[cfe-dev] Late parsing of CXX11 attributes

[Aaron Ballman via cfe-dev]

On Wed, Jun 27, 2018 at 6:15 AM, Eric Fiselier via cfe-dev
<cfe-dev at lists.llvm.org> wrote:
> Wooh! Thanks for working on this.
>
> Clang's `diagnose_if` attribute would certainly benefit from this change.
> Currently it's usable only
> as a GCC attribute.
>
> I tried working on this a while back. IIRC the main issue is that C++11
> attributes placed at the end of
> a function declaration apply to the function type and not the declaration
> itself. (See [dcl.spec]p1).
>
> After discussing this with Richard and Aaron about attributes appearing
> after a function-specifier, I believe the
> consensus was to only apply the attribute to the type if said attribute is a
> "type attribute". Otherwise the
> attribute would apply to the entity being declared. For example, I think we
> should accept `int foo() [[noreturn]];`

It's been a while, but I thought we were exploring making diagnose_if
(and friends) into actual type attributes because they seem to be
type-ish. For instance, if the API designer says "please diagnose if
this argument is bad", they likely expect that to happen when calling
the function directly or indirectly through a function pointer.

~Aaron

>
> /Eric
>
> On Wed, Jun 27, 2018 at 2:20 AM, Javier López via cfe-dev
> <cfe-dev at lists.llvm.org> wrote:
>>
>> OK, unless Aaron replies that someone is currently implementing this, I
>> will be working on a patch.
>>
>> I know :-) I have been working for months in the implementation of P0542
>> in Clang. Late parsing is one of the missing features.
>>
>> El mar, 26-06-2018 a las 17:05 -0700, Richard Smith escribió:
>>
>> I'm not aware of anyone working on this (CC'd Aaron, who might know if
>> someone is). Patches would be very much welcome :)
>>
>> Also relevant is http://wg21.link/p0542r5 (voted into the current C++
>> working draft a couple of weeks ago), which requires late parsing for C++11
>> attributes within a class.
>>
>> On 21 June 2018 at 04:16, Javier López via cfe-dev
>> <cfe-dev at lists.llvm.org> wrote:
>>
>> Hello everyone,
>>
>> AFAIK, GNU attributes can be late parsed within a class (see
>> ParseDecl.cpp, Parser::ParseGNUAttributes), but late parsing of CXX11
>> attributes is not yet implemented.
>>
>> Is there any plans to do it or anyone already working on it? Anyway, if no
>> one is owning that issue, I could work on it.
>>
>> Thanks,
>> --
>> Javier López
>> 2.2.B.08 ARCOS lab, Computer Architecture Group
>> University Carlos III of Madrid
>> e-mail: jalopezg at inf.uc3m.es
>>
>> _______________________________________________
>> cfe-dev mailing list
>> cfe-dev at lists.llvm.org
>> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
>>
>>
>> --
>>
>> Javier López
>> 2.2.B.08 ARCOS lab, Computer Architecture Group
>> University Carlos III of Madrid
>> e-mail: jalopezg at inf.uc3m.es
>>
>> _______________________________________________
>> cfe-dev mailing list
>> cfe-dev at lists.llvm.org
>> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
>>
>
>
> _______________________________________________
> cfe-dev mailing list
> cfe-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
>