[LLVMdev] Using LLVM with clang for a homebrew kernel

[David Greene]

On Thursday 08 April 2010 08:27:20 Jochen Wilhelmy wrote:
> Hi!
>
> In the llvm-doc is the following:
>
> Also, since many platforms define their ABIs in terms of C, and since
> LLVM is lower-level than C, front-ends currently must emit
> platform-specific IR in order to have the result conform to the platform
> ABI.
>
> Can you give an example for this except system calls (which e.g. on
> windows use
> a different calling convention)?
> If you write your own operating system then how does llvm-IR depend on
> the ABI?

varargs is the poster boy.  Right now llvm proper only has support for
some pieces of varargs translation on x86_64.  Frontends handle the bulk of 
the work.

I hope to add some more code in this area relatively soon.

Of course, anything having to do with Fortran is done completely by
the frontend as there is no standard ABI for that language.

                                  -Dave