[clang] [Clang] Apply exclude_from_explicit_instantiation to dllimport/dllexport (PR #168171)

[Tomohiro Kashiwada via cfe-commits]

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@@ -6592,6 +6592,11 @@ void Sema::checkClassLevelDLLAttribute(CXXRecordDecl *Class) {
   // seem to be true in practice?
 
   for (Decl *Member : Class->decls()) {
+    if ((TSK == TSK_ExplicitInstantiationDeclaration ||
+         TSK == TSK_ExplicitInstantiationDefinition) &&
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kikairoya wrote:

Changed to `isTemplateInstantiation`, to avoid affecting non-template contexts.

https://github.com/llvm/llvm-project/pull/168171