Re: [musl] ./src/internal/atomic.h:229:14: error: size of array 'a_cas_p_undefined_but_pointer_not_32bit' is negative on PowerPC

[Thomas Petazzoni <thomas.petazzoni@bootlin.com>]

Hello,

On Fri, 22 Jul 2022 18:29:00 +0200
Szabolcs Nagy <nsz@port70.net> wrote:

> * Thomas Petazzoni <thomas.petazzoni@bootlin.com> [2022-07-22 09:12:24 +0200]:
> > Hello,
> > 
> > We've "recently" started in Buildroot the build testing of fully random
> > configurations, so we're now testing many more cases and seeing new
> > build failures.
> > 
> > As part of this, we're now seeing build failures of musl on PowerPC
> > 32-bit architectures. So far, we've seen the problem on power4
> > (-mcpu=power4), power5 (-mcpu=power5) and power6 (-mcpu=power6), 970
> > (-mcpu=970), power8 (-mcpu=power8), 620 (-mcpu=620), 630 (-mcpu=630).
> > 
> > The failure is:
> > 
> > ./src/internal/atomic.h:229:14: error: size of array 'a_cas_p_undefined_but_pointer_not_32bit' is negative
> >   229 | typedef char a_cas_p_undefined_but_pointer_not_32bit[-sizeof(char) == 0xffffffff ? 1 : -1];
> >       |              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
> 
> the compiler is not configured for 32-bit target abi, but the triplet
> (powerpc-buildroot-linux-musl) selects the 32-bit target in musl.
> 
> please use powerpc64* --target triplet when configuring musl or configure
> gcc to default to 32-bit abi if that's what you want.
> 
> (the bug would be more obvious looking at gcc -v)

Thanks a lot for the feedback. I have added in Cc Joel and Cédric, who
help maintain the PowerPC support in Buildroot. Joel has submitted just
today a patch series to Buildroot that I believe should help address
this particular issue. Joel, do you confirm?

Thanks a lot!

Thomas
-- 
Thomas Petazzoni, co-owner and CEO, Bootlin
Embedded Linux and Kernel engineering and training
https://bootlin.com