[PATCH] Change representation of dllexport/dllimport

[Bill Wendling]

On Jul 11, 2013, at 5:15 AM, Reid Kleckner <rnk at google.com> wrote:

> On Wed, Jul 10, 2013 at 9:31 PM, Bill Wendling <wendling at apple.com> wrote:
> My initial thought would be that adding new linkage types would be the way to go. However, if there are going to be a lot of them, then it's a combinatoric nightmare. If you can mix all other linkage types with the dll* types, then maybe it should be a new field (sub-linkage type?) in the GlobalValue object. Or even expand the size of the linkage field and make it a bit-mask with the dll linkage types.
> 
> I think this approach was essentially rejected in the original thread on llvm-dev:
> http://lists.cs.uiuc.edu/pipermail/llvmdev/2013-March/060646.html
> 
> Basically, it's a bit of a combinatoric nightmare.  We don't need the full combination of (export, import) cross all linkages, but we need a bunch.
> 
> Again, I think dllexport/import should be visibilities.

If they naturally fit into the semantics of visibilities (i.e., they really are visibilities, which appears to be the case here), then that's probably the best way to do this...

-bw