[LLVMdev] Potential Google Summer of Code Applicant

Yiannis Tsiouris
Fri, 06 Apr 2012 08:24:46 -0000

On 4/6/12 2:21 AM, Talin wrote:
> I would really like to see someone work on LLVM's garbage collection
> support - it hasn't been updated in 4 years, and while there's been
a
> lot of talk about ways that it could be improved, there's been no
action.
That is *sooo* true! :-) I'm one of the authors of an LLVM backend for
Erlang (ErLLVM [1]); we have tested and measured our backend  and
noticed that with the current GC infrastructure we see 20-40%
performance degradation (because of the loads/stores on the stack for
all gcroots). It is clear to me and the rest of the team that with this
infrastructure the LLVM might not be suitable for languages with
explicit garbage collection, like Erlang. I've also studied the way the
Vmkit project handles GC and they seem to face the same deficiency too.

offtopic: I am working on an email (more like an RFC) with all the
details and patches to the LLVM project in order to support our Erlang
backend. I hope I will be able to send it by next week. Note, that we
have already talked with the Ericsson/OTP team about integrating our
work in a future release of Erlang/OTP (as a new HiPE backend).

Yiannis

[1]: http://erllvm.softlab.ntua.gr

--
Yiannis Tsiouris
Ph.D. student,
Software Engineering Laboratory,
National Technical University of Athens
WWW: http://www.softlab.ntua.gr/~gtsiour