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<p>Hello Lang, David,</p>
<p><br>
</p>
<p>I am just using an ObjectLinkingLayer and an IRCompileLayer. I
had a look at Chapter 4 of "Building A JIT" and I found exactly
what I needed.<br>
<br>
I have a working implementation.<br>
</p>
<p>Thanks a lot for the help,</p>
<p>Theodor</p>
<p><br>
</p>
<div class="moz-cite-prefix">On 05/28/2016 12:15 AM, Lang Hames
wrote:<br>
</div>
<blockquote
cite="mid:CALLttgrfZEj2GucESWuUzs0Q01fTP=sv8mpUdckoyCVvinhniw@mail.gmail.com"
type="cite">
<div dir="ltr">H Theodoros, David,
<div><br>
</div>
<div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">What
I am trying to figure out is how the function pointer can be
updated to point to the newly compiled version.</blockquote>
</div>
<div><br>
</div>
<div>As Dave implied, it depends on how you've set up your ORC
stack. These days, the API directly responsible for this is
the IndirectStubsManager (see
llvm/include/llvm/ExecutionEngine/Orc/IndirectionUtils.h). If
you have access to the appropriate IndirectStubsManager you
just need to call the updatePointer method with the name of
the function you want to update and the new address.</div>
<div><br>
</div>
<div>If you're using the CompileOnDemand layer to compile lazily
from IR, the problem is that that layer doesn't (currently)
expose the IndirectStubManager for each module. I think it
would be reasonable to add support for that if you need it
though.</div>
<div><br>
</div>
<div>So - what is your current setup?</div>
<div><br>
</div>
<div>You may also be interested in the latest chapter of the
Building A JIT tutorial series that I'm working on. There's no
chapter text yet, but the code was just committed as r271054
and is (hopefully) fairly readable if you're already familiar
with Orc.</div>
<div><br>
</div>
<div>Cheers,</div>
<div>Lang.</div>
<div><br>
</div>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Fri, May 27, 2016 at 10:38 AM, David
Blaikie <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:dblaikie@gmail.com" target="_blank">dblaikie@gmail.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="ltr">+Lang<br>
<br>
Ultravague answer: There are a few different Orc layers
for different levels of indirection needed for different
levels of substitutability. One way is to indirect every
call through global function pointers - so when you want
to replace the function you write the new function pointer
to the global variable. I forget which layers do which
kinds of indirection.<br>
<br>
- Dave</div>
<div class="HOEnZb">
<div class="h5">
<div class="gmail_extra"><br>
<div class="gmail_quote">On Thu, May 26, 2016 at 11:49
PM, Theodoros Theododiris via llvm-dev <span
dir="ltr"><<a moz-do-not-send="true"
href="mailto:llvm-dev@lists.llvm.org"
target="_blank">llvm-dev@lists.llvm.org</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">Hello,<br>
<br>
I am trying to figure out how to recompile
functions multiple times during run-time with ORC
JIT<br>
<br>
and I'd appreciate any help/advice.<br>
<br>
<br>
My use case is t he following: every time a
function of interest (annotated) is called,
profiling data<br>
<br>
are gathered. Given enough data the function is
recompiled using different optimizations. This
happens<br>
<br>
repeatedly until the "best" optimization
parameters are found.<br>
<br>
<br>
A similar question was asked before and a solution
was suggested:<br>
<br>
<a moz-do-not-send="true"
href="http://lists.llvm.org/pipermail/llvm-dev/2015-July/088665.html"
rel="noreferrer" target="_blank">http://lists.llvm.org/pipermail/llvm-dev/2015-July/088665.html</a><br>
<br>
<br>
What I am trying to figure out is how the function
pointer can be updated to point to the newly<br>
<br>
compiled version.<br>
<br>
<br>
Thanks,<br>
<br>
Theodor<br>
<br>
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rel="noreferrer" target="_blank">http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev</a><br>
</blockquote>
</div>
<br>
</div>
</div>
</div>
</blockquote>
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