On Sat, Dec 08, 2018 at 02:30:48PM -0800, Linus Torvalds wrote:
> On Sat, Dec 8, 2018 at 2:04 PM Luc Van Oostenryck
> <luc.vanoostenryck@xxxxxxxxx> wrote:
> >
> > Since directly using the name instead of an number creates some
> > problems internally, allow this syntax but for the moment keep
> > the address space number and use a table to lookup the number
> > from the name.
>
> I suspect it would be much nicer to just make ctype.as be a "struct ident *".
>
> It wouldn't even make "struct ctype" any bigger, because we already
> pack that "unsigned int as" between two pointers, so making it a
> pointer would just get rid of possible padding with 64-bit pointers.
>
> Is it the odd combination rules that keeps us from doing that?
Partly that and partly because I an old patch somewhere which
combined ctype.as and ctype.alignment.
> We have
> a couple of cases that treat address space numbers as bitmasks, and do
>
> as |= sym->ctype.as;
>
> but I think we could just do it as some kind of
>
> struct ident *combine_address_space(struct ident *as1, struct ident *as2)
> {
> static struct ident bad_address_space = { .len = 6, .name="bad AS" };
> if (!as1) return as2;
> if (!as2) return as1;
> if (as1 == as2) return as1;
> return &bad_address_space;
> }
>
> or something instead.
>
> And yes, you'd obviously have to have the opposite "generate a ident
> for numeric users" when parsing an old-style address space with just a
> number, but that should be no worse than the current "generate a
> string from numbers". In fact, it should be simpler, since you can
> just do something like
>
> struct ident *numeric_ident(unsigned int num)
> {
> static char buf[20];
> int len = snprintf(buf, sizeof(buf), "%u", num);
> return create_hashed_ident(name, len, hash_name(name, len));
> }
>
> or similar.
>
> Hmm?
>
> Maybe I'm missing some other use of 'ctype.as'.
No, not really (IIRC there is a single other case where ctype.as
can't be used as a pointer but it shouldn't be a problem).
Anyway, I wan't really happy about this series with its names array.
I'll rewrite it using directly an ident it will be cleaner (and
ctype will indded not increase in size).
Thanks,
-- Luc
