[gcc] Enable TLS support for RTEMS in libstdc++

[Sebastian Huber]

On 08/06/2022 16:11, Joel Sherrill wrote:
> On Wed, Jun 8, 2022 at 8:47 AM Sebastian Huber 
> <sebastian.huber at embedded-brains.de 
> <mailto:sebastian.huber at embedded-brains.de>> wrote:
> 
>     On 08/06/2022 15:39, Joel Sherrill wrote:
>      > Is TLS actually supported on all targets except MIPS?
> 
>     I only added MIPS since this target has a fundamental issue with the
>     TLS
>     support.
> 
>     Which target would you also exclude?
> 
> 
> About half of them.

It seems to be only bfin, lm32, moxie, or1k, and v850. Are these targets 
still in use? Do we have a maintainer for these targets?

> 
> arch64 - Yes
> arm - Yes
> bfin - ?
> i386 - Yes
> lm32 - ?
> m68k - Yes
> microblaze - Yes
> mips - No
> moxie - ?
> nios2 -?

nios2 - Yes

> or1k - ?
> powerpc - Yes
> riscv - Probably

riscv - Yes

> sh - ?
> sparc - Yes
> sparc64 - ?
> v850 - ?
> x86_64 - Likely
> 
> I'm not even sure there is a definition of how TLS is implemented
> on some of these architectures. Maybe GCC has a generic way of
> handling TLS that a port could fall back on, but I am unaware of it.
> 
> If we are to maintain a thread safe C Library, then we have to be
> sure TLS is always supported or we have to have a fallback
> method.

The fallback method for C++ is only thread safe if you have enough POSIX 
keys configured.

-- 
embedded brains GmbH
Herr Sebastian HUBER
Dornierstr. 4
82178 Puchheim
Germany
email: sebastian.huber at embedded-brains.de
phone: +49-89-18 94 741 - 16
fax:   +49-89-18 94 741 - 08

Registergericht: Amtsgericht München
Registernummer: HRB 157899
Vertretungsberechtigte Geschäftsführer: Peter Rasmussen, Thomas Dörfler
Unsere Datenschutzerklärung finden Sie hier:
https://embedded-brains.de/datenschutzerklaerung/