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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">When we were using MCJIT, I could do this:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">// Attach the event listener<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> Context.EE->RegisterJITEventListener(<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> LLILCJitEventListener::createLLILCJitEventListener(<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> new LLILCJitEventWrapper(&Context)));<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">The event listeners listened for when an object is emitted (NotifyObjectEmitted), and that’s when we’d go through and extract debug info from the ObjectFile.
Now, I imagine I’d need to add some sort of layer, I’m just not sure when, where or how to get that set up, and am looking for some guidance on it.<o:p></o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> Joseph Tremoulet
<br>
<b>Sent:</b> Thursday, June 4, 2015 11:29 AM<br>
<b>To:</b> Michelle McDaniel; Lang Hames<br>
<b>Cc:</b> llvmdev@cs.uiuc.edu<br>
<b>Subject:</b> RE: [LLVMdev] MCJit interface question<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#993366">Which events do you need to listen to? The ObjectLinkingLayer that we're using has notifications when an object is loaded and when it is finalized. So I'd expect
e.g. if you're listening to the loading event then you could create a functor class (with signature similar to DoNothingOnNotifyLoaded), put your logic in its operator() (changing to allow that you'll now be passed sets of Objects/LoadedObjectInfos), then
change LLILCJit's LoaderT typedef to supply your functor type as the template argument and change the Loader constructor to supply an instance of the functor.<o:p></o:p></span></p>
<p class="MsoNormal"><a name="_MailEndCompose"></a><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#993366"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> Michelle McDaniel
<br>
<b>Sent:</b> Thursday, June 4, 2015 1:27 PM<br>
<b>To:</b> Lang Hames; Joseph Tremoulet<br>
<b>Cc:</b> <a href="mailto:llvmdev@cs.uiuc.edu">llvmdev@cs.uiuc.edu</a><br>
<b>Subject:</b> RE: [LLVMdev] MCJit interface question<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Hi all,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">So I’m also working on LLILC. Specifically, I have been working on a JITEventListener to pass debug line info to the CoreCLR EE. With Joe’s change, I’ve lost
the ability (or as far as I can tell) to attach an event listener. Is there a way within Orc to do the sorts of things that the JITEventListeners do in MCJIT? How would I go about adding a layer to add debugging support?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Thanks,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Michelle<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">
<a href="mailto:llvmdev-bounces@cs.uiuc.edu">llvmdev-bounces@cs.uiuc.edu</a> [<a href="mailto:llvmdev-bounces@cs.uiuc.edu">mailto:llvmdev-bounces@cs.uiuc.edu</a>]
<b>On Behalf Of </b>Lang Hames<br>
<b>Sent:</b> Monday, June 1, 2015 10:41 AM<br>
<b>To:</b> Joseph Tremoulet<br>
<b>Cc:</b> <a href="mailto:llvmdev@cs.uiuc.edu">llvmdev@cs.uiuc.edu</a><br>
<b>Subject:</b> Re: [LLVMdev] MCJit interface question<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Hi Russell, Joseph,<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">> <span style="font-size:11.5pt;font-family:"Calibri",sans-serif;color:#993366"> I'll look into moving LLILC to ORC.</span><o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Sounds good. Please let me know how your experiments go. I'm keen to improve the Orc APIs further, so your feedback would be very welcome. <o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Cheers,<o:p></o:p></p>
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<p class="MsoNormal">Lang.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">On Sat, May 30, 2015 at 11:14 AM, Joseph Tremoulet <<a href="mailto:jotrem@microsoft.com" target="_blank">jotrem@microsoft.com</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#993366">Agreed, that sounds like the best plan. I'll look into moving LLILC to ORC.</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#993366"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#993366">Thanks</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#993366">-Joseph</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><a name="14da608b2f52bd94__MailEndCompose"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#993366"> </span></a><o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> Russell Hadley
<br>
<b>Sent:</b> Friday, May 29, 2015 8:13 PM<br>
<b>To:</b> Lang Hames; Joseph Tremoulet<br>
<b>Cc:</b> <a href="mailto:llvmdev@cs.uiuc.edu" target="_blank">llvmdev@cs.uiuc.edu</a><br>
<b>Subject:</b> RE: [LLVMdev] MCJit interface question</span><o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Hey Joseph,
</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">What Lang said made me wonder. Is it the right time for us (LLILC) to move to ORC? The long term
plan was to go there but this could be our forcing function.</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">-R</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">
<a href="mailto:llvmdev-bounces@cs.uiuc.edu" target="_blank">llvmdev-bounces@cs.uiuc.edu</a> [<a href="mailto:llvmdev-bounces@cs.uiuc.edu" target="_blank">mailto:llvmdev-bounces@cs.uiuc.edu</a>]
<b>On Behalf Of </b>Lang Hames<br>
<b>Sent:</b> Friday, May 29, 2015 2:23 PM<br>
<b>To:</b> Joseph Tremoulet<br>
<b>Cc:</b> <a href="mailto:llvmdev@cs.uiuc.edu" target="_blank">llvmdev@cs.uiuc.edu</a><br>
<b>Subject:</b> Re: [LLVMdev] MCJit interface question</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Hi Joseph,<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">There are several reasons that a client might want to access the object before it's loaded, so a general API like #2 seems like the way to go.<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">To support this in MCJIT you can add this to the event listener API. Orc clients can already do this by adding a custom object-file layer.<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">- Lang.<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">On Fri, May 29, 2015 at 9:05 AM, Joseph Tremoulet <<a href="mailto:jotrem@microsoft.com" target="_blank">jotrem@microsoft.com</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Hi,<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">I think I need to make a small change to the MCJit interface, and would like some feedback on what the most appropriate option would be.<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">I'm working on LLILC (a jit for the CoreCLR built on MCJit, which creates one module for each MSIL method, containing the main function and zero or more EH handler functions extracted
from the MSIL method). The CoreCLR requires the jit to notify it of the size of the unwind info descriptors for each function in the module
<i>before</i> reserving the memory it will be loaded into. So we need a call (or calls) from the Jit/loader into the MemoryManager that runs at-or-before reserveAllocationSpace, is conceptually similar to registerEHFrames in that it's reserving EH frames,
but that additionally needs to separate out the per-function information.<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">A few options come to mind:<o:p></o:p></p>
<p>1.<span style="font-size:7.0pt"> </span>Add a needsToReserveEHFrames callback on MemoryManager (to parallel needsToReserveAllocationSpace), and a reserveEHFrames callback (parallel to registerEHFrames) that the loader would use to notify the memory
manager if needsToReserveEHFrames() is true. This seems at a high-level the most straightforward fit for the LLILC requirement, but I don't know if for other targets it would even be possible to move the identification of EH frames (which depends on the 'LocalSections'
computed in loadObjectImpl) to before calling reserveAllocationSpace. I also don't know if that would be an undesirable "tight coupling" of RuntimeDyld with CoreCLR's particular interface. (and note that this is really two options, in that the code to separate
out the per-function EH frame contribution could go in either the client memory manager or in the loader.)<o:p></o:p></p>
<p>2.<span style="font-size:7.0pt"> </span>Add a notification similar to NotifyObjectEmitted, but which runs just
<i>before</i> the call to Dyld.loadObject. Something like NotifyObjectPreLoaded. The LLILC-specific MemoryManager could use this hook to scan the object::ObjectFile and pass whatever it needs to the CoreCLR. This seems like a decent option to me, but I don't
know if it would be considered a bad loss of encapsulation to passs out the object::ObjectFile in the state where it's been 'created' but not yet 'loaded'.<o:p></o:p></p>
<p>3.<span style="font-size:7.0pt"> </span>Similar to #2, the existing reserveAllocationSpace callback on MemoryManager could simply take an additional parameter which is the object::ObjectFile. This would be a more minimal change than #2 in terms of
how much surface area it adds to the MCJit interface, but also a more invasive change in that all MemoryManager implementations would need to be updated with the reserveAllocationSpace signature change (though they could just ignore the new parameter).<o:p></o:p></p>
<p>4.<span style="font-size:7.0pt"> </span>We could avoid needing to crack the object file for this information altogether; MCJit could add a hook where a client could insert passes into the PassManager used in emitObject; LLILC could attach a pass that
would consult the MachineModuleInfo, where this information could be stored (it's similar to what's stored in the WinEHFuncInfos hanging off the MMI today). But adding hooks for client passes might be opening a can of worms…<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">My inclination would be #2 or #3, but I would love some feedback on which of the tradeoffs seem most agreeable (and/or what options I've overlooked).<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Thanks<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="color:#888888">-Joseph</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="color:#888888"> </span><o:p></o:p></p>
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<a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev" target="_blank">http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev</a><o:p></o:p></p>
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