diff --git a/clang/include/clang/AST/DeclTemplate.h b/clang/include/clang/AST/DeclTemplate.h
index 2db4910ccdc6..e5e69af0497d 100644
--- a/clang/include/clang/AST/DeclTemplate.h
+++ b/clang/include/clang/AST/DeclTemplate.h
@@ -576,14 +576,14 @@ protected:
 
   /// \brief Pointer to the common data shared by all declarations of this
   /// template.
-  CommonBase *Common;
+  mutable CommonBase *Common;
   
   /// \brief Retrieves the "common" pointer shared by all (re-)declarations of
   /// the same template. Calling this routine may implicitly allocate memory
   /// for the common pointer.
-  CommonBase *getCommonPtr();
+  CommonBase *getCommonPtr() const;
 
-  virtual CommonBase *newCommon(ASTContext &C) = 0;
+  virtual CommonBase *newCommon(ASTContext &C) const = 0;
 
   // Construct a template decl with name, parameters, and templated element.
   RedeclarableTemplateDecl(Kind DK, DeclContext *DC, SourceLocation L,
@@ -618,7 +618,7 @@ public:
   /// template<> template<typename T>
   /// struct X<int>::Inner { /* ... */ };
   /// \endcode
-  bool isMemberSpecialization() {
+  bool isMemberSpecialization() const {
     return getCommonPtr()->InstantiatedFromMember.getInt();
   }
 
@@ -665,7 +665,7 @@ public:
   /// template<typename U>
   /// void X<T>::f(T, U);
   /// \endcode
-  RedeclarableTemplateDecl *getInstantiatedFromMemberTemplate() {
+  RedeclarableTemplateDecl *getInstantiatedFromMemberTemplate() const {
     return getCommonPtr()->InstantiatedFromMember.getPointer();
   }
 
@@ -729,7 +729,7 @@ protected:
                        TemplateParameterList *Params, NamedDecl *Decl)
     : RedeclarableTemplateDecl(FunctionTemplate, DC, L, Name, Params, Decl) { }
 
-  CommonBase *newCommon(ASTContext &C);
+  CommonBase *newCommon(ASTContext &C) const;
 
   Common *getCommonPtr() {
     return static_cast<Common *>(RedeclarableTemplateDecl::getCommonPtr());
@@ -1798,7 +1798,7 @@ protected:
     : RedeclarableTemplateDecl(ClassTemplate, 0, SourceLocation(),
                                DeclarationName(), 0, 0) { }
 
-  CommonBase *newCommon(ASTContext &C);
+  CommonBase *newCommon(ASTContext &C) const;
 
   Common *getCommonPtr() {
     return static_cast<Common *>(RedeclarableTemplateDecl::getCommonPtr());
@@ -2063,7 +2063,7 @@ protected:
                         TemplateParameterList *Params, NamedDecl *Decl)
     : RedeclarableTemplateDecl(TypeAliasTemplate, DC, L, Name, Params, Decl) { }
 
-  CommonBase *newCommon(ASTContext &C);
+  CommonBase *newCommon(ASTContext &C) const;
 
   Common *getCommonPtr() {
     return static_cast<Common *>(RedeclarableTemplateDecl::getCommonPtr());
diff --git a/clang/lib/AST/DeclTemplate.cpp b/clang/lib/AST/DeclTemplate.cpp
index 63616e064a96..bd5ab8a5b9b6 100644
--- a/clang/lib/AST/DeclTemplate.cpp
+++ b/clang/lib/AST/DeclTemplate.cpp
@@ -128,12 +128,12 @@ static void AdoptTemplateParameterList(TemplateParameterList *Params,
 // RedeclarableTemplateDecl Implementation
 //===----------------------------------------------------------------------===//
 
-RedeclarableTemplateDecl::CommonBase *RedeclarableTemplateDecl::getCommonPtr() {
+RedeclarableTemplateDecl::CommonBase *RedeclarableTemplateDecl::getCommonPtr() const {
   if (!Common) {
     // Walk the previous-declaration chain until we either find a declaration
     // with a common pointer or we run out of previous declarations.
-    SmallVector<RedeclarableTemplateDecl *, 2> PrevDecls;
-    for (RedeclarableTemplateDecl *Prev = getPreviousDecl(); Prev;
+    SmallVector<const RedeclarableTemplateDecl *, 2> PrevDecls;
+    for (const RedeclarableTemplateDecl *Prev = getPreviousDecl(); Prev;
          Prev = Prev->getPreviousDecl()) {
       if (Prev->Common) {
         Common = Prev->Common;
@@ -241,7 +241,7 @@ FunctionTemplateDecl *FunctionTemplateDecl::CreateDeserialized(ASTContext &C,
 }
 
 RedeclarableTemplateDecl::CommonBase *
-FunctionTemplateDecl::newCommon(ASTContext &C) {
+FunctionTemplateDecl::newCommon(ASTContext &C) const {
   Common *CommonPtr = new (C) Common;
   C.AddDeallocation(DeallocateCommon, CommonPtr);
   return CommonPtr;
@@ -328,7 +328,7 @@ ClassTemplateDecl::getPartialSpecializations() {
 }  
 
 RedeclarableTemplateDecl::CommonBase *
-ClassTemplateDecl::newCommon(ASTContext &C) {
+ClassTemplateDecl::newCommon(ASTContext &C) const {
   Common *CommonPtr = new (C) Common;
   C.AddDeallocation(DeallocateCommon, CommonPtr);
   return CommonPtr;
@@ -919,7 +919,7 @@ void TypeAliasTemplateDecl::DeallocateCommon(void *Ptr) {
   static_cast<Common *>(Ptr)->~Common();
 }
 RedeclarableTemplateDecl::CommonBase *
-TypeAliasTemplateDecl::newCommon(ASTContext &C) {
+TypeAliasTemplateDecl::newCommon(ASTContext &C) const {
   Common *CommonPtr = new (C) Common;
   C.AddDeallocation(DeallocateCommon, CommonPtr);
   return CommonPtr;