Re: [RFC] bloody mess with __attribute__() syntax

From: Al Viro
Date: Thu Jul 05 2007 - 12:53:59 EST


On Thu, Jul 05, 2007 at 09:41:55AM -0700, Linus Torvalds wrote:
> > Note that gcc rules for __attribute__() (and that's the only source
> > of rules we _have_ for the damn thing) clearly say that
> > int __user *p;
> > is the same thing as
> > int *__user p;
>
> Quick question: is there some reason why we have to honor the crazy gcc
> rules, and cannot try to convince gcc people that they are insane?

AFAICS, they started with storage-class-like attributes. Consider e.g.
always_inline or section; these are not qualifiers at all and you want
to have
static __attribute__((always_inline)) int foo(int *p);
interpreted with attribute applied to foo, not to its return type.

So they have fsckloads of existing code relying on that parsing. BTW,
they want things like
int *p __attribute__((section(...)))
and that's a position where qualifiers just do not appear. Again, existing
codebase (and quite a bit of that is present in the kernel, BTW).

I rather doubt that they'll be able to kill that off and making parsing
dependent on the nature of attribute is not a viable option either -
think of __attribute__((this,that)) where "this" is storage-class-like
and "that" - qualifier-like.
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