[llvm-dev] Clang attributes issue

[Андрей Тищенко via llvm-dev]

I'm not sure I got your idea. AttrHasAttributeImpl.inc works perfectly with
new namespaces but it is not enough that's why I was forced to change
AttrParserStringSwitches.inc.
(in fact I changed TableGen of course.)
It seems I don't understand something that's why it'd be better if you
implement the fix by yourself.

 Andrew V. Tischenko

2015-08-10 20:53 GMT+03:00 Aaron Ballman <aaron at aaronballman.com>:

> On Mon, Aug 10, 2015 at 4:43 AM, Андрей Тищенко
> <andrew.v.tischenko at gmail.com> wrote:
> > Hi All,
> >
> >
> > Sorry for my previous email: there was some issue with my email system.
> >
> > Hope you don't have any problems with reading my message now.
> >
> >
> > Aaron,
> >
> >
> >
> > Not long ago I met a problem related to clang attributes implementation.
> I
> > tried to add a new CXX11 attribute with separated namespace like here:
> >
> >
> >
> > def FooAligned : InheritableAttr {
> >
> >   let Spellings = [CXX11<"_Foo_attrs", "aligned">];
> >
> >   ….
> >
> >
> >
> > But I was not able to do it because name “aligned” was used in another
> > well-known attribute. After some research I found that the problem was in
> > file “AttrParserStringSwitches.inc” generated by TableGen. Its content
> was
> > unaware about namespaces. As result my new “aligned” attribute was
> mentioned
> > like here:
> >
> >
> >
> > #if defined(CLANG_ATTR_IDENTIFIER_ARG_LIST)
> >
> > ….
> >
> > .Case("aligned", true)
> >
> > ….
> >
> > #endif // CLANG_ATTR_IDENTIFIER_ARG_LIST
> >
> >
> >
> > and there was real ambiguity in selection of proper attribute:
> GNU::aligned,
> > CXX11::aligned or CXX11:: _Foo_attrs::aligned.
> >
> >
> >
> > The simplest way to resolve the issue is to change the new attribute name
> > but why should I do it if I use the unique namespace?
>
> Since the attribute is in its own namespace, it *really* should not
> have to be unique. That's a bug.
>
> > In my case I created a special patch allowing me to generate full
> qualified
> > names of attributes inside CLANG_ATTR_IDENTIFIER_ARG_LIST section:
> >
> >
> >
> > #if defined(CLANG_ATTR_IDENTIFIER_ARG_LIST)
> >
> > ….
> >
> > .Case("CXX11:: _Foo_attrs::aligned", true)
> >
> > ….
> >
> > #endif // CLANG_ATTR_IDENTIFIER_ARG_LIST
> >
> >
> >
> > My problem was resolved with this patch.
> >
> > Is it interesting for anybody?
> >
> > Should I create the corresponding bug record in Bugzilla?
> >
> > Do you like to review my patch?
> >
> > What about other sections inside “AttrParserStringSwitches.inc” using
> > unqualified attribute names?
>
> I would be interested in reviewing your patch if you would like to go
> through the process. If you would prefer not to, or don't have the
> time, etc, I am happy to spend a bit of effort on this as well. I
> don't think AttrParserStringSwitches.inc should have fully-qualified
> names in the string switch cases. Instead, it should be modeled
> (slightly) after AttrHasAttributeImpl.inc where it accepts the syntax
> used as well as the scope and attribute name.
>
> Thanks!
>
> ~Aaron
>
> >
> >
> >
> > Andrew V. Tischenko
> >
> >
>
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