Re: Work on adding TLS support to LLVM on m68k

[Karoly Balogh <charlie%scenergy.dfmk.hu@localhost>]

Hi,

On Sat, 28 Jan 2023, Chris Hanson wrote:

> That said, any compiler or linker for 68K needs to support multiple ABI
> standards since Mac OS, Atari, Amiga, and all the different UNIX and
> UNIX-like operating systems had their own ABI. Fortunately LLVM itself
> supports the concept of multiple ABIs…

Indeed, but the systems you mention A., use a mixure of ABIs, I mean one
system with many ABIs, even if there are some "basic assumptions" about
volatile/nonvolatile registers and so on, but otherwise "you're on your
own", and B., neither of these have "threads" as such, let alone anything
that resembles the concept of a Thread Local Storage in the modern sense.

Point is: it's safe to start on Linux/NetBSD, because there the OS at
least knows about these as a concept, so there's some framework for it to
follow as guard rails. Elsewhere - prepare for a lot of faking, and
hacking, and cheating. :)

(Ask me where I know... ;) )

Charlie