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<p class="MsoNormal"><span lang="EN-GB">Hello LLVM-Mailing-List and Lang,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">I played around with this problem a bit and found a way of doing this – however I’m not sure about the consequences and if this is really a good idea.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">I went trough all of the global symbols and functions being defined in the llvm::Module and set for each of them a new section name (based on there name). With this approach the memorymanager could tell me already the
addresses of my symbols, which I could then share with the other process. However, this approach needed to load the module two times, first to get the future address and in a second run to use the addresses to resolve the symbols.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">The only disadvantage I noticed so far was that the overall size of the emitted code was bigger then having the regular sections. Are there any other risks I might have overseen?
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Kind greetings<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Björn<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span lang="EN-US" style="mso-fareast-language:DE">From:</span></b><span lang="EN-US" style="mso-fareast-language:DE"> llvm-dev <llvm-dev-bounces@lists.llvm.org>
<b>On Behalf Of </b>Gaier, Bjoern via llvm-dev<br>
<b>Sent:</b> 06 March 2020 14:24<br>
<b>To:</b> LLVM Developers Mailing List <llvm-dev@lists.llvm.org>; Lang Hames <lhames@gmail.com><br>
<b>Subject:</b> [llvm-dev] [ORC JIT] -Resolving cross references in a multi-process scenario<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span lang="EN-GB">Hello LLVM-Mailing-List and Lang,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">I have a very weird (or strict?) scenario and was curious if the ORC JIT can help me with it. Soo here it comes:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">I have currently a windows process ("Runtime") which does nothing but creating a shared memory with read, write and execute rights - and also writing some function addresses like from printf to it.
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Then I have two or more processes which are using the ORC JIT to load modules to this shared memory, in "perspective" of the process I mentioned above ("Runtime"). The sections are remapped from the other processes to
be correct for "Runtime", also they resolve the undefined references for "Runtime" - like for printf and so on.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">This works quite well so far! Wuhuhu x3<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">However, there is one issue about it. Given that those two (or more processes) are now loading modules that reference each other. Like Module A is using a function of Module B - but Module B also uses a function of Module
A. How could I resolve those modules when they are loaded from different processes? Normally I would use llvm-link to link those modules but in my current scenario this is sadly not possible.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Can the ORC JIT help me with that? Can I solve this problem differently? Like replacing all the functions of Module A that rely on Module B with function pointers? Is something like that possible?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">I know this situation is pretty uncommon but sadly I ran into that issue.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Kind greetings<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Björn<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:DE">Als GmbH eingetragen im Handelsregister Bad Homburg v.d.H. HRB 9816, USt.ID-Nr. DE 114 165 789 Geschäftsführer: Dr. Hiroshi Nakamura, Dr. Robert Plank, Markus Bode, Heiko Lampert, Takashi Nagano, Takeshi
Fukushima. Junichi Tajika <o:p></o:p></span></p>
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Als GmbH eingetragen im Handelsregister Bad Homburg v.d.H. HRB 9816, USt.ID-Nr. DE 114 165 789 Geschäftsführer: Dr. Hiroshi Nakamura, Dr. Robert Plank, Markus Bode, Heiko Lampert, Takashi Nagano, Takeshi Fukushima. Junichi Tajika
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