Re: [PATCH 0/3] picolibc: Add picolibc linking help

[Andrew Pinski <pinskia@gmail.com>]

On Wed, Aug 24, 2022 at 11:12 AM Keith Packard via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> Picolibc is a C library for embedded systems based on code from newlib
> and avr libc. To connect some system-dependent picolibc functions
> (like stdio) to an underlying platform, the platform may provide an OS
> library.
>
> This OS library must follow the C library in the link command line. In
> current picolibc, that is done by providing an alternate .specs file
> which can rewrite the *lib spec to insert the OS library in the right
> spot.

Why do you need to change the specs to support picolibc? Why not have
the library supply the specs file instead, like what is done for
newlib and libgloss?

>
> This patch series adds the ability to specify the OS library on the
> gcc command line when GCC is configured to us picolibc as the default
> C library, and then hooks that up for arm, nds32, riscv and sh targets.


What OS libraries are not included in libc? I trying to figure out why
this needs to be special cased here.

Thanks,
Andrew Pinski

>
> Keith Packard (3):
>   Allow default libc to be specified to configure
>   Add newlib and picolibc as default C library choices
>   Add '--oslib=' option when default C library is picolibc
>
>  gcc/config.gcc            | 56 ++++++++++++++++++++++++++++++++-------
>  gcc/config/arm/elf.h      |  5 ++++
>  gcc/config/nds32/elf.h    |  4 +++
>  gcc/config/picolibc.opt   | 26 ++++++++++++++++++
>  gcc/config/riscv/elf.h    |  4 +++
>  gcc/config/sh/embed-elf.h |  5 ++++
>  gcc/configure.ac          |  4 +++
>  7 files changed, 95 insertions(+), 9 deletions(-)
>  create mode 100644 gcc/config/picolibc.opt
>
> --
> 2.36.1
>