Re: [Qemu-devel] [PATCH] configure: workaround for Clang 3.5.0

[John Snow <jsnow@redhat.com>]

On 10/29/2015 05:25 PM, Peter Maydell wrote:
> On 29 October 2015 at 21:20, Laszlo Ersek <lersek@redhat.com> wrote:
>> On 10/29/15 21:29, John Snow wrote:
>>> Here's a good takeaway quote:
>>>
>>> 'Also, _FORTIFY_SOURCE + glibc + clang is not supported and does not
>>> work (for instance, it relies on __builtin_va_pack_len and friends,
>>> which we have no intention of supporting), so glibc compatibility is
>>> unlikely to be a strong motivator for a change here.'
>>
>> this quote would be compelling enough for me to disable _FORTIFY_SOURCE
>> when clang is seen, no questions asked. The above is a public no-support
>> statement from an apparently core clang developer, so "it happens to
>> build without errors with version X.Y.Z." just don't cut it. A positive
>> claim (bugzilla comment, release note, etc) would be necessary.
>>
>> ... As far as I'm concerned, of course. :)
> 
> I think I would agree with that.
> 
> thanks
> -- PMM
> 

OK. I'll spin a new one that disables FORTIFY SOURCE without test if it
detects you are using Clang.

(I am curious as to why it now magically works in later versions of
Clang though, despite such a strong "no support" statement from the
developer above. I might do a little digging.)

--js