r205197 - Sema: Check dll attributes on redeclarations

[Reid Kleckner]

On Wed, Jul 16, 2014 at 7:13 AM, Nico Rieck <nico.rieck at gmail.com> wrote:

> On 14.07.2014 16:33, Alp Toker wrote:
> > We just started internal integration testing for 3.5. This commit breaks
> > cross-compilation bootstrap builds to Windows from Fedora 20, Ubuntu
> > 14.04 and other current distributions, I believe due to a MinGW64 header
> > bug that was only fixed upstream in April 2014.
> >
> > We'll want to remove setInvalidDecl() and make the diagnostic either (a)
> > a DefaultError warning complete with a warning group name or (b) a
> > SuppressInSystemHeader error.
> >
> > Do you know what the correct recovery is when accepting the invalid
> > code? Should we drop or accept the attribute, and does that decision
> > change based on whether we're in GCC or MSVC compatibility mode?
>
> GCC's behavior here seems strange. They don't diagnose the case of
> adding a dll attribute. If you define a function, then declare it as
> imported, the definition will be emitted, but the imported declaration
> is used. Which code triggers this diagnostic?
>
> So for GCC-compat the attribute has to be accepted. But I have no idea
> whether user code relies on this so I would tend to (a).


I don't think this extension-of-an-extension is so bad that it needs a
DefaultError warning.  I'd just do a regular warning, which of course will
be silenced in a system header.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/cfe-commits/attachments/20140716/bb900df5/attachment.html>