[PATCH v2 0/3] Support --enable-newlib-reent-thread-local Newlib configuration option

[Chris Johns]

+1

Really great patch and change. I think the performance improvements will be
excellent.

As an aside, does gdb know about TLS variables and so will `errno` be visible?

Chris

On 21/7/2022 5:09 pm, Sebastian Huber wrote:
> This patch set adds support for the --enable-newlib-reent-thread-local
> (_REENT_THREAD_LOCAL_STORAGE) Newlib configuration option.
> 
> By default, Newlib uses a huge object of type struct _reent to store
> thread-specific data.  This object is returned by __getreent() if the
> __DYNAMIC_REENT__ Newlib configuration option is defined.
>   
> The reentrancy structure contains for example errno and the standard input,
> output, and error file streams.  This means that if an application only uses
> errno it has a dependency on the file stream support even if it does not use
> it.  This is an issue for lower end targets and applications which need to
> qualify the software according to safety standards (for example ECSS-E-ST-40C,
> ECSS-Q-ST-80C, IEC 61508, ISO 26262, DO-178, DO-330, DO-333).
>   
> If the new _REENT_THREAD_LOCAL configuration option is enabled, then struct
> _reent is replaced by dedicated thread-local objects for each struct _reent
> member.  The thread-local objects are defined in translation units which use
> the corresponding object.
> 
> v2:
> 
> * Remove i386, microblaze, and m68k from default enabled list.
> 
> * Support --with-newlib-tls and --without-newlib-tls.
> 
> Sebastian Huber (3):
>   6/7: Update Newlib
>   newlib: Support --with/without-newlib-tls
>   6/7: Use TLS in Newlib for some targets by default
> 
>  rtems/config/6/rtems-aarch64.bset             |  1 +
>  rtems/config/6/rtems-arm.bset                 |  1 +
>  rtems/config/6/rtems-nios2.bset               |  1 +
>  rtems/config/6/rtems-powerpc.bset             |  1 +
>  rtems/config/6/rtems-riscv.bset               |  1 +
>  rtems/config/6/rtems-sparc.bset               |  1 +
>  rtems/config/7/rtems-aarch64.bset             |  1 +
>  rtems/config/7/rtems-arm.bset                 |  1 +
>  rtems/config/7/rtems-nios2.bset               |  1 +
>  rtems/config/7/rtems-powerpc.bset             |  1 +
>  rtems/config/7/rtems-riscv.bset               |  1 +
>  rtems/config/7/rtems-sparc.bset               |  1 +
>  .../config/tools/rtems-gcc-10-newlib-head.cfg |  4 +--
>  .../tools/rtems-gcc-10.4-newlib-head.cfg      | 27 +++++++++++++++++++
>  .../config/tools/rtems-gcc-12-newlib-head.cfg |  5 ++--
>  .../tools/rtems-gcc-head-newlib-head.cfg      |  4 +--
>  source-builder/config/checks.cfg              |  9 +++++++
>  source-builder/config/gcc-common-1.cfg        |  1 +
>  18 files changed, 55 insertions(+), 7 deletions(-)
>  create mode 100644 rtems/config/tools/rtems-gcc-10.4-newlib-head.cfg
>