diff --git a/clang/lib/AST/ODRHash.cpp b/clang/lib/AST/ODRHash.cpp
index 121724a..c968a55 100644
--- a/clang/lib/AST/ODRHash.cpp
+++ b/clang/lib/AST/ODRHash.cpp
@@ -199,6 +199,7 @@
   return ID.ComputeHash();
 }
 
+namespace {
 // Process a Decl pointer.  Add* methods call back into ODRHash while Visit*
 // methods process the relevant parts of the Decl.
 class ODRDeclVisitor : public ConstDeclVisitor<ODRDeclVisitor> {
@@ -343,6 +344,7 @@
     }
   }
 };
+} // namespace
 
 // Only allow a small portion of Decl's to be processed.  Remove this once
 // all Decl's can be handled.
@@ -420,6 +422,7 @@
   }
 }
 
+namespace {
 // Process a Type pointer.  Add* methods call back into ODRHash while Visit*
 // methods process the relevant parts of the Type.
 class ODRTypeVisitor : public TypeVisitor<ODRTypeVisitor> {
@@ -608,6 +611,7 @@
     AddDecl(T->getDecl());
   }
 };
+} // namespace
 
 void ODRHash::AddType(const Type *T) {
   assert(T && "Expecting non-null pointer.");