[cfe-dev] [RFC][libcxx] Fix and maintain the no-exceptions build of libcxx

[Asiri Rathnayake via cfe-dev]

Hi Eric,


> If you're going to change exceptional cases to call abort though, then
> it'd be good to make other cases to be consistent with that approach, like
> vector's __throw_length_error and __throw_out_of_range, regex's
> __throw_regex_error, and possibly others.
>

The initial patch [1] only proposes the framework for fixing the tests and
updating the library sources. I kept it minimal to make the review easier.
I have a giant local patch that fixes the rest of the tests (removes the
XFAILS) and the remaining library sources. And yes, vector's
__throw_length_error, __throw_out_of_range and regex's __throw_regex_error
are all updated in it (and many other places).

I'm still waiting for the approval of this initial patch so that I can
upstream the rest.

Best,

- Asiri

[1] http://reviews.llvm.org/D14653



>
> On Fri, Nov 27, 2015 at 7:03 AM, Asiri Rathnayake <
> asiri.rathnayake at gmail.com> wrote:
>
>> Hello,
>>
>> Asserts getting optimized away is a problem, as then an exceptional code
>> path will simply ignore the error and continue. Of course, one can argue
>> that an exceptional state in a no-exceptions library is something that is
>> OK to be ignored.
>>
>> In my latest patch [1], the user has the option to override the default
>> abort behaviour by providing a custom __libcxx_noexceptions_abort()
>> function. I think with this mechanism you can achieve the old behaviour if
>> desired.
>>
>> Cheers,
>>
>> - Asiri
>>
>> [1] http://reviews.llvm.org/D14653
>>
>>
>> On Thu, Nov 26, 2015 at 5:00 PM, via cfe-dev <cfe-dev at lists.llvm.org>
>> wrote:
>>
>>> Wouldn’t the better thing to do be to assert rather than call abort
>>> (like vector’s exceptions already do, for instance)?  One important use
>>> case of no-exception builds is to completely optimize out throwing paths
>>> and the checks leading to them, which wouldn’t happen if the exceptional
>>> path called abort.
>>>
>>> _______________________________________________
>>> cfe-dev mailing list
>>> cfe-dev at lists.llvm.org
>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
>>>
>>>
>>
>
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