Re: [Qemu-devel] [PATCH] pixman: remove -Wredundand-decls

[Alexey Kardashevskiy <aik@ozlabs.ru>]

On 04/15/2013 05:30 PM, Peter Maydell wrote:
> On 15 April 2013 08:26, Alexey Kardashevskiy <aik@ozlabs.ru> wrote:
>> On 04/15/2013 05:18 PM, Peter Maydell wrote:
>>>
>>> On 15 April 2013 03:31, Alexey Kardashevskiy <aik@ozlabs.ru> wrote:
>>>>
>>>> The assert.h header file from Fedora18 does not have #ifdef-#endif
>>>> brackets around __assertXXXX function so it cannot compile with
>>>> the -Wredundant-decls switch on.
>>>>
>>>> Some Linux distributions (such as Debian Wheezy) still do have those
>>>> brackets arounb __assertXXXX functions (#ifndef _ASSERT_H_DECLS) but
>>>> the version of assert.h on http://sourceware.org/git/?p=glibc.git does
>>>> not
>>>> so we should not be using -Wredundant-decls.
>>>>
>>>> The patch removes it.
>>>
>>>
>>> This commit message seems to be missing any mention of
>>> which versions of pixman this change breaks and why
>>> it's OK now to break compiling against them...
>>
>>
>>
>> The change does not _break_ anything.
>
> The change breaks the fix that the code was put in to deal with,
> ie that pixman-0.16's header files generate warnings, which the
> default development qemu will turn into errors with -Werror, which
> means we won't compile.
>
>> The second removed chunk in the patch is the problem as it:
>> 1) enables -Wredundant-decls even if it was not enabled before;
>> 2) makes -Wredundant-decls an error, not just a warning.
>
> This is because not all versions of gcc have the push/pop warning
> pragma.
>
>> Default assert.h shipped with Fedora Core 18 (pretty recent and popular
>> distribution, I would say) cannot compile with -Wredundant-decls as an error
>
> This appears to be a bug in Fedora.


Rather glibc as it is still in glibc's master branch:
http://sourceware.org/git/?p=glibc.git;a=blob;f=assert/assert.h;h=1bb9b2d50f92da3b17cc0b937ecd6141a87dc196;hb=HEAD

Or am I looking at wrong git?

> I guess the correct workaround for that bug is going to be either:
>
>   * wrap assert.h the same way we wrap pixman.h
>   * drop -Wredundant-decls :-(


The second option seems less ugly.


-- 
Alexey