Index: cfe/trunk/include/clang/Index/IndexingAction.h
===================================================================
--- cfe/trunk/include/clang/Index/IndexingAction.h
+++ cfe/trunk/include/clang/Index/IndexingAction.h
@@ -39,6 +39,7 @@
   SystemSymbolFilterKind SystemSymbolFilter
     = SystemSymbolFilterKind::DeclarationsOnly;
   bool IndexFunctionLocals = false;
+  bool IndexImplicitInstantiation = false;
 };
 
 /// Creates a frontend action that indexes all symbols (macros and AST decls).
Index: cfe/trunk/lib/Index/IndexDecl.cpp
===================================================================
--- cfe/trunk/lib/Index/IndexDecl.cpp
+++ cfe/trunk/lib/Index/IndexDecl.cpp
@@ -726,7 +726,7 @@
   if (D->isImplicit() && shouldIgnoreIfImplicit(D))
     return true;
 
-  if (isTemplateImplicitInstantiation(D))
+  if (isTemplateImplicitInstantiation(D) && !shouldIndexImplicitInstantiation())
     return true;
 
   IndexingDeclVisitor Visitor(*this);
Index: cfe/trunk/lib/Index/IndexTypeSourceInfo.cpp
===================================================================
--- cfe/trunk/lib/Index/IndexTypeSourceInfo.cpp
+++ cfe/trunk/lib/Index/IndexTypeSourceInfo.cpp
@@ -129,7 +129,7 @@
   template<typename TypeLocType>
   bool HandleTemplateSpecializationTypeLoc(TypeLocType TL) {
     if (const auto *T = TL.getTypePtr()) {
-      if (IndexCtx.shouldIndexImplicitTemplateInsts()) {
+      if (IndexCtx.shouldIndexImplicitInstantiation()) {
         if (CXXRecordDecl *RD = T->getAsCXXRecordDecl())
           IndexCtx.handleReference(RD, TL.getTemplateNameLoc(),
                                    Parent, ParentDC, SymbolRoleSet(), Relations);
Index: cfe/trunk/lib/Index/IndexingContext.h
===================================================================
--- cfe/trunk/lib/Index/IndexingContext.h
+++ cfe/trunk/lib/Index/IndexingContext.h
@@ -60,9 +60,7 @@
 
   bool shouldIndexFunctionLocalSymbols() const;
 
-  bool shouldIndexImplicitTemplateInsts() const {
-    return false;
-  }
+  bool shouldIndexImplicitInstantiation() const;
 
   static bool isTemplateImplicitInstantiation(const Decl *D);
 
Index: cfe/trunk/lib/Index/IndexingContext.cpp
===================================================================
--- cfe/trunk/lib/Index/IndexingContext.cpp
+++ cfe/trunk/lib/Index/IndexingContext.cpp
@@ -37,6 +37,10 @@
   return IndexOpts.IndexFunctionLocals;
 }
 
+bool IndexingContext::shouldIndexImplicitInstantiation() const {
+  return IndexOpts.IndexImplicitInstantiation;
+}
+
 bool IndexingContext::handleDecl(const Decl *D,
                                  SymbolRoleSet Roles,
                                  ArrayRef<SymbolRelation> Relations) {