[LLVMdev] MCJIT or ORC JIT for new project?

[Kevin Atkinson]

Thanks for the advice.

I think I will switch to the ToT[1] and try out the ORC JIT,  I think I will 
switch to to a release version once 3.7 is out (assuming it included the ORC 
JIT.)

I let you know how it goes.

Kevin


[1] which by the way I had to google as I never herd that term before :)


On Fri, 3 Jul 2015, Lang Hames wrote:

> Hi Kevin,
>
> My recommendation for people starting new projects is to use ORC rather
> than MCJIT where possible, as ORC has a strict superset of MCJIT's
> functionality. There are no guarantees on ORC API stability however, so if
> that's truly critical then MCJIT's C API would be a better fit for you.
>
> If you're living on ToT (which we also generally recommend), then the
> minimal day-to-day churn on Orc should be manageable. If you're planning to
> live on stable releases you'll have the usual (and difficult-to-predict)
> inter-release headaches.
>
> Either way, let me know how your choice works out for you: I'm keen to keep
> improving LLVM's JIT support.
>
> Cheers,
> Lang.
>
>
> On Wed, Jul 1, 2015 at 10:50 PM, Kevin Atkinson <k at kevina.org> wrote:
>
>>
>> Hi,
>>
>> For a new language I am developing (in the very early stages, nothing
>> public posted yet) I would like to able to use a JIT for several purposes:
>>
>> 1) Create a functional REPL as is done is done with in the Kaleidoscope
>> tutorial.
>>
>> 2) Be able to interpret my language in addition to compiling.
>>
>> 3) While compiling, be able to execute arbitrary code at compile time.
>> The simple case will be to get a value, similar to C++ constexpr but
>> without any restrictions.  The complicated case will be to support a full
>> macro system similar to syntax-rules in Racket or defmacro in Lisp.
>>
>> For (1) I would require being able to execute a function at a time. I
>> would also like to be able to discard temporary functions used just to get
>> a value.
>>
>> For (2) and (3) lazy compilation is required, catching the results would
>> also be great.
>>
>> For right now I plan to use a direct AST based interpreter, but I would
>> also like have JIT available when it is needed.
>>
>> It looks like the new ORC JIT will be better suited for my needs.  Would
>> it be better to use the devel version of LLVM and the new JIT?  Or is the
>> new ORC JIT too much of a moving target and would it be better to stick
>> with MCJIT?
>>
>> If it is best to stick with MCJIT can someone point me to a working
>> Kaleidoscope that will work with MCJIT and the latest released version of
>> LLVM.  There are several versions floating around and I am confused on what
>> version to use.  The examples in Kaleidoscope/MCJIT/lazy don't compile with
>> 3.6.1 and I was hoping there was a version that would compile.
>>
>> Let me know if anything is unclear.
>>
>> Thanks in Advance,
>> Kevin
>>
>>
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