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<div class="moz-cite-prefix">On 6/20/14, 4:31 PM, sathvik wrote:<br>
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cite="mid:CAA9Ha9FKyjsj7xt5WKxbHy4FOZQPrBvPz3kwy8G2BMf-pjgkaQ@mail.gmail.com"
type="cite">
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<div class="gmail_default"
style="font-family:verdana,sans-serif;font-size:small"><span
style="font-family:tahoma,sans-serif">Hi John,<br>
<br>
</span></div>
<div class="gmail_default"
style="font-family:verdana,sans-serif;font-size:small">
<span style="font-family:tahoma,sans-serif">I don't think its
possible to add/insert an inline assembly into the LLVM IR
unless the IR interface provides some kind of stream writer
into which inline instructions can be written into.<br>
</span></div>
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</blockquote>
<br>
The LLVM IR supports inline assembly instructions. See the Language
Reference Manual and the doxygen information on the llvm::InlineAsm
class.<br>
<br>
<blockquote
cite="mid:CAA9Ha9FKyjsj7xt5WKxbHy4FOZQPrBvPz3kwy8G2BMf-pjgkaQ@mail.gmail.com"
type="cite">
<div dir="ltr">
<div class="gmail_default"
style="font-family:verdana,sans-serif;font-size:small"><span
style="font-family:tahoma,sans-serif">
<br>
</span></div>
<div class="gmail_default"
style="font-family:verdana,sans-serif;font-size:small"><span
style="font-family:tahoma,sans-serif">I was thinking having
an LLVM intrinsic function could be a first step towards
introducing PMU tool support in LLVM with which you can
generate code with built-in instrumentation. What do you
think ?<br>
</span></div>
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<br>
If you wanted to build a processor-independent tool to collect the
information that RDPMC provides, then I think an intrinsic would be
the way to go. However, that might be a greater goal than what you
currently need. It certainly seems like a difficult issue to make
them portable given how different PMCs are across different Intel
processors.<br>
<br>
Regards,<br>
<br>
John Criswell<br>
<blockquote
cite="mid:CAA9Ha9FKyjsj7xt5WKxbHy4FOZQPrBvPz3kwy8G2BMf-pjgkaQ@mail.gmail.com"
type="cite">
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<div class="gmail_default"
style="font-family:verdana,sans-serif;font-size:small"><span
style="font-family:tahoma,sans-serif">
<br>
</span></div>
<div class="gmail_default"
style="font-family:verdana,sans-serif;font-size:small"><span
style="font-family:tahoma,sans-serif">Sathvik <br>
</span></div>
<div class="gmail_default"
style="font-family:verdana,sans-serif;font-size:small">
<span style="font-family:tahoma,sans-serif"><br>
<br>
</span></div>
<div class="gmail_default"
style="font-family:verdana,sans-serif;font-size:small"><span
style="font-family:tahoma,sans-serif"><br>
</span><br>
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<div class="gmail_extra">
<br>
<br>
<div class="gmail_quote">On Fri, Jun 20, 2014 at 8:21 AM, John
Criswell <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:criswell@illinois.edu" target="_blank">criswell@illinois.edu</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
<div class="">
<div>On 6/19/14, 7:12 PM, sathvik wrote:<br>
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<blockquote type="cite">
<div dir="ltr">
<div class="gmail_default"
style="font-family:verdana,sans-serif;font-size:small">I
want to measure the performance of a JITed code
snippet on MCJIT. </div>
<div class="gmail_default"
style="font-family:verdana,sans-serif;font-size:small">
so I was planning to inject the RDPMC inst for the
code generated through a llvm IR builder. <br>
</div>
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</blockquote>
<br>
</div>
I assume the easier way to do this is to add an inline
assembly call that uses the RDPMC instruction. I don't
think there's an LLVM IR intrinsic function that does it.<br>
<br>
Regards,<br>
<br>
John Criswell<br>
<br>
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<div class="">
<div dir="ltr">
<div class="gmail_default"
style="font-family:verdana,sans-serif;font-size:small"><br>
</div>
<div class="gmail_default"
style="font-family:verdana,sans-serif;font-size:small">
Is there a patch available ? If there's a better
way to do it please chime in.</div>
<div class="gmail_default"
style="font-family:verdana,sans-serif;font-size:small"><br>
</div>
<div class="gmail_default"
style="font-family:verdana,sans-serif;font-size:small">
Thanks</div>
<div class="gmail_default"
style="font-family:verdana,sans-serif;font-size:small">sathvik
</div>
</div>
<br>
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