ToT glibc build problem with ToT GCC

[Jeff Law]

On 8/29/19 10:26 AM, Steve Ellcey wrote:
> I am building the latest glibc with the latest GCC and getting an error.
> I see where, in locale/programs/charmap.h we declare bytes as a zero
> length array in charseq but I am not sure where the write in
> locale/programs/ld-ctype.c is.  The only line references that GCC seems
> to be outputing refer to the declaration, not the use.
> 
> Is anyone else seeing this?  Any ideas on what we should be changed?
> The declaration?  The use?  Or is this a bogus warning from GCC that
> we want to ignore?  I think that GCC is reporting this now due to Martin
> Sebor's GCC patch for PR 83431 but I haven't verified that.
> 
> Steve Ellcey
> sellcey@marvell.com
> 
> 
> 
> cc1: error: writing 1 byte into a region of size 0 [-Werror=stringop-overflow=]
> In file included from programs/repertoire.h:24,
>                  from programs/localedef.h:32,
>                  from programs/ld-ctype.c:35:
> programs/charmap.h:63:17: note: destination object declared here
>    63 |   unsigned char bytes[0];
>       |                 ^~~~~
> cc1: error: writing 1 byte into a region of size 0 [-Werror=stringop-overflow=]
> programs/charmap.h:63:17: note: destination object declared here
> cc1: error: writing 1 byte into a region of size 0 [-Werror=stringop-overflow=]
> programs/charmap.h:63:17: note: destination object declared here
> cc1: error: writing 1 byte into a region of size 0 [-Werror=stringop-overflow=]
> programs/charmap.h:63:17: note: destination object declared here
> cc1: all warnings being treated as errors
> ../o-iterator.mk:9: recipe for target '/home/sellcey/tot/obj/glibc64/locale/ld-ctype.o' failed
> make[2]: *** [/home/sellcey/tot/obj/glibc64/locale/ld-ctype.o] Error 1
> 
I've already been discussing this with Carlos internally.  The code
works, but is a bit fishy.  Not sure what the resolution will be yet,
but we're definitely aware of it.

jeff