Open Source C/C++ Truffle languages available?

Chris Seaton chris.seaton at
Sun Jul 24 13:19:45 UTC 2016

Hello Gerard,

The old C implementation was called TruffleC. It interpreted the C language AST. Sulong interprets the LLVM IR instead. That’s not really a huge difference in practice. LLVM IR is a bit like a linearised version of the AST and doesn’t include much lowering or optimisation. TruffleC uses the same clever hacks as Sulong.

JRuby's C extensions (which are still at an early stage) used to use TruffleC, but they now use Sulong.

TruffleC isn’t open source, and there aren’t any plans that I’m aware of to open source it. Sulong is open source already. If you were happy with the TruffleC approach there’s not any reason that I know of that would mean Sulong wouldn’t also be appropriate, so I see TruffleC as deprecated by Sulong which is why there isn’t a great demand to open source it.


> On 24 Jul 2016, at 09:12, Gerard Krol <gerard at> wrote:
> Hi,
> I've recently learned about Tuffle/Graal. It seems great technology.
> I'm interested in running C++ code on the JVM, without resorting to the
> (admittedly clever) Sulong hack. I've seen some presentations and read some
> papers about a C implementation, but that one doesn't seem to be open
> source. The same goes for the C extensions for JRuby. Is that correct?
> If so, what are the reasons for not open sourcing it? Any plans to do so in
> the future?
> Regards,
> Gerard

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