[clang] [C++20] [Modules] [Itanium ABI] Generate the vtable in the module unit of dynamic classes (PR #75912)

[Chuanqi Xu via cfe-commits]

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@@ -318,6 +318,9 @@ namespace {
       if (Diags.hasUnrecoverableErrorOccurred())
         return;
 
+      if (RD->shouldEmitInExternalSource())
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ChuanqiXu9 wrote:

Yes, I think it is not bad to put the check `RD->shouldEmitInExternalSource()` into `HandleVTable`. I feel the most natural logic may be, I see a vtable then I pass it to the consumer and it is the job of the consumer to decide whether or not to emit it. WDYT?

https://github.com/llvm/llvm-project/pull/75912