[PATCH] D156337: [clang] Allow setting the uninitialized attribute on record

[serge via Phabricator via cfe-commits]

serge-sans-paille added a comment.

In D156337#4558410 <https://reviews.llvm.org/D156337#4558410>, @aaron.ballman wrote:

> Was there an RFC for this extension to the attribute? (There doesn't need to be one, I'm just wondering if there's more background info on what's driving this patch forward and discussion around the design.)
>
> I'd like some more details about how this attribute impacts class hierarchies. e.g., if you put the attribute on the base class, does it impact the derived class members as well, or just the base class members? Also, what should happen in a case like this:
>
>   template <typename Ty>
>   void func() {
>     Ty Val; // Does this know it's uninitialized? Or did we lose that information because this isn't a type attribute?
>   }
>   
>   struct __attribute__((uninitialized)) S { int  value; };
>   
>   int main() {
>     func<S>();
>   }

All very relevant topics. Concerning inheritance, I'd say that if the base class is marked as uninitialized and the child class is not, then base members are uninitialized and child members are not.

Concerning your example, I'd expect `Val` to be uninitialized as it's type has the according attribute, but I also don't quite understand "Or did we lose that information because this isn't a type attribute?"


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  https://reviews.llvm.org/D156337/new/

https://reviews.llvm.org/D156337