Re: [PATCH] C undefined behavior fix

Tom Rini
2002-01-02T23:28:36Z

On Thu, Jan 03, 2002 at 10:11:53AM +1100, Paul Mackerras wrote:
> Tom Rini writes:
>
> > Okay, here's a summary of all of the options we have:
> > 1) Change this particular strcpy to a memcpy
> > 2) Add -ffreestanding to the CFLAGS of arch/ppc/kernel/prom.o (If this
> > optimization comes back on with this flag later on, it would be a
> > compiler bug, yes?)
> > 3) Modify the RELOC() marco in such a way that GCC won't attempt to
> > optimize anything which touches it [1]. (Franz, again by Jakub)
> > 4) Introduce a function to do the calculations [2]. (Corey Minyard)
> > 5) 'Properly' set things up so that we don't need the RELOC() macros
> > (-mrelocatable or so?), and forget this mess altogether.
>
> I would add:
>
> 6) change strcpy to string_copy so gcc doesn't think it knows what the
> function does
> 7) code RELOC etc. in assembly, which would let us get rid of the
> offset = reloc_offset();
> at the beginning of each function which uses RELOC.

I think 7 sounds good for 2.4 at least, and maybe we can convince Franz
to look into 5 for 2.5 (since that would make things look a bit more
clean)..

--
Tom Rini (TR1265)