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<p class="MsoNormal">Is… Lang now added? I’m not sure about this system…<br>
<br>
My problem is that I can not change the size of the shared memory I’m targeting – so I can only allocate it once, but how do I know how much memory I’m going to need, when each sections requests the memory after each other?<br>
To work around this I first allocate the memory locally and count the bytes it needed. After notifyObjectLoaded I can request the shared memory and do the mapping. But this only covers one module. If I have two modules for example, then I will end up having
two shared memories, because the second module will go through the same steps as the first one. But I want to have one coherent memory.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Also the applying of the mapping causes a bug with the new LLVM7 – I already filled out a bug report for this. But I have no idea how things will progress from that point… Still I have no idea about the system…<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><b>From:</b> David Blaikie <dblaikie@gmail.com> <br>
<b>Sent:</b> Mittwoch, 7. November 2018 17:34<br>
<b>To:</b> Gaier, Bjoern <Bjoern.Gaier@horiba.com><br>
<b>Cc:</b> llvm-dev <llvm-dev@lists.llvm.org><br>
<b>Subject:</b> Re: [llvm-dev] JIT-Client for Shared Memory<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt">Adding Lang here in case he's got some insight.<br>
<br>
I take it the system you're targeting doesn't have the memory limitations that some systems have, where once memory is set executable, it can never be written to? & so you'd like to write some code into a page, execute it, write some more code into the same
page and have that execute too?<br>
<br>
(I don't know teh JIT architecture well enough to know if that's supported, or if I'm accurately understanding your situation, etc)<o:p></o:p></p>
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<p class="MsoNormal">On Thu, Nov 1, 2018 at 11:49 PM Gaier, Bjoern via llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org" target="_blank">llvm-dev@lists.llvm.org</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Hello everyone,<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">I want to use the LLVM to write a JIT client, that works with shared memory. Currently I proceed as following:<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">I wrote an own class that inherits "<i>RTDyldMemoryManager</i>". The functions "<i>allocateCodeSection</i>" and "<i>allocateDataSection</i>" are allocating local non-shared memory.
I store there addresses in a std::vector.<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">When the function "<i>notifyObjectLoaded</i>" is invoked, I allocate the shared memory - I'm getting the size from the local non-shared memory - and apply the address mapping.<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">When the function "<i>finalizeMemory</i>" is invoked I copy the code from the local non-shared memory to the shared memory but only one time.
<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">So far so good, this works actually good! Yippie x3<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">BUT... There is one problem. The shared memory can't be dynamical adjusted. So if I add another module to the current module, then I would go through this process again! Not the
"<i>finalizeMemory</i>" process though, but I would allocate another shared memory. This is not what I want! Currently I use the linker first, to work around this problem, but this will not help me if I add object files or libraries to the JIT process - or
does it?<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">So is there any way to work around this?<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Kind greetings<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Björn<o:p></o:p></p>
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<o:p></o:p></p>
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<p class="MsoNormal">_______________________________________________<br>
LLVM Developers mailing list<br>
<a href="mailto:llvm-dev@lists.llvm.org" target="_blank">llvm-dev@lists.llvm.org</a><br>
<a href="http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev" target="_blank">http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev</a><o:p></o:p></p>
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