[PATCH] D158137: Rename warn_drv_overriding_flag_option (-Woverriding-t-option) to warn_drv_overriding_flag_option (-Woverriding-option)

Fri Aug 18 10:06:00 PDT 2023

MaskRay added a comment.

In D158137#4599461 <https://reviews.llvm.org/D158137#4599461>, @dblaikie wrote:

> In D158137#4597491 <https://reviews.llvm.org/D158137#4597491>, @dexonsmith wrote:
>
>> In D158137#4597009 <https://reviews.llvm.org/D158137#4597009>, @MaskRay wrote:
>>
>>> In D158137#4596948 <https://reviews.llvm.org/D158137#4596948>, @dexonsmith wrote:
>>>
>>>> Can you explain the downside of leaving behind an alias?
>>>
>>> Two minor ones. (a) Existing `-Wno-overriding-t-option` will not notice that they need to migrate and (b) Clang has accrued tiny tech debt.
>>> If we eventually remove `-Wno-overriding-t-option` for tidiness, we will have to break `-Werror -Wno-overriding-t-option` users.
>>
>> I guess it's not clear to me we'd need to remove the alias. The usual policy (I think?) is that clang driver options don't disappear. It seems like a small piece of debt to maintain the extra alias in this case, and if it's kept, then users don't actually need to migrate. And then you can feel safe updating Darwin.cpp as well.
>
> +1 to this, FWIW - I wouldn't consider it technical debt to keep a compatible warning flag name that's been around for a decade & isn't a name we're trying to free up for some other use or because it causes any great confusion, etc.

I think my previous comment has answered this.
Think: every Clang release may emit some new warnings. `-Werror` users has actually provided a promise that they will fix reasonable toolchain changes. Toolchain contributors check how disruptive a change will be, but cannot promise that we never emit new warnings.
In this case, `overriding-t-options` seems a fairly rare and LLVM/Clang side has far too many other fp-model/fast-math changes to make "whether we will get a new warning" a fairly minor issue.
I am unfamiliar with Darwin.cpp though. If it turns out that want to disable the warning even with `-Wno-overriding-t-option`, we can add a workaround specific to Darwin.cpp, but not to fp-model/Tc.

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  https://reviews.llvm.org/D158137/new/

https://reviews.llvm.org/D158137