[llvm-dev] saving and restoring multiple modules for Orc JIT

[Geoff Levner via llvm-dev]

OK, thanks, Lang. No rush, now that I have found my own solution.

Geoff

On Fri, Feb 12, 2021 at 12:40 AM Lang Hames <lhames at gmail.com> wrote:

> Hi Geoff,
>
> If I save each module to its own file, I have no problem. But I would like
>> to save them to a single file. When I do that, I sometimes get duplicate
>> symbol definitions when I reload the modules:
>>     Duplicate definition of symbol '$./path/to/my/file.bc.__inits.0'
>
>
> That's a pseudo-symbol representing the static initializers. Orc
> auto-generates it based on the module identifier, and the module identifier
> defaults to the path-name of the module file (I don't recall whether this
> happens when the module is stored or loaded). I think you could fix this by
> setting the module identifier for each module to a unique string (via
> Module::setModuleIdentifier) before adding it to the JIT.
>
> I'll see if I can add de-duping logic to the JIT API side too.
>
> -- Lang.
>
> On Sat, Feb 6, 2021 at 12:32 AM Geoff Levner <glevner at gmail.com> wrote:
>
>> Well, I have worked around this problem by implementing my own little
>> file format to hold the simple concatenation of any number of bitcode
>> files. It does not seem like this should be necessary, though. If anyone
>> comes up with a better solution in the future, I am interested...
>>
>> Geoff
>>
>> On Tue, Feb 2, 2021 at 12:26 PM Geoff Levner <glevner at gmail.com> wrote:
>>
>>> Greetings, LLVM developers.
>>>
>>> I am trying to save the bitcode for multiple modules so that I can
>>> reload them later and add them to my Orc-based JIT.
>>>
>>> If I save each module to its own file, I have no problem. But I would
>>> like to save them to a single file. When I do that, I sometimes get
>>> duplicate symbol definitions when I reload the modules:
>>>
>>>     Duplicate definition of symbol '$./path/to/my/file.bc.__inits.0'
>>>
>>> It looks to me as though this is a problem with static constructors in
>>> the modules, as though each module puts its constructors in a symbol with
>>> the same name...?
>>>
>>> Does anybody have a better idea than I am of what is going on, or how to
>>> solve this?
>>>
>>> I am using the 11.x release branch on Linux, FWIW. To reload the
>>> modules, I use a call to getBitcodeModuleList(), followed by calls to
>>> BitcodeModule::parseModule(), and finally calls to
>>> orc::LLJIT::addIRModule().
>>>
>>> Geoff
>>>
>>
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