<div dir="ltr">Hi Russell,<br><br>Instead of hiding bits inside the debug metadata, why not just attach additional metadata to each instruction and look for that during emission? You'll probably want to take a look at how things like the vectorizer are taking advantage of metadata if you want to encode things. Then during your front end compilation for MSIL->LLVM IR you can just attach random metadata to some instructions. This does have the drawback that, theoretically at least, you can strip metadata from LLVM IR and get a working binary. If that's not the case for CoreCLR you might want to look into a way to overload some of the instructions or ... something. Or just require people not delete your metadata I guess.<div><br></div><div>Does this help?</div><div><br></div><div>-eric</div></div><br><div class="gmail_quote">On Wed, May 13, 2015 at 3:27 PM Russell Hadley <<a href="mailto:rhadley@microsoft.com">rhadley@microsoft.com</a>> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">(background) The CoreCLR expects a JIT to produce a MSIL bytecode offset to code offset mapping annotated with a few extra bits denoting if it’s prolog/epilog,
or it’s a call, or if there’s operands remaining on the MSIL virtual stack in some cases. Our initial prototype has the MSIL offset stashed in the line number field. We could stash the extra bits in the column info but that’s starting to feel too much like
a hack. We’re looking for a way to 1) extend the debug metadata to hold our info and get it dumped into the in memory object – a new section would be fine if it’s not too complicated. Or 2) a place to extract the data we need when we have both encoded offset
and access to the instructions. We’re looking for some advice. </span><span style="font-size:11.0pt;font-family:Wingdings;color:#1f497d">J</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">-R<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><u></u> <u></u></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" target="_blank">llvmdev-bounces@cs.uiuc.edu</a> [mailto:<a href="mailto:llvmdev-bounces@cs.uiuc.edu" target="_blank">llvmdev-bounces@cs.uiuc.edu</a>]
<b>On Behalf Of </b>Eric Christopher<br>
<b>Sent:</b> Wednesday, May 13, 2015 2:55 PM</span></p></div></div><div lang="EN-US" link="blue" vlink="purple"><div><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><br>
<b>To:</b> Michelle McDaniel; <a href="mailto:llvmdev@cs.uiuc.edu" target="_blank">llvmdev@cs.uiuc.edu</a><br>
<b>Subject:</b> Re: [LLVMdev] Extending AsmPrinterHandler<u></u><u></u></span></p></div></div><div lang="EN-US" link="blue" vlink="purple"><div>
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<p class="MsoNormal">You could write the debug information you want into just a section in memory and have your external/alternate/other process/thread/etc pick it up on the other end? I don't see how the extra info you want to send is important here, you'd
just be extending the existing debug support. Or I'm missing something at which point I'm not sure which additional questions to ask :)<u></u><u></u></p>
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<p class="MsoNormal">-eric<u></u><u></u></p>
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<p class="MsoNormal">On Wed, May 13, 2015 at 2:45 PM Michelle McDaniel <<a href="mailto:michelm@microsoft.com" target="_blank">michelm@microsoft.com</a>> wrote:<u></u><u></u></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">I work on the LLILC team, and we are trying to send debug line info through to the CoreCLR EE without
using an EventListener because we need to send extra info (more than just available in DebugLoc) like if it’s a call instruction, a call site, etc. We thought extending AsmPrinterHandler would be useful since it seems to have information about debug locations,
label offsets, and instruction specific information.</span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"> </span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"> </span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"> </span><u></u><u></u></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"> Eric Christopher [mailto:<a href="mailto:echristo@gmail.com" target="_blank">echristo@gmail.com</a>]
<br>
<b>Sent:</b> Wednesday, May 13, 2015 2:37 PM<br>
<b>To:</b> Michelle McDaniel; <a href="mailto:llvmdev@cs.uiuc.edu" target="_blank">
llvmdev@cs.uiuc.edu</a><br>
<b>Subject:</b> Re: [LLVMdev] Extending AsmPrinterHandler</span><u></u><u></u></p>
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<p class="MsoNormal">We generally don't extend the AsmPrinter... can you be more specific about what you're trying to do?<br>
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-eric<u></u><u></u></p>
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<p class="MsoNormal"> <u></u><u></u></p>
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<p class="MsoNormal">On Wed, May 13, 2015 at 2:34 PM Michelle McDaniel <<a href="mailto:michelm@microsoft.com" target="_blank">michelm@microsoft.com</a>> wrote:<u></u><u></u></p>
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<p class="MsoNormal">Hey everyone,<u></u><u></u></p>
<p class="MsoNormal"> <u></u><u></u></p>
<p class="MsoNormal">I’m looking into extending AsmPrinterHandler out of tree, to communicate information back to the CoreCLR EE, but all of the headers are in the lib directory. Is there any way to
extend it out of tree, or is that not supported? The reason I’d like to do this out of tree is because we want to include clr headers as well, and we don’t want to introduce that into llvm sources.<u></u><u></u></p>
<p class="MsoNormal"> <u></u><u></u></p>
<p class="MsoNormal">Thanks,<u></u><u></u></p>
<p class="MsoNormal">Michelle<u></u><u></u></p>
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