[PATCH] D86049: RFC: Implement optional exportable wrapper function generation for objc_direct methods.

[Akira Hatanaka via Phabricator via cfe-commits]

ahatanak added a comment.

In D86049#3819109 <https://reviews.llvm.org/D86049#3819109>, @mwyman wrote:

> In D86049#3818981 <https://reviews.llvm.org/D86049#3818981>, @plotfi wrote:
>
>> @ahatanak I can revive some of what I was working on from https://reviews.llvm.org/D86049?id=285923 if we think we need a thunk for the checks as @rjmccall mentioned.
>
> I believe the generated direct methods already handle the null checks and class init in `CGObjCCommonMac::GenerateDirectMethodPrologue`, meaning the thunks aren't strictly necessary for the callee to handle them.

I don't know exactly what the thunk is supposed to do, but it sounds like the thunk is going to do the initialization by calling `objc_opt_self` and then call the direct class method. So the initialization isn't done inside the direct method.

If the thunk is inlined, the call to `objc_opt_self` can be optimized away if it we can prove `self` is already initialized. But we'd have to teach llvm to remove the call to `objc_opt_self` or add a new optimization pass to do so (see https://github.com/llvm/llvm-project/blob/main/clang/lib/CodeGen/CGObjCMac.cpp#L4057).

John, is that what you had in mind?


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