[PATCH] D137753: [Clang][GNU][AIX][p]Enable -p Functionality

[Michael Francis via Phabricator via cfe-commits]

francii added a comment.

In D137753#3935391 <https://reviews.llvm.org/D137753#3935391>, @MaskRay wrote:

> In D137753#3935305 <https://reviews.llvm.org/D137753#3935305>, @francii wrote:
>
>> Recall that the goal with `-p` is to create parity with GCC (at least with Linux and AIX), as per the RFC discussion.
>>
>> In D137753#3935138 <https://reviews.llvm.org/D137753#3935138>, @MaskRay wrote:
>>
>>> In D137753#3935126 <https://reviews.llvm.org/D137753#3935126>, @francii wrote:
>>>
>>>> In D137753#3934932 <https://reviews.llvm.org/D137753#3934932>, @MaskRay wrote:
>>>>
>>>>> Please make `-p` accepted for AIX only and don't change the semantics for other targets in this patch. For FreeBSD and Linux (musl and gnu) we can try rejecting `-p`. If OpenBSD wants to make `-p` an alias for `-pg`, that's fine.
>>>>
>>>> We can make `-p` emit a message on Linux while also accepting it as an alias to `-pg`. Do you have a suggestion as to what that message would be?
>>>
>>> The current `warning: argument unused during compilation: '-p' [-Wunused-command-line-argument]` is good for Linux.
>>> In the future Linux can try removing `-p`.
>>
>> The current behaviour of ignoring the option without stopping with an error return code is not a good one.
>>
>> Recall that the goal is to create parity with GCC, as per the RFC post.
>>
>> Is there a reason this flag shouldn't be supported on Linux? Specifically, what is your justification for diverging from GCC on this matter?
>
> It's a legacy option (at least for Linux, FreeBSD, etc) and we don't want the usage to grow. I objected in the RFC, either. Note that the objection is not only from me, also from a Linux distro folk I checked with.

If we aren't adding Linux functionality, we should make it throw an error at the same time.

Once again, ignoring the option without stopping with an error code is not ideal.

I can update this patch to throw an error, much like this patch for z/OS: https://reviews.llvm.org/D137756

In D137753#3935674 <https://reviews.llvm.org/D137753#3935674>, @MaskRay wrote:

> In D137753#3935617 <https://reviews.llvm.org/D137753#3935617>, @francii wrote:
>
>> In D137753#3935391 <https://reviews.llvm.org/D137753#3935391>, @MaskRay wrote:
>>
>>> In D137753#3935305 <https://reviews.llvm.org/D137753#3935305>, @francii wrote:
>>>
>>>> Recall that the goal with `-p` is to create parity with GCC (at least with Linux and AIX), as per the RFC discussion.
>>>>
>>>> In D137753#3935138 <https://reviews.llvm.org/D137753#3935138>, @MaskRay wrote:
>>>>
>>>>> In D137753#3935126 <https://reviews.llvm.org/D137753#3935126>, @francii wrote:
>>>>>
>>>>>> In D137753#3934932 <https://reviews.llvm.org/D137753#3934932>, @MaskRay wrote:
>>>>>>
>>>>>>> Please make `-p` accepted for AIX only and don't change the semantics for other targets in this patch. For FreeBSD and Linux (musl and gnu) we can try rejecting `-p`. If OpenBSD wants to make `-p` an alias for `-pg`, that's fine.
>>>>>>
>>>>>> We can make `-p` emit a message on Linux while also accepting it as an alias to `-pg`. Do you have a suggestion as to what that message would be?
>>>>>
>>>>> The current `warning: argument unused during compilation: '-p' [-Wunused-command-line-argument]` is good for Linux.
>>>>> In the future Linux can try removing `-p`.
>>>>
>>>> The current behaviour of ignoring the option without stopping with an error return code is not a good one.
>>>>
>>>> Recall that the goal is to create parity with GCC, as per the RFC post.
>>>>
>>>> Is there a reason this flag shouldn't be supported on Linux? Specifically, what is your justification for diverging from GCC on this matter?
>>>
>>> It's a legacy option (at least for Linux, FreeBSD, etc) and we don't want the usage to grow. I objected in the RFC, either. Note that the objection is not only from me, also from a Linux distro folk I checked with.
>>
>> If we aren't adding Linux functionality, we should make it throw an error at the same time.
>>
>> Once again, ignoring the option without stopping with an error code is not ideal. I can update this patch to throw an error on Linux, much like this patch for z/OS: https://reviews.llvm.org/D137756
>
> I acknowledge that the current state is bad. Reject it for FreeBSD/Linux (perhaps most OSes. An OS can opt in if their platform really needs this) is likely fine. I don't think `-p` has many uses.
>
> Something like D137756 <https://reviews.llvm.org/D137756> will be nice, but I think it can be done in clang/lib/Driver/ToolChains/Clang.cpp: D138255 <https://reviews.llvm.org/D138255>

Thank you, I will remove the Linux/Gnu changes from this patch shortly.


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