[PATCH] D158301: Add back overriding-t-options for -m<os>-version-min diagnostic

[Fangrui Song via Phabricator via cfe-commits]

MaskRay added inline comments.


================
Comment at: clang/test/Driver/darwin-version.c:217
 // RUN:   FileCheck --check-prefix=CHECK-VERSION-TNO-OSV1 %s
-// CHECK-VERSION-TNO-OSV1: overriding '-mmacos-version-min=10.6' option with '-target x86_64-apple-macos10.11.2'
+// CHECK-VERSION-TNO-OSV1: overriding '-mmacos-version-min=10.6' option with '-target x86_64-apple-macos10.11.2' [-Woverriding-t-option]
 
----------------
hans wrote:
> MaskRay wrote:
> > hans wrote:
> > > dexonsmith wrote:
> > > > MaskRay wrote:
> > > > > dexonsmith wrote:
> > > > > > Why would we want to use the old name here? An alias seems strictly better to me. 
> > > > > Making `overriding-t-option` an alias for `overriding-option` would make `-Wno-overriding-t-option` applies to future overriding option diagnostics, which is exactly what I want to avoid.
> > > > > 
> > > > I understand that you don't want `-t-` to apply to work on future overriding option diagnostics, but I think the platform divergence you're adding here is worse.
> > > > 
> > > > Having a few Darwin-specific options use `-Woverriding-t-option` (and everything else use `-Woverriding-option`) as the canonical spelling is hard to reason about for maintainers, and for users.
> > > > 
> > > > And might not users on other platforms have `-Woverriding-t-option` hardcoded in  build settings? (So @dblaikie's argument that we shouldn't arbitrarily make things hard for users would apply to all options?)
> > > > 
> > > > IMO, if we're not comfortable removing `-Woverriding-t-option` entirely, then it should live on as an alias (easy to reason about), not as canonical-in-special-cases (hard to reason about).
> > > > IMO, if we're not comfortable removing -Woverriding-t-option entirely, then it should live on as an alias (easy to reason about), not as canonical-in-special-cases (hard to reason about).
> > > 
> > > +1 if we can't drop the old spelling, an alias seems like the best option.
> > Making `overriding-t-option` an alias for `overriding-option`, as I mentioned, will make `-Wno-overriding-t-option` affect new overriding-options uses. This is exactly what I want to avoid.
> > 
> > I know there are some `-Wno-overriding-t-option` uses. Honestly, they are far fewer than other diagnostics we are introducing or changing in Clang. I can understand the argument "make -Werror users easier for this specific diagnostic" (but `-Werror` will complain about other new diagnostics), but do we really want to in the Darwin case? I think no. They can remove the version from the target triple like https://github.com/facebook/ocamlrep/blame/abc14b8aafcc6746ec37bf7bf0de24bfc58d63a0/prelude/apple/apple_target_sdk_version.bzl#L50　or make the version part consistent with `-m.*os-version-min`.
> > 
> > This change may force these users to re-think how they should fix  their build. I apology to these users, but I don't feel that adding an alias is really necessary.
> > Making overriding-t-option an alias for overriding-option, as I mentioned, will make -Wno-overriding-t-option affect new overriding-options uses. This is exactly what I want to avoid.
> 
> Is keeping them separate actually important, though? -Wno-overriding-option has the same issue in that case, that using the flag will also affect any new overriding-options uses, and I don't think that's a problem.
`-Wno-overriding-option` is properly named, so affecting new overriding-options uses looks fine to me.
`-Wno-overriding-t-option` is awkward, and making it affect new uses makes me nervous.

The gist of my previous comment is whether the uses cases really justify a tiny bit of tech bit in clang and I think the answer is no.

This change is not about changing a semantic warning that has mixed opinions, e.g. `-Wbitwise-op-parentheses` (many consider it not justified).


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D158301/new/

https://reviews.llvm.org/D158301