Avoid producing implicit methods when we have a explicit template instantiation
declaration.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@99311 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGVtable.cpp b/lib/CodeGen/CGVtable.cpp
index 9204e4e..cedefba 100644
--- a/lib/CodeGen/CGVtable.cpp
+++ b/lib/CodeGen/CGVtable.cpp
@@ -3805,7 +3805,17 @@
     return;
 
   TemplateSpecializationKind kind = RD->getTemplateSpecializationKind();
-  if (kind == TSK_ImplicitInstantiation)
+
+
+  // The reason we have TSK_ExplicitInstantiationDeclaration in here (but not
+  // in  Sema::MaybeMarkVirtualMembersReferenced) is for the case
+  // template<> void stdio_sync_filebuf<wchar_t>::xsgetn() {
+  // }
+  // extern template class stdio_sync_filebuf<wchar_t>;
+  // Since we are called after the extern declaration is seen.
+
+  if (kind == TSK_ImplicitInstantiation ||
+      kind == TSK_ExplicitInstantiationDeclaration)
     CGM.DeferredVtables.push_back(RD);
   else
     GenerateClassData(CGM.getVtableLinkage(RD), RD);