[PATCH] D135202: [IR] Add an opaque type to LLVM.

[Nicolai Hähnle via Phabricator via llvm-commits]

nhaehnle added inline comments.


================
Comment at: llvm/docs/LangRef.rst:3609
+
+Opaque Type
+"""""""""""
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nikic wrote:
> Something that's a bit confusing is that we have both "opaque type" and "opaque structure type", the former spelled `%x = type opaque`, the latter spelled `opaque("x")`. This seems rather unfortunate.
> 
> I think a viable way forward would be to keep the old notion of opaque types, but move away from the "opaque" terminology for them. Effectively, an opaque struct type is just an identified struct type with zero members.
Thinking about this a bit more, I think it would be good to move away from the "opaque" naming entirely and instead call these new types something like an "extension" type or a "generic" type.

It's a bit of a philosophical point, but the types being added here aren't necessarily opaque in a universal sense. They are opaque to core IR instructions, but they are not opaque to e.g. intrinsics that are added specifically for working with them.

(And the same is true for the "opaque" structs as well. "Identified struct type with zero members" is what they are, so why not just run with it.)


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  https://reviews.llvm.org/D135202/new/

https://reviews.llvm.org/D135202