[FFmpeg-devel] MinGW-w64 x86_64 spams warning: -fPIC ignored for target

[Hendrik Leppkes]

On Mon, Apr 8, 2013 at 6:31 AM, Gianluigi Tiesi <mplayer at netfarm.it> wrote:

> Hi,
>
> By looking at configure script the code for PIC detection checks if
> __PIC__, __pic__ or PIC are defined (on linux only when passing shared)
>
> mingw-w64 on x86_64 targets always defines __PIC__ and __pic__
> but warns when passing -fPIC as gcc option:
> warning: -fPIC ignored for target (all code is position independent)
> [enabled by default]
>
> the resulting compilation is somehow unreadable (each gcc call has a
> warning printed)
>
> I've changed configure using this check:
>
> if test $target_os != "mingw32"; then
>     check_cpp_condition stdlib.h "defined(__PIC__) || defined(__pic__) ||
> defined(PIC)" && enable pic
> fi
>
> but is obiviously ugly
>
> do you known a better solution? using a flag filter looks like an overkill
> to me
>
>
This is not the correct solution. The "pic" option still needs to be
enabled, because its also used in the codebase to determine if some
assembler-related things need to be handled differently.
Instead, the proper solution is to filter out the flag from actually being
added to CFLAGS

In any case, i consider this a GCC bug. If an option is always-on, what
harm is it to explicitly set it? Why warn about this?

- Hendrik