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<p class="MsoNormal">Hi David,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Following up on the problems we discussed yesterday on IRC regarding TLS with MCJIT, I’ve put together the attached experimental patch.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">This patch makes three changes:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="mso-list:Ignore">1.<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>SectionMemoryManager is changed to request memory below the 2GB boundary by default.<o:p></o:p></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="mso-list:Ignore">2.<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>sys::Memory::allocateMappedMemory is changed to set the MAP_32BIT flag if the requested “near” block is below the 2GB boundary.<o:p></o:p></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="mso-list:Ignore">3.<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>RuntimeDyldELF is changed to recognize the possibility of external data symbols.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Of these changes, items 2 and 3 are probably reasonable things to commit into trunk, and depending on how this turns out I will do so. Item 1 is a bit heavy-handed as presented here, but it suggests the type of thing that subclasses of
SectionMemoryManager could do to make this work. If we had a way to communicate the code model to the memory manager from RuntimeDyld/MCJIT (and we obviously should!) then SectionMemoryManager could do something like this when small or medium memory models
are selected on applicable platforms.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">When I tried this patch with the test case you provided yesterday it got through the compilation phase with lli using the small code model and the static relocation model, but it ultimately failed (but failed gracefully) because it couldn’t
resolve the ‘_ThreadRuneLocale’ symbol. Resolution of external symbols is meant to be handled by the memory manager, so I thought perhaps you could get something working with this patch.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Please give this a try and let me know how it works.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thanks,<o:p></o:p></p>
<p class="MsoNormal">Andy<o:p></o:p></p>
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