Re-land "[MS] Don't expect vftables to be provided for extern template instantiations"
Reverts r273305 and re-instates r273296.
We needed to fix a bug in Sema::MarkVTableUsed to ensure that operator
delete lookup occurs when the vtable is referenced. We already had a
special case to look up operator delete when dllimport was used, but I
think should really mark virtual destructors referenced any time the
vtable is used.
llvm-svn: 274147
diff --git a/clang/lib/AST/VTableBuilder.cpp b/clang/lib/AST/VTableBuilder.cpp
index e43acc4..640fbf4 100644
--- a/clang/lib/AST/VTableBuilder.cpp
+++ b/clang/lib/AST/VTableBuilder.cpp
@@ -2545,14 +2545,13 @@
MostDerivedClassLayout(Context.getASTRecordLayout(MostDerivedClass)),
WhichVFPtr(*Which),
Overriders(MostDerivedClass, CharUnits(), MostDerivedClass) {
- // Only include the RTTI component if we know that we will provide a
- // definition of the vftable. We always provide the definition of
- // dllimported classes.
+ // Provide the RTTI component if RTTIData is enabled. If the vftable would
+ // be available externally, we should not provide the RTTI componenent. It
+ // is currently impossible to get available externally vftables with either
+ // dllimport or extern template instantiations, but eventually we may add a
+ // flag to support additional devirtualization that needs this.
if (Context.getLangOpts().RTTIData)
- if (MostDerivedClass->hasAttr<DLLImportAttr>() ||
- MostDerivedClass->getTemplateSpecializationKind() !=
- TSK_ExplicitInstantiationDeclaration)
- HasRTTIComponent = true;
+ HasRTTIComponent = true;
LayoutVFTable();