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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">The way I was looking at it, if the client uses a NULL JMM in the current implementation, it might work (or it might fail), whereas with your change it will
definitely fail.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">I can understand why you would consider the definite failure to be preferable, but the circumstances under which the current implementation works (relatively
small modules) are such that many clients may never see the failure, and it would be a shame to break existing clients when we don’t need to.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><br>
That said, I don’t have extremely strong feelings about this and am willing to live with it either way.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">-Andy<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> Danil Malyshev [mailto:dmalyshev@accesssoftek.com]
<br>
<b>Sent:</b> Thursday, July 26, 2012 3:50 PM<br>
<b>To:</b> Kaylor, Andrew; llvm-commits@cs.uiuc.edu<br>
<b>Subject:</b> RE: [llvm-commits] [PATCH][MCJIT] Removing DefaultJITMemoryManager from MCJITMemoryManager<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">Hi Andrew<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">I agree that the absence of default does not looks good.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">But in my view, using a non-working MemoryManager as default is even worse, because misleading.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">I think that LLIMCJITMemoryManager a good candidate for the default value, but I do not see as it's possible to use it for that right now. When the JIT goes out,
the DefaultJITMemoryManager can be merged with LLIMCJITMemoryManager and then it can be used as default MM again.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">Regards,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">Danil<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span lang="RU" style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span lang="RU" style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> Kaylor, Andrew [<a href="mailto:andrew.kaylor@intel.com">mailto:andrew.kaylor@intel.com</a>]
<br>
<b>Sent:</b> Thursday, July 26, 2012 10:29 PM<br>
<b>To:</b> Danil Malyshev; <a href="mailto:llvm-commits@cs.uiuc.edu">llvm-commits@cs.uiuc.edu</a><br>
<b>Subject:</b> RE: [llvm-commits] [PATCH][MCJIT] Removing DefaultJITMemoryManager from MCJITMemoryManager</span><span lang="RU"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="RU"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">It seems like a bad idea to start requiring a non-NULL JMM. It wasn’t long ago that the reference implementations like lli were leaving that NULL, and I believe
that for small objects it works. That said, I do think something needs to be done to get a better default behavior for MCJIT.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Did you happen to see my recent proposal for MCJIT enhancements?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">-Andy<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">
<a href="mailto:llvm-commits-bounces@cs.uiuc.edu">llvm-commits-bounces@cs.uiuc.edu</a> [<a href="mailto:llvm-commits-bounces@cs.uiuc.edu">mailto:llvm-commits-bounces@cs.uiuc.edu</a>]
<b>On Behalf Of </b>Danil Malyshev<br>
<b>Sent:</b> Wednesday, July 25, 2012 5:18 PM<br>
<b>To:</b> <a href="mailto:llvm-commits@cs.uiuc.edu">llvm-commits@cs.uiuc.edu</a><br>
<b>Subject:</b> [llvm-commits] [PATCH][MCJIT] Removing DefaultJITMemoryManager from MCJITMemoryManager<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">Hi everyone,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">Please review attached the patch.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">The MCJITMemoryManager shouldn't use the DefaultJITMemoryManager by following reason:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">1. It does not have any methods for invalidating instruction cache, so attempt to execute the code might be fail in ARM platforms.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">2. The repeated call of DefaultJITMemoryManager.allocateDataSection() fails.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">But the MCJITMemoryManager misleading because his constructor create the DefaultJITMemoryManager if jmm parameter is empty. This patch fixed it.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">Regards,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">Danil<o:p></o:p></span></p>
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