BUG_ON and gcc don't mix

[Benjamin Herrenschmidt]

On Tue, 2013-08-20 at 12:37 +1000, Anton Blanchard wrote:
>    0:   00 00 23 a1     lhz     r9,0(r3)
>    4:   01 00 60 38     li      r3,1
>    8:   20 00 a9 0c     twlgei  r9,32
>    c:   20 00 80 4e     blr
> 
> Nice! I remember chasing this down before and the issue is we need the
> address of the trap instruction for our bug exception table. Maybe
> we need a gcc builtin in which we can get a label on the trap
> instruction. Would that be possible?

I suppose we can always just do a label before builtin_trap and have
the BUG code search a few instructions :-)

Cheers,
Ben.