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Re: PC-relative TLS support

On Thu, Aug 15, 2019 at 01:24:07PM -0500, Segher Boessenkool wrote:
> Hi!
> On Thu, Aug 15, 2019 at 01:35:10PM +0930, Alan Modra wrote:
> > Supporting TLS for -mpcrel turns out to be relatively simple, in part
> > due to deciding that !TARGET_TLS_MARKERS with -mpcrel is silly.  No
> > assembler that I know of supporting prefix insns lacks TLS marker
> > support.
> Will this stay that way?  (Or do we not care, not now anyway?)

I'd say we leave that problem to someone who wants pcrel without tls
markers.  It's not hard to do, just extend rs6000_output_tlsargs and
adjust IS_NOMARK_TLSGETADDR length attribute expressions.

> > Also, at some point powerpc gcc ought to remove
> > !TARGET_TLS_MARKERS generally and simplify all the occurrences of
> > IS_NOMARK_TLSGETADDR in rather than complicating them.
> The last time this came up (a year ago) the conclusion was that we first
> would have to remove AIX support.

Hmm, I wonder has that changed?  A quick look at the source says the
AIX TLS support uses completely different patterns and shouldn't care.

> (Changelog has whitespace damage, I guess that is just from how you
> mailed this?  Please fix when applying it).

Fixed.  (It wasn't the mailer..)

Alan Modra
Australia Development Lab, IBM

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