rjmccall added inline comments.
================
Comment at: lib/AST/RecordLayoutBuilder.cpp:3069
const Decl *Result =
Entry ? Entry.get(getExternalSource()) : computeKeyFunction(*this, RD);
----------------
rsmith wrote:
> rjmccall wrote:
> > Why not just change `computeKeyFunction` to decide that the class doesn't
> > have a key function if it would be an inline definition? We can do the
> > same updating we do with the ARM rule except just bailing out instead of
> > scanning for another candidate.
> It seems desirable to me for Clang's notion of what the "key function" is to
> exactly match the ABI specification. That way, the decision to not emit a
> vtable with an inline key function is purely a lowering concern, not part of
> the program model represented by the frontend, and non-compiler tools who
> query this data will get correct answers. Also, if we made the suggested
> change, I'd still want to perform the linkage check to avoid unnecessary
> emission of vtables for explicit instantiation definitions, so this wouldn't
> remove any complexity from CodeGen.
>
> If we want to go down this path, I'd prefer that we also change the ABI
> document to say that an inline virtual function definition results in the
> class having no key function.
That's fair. We could instead wrap all the calls to the function from IRGen to
apply this rule retroactively; that should be easy.
Repository:
rC Clang
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D54986/new/
https://reviews.llvm.org/D54986
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