Re: [PATCH B1/2] Redefine assert to use its expression

[Roland McGrath <roland at hack dot frob dot com>]

I thought I argued before for using a new internal macro instead of
overloading assert with different semantics.  That's more immediate
make-work of replacing existing assert uses, but IMHO more maintainable in
the long run.  But I don't recall any more exactly how the previous
discussion went.

> This also fixes the -Werrors from -DNDEBUG on x86_64, but in
> the opposite direction.  We make assert always use its expression.
> This requires removing some existing ifndefs that were working
> around this same problem of unused variables.

This is the approach I like, certainly, regardless of whether we decide to
change assert itself or use a new macro name.

> There is exactly one compilation difference from patch A1, in
> fork.os, where the THREAD_GETMEM read cannot be optimized away,
> because the asm is marked volatile.  (Yet another reason to finish
> code in gcc to expose segments as address spaces, so that this can
> be written in C.)

Not to discourage you from implementing something in GCC, but why do those
asm's use volatile?  I don't see a reason they should.  Obviously the
storing ones need to, but the fetching ones shouldn't.


Thanks,
Roland