RSB LLVM Package (chrisj at rtems.org)

[Chris Johns]

On 15/9/19 1:52 pm, yorda wrote:
> It’s great to hear about rtems has made some progress on LLVM.

Thanks

> I’m quite new to rtems,

Welcome.

> so I have questions about the rtems-llvm packages

Excellent :)

> 1. Can I use rtems-llvm clang compiler build application c code?

Not yet unless you can prove the ABI matches the RTEMS kernel which we currently
only support being built by gcc. The user manual section ...

https://docs.rtems.org/branches/master/user/exe/executables.html#machine-flags-and-abi

... describes how all parts of the executable need to match the ABI for your
target and this is controlled by the machine flags to the compiler.

So in theory you may be able too but I am not sure.

> 2. Does rtems code and newlib still need use arm gcc toolchain?

We still need to add support to ..

1. Build newlib with clang
2. Build RTEMS with clang and the clang built newlib

This patch is a step as it gives more developers easier access to the tool chain.

Note, gcc support will be maintain and a core focus because it supports more
architectures than clang.

Also adding LLVM as a package to the RSB means we can grow the support in
rtems-tools and deprecate the existing support with the efltoolchain over time.
The LLVM libraries give us fast clean DWARF support plus 64bit support.

Chris