Re: [PATCH] ARM gas: handle {...} operands in macros

[Richard Earnshaw <rearnsha at arm dot com>]

On 03/06/13 17:08, Jan Beulich wrote:
> > > > On 03.06.13 at 18:01, Richard Earnshaw <rearnsha@arm.com> wrote:
> > On 03/06/13 16:58, Jan Beulich wrote:
> > > > > > On 03.06.13 at 17:49, Richard Earnshaw <rearnsha@arm.com> wrote:
> > > > On 28/05/13 20:18, Roland McGrath wrote:
> > > > > Here's another case where the presumptions about whitespace stripping don't
> > > > > mesh with macros quite right.  There may be more cases affected; I didn't
> > > > > try to add test cases for all of them.
> > > > >
> > > > > OK for trunk and 2.23?
> > > >
> > > > This seems all wrong to me.  If you're having to pretend that all these
> > > > special characters are symbol characters, then something else must be
> > > > fundamentally wrong.  That makes this patch a crutch for something else
> > > > that's broken.
> > > >
> > > > I think you need to dig further into why macros aren't working properly.
> > > >     Is it the implementation of macros, the documentation, or your
> > > > expectations that are wrong?
> > >
> > > Others (including me) have done this before - it's an effect of
> > > how the scrubber works, eating whitespace that it thinks isn't
> > > necessary. It's been years back that I looked into that, but iirc
> > > in the end I was told to better leave the scrubber untouched to
> > > not risk breakage elsewhere. So one or the other workaround
> > > needs to be found anyway...
> > This is more than just the white-space scrubbing.  It's changing the
> > definition of what characters are legal in symbols.  I'm concerned that
> > that may have other potential implications for parsing as well.
>
> Oh, yes, I understand that this has the potential for breakage
> elsewhere. But that was true for the earlier addition of [ and ] too.
> Perhaps there are other solutions, but likely much more intrusive
> to the code.
>
> Jan

I guess the real question is, when is this going to stop?  All these 
additions are wrong and it's looking to me as though this is going to be 
a drip drip drip of 'Oh, here's another one'.  Fundamentally, these 
changes are all wrong; these aren't symbol characters and trying to 
pretend that they are is papering over the real problem and potentially 
introducing new bugs.

R.