation Location,
-                                     ASTUnit *TU);
+                                     CXTranslationUnit TU);
 
 /// \brief Create a overloaded declaration reference cursor for a template name.
 CXCursor MakeCursorOverloadedDeclRef(TemplateName Template, 
-                                     SourceLocation Location, ASTUnit *TU);
+                                     SourceLocation Location,
+                                     CXTranslationUnit TU);
 
 /// \brief Internal storage for an overloaded declaration reference cursor;
 typedef llvm::PointerUnion3<OverloadExpr *, Decl *, 
@@ -177,6 +187,7 @@
 
 ASTContext &getCursorContext(CXCursor Cursor);
 ASTUnit *getCursorASTUnit(CXCursor Cursor);
+CXTranslationUnit getCursorTU(CXCursor Cursor);
   
 bool operator==(CXCursor X, CXCursor Y);
   
diff --git a/tools/libclang/CXString.cpp b/tools/libclang/CXString.cpp
index 341b720..a2860a1 100644
--- a/tools/libclang/CXString.cpp
+++ b/tools/libclang/CXString.cpp
@@ -16,20 +16,25 @@
 #include "CXString.h"
 #include "clang/Frontend/ASTUnit.h"
 #include "clang-c/Index.h"
+#include "llvm/ADT/SmallString.h"
 #include "llvm/Support/ErrorHandling.h"
 
 using namespace clang;
 using namespace clang::cxstring;
 
-enum CXStringFlag { CXS_Unmanaged, CXS_Malloc };
+enum CXStringFlag { CXS_Unmanaged, CXS_Malloc, CXS_StringBuf };
+
+//===----------------------------------------------------------------------===//
+// Basic generation of CXStrings.
+//===----------------------------------------------------------------------===//
 
 CXString cxstring::createCXString(const char *String, bool DupString){
   CXString Str;
   if (DupString) {
-    Str.Spelling = strdup(String);
+    Str.data = strdup(String);
     Str.private_flags = (unsigned) CXS_Malloc;
   } else {
-    Str.Spelling = String;
+    Str.data = (void*)String;
     Str.private_flags = (unsigned) CXS_Unmanaged;
   }
   return Str;
@@ -41,27 +46,84 @@
     char *Spelling = (char *)malloc(String.size() + 1);
     memmove(Spelling, String.data(), String.size());
     Spelling[String.size()] = 0;
-    Result.Spelling = Spelling;
+    Result.data = Spelling;
     Result.private_flags = (unsigned) CXS_Malloc;
   } else {
-    Result.Spelling = String.data();
+    Result.data = (void*) String.data();
     Result.private_flags = (unsigned) CXS_Unmanaged;
   }
   return Result;
 }
 
+CXString cxstring::createCXString(CXStringBuf *buf) {
+  CXString Str;
+  Str.data = buf;
+  Str.private_flags = (unsigned) CXS_StringBuf;
+  return Str;
+}
+
+
+//===----------------------------------------------------------------------===//
+// String pools.
+//===----------------------------------------------------------------------===//
+
+  
+typedef std::vector<CXStringBuf *> CXStringPool;
+
+void *cxstring::createCXStringPool() {
+  return new CXStringPool();
+}
+
+void cxstring::disposeCXStringPool(void *p) {
+  CXStringPool *pool = static_cast<CXStringPool*>(p);
+  if (pool) {
+    for (CXStringPool::iterator I = pool->begin(), E = pool->end();
+         I != E; ++I) {
+      delete *I;
+    }
+    delete pool;
+  }
+}
+
+CXStringBuf *cxstring::getCXStringBuf(CXTranslationUnit TU) {
+  CXStringPool *pool = static_cast<CXStringPool*>(TU->StringPool);
+  if (pool->empty())
+    return new CXStringBuf(TU);
+  CXStringBuf *buf = pool->back();
+  buf->Data.clear();
+  pool->pop_back();
+  return buf;
+}
+
+void cxstring::disposeCXStringBuf(CXStringBuf *buf) {
+  if (buf)
+    static_cast<CXStringPool*>(buf->TU->StringPool)->push_back(buf);
+}
+
 //===----------------------------------------------------------------------===//
 // libClang public APIs.
 //===----------------------------------------------------------------------===//
 
 extern "C" {
 const char *clang_getCString(CXString string) {
-  return string.Spelling;
+  if (string.private_flags == (unsigned) CXS_StringBuf) {
+    return ((CXStringBuf*)string.data)->Data.data();
+  }
+  return (const char*) string.data;
 }
 
 void clang_disposeString(CXString string) {
-  if (string.private_flags == CXS_Malloc && string.Spelling)
-    free((void*)string.Spelling);
+  switch ((CXStringFlag) string.private_flags) {
+    case CXS_Unmanaged:
+      break;
+    case CXS_Malloc:
+      if (string.data)
+        free((void*)string.data);
+      break;
+    case CXS_StringBuf:
+      disposeCXStringBuf((CXStringBuf *) string.data);
+      break;
+  }
 }
 } // end: extern "C"
 
diff --git a/tools/libclang/CXString.h b/tools/libclang/CXString.h
index 6ac770c..f03a6b2 100644
--- a/tools/libclang/CXString.h
+++ b/tools/libclang/CXString.h
@@ -16,15 +16,35 @@
 
 #include "clang-c/Index.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/SmallString.h"
 
 namespace clang {
 namespace cxstring {
+  
+struct CXStringBuf {
+  llvm::SmallString<128> Data;
+  CXTranslationUnit TU;
+  CXStringBuf(CXTranslationUnit tu) : TU(tu) {}
+};
 
 /// \brief Create a CXString object from a C string.
 CXString createCXString(const char *String, bool DupString = false);
 
-/// \brief Create a CXString ojbect from a StringRef.
-CXString createCXString(llvm::StringRef String, bool DupString = true);  
+/// \brief Create a CXString object from a StringRef.
+CXString createCXString(llvm::StringRef String, bool DupString = true);
+
+/// \brief Create a CXString object that is backed by a string buffer.
+CXString createCXString(CXStringBuf *buf);
+
+/// \brief Create an opaque string pool used for fast geneneration of strings.
+void *createCXStringPool();
+
+/// \brief Dispose of a string pool.
+void disposeCXStringPool(void *pool);
+  
+CXStringBuf *getCXStringBuf(CXTranslationUnit TU);
+ 
+void disposeCXStringBuf(CXStringBuf *buf);
 
 }
 }
diff --git a/tools/libclang/CXType.cpp b/tools/libclang/CXType.cpp
index 45a5bed..90c6658 100644
--- a/tools/libclang/CXType.cpp
+++ b/tools/libclang/CXType.cpp
@@ -89,7 +89,7 @@
 }
 
 
-CXType cxtype::MakeCXType(QualType T, ASTUnit *TU) {
+CXType cxtype::MakeCXType(QualType T, CXTranslationUnit TU) {
   CXTypeKind TK = GetTypeKind(T);
   CXType CT = { TK, { TK == CXType_Invalid ? 0 : T.getAsOpaquePtr(), TU }};
   return CT;
@@ -101,8 +101,8 @@
   return QualType::getFromOpaquePtr(CT.data[0]);
 }
 
-static inline ASTUnit* GetASTU(CXType CT) {
-  return static_cast<ASTUnit*>(CT.data[1]);
+static inline CXTranslationUnit GetTU(CXType CT) {
+  return static_cast<CXTranslationUnit>(CT.data[1]);
 }
 
 extern "C" {
@@ -110,27 +110,26 @@
 CXType clang_getCursorType(CXCursor C) {
   using namespace cxcursor;
   
-  ASTUnit *AU = cxcursor::getCursorASTUnit(C);
-
+  CXTranslationUnit TU = cxcursor::getCursorTU(C);
   if (clang_isExpression(C.kind)) {
     QualType T = cxcursor::getCursorExpr(C)->getType();
-    return MakeCXType(T, AU);
+    return MakeCXType(T, TU);
   }
 
   if (clang_isDeclaration(C.kind)) {
     Decl *D = cxcursor::getCursorDecl(C);
 
     if (TypeDecl *TD = dyn_cast<TypeDecl>(D))
-      return MakeCXType(QualType(TD->getTypeForDecl(), 0), AU);
+      return MakeCXType(QualType(TD->getTypeForDecl(), 0), TU);
     if (ObjCInterfaceDecl *ID = dyn_cast<ObjCInterfaceDecl>(D))
-      return MakeCXType(QualType(ID->getTypeForDecl(), 0), AU);
+      return MakeCXType(QualType(ID->getTypeForDecl(), 0), TU);
     if (ValueDecl *VD = dyn_cast<ValueDecl>(D))
-      return MakeCXType(VD->getType(), AU);
+      return MakeCXType(VD->getType(), TU);
     if (ObjCPropertyDecl *PD = dyn_cast<ObjCPropertyDecl>(D))
-      return MakeCXType(PD->getType(), AU);
+      return MakeCXType(PD->getType(), TU);
     if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
-      return MakeCXType(FD->getType(), AU);
-    return MakeCXType(QualType(), AU);
+      return MakeCXType(FD->getType(), TU);
+    return MakeCXType(QualType(), TU);
   }
   
   if (clang_isReference(C.kind)) {
@@ -139,21 +138,21 @@
       return MakeCXType(
                 QualType(getCursorObjCSuperClassRef(C).first->getTypeForDecl(), 
                          0), 
-                        AU);
+                        TU);
       
     case CXCursor_ObjCClassRef:
       return MakeCXType(
                       QualType(getCursorObjCClassRef(C).first->getTypeForDecl(), 
                                0), 
-                        AU);
+                        TU);
       
     case CXCursor_TypeRef:
       return MakeCXType(QualType(getCursorTypeRef(C).first->getTypeForDecl(), 
                                  0), 
-                        AU);
+                        TU);
       
     case CXCursor_CXXBaseSpecifier:
-      return cxtype::MakeCXType(getCursorCXXBaseSpecifier(C)->getType(), AU);
+      return cxtype::MakeCXType(getCursorCXXBaseSpecifier(C)->getType(), TU);
       
     case CXCursor_ObjCProtocolRef:        
     case CXCursor_TemplateRef:
@@ -164,10 +163,10 @@
       break;
     }
     
-    return MakeCXType(QualType(), AU);
+    return MakeCXType(QualType(), TU);
   }
 
-  return MakeCXType(QualType(), AU);
+  return MakeCXType(QualType(), TU);
 }
 
 CXType clang_getCanonicalType(CXType CT) {
@@ -175,12 +174,13 @@
     return CT;
 
   QualType T = GetQualType(CT);
+  CXTranslationUnit TU = GetTU(CT);
 
   if (T.isNull())
-    return MakeCXType(QualType(), GetASTU(CT));
+    return MakeCXType(QualType(), GetTU(CT));
 
-  ASTUnit *AU = GetASTU(CT);
-  return MakeCXType(AU->getASTContext().getCanonicalType(T), AU);
+  ASTUnit *AU = static_cast<ASTUnit*>(TU->TUData);
+  return MakeCXType(AU->getASTContext().getCanonicalType(T), TU);
 }
 
 CXType clang_getPointeeType(CXType CT) {
@@ -188,7 +188,7 @@
   Type *TP = T.getTypePtr();
   
   if (!TP)
-    return MakeCXType(QualType(), GetASTU(CT));
+    return MakeCXType(QualType(), GetTU(CT));
   
   switch (TP->getTypeClass()) {
     case Type::Pointer:
@@ -208,7 +208,7 @@
       T = QualType();
       break;
   }
-  return MakeCXType(T, GetASTU(CT));
+  return MakeCXType(T, GetTU(CT));
 }
 
 CXCursor clang_getTypeDeclaration(CXType CT) {
@@ -263,7 +263,7 @@
   if (!D)
     return cxcursor::MakeCXCursorInvalid(CXCursor_NoDeclFound);
 
-  return cxcursor::MakeCXCursor(D, GetASTU(CT));
+  return cxcursor::MakeCXCursor(D, GetTU(CT));
 }
 
 CXString clang_getTypeKindSpelling(enum CXTypeKind K) {
@@ -324,24 +324,24 @@
 CXType clang_getResultType(CXType X) {
   QualType T = GetQualType(X);
   if (!T.getTypePtr())
-    return MakeCXType(QualType(), GetASTU(X));
+    return MakeCXType(QualType(), GetTU(X));
   
   if (const FunctionType *FD = T->getAs<FunctionType>())
-    return MakeCXType(FD->getResultType(), GetASTU(X));
+    return MakeCXType(FD->getResultType(), GetTU(X));
   
-  return MakeCXType(QualType(), GetASTU(X));
+  return MakeCXType(QualType(), GetTU(X));
 }
 
 CXType clang_getCursorResultType(CXCursor C) {
   if (clang_isDeclaration(C.kind)) {
     Decl *D = cxcursor::getCursorDecl(C);
     if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D))
-      return MakeCXType(MD->getResultType(), cxcursor::getCursorASTUnit(C));
+      return MakeCXType(MD->getResultType(), cxcursor::getCursorTU(C));
 
     return clang_getResultType(clang_getCursorType(C));
   }
 
-  return MakeCXType(QualType(), cxcursor::getCursorASTUnit(C));
+  return MakeCXType(QualType(), cxcursor::getCursorTU(C));
 }
 
 unsigned clang_isPODType(CXType X) {
diff --git a/tools/libclang/CXType.h b/tools/libclang/CXType.h
index 94151ed..7660beb 100644
--- a/tools/libclang/CXType.h
+++ b/tools/libclang/CXType.h
@@ -23,7 +23,7 @@
   
 namespace cxtype {
   
-CXType MakeCXType(QualType T, ASTUnit *TU);
+CXType MakeCXType(QualType T, CXTranslationUnit TU);
   
 }} // end namespace clang::cxtype
 #endif