[cfe-dev] Wframe-larger-than flag bug

[Ohad Alali via cfe-dev]

Ok, thanks a lot for your help.
‫בתאריך יום א׳, 26 בינו׳ 2020 ב-8:42 מאת ‪David Blaikie‬‏ <‪
dblaikie at gmail.com‬‏>:‬

> Doesn't look like it, no.
>
> I wouldn't recommend using -Wframe-larger-than and -save-temps (even
> without -Werror) really, since that seems to crash the compiler, there's
> probably no great guarantees about what that's doing.
>
> On Sat, Jan 25, 2020 at 10:40 PM Ohad Alali <ohad.alali at gmail.com> wrote:
>
>> Just to clarify, I cannot use flags -Wframe-larger-than, -Werror and
>> -save-temps=obj and get error instead of warning. right?
>>
>> ‫בתאריך יום א׳, 26 בינו׳ 2020 ב-8:35 מאת ‪Ohad Alali‬‏ <‪
>> ohad.alali at gmail.com‬‏>:‬
>>
>>> Thanks
>>>
>>> ‫בתאריך יום א׳, 26 בינו׳ 2020 ב-5:56 מאת ‪David Blaikie‬‏ <‪
>>> dblaikie at gmail.com‬‏>:‬
>>>
>>>> Ah, right, sorry I didn't reproduce your steps exactly - thanks for
>>>> highlighting the save-temps aspect.
>>>>
>>>> Yeah, testing this with clang trunk (which, on godbolt, is built with
>>>> assertions enabled) this crashes the compiler. Something about
>>>> frame-larger-than doesn't work with save-temps, which doesn't super
>>>> surprise me, -Wframe-larger-than with -fsyntax-only doesn't produce any
>>>> warning (frame-larger-than is implemented in the code generation pipeline,
>>>> as much as we try to avoid doing that for warnings in clang, this one's an
>>>> exception).
>>>>
>>>>
>>>> On Sat, Jan 25, 2020 at 2:15 PM Ohad Alali <ohad.alali at gmail.com>
>>>> wrote:
>>>>
>>>>> Thanks for your response.
>>>>> I've opened your link and it's seems that clang (trunk) is not handle
>>>>> the flag -save-temps=obj. compilation with -save-temps:
>>>>> https://godbolt.org/z/-neaMs
>>>>> When changing the compiler to clang v0.8, same behaviour as describe
>>>>> before.
>>>>> with flag -save-temps=obj: https://godbolt.org/z/gzpFGD
>>>>> without flag -save-temps=obj: https://godbolt.org/z/5uABvL
>>>>>
>>>>> Thanks,
>>>>> Ohad
>>>>>
>>>>>
>>>>>
>>>>> ‫בתאריך שבת, 25 בינו׳ 2020 ב-8:16 מאת ‪David Blaikie‬‏ <‪
>>>>> dblaikie at gmail.com‬‏>:‬
>>>>>
>>>>>> Works for me: https://godbolt.org/z/kMijQ7
>>>>>>
>>>>>> On Sun, Jan 5, 2020 at 6:45 AM Ohad Alali via cfe-dev <
>>>>>> cfe-dev at lists.llvm.org> wrote:
>>>>>>
>>>>>>> Hi,
>>>>>>>
>>>>>>> I'm compiling my project with clang version 7.0.0-3.
>>>>>>> I added compilation flag frame-larger-than in order to warning using
>>>>>>> more than 1024 bytes.
>>>>>>>
>>>>>>> clang indeed warning as expected, but when I added -Werror in order
>>>>>>> to treat the warning as error clang ignore this flag and it stays warning.
>>>>>>>
>>>>>>> the compilation flags include also save-temps=obj, when I remove
>>>>>>> this flag the warning treated as error.
>>>>>>>
>>>>>>> Does save-temps flag should be related to -Werror or
>>>>>>> -Wframe-larger-than?
>>>>>>>
>>>>>>> full compilation flags:
>>>>>>> clang++-7 -D_SYS_LINUX_ -D_HOSTSYS_LINUX_ -D_CPU_  -D_SYS64_
>>>>>>> -D_DEBUG_ -O2  -Wframe-larger-than=1024 -MD -Wall -save-temps=obj -Wextra
>>>>>>> -Wshadow -Werror -g -ggdb -fPIC
>>>>>>>
>>>>>>> Thanks,
>>>>>>> Ohad
>>>>>>> _______________________________________________
>>>>>>> cfe-dev mailing list
>>>>>>> cfe-dev at lists.llvm.org
>>>>>>> https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
>>>>>>>
>>>>>>
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