[LLVMdev] Adding support for explicitly specified TLS models (PR9788)

[Joerg Sonnenberger]

On Wed, Apr 25, 2012 at 03:17:13PM +0100, Hans Wennborg wrote:
> On Wed, Apr 25, 2012 at 14:04, Joerg Sonnenberger
> <joerg at britannica.bec.de> wrote:
> > On Wed, Apr 25, 2012 at 12:39:49PM +0100, Hans Wennborg wrote:
> >> Just as it is illegal to specify thread_local for a target that
> >> doesn't support it, specifying a TLS model that isn't supported by the
> >> target would be illegal.
> >
> > For ELF, it doesn't make sense to reject one as it can always be
> > relaxed. An application program shouldn't have to worry about that, it
> > is just an implementation detail.
> 
> I'd be fine with that.
> 
> (Clang should still worry about it though, so it can provide a "the
> TLS model you selected is not supported by the target, it will fall
> back to another one" warning.)

There is no point in warning about it. Basically, anything but global
dynamic a pure performance optimisation.

Joerg