Re: [PATCH] BUILD_BUG_ON sucks

[Rusty Russell]

On Saturday 16 August 2008 20:09:48 Alexey Dobriyan wrote:
> BUILD_BUG_ON should have never existed -- BUG_ON could upgrade itself to
> compile-breaking version if compiler has enough information and this is
> what patch does.
>
> The only downside is that one can't write BUG_ON(1) anymore.

Interesting idea, but I've come to actually like the semantic explicitness of 
BUILD_BUG_ON.  There's a difference between "we should never get here" 
and "this should never exist".

But maybe I just like it because we have it.  At very least BUILD_BUG_ON 
should definitely compile-barf on a non-constant expr, and vice versa for 
BUG_ON().

Note that BUG_ON() is a hack caused by lack of attribute((cold)).  "if (x) 
BUG()" is clearer, and possible in the long run as people upgrade compilers.

Cheers,
Rusty.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/