[llvm-dev] re-compile a function

[Lang Hames via llvm-dev]

Hi Marwa,

There are no tutorials that focus on constructing a JIT using the Orc
layers (though I hope to write one in the future). There are several
complete example JITs in-tree though. The simplest example is the
Kaleidoscope JIT. See llvm/examples/Kaleidoscope/include/KaleidoscopeJIT.h .

Cheers,
Lang.

On Sun, Apr 10, 2016 at 4:13 AM, marwayusuf at feng.bu.edu.eg <
marwayusuf at feng.bu.edu.eg> wrote:

> Hi Lang,
>
> Is there any detailed instructions or tutorial for using orc layers?
>
> Thanks in advance.
>
>
> Regards,
> Marwa Yusuf
> Teaching Assistant - Computer Engineering Department
> Faculty of Engineering - Benha University
> E-JUST PhD Student
> Computer Science & Engineering Dept.
>
>
> ------------------------------
> *From:* Lang Hames <lhames at gmail.com>
> *Sent:* Wednesday, December 2, 2015 11:29 PM
> *To:* marwayusuf at feng.bu.edu.eg
> *Cc:* llvm-dev at lists.llvm.org
> *Subject:* Re: [llvm-dev] re-compile a function
>
> Hi Marwa,
>
> MCJIT doesn't provide any support for recompilation. The best you can do
> is use multiple MCJIT instances and destroy whichever one contains the
> function "foo" that you want to recompile. MCJIT does not do any dependence
> tracking either, so you'll also need to destroy and recompile any direct
> callers of "foo" (and their direct callers, and so on). If you know you
> want to be able to recompile a function it may be best to only call it
> indirectly - that way all you have to do is delete the containing MCJIT
> instance, create a new MCJIT instance, and update your function pointer.
>
> You may find the Orc APIs a better fit for what you're doing: they at
> least support removing individual modules from the JIT session, so you
> don't have to maintain multiple JIT instances yourself. You'll still need
> to manage the invalidation and/or function pointer update. If you come up
> with a scheme for that though we could look at adding it in-tree. You might
> also be able to make some use of the utilities in
> include/llvm/ExecutionEngine/Orc/IndirectionUtils.h.
>
> In case it's useful, I've attached an example that uses the Orc APIs to do
> recompilation at higher optimization levels, based on the Kaleidoscope
> tutorials. This was motivated by the following mailing list discussion:
> http://lists.llvm.org/pipermail/llvm-dev/2015-July/087776.html, which may
> also be related to what you want to do.
>
> Cheers,
> Lang.
>
>
> On Sat, Nov 21, 2015 at 11:05 AM, marwayusuf at feng.bu.edu.eg via llvm-dev <
> llvm-dev at lists.llvm.org> wrote:
>
>> Dear All
>>
>> Is there is a way to recompile a function at runtime?
>>
>> It seems that I need to -like - invalidate the recompiled function to
>> force the MCJIT to recompile it, cause when I just call runFunction, it
>> neglects any modifications in the function code.
>>
>> Thanks in advance.
>>
>>
>> Regards,
>> Marwa Yusuf
>> Teaching Assistant - Computer Engineering Department
>> Faculty of Engineering - Benha University
>> E-JUST PhD Student
>> Computer Science & Engineering Dept.
>>
>> _______________________________________________
>> LLVM Developers mailing list
>> llvm-dev at lists.llvm.org
>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>
>>
>
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