[PATCH] Change representation of dllexport/dllimport

[Robinson, Paul]

> From: Nick Lewycky [mailto:nlewycky at google.com] 
> Sent: Wednesday, September 11, 2013 11:33 AM
> To: Robinson, Paul
> Cc: Reid Kleckner; Nico Rieck; Chandler Carruth; reviews+D1110+public+872068f434b7231c at llvm-reviews.chandlerc.com; llvm-commits
> Subject: Re: [PATCH] Change representation of dllexport/dllimport
>
> On 11 September 2013 11:25, Robinson, Paul <Paul_Robinson at playstation.sony.com> wrote:
> > My linker guys say that visibility and dllimport/dllexport are orthogonal, 
> > therefore I conclude that dllimport/dllexport should not be modeled as
> > visibility values.  It may be that some combinations of visibility and 
> > import/export don't make sense, but that doesn't mean you have to make 
> > it syntactically impossible to express them.  (That's what semantic checking 
> > is for.)
> >
> > My linker guys are also agitating to make -fvisibility=hidden the default 
> > for our platform, which caused me to double-take at the thought of 
> > dllexport'ing a hidden symbol but they say it is a reasonable thing to do.  
> > We already default to -fPIC so we'd get a bit of a win by defaulting to 
> > -fvisibility=hidden as well (references to hidden symbols don't have to go 
> > through the GOT).  I'm not saying we want it to be the default for everybody, 
> > but rather it should be target-specific.
> >
> > I think this was settled previously in the thread but I thought I'd chime in 
> > that we use dllimport/dllexport and we are an ELF/non-Windows target.
> >
> Could you explain what it means to use dllimport and dllexport on an ELF target?
>
> Nick

It means we have a proprietary extension to ELF that does the right things.
Sorry, should have made that clear the first time.
--paulr