[cfe-dev] libc++/libc++abi - compilation on armv7

[Renato Golin]

On 15 February 2015 at 02:36, Goncalo Carvalho <glslang at gmail.com> wrote:
> : undefined reference to `__aeabi_uidiv'
>
> so it relies on linking against libgcc_s but that's missing from the
> CMakeLists.txt. When adding it then I can build it :).

Hi Goncalo,

The above dependency is with any compiler library, including libgcc
and compiler-rt. Just like the other dependencies are with any
unwinder libraries, being that libgcc or libunwind.

This issue with cross-dependencies between libc++, libc++abi and
compiler-rt are well known and we're trying to fix it by splitting the
Unwind part in its own repository called libunwind. In the future,
both libc++abi and compiler-rt will depend on libunwind, rather than
on each other, which will simplify the build process.

Also, we're planning on teaching Clang about these dependencies and
help the user chose the appropriate libraries in a way that is not
confusing or needing too many flags. This is not done yet, though.


> The question then is the above expected, or simply arm sbc were never
> considered as a possible platform and as such no one maintains it in
> terms of getting it to compile and regression test?

ARM EHABI adds a few more dependencies than we'd like, so yes, this is
a complication to the general case.

The first few steps are in progress:

http://thread.gmane.org/gmane.comp.compilers.llvm.devel/81577

cheers,
--renato