<html>
<head>
<meta content="text/html; charset=UTF-8" http-equiv="Content-Type">
</head>
<body bgcolor="#FFFFFF" text="#000000">
Hi Gael<br>
Thanks for your guidance . I will try patchpoint
method to solve this issue . <br>
<br>
Thanks <br>
<br>
With regards <br>
Sri.<br>
<div class="moz-cite-prefix">On 04/27/2014 07:15 PM, Gaël Thomas
wrote:<br>
</div>
<blockquote
cite="mid:CAOWuPDcSiqpr0VHiKPqLWEB_NBGF-He69UBUzi4aWcevTKyHFg@mail.gmail.com"
type="cite">
<p dir="ltr">Hi Sri,</p>
<p dir="ltr">If main is compiled before the call to recompile, it
will call test with a direct call. After the update of the test
function, the second call site is not updated. To call the new
test, you can either call test with an indirect call, recompile
also main, or use a patchpoint to update the second call. The
last solution is probably the best one.</p>
<p dir="ltr">Gaël </p>
<div class="gmail_quote">Le 27 avr. 2014 20:01, "Sri" <<a
moz-do-not-send="true" href="mailto:emdcdeveloper@gmail.com">emdcdeveloper@gmail.com</a>>
a écrit :<br type="attribution">
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000"> Hi Phil<br>
Thank you for your clarification, Actually I
compiled VMKit 3.2 with llvm 3.2 and trying do <i><b>recompileAndRelinkFunction</b></i>()
. Could you please verity the following things to me. For
instance , code need to be executed as follows <br>
<b><i> main()</i></b><b><i>{</i></b><b><i><br>
</i></b><b><i> test()</i></b><b><i>;</i></b><b><i><br>
</i></b><b><i>
differentTest();</i></b><b><i><br>
</i></b><b><i> test();</i></b><b><i><br>
</i></b><b><i> }</i></b><br>
as soon as I executed the first <b>test</b>() function ,
I modified the llvm IR ( modified some instruction) of test
, then when I execute differentTest(), I used <i>recompileAndRelinkFunction</i>()
to link the modified test() before I execute the last test()
function. Actually , I was expecting the different result
when I was executing the last <b>test</b>() function but
unfortunately it execute the previous test() function not
modified one. How can I use this <i><b>recompileAndRelinkFunction()
to modify the native code during the execution. <br>
<br>
Thanks .<br>
<br>
With regards <br>
Sri.<br>
</b></i> <br>
<div>On 04/26/2014 06:19 PM, Filip Pizlo wrote:<br>
</div>
<blockquote type="cite">
<div
style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto">That's
a good point. But it's worth noting that
recompileAndRelinkFunction()
and freeMachineCodeForFunction() are both vestiges of
the old JIT (i.e. the "JIT" as opposed to the "MCJIT").
The old JIT is no longer actively supported.</div>
<div
style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto"><br>
</div>
<div>
<div style="font-family:helvetica,arial;font-size:13px">-Phil</div>
<div style="font-family:helvetica,arial;font-size:13px"><br>
</div>
</div>
<br>
<p style="">On April 26, 2014 at 9:47:05 AM, Sri (<a
moz-do-not-send="true"
href="mailto:emdcdeveloper@gmail.com" target="_blank">emdcdeveloper@gmail.com</a>)
wrote:</p>
<blockquote type="cite"><span>
<div bgcolor="#FFFFFF" text="#000000">
<div> Hi Fillip<br>
Addition to my previous mail,
llvm has recompileAndRelinkFunction function , so,
once we modified the llvm function, and pass IR
to recompileAndRelinkFunction , I hope it should
be compiled and linked with previous one.<br>
<br>
Thanks<br>
<br>
Regards<br>
Sri.<br>
<div>On 04/26/2014 12:15 PM, Sri wrote:<br>
</div>
<blockquote type="cite">Hi Filip<br>
Thank you for your detailed
explanation, I was actually looking to implement
an adaptive approach which is basically when
some function executed more frequently, I was
trying to drop that function and compiled and
linked with new optimized function. I just did
the following -<br>
whenever some function executed more
times , I called-back to program, so I that I
could be able to call freeMachineCodeForFunction
(F) then I compiled that more frequent function
with some kind of optimization. But , still I am
getting previous function signature and not
newest one. Could you please explain , why we
can not use this freeMachineCodeForFunction for
this purpose. If not, how we can hook some
instruction in emitted machine code that will
call back to our code in llvm.<br>
<br>
Thanks<br>
<br>
With regards<br>
Sri.<br>
<div>On 04/26/2014 05:39 AM, Filip Pizlo wrote:<br>
</div>
<blockquote type="cite">
<div>This isn't currently supported directly.
It depends on what you're doing, which JIT
you're using, how you use modules, and to
what extent you're relying on LLVM to do
linking for you. </div>
<div><br>
</div>
<div>You can't safely drop a function's code
if you have other functions in that module. </div>
<div><br>
</div>
<div>You can't safely drop a module if there
are other modules that have calls that
you've already resolved to functions in the
module you're dropping unless you have your
own mechanism for unlinking those calls. </div>
<div><br>
</div>
<div>The MCJIT currently does support dropping
the memory for a module, but it involves
destroying the MCJIT execution engine
object. This works best if you use your own
JIT memory manager and you steal the
executable memory from the MCJIT, and delete
the MCJIT after code is generated. Then your
own memory manager can manage the memory
however you like. This depends on not having
LLVM call instructions resolve to any of the
functions you would be dropping. WebKit is
an example of a system that does this. Each
function gets it's own module and all LLVM
data structures are dropped once the code is
compiled. Call instructions are only used
for intrinsics and for runtime calls; source
level calls are implemented as patchpoints
and WebKit does all of the linking (and
unlinking). </div>
<div><br>
</div>
<div>Long story short, there is no
shrink-wrapped solution but it's doable if
you're willing to get dirty. <br>
<br>
-Fil</div>
<div><br>
On Apr 25, 2014, at 3:44 PM, Sri <<a
moz-do-not-send="true"
href="mailto:emdcdeveloper@gmail.com"
target="_blank">emdcdeveloper@gmail.com</a>>
wrote:<br>
<br>
</div>
<blockquote type="cite">
<div>Hi<br>
Currently , I have doing some
experimental work by using llvm, Is it
possible to drop the machine code once it
has been generated for particular function
while program executing. For example some
<b>void test(int)</b> function has been
executed on native machine , I want to
drop the code before I start execute some
other function in my long running program.<br>
<br>
Thanks.<br>
<br>
With regards<br>
Sri.<br>
<div> </div>
</div>
</blockquote>
<blockquote type="cite">
<div> <span>_______________________________________________</span><br>
<span>LLVM Developers mailing list</span><br>
<span><a moz-do-not-send="true"
href="mailto:LLVMdev@cs.uiuc.edu"
target="_blank">LLVMdev@cs.uiuc.edu</a>
<a moz-do-not-send="true"
href="http://llvm.cs.uiuc.edu"
target="_blank">http://llvm.cs.uiuc.edu</a></span><br>
<span><a moz-do-not-send="true"
href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev"
target="_blank">http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev</a></span><br>
</div>
</blockquote>
</blockquote>
<br>
<div> </div>
</blockquote>
<br>
</div>
</div>
</span></blockquote>
</blockquote>
<br>
<div> </div>
</div>
<br>
_______________________________________________<br>
LLVM Developers mailing list<br>
<a moz-do-not-send="true" href="mailto:LLVMdev@cs.uiuc.edu">LLVMdev@cs.uiuc.edu</a>
<a moz-do-not-send="true"
href="http://llvm.cs.uiuc.edu" target="_blank">http://llvm.cs.uiuc.edu</a><br>
<a moz-do-not-send="true"
href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev"
target="_blank">http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev</a><br>
<br>
</blockquote>
</div>
</blockquote>
<br>
</body>
</html>