<html><head><meta http-equiv="Content-Type" content="text/html charset=iso-8859-1"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;">Ah, that's helpful. I knew that I'd need to end up with PTX as text, not a true binary, but I would have figured that it would come out of MCJIT. Thanks for helping to steer me away from the wrong trail.<div><br></div><div>OK, one more question: Can anybody clarify the pros and cons of generating the PTX through the standard LLVM distro, versus using the "libnvvm" that comes with the Cuda SDK?</div><div><br></div><div><span class="Apple-tab-span" style="white-space:pre"> </span>-- lg</div><div><br></div><div><br><div><div>On Dec 9, 2013, at 7:00 AM, Justin Holewinski <<a href="mailto:justin.holewinski@gmail.com">justin.holewinski@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div dir="ltr"><div><div><div><div><div><div><div><div>There is no MCJIT support for PTX at the moment (mainly because PTX does not have a binary format, and is not machine code per se).<br><br></div>To generate PTX at run-time, you just set up a standard codegen pass manager like you would like an off-line compiler. The output will be a string buffer that contains the PTX, which you can load into the CUDA runtime.<br>
<br></div>As for determining if PTX support is compiled into the LLVM binary you are using, you could register all targets and then check if you can create a Target for the "nvptx" or "nvptx64" triple:<br>
<span style="font-family:courier new,monospace"><br> InitializeAllTargets();<br> InitializeAllTargetMCs();<br> InitializeAllAsmPrinters();<br> InitializeAllAsmParsers();<br><br></span></div><div><span style="font-family:courier new,monospace"> std::string Err;<br>
</span></div><span style="font-family:courier new,monospace"> const Target *Tgt = TargetRegistry::lookupTarget("nvptx64", Err);<br></span></div><span style="font-family:courier new,monospace"> if (Tgt) {<br></span></div>
<span style="font-family:courier new,monospace"> // nvptx target is available<br></span></div><span style="font-family:courier new,monospace"> } else {<br></span></div><span style="font-family:courier new,monospace"> // nvptx target is not available<br>
}</span><br><br><br></div><div>More information about the PTX target can be found at: <a href="http://llvm.org/docs/NVPTXUsage.html">http://llvm.org/docs/NVPTXUsage.html</a><br><br></div></div><div class="gmail_extra"><br>
<br><div class="gmail_quote">On Fri, Dec 6, 2013 at 3:43 PM, Larry Gritz <span dir="ltr"><<a href="mailto:lg@larrygritz.com" target="_blank">lg@larrygritz.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div style="word-wrap:break-word">OK, fine -- an example of MCJIT that sets up for PTX JIT would also be helpful.<div><br></div><div><div class="im"><br><div><div>On Dec 6, 2013, at 12:32 PM, Eli Bendersky <<a href="mailto:eliben@google.com" target="_blank">eliben@google.com</a>> wrote:</div>
<br><blockquote type="cite"><div dir="ltr"><br><div class="gmail_extra"><div class="gmail_quote"><div>You'll have to switch to MCJIT for this purpose. Legacy JIT doesn't emit PTX.</div><div><br></div><div>Eli </div>
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<span style="text-indent:0px;letter-spacing:normal;font-variant:normal;text-align:-webkit-auto;font-style:normal;font-weight:normal;line-height:normal;border-collapse:separate;text-transform:none;white-space:normal;font-family:Helvetica;word-spacing:0px">--<br>
Larry Gritz<br><a href="mailto:lg@larrygritz.com" target="_blank">lg@larrygritz.com</a><br><br><br></span>
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<br></blockquote></div><br><br clear="all"><br>-- <br><br><div>Thanks,</div><div><br></div><div>Justin Holewinski</div>
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<span class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px;">--<br>Larry Gritz<br><a href="mailto:lg@larrygritz.com">lg@larrygritz.com</a><br><br><br></span>
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