llvm dev - May 2018 - LLVM JIT 3.9 vs 6.0: How to emitAndFinalize multiple modules correctly?

Hi all,

I am having hard time figuring out how I should use the API for JIT in LLVM 6.

In LLVM 3.9 I am used to adding all objects at once and
emitAndFinalizing them all:

handle = objectLayer.addObjectSet(objectFiles, memoryManager, resolver);
objectLayer.emitAndFinalize(handle);

In LLVM 6.0 the objects are added one by one:

auto handle = objectLayer.addObject(objectFile, resolver).get();
objectLayer.emitAndFinalize(handle);

The problem is that emitAndFinalize in this case works for one module
and JIT exits on
"LLVM ERROR: Program used external function 'XXXX' which could not
be resolved!"
errors because it seems to not see the other modules loaded with addObject.

What am I missing?

Thanks,

Stanislav

Hi Stan, the change happend with 5.0 [1]. There's a few options:
(1) Submit all modules and then explicitly finalize one after the other.
(2) Skip the explicit finalization, it should happen lazily for the
respective modules, when querying a function name.
(3) Last but not least, you could also merge all your modules into one
using Linker::link() [2] and submit this one. (This should be the
closest to pre-5.0)

You probably want to use a single resolver for all of them. Simply
forward symbol queries to your top ORC layer, and (again) it should
on-demand emit & finalize the respective module if it hasn't happened
already. E.g.:
https://github.com/weliveindetail/JitFromScratch/blob/jit-basics/SimpleOrcJit.h#L31

Hope it helps!
Best, Stefan

[1]
https://weliveindetail.github.io/blog/post/2017/08/23/llvm50-release-orc-api-changes.html#orclayerconceptaddmodule
[2]
http://llvm.org/doxygen/classllvm_1_1Linker.html#a72e11e8404db974fa400748b888ea49d

Am 16.05.18 um 21:06 schrieb Stanislav Pankevich:
> Hi all,
>
> I am having hard time figuring out how I should use the API for JIT in LLVM
6.
>
> In LLVM 3.9 I am used to adding all objects at once and
> emitAndFinalizing them all:
>
> handle = objectLayer.addObjectSet(objectFiles, memoryManager, resolver);
> objectLayer.emitAndFinalize(handle);
>
> In LLVM 6.0 the objects are added one by one:
>
> auto handle = objectLayer.addObject(objectFile, resolver).get();
> objectLayer.emitAndFinalize(handle);
>
> The problem is that emitAndFinalize in this case works for one module
> and JIT exits on
> "LLVM ERROR: Program used external function 'XXXX' which could
not be resolved!"
> errors because it seems to not see the other modules loaded with addObject.
>
> What am I missing?
>
> Thanks,
>
> Stanislav
-- 
https://weliveindetail.github.io/blog/
https://cryptup.org/pub/stefan.graenitz at gmail.com