diff --git a/lib/AST/DeclCXX.cpp b/lib/AST/DeclCXX.cpp
index 4de157e..11a5260 100644
--- a/lib/AST/DeclCXX.cpp
+++ b/lib/AST/DeclCXX.cpp
@@ -60,6 +60,14 @@
     NumVBases(0), Bases(), VBases(), Definition(D), FirstFriend(0) {
 }
 
+CXXBaseSpecifier *CXXRecordDecl::DefinitionData::getBasesSlowCase() const {
+  return Bases.get(Definition->getASTContext().getExternalSource());
+}
+
+CXXBaseSpecifier *CXXRecordDecl::DefinitionData::getVBasesSlowCase() const {
+  return VBases.get(Definition->getASTContext().getExternalSource());
+}
+
 CXXRecordDecl::CXXRecordDecl(Kind K, TagKind TK, DeclContext *DC,
                              SourceLocation StartLoc, SourceLocation IdLoc,
                              IdentifierInfo *Id, CXXRecordDecl *PrevDecl)