Re: SH2 kernel fails to build with recent GCC

[Rich Felker <dalias@libc.org>]

On Wed, Aug 12, 2015 at 09:34:32AM +0200, Geert Uytterhoeven wrote:
> Hi Rich,
> 
> On Wed, Aug 12, 2015 at 3:56 AM, Rich Felker <dalias@libc.org> wrote:
> > The commit that resolved GCC issue #54089 broke building the kernel
> > for SH2, by causing GCC to generate calls to new libgcc functions
> > which the kernel's fake libgcc does not provide. See the GCC issue
> > tracker for details:
> >
> > https://gcc.gnu.org/bugzilla/show_bug.cgi?idT089
> >
> > The relevant commit is linked from comment 16; comments 33-43 (and
> > perhaps beyond) discuss the issue in detail and possible fixes.
> >
> > Before I work on a fix, would dropping the kernel's copy of libgcc
> > functions for SH and using the real libgcc (like some archs do; see
> > comment 43) be acceptable, or do we need to get updated
> > libgcc[-compatible] code into the kernel?
> 
> Which libgcc functions are missing? I couldn't find that list in the bug
> report...

At least __ashlsi3_r0 and __lshrsi3_r0. It's been a while since I
tried building with an affected GCC (see the dates on the comments I
linked) so I don't remember if there were any others. I can try to
build again and let you know.

Rich