Re: musl risc-v port & gsoc - resources & ideas

[Rich Felker <dalias@libc.org>]

On Thu, Mar 03, 2016 at 10:58:12PM -0500, Rich Felker wrote:
> Since a port of musl to a new arch does not actually involve much
> code, mainly attention to detail to make sure that all of the type
> definitions/ABI/etc. are correct, I think that for a proposal to be
> big enough to make a reasonable GSoC project, it should go beyond just
> the basic porting. Some ideas for things to include would be:
> 
> - Improvement of porting documentation
> 
> - Feedback/patches on where there's too much redundancy between ports
>   and how to reduce it (i.e. making improvements to musl that reduce
>   the amount of code/headers needed for a new port).
> 
> - Patches for musl-cross and/or musl-cross-make (build systems for
>   generating a cross-compiler toolchain) to make it easy to build a
>   musl/riscv cross compiler.
> 
> - Optimizing performance-critical code like memcpy or floating point
>   math functions for riscv.
> 
> - Improving test coverage, especially for things that are easy to get
>   wrong in a new port.
> 
> I'll follow up with more ideas if I think of any.
> 
> Students interested in the project are welcome (and encouraged!) to
> ask questions and discuss here on the musl list. Obviously everyone
> should have in mind writing their own proposals but I want everyone to
> have access to knowledge/resources/community for ideas.

One other thing I forgot: I believe the riscv ABIs use IEEE quad for
long double, but musl has very poor support for quad right now, Most
functions just call out to the double functions; only a few that
critically need to be exact actually do the right thing. Improving
this situation is important for making riscv and other archs (aarch64,
mips64) that use quad polished/first-class.

Also the lowrisc-dev cc seems to have gotten dropped on these emails
which are very relevant:

http://www.openwall.com/lists/musl/2016/03/06/17
http://www.openwall.com/lists/musl/2016/03/06/24
http://www.openwall.com/lists/musl/2016/03/06/25

Rich