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<p class="MsoNormal"><span lang="EN-GB">Hello everyone 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 another design or "how-to" question about the ORC JIT. Sorry for having so many about them, to me this is a really complicated yet fascinating subject...<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">How would I design an ORC JIT with the following requirements?
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">At any time it should be possible to load a LLVM Module, every Module is independent and is not allowed to be linked with the other modules, every module can be removed at any time.<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">My first idea was to have an ORC JIT for every module I load, but then I wondered if I could use a single ORC JIT for it.<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">So, I would create an ORC JIT:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">- using llvm::orc::LLJITBuilder<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">- configurating it<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">- adding a custom memory manager that requests the entire memory size<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">Then I would call "getMainJITDylib" and fill it with symbols that are valid for every module:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">- adding printf, strlen, usw. <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">Now when I get a request to load a module:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">- load module <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">- get symbols I want to look up<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">- create new DyLib and add module to that<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">Now I would do a lookup on that module, plus the main module to get symbol addresses and stuff<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">If a new module is added, it goes to a new DyLib as well and so on.<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>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">However, now I want to delete a module again. Killing the memory is fairly easy with my custom memory manager, but I still have my DyLib of the now dead code... Can I get rid of it without dumping the others or the entire
ORC JIT?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Or is there a different approach to do this? My goal with this is to speed up the setup phase for a module and also to reduce dynamic memory usage.<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">Also a related but different question: <o:p>
</o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">When using llvm::parseIRFile I need to pass it a LLVMContext - should this be a unique one for every module I pass or can I use a global one?<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 and thank you all again,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Björn<o:p></o:p></span></p>
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