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<p class="MsoNormal"><span style="color:#1F4E79;mso-style-textfill-fill-color:#1F4E79;mso-style-textfill-fill-alpha:100.0%">Hi,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F4E79;mso-style-textfill-fill-color:#1F4E79;mso-style-textfill-fill-alpha:100.0%"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F4E79;mso-style-textfill-fill-color:#1F4E79;mso-style-textfill-fill-alpha:100.0%">Attempting to use LLVM in jitting mode for AMD64, we met a problem.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F4E79;mso-style-textfill-fill-color:#1F4E79;mso-style-textfill-fill-alpha:100.0%">When the jitted routine needs a big stack frame (> 1 page), the system attempts to call __chkstk to probe the stack.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F4E79;mso-style-textfill-fill-color:#1F4E79;mso-style-textfill-fill-alpha:100.0%">This attempt results in assertion in
</span><span style="color:#1F4E79;mso-style-textfill-fill-color:#1F4E79;mso-style-textfill-fill-alpha:100.0%;background:white;mso-highlight:white">RuntimeDyldELF::resolveX86_64Relocation</span><span style="color:#1F4E79;mso-style-textfill-fill-color:#1F4E79;mso-style-textfill-fill-alpha:100.0%">(),
<span style="background:white;mso-highlight:white">case ELF::R_X86_64_PC32</span>,</span><span style="color:#1F4E79;mso-style-textfill-fill-color:#1F4E79;mso-style-textfill-fill-alpha:100.0%"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F4E79;mso-style-textfill-fill-color:#1F4E79;mso-style-textfill-fill-alpha:100.0%">because the RealOffset does not fit in 32 bits.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F4E79;mso-style-textfill-fill-color:#1F4E79;mso-style-textfill-fill-alpha:100.0%"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F4E79;mso-style-textfill-fill-color:#1F4E79;mso-style-textfill-fill-alpha:100.0%">Same happens with
</span><span style="color:#1F4E79;mso-style-textfill-fill-color:#1F4E79;mso-style-textfill-fill-alpha:100.0%;background:white;mso-highlight:white">__alloca</span><span style="color:#1F4E79;mso-style-textfill-fill-color:#1F4E79;mso-style-textfill-fill-alpha:100.0%">
(when <span style="background:white;mso-highlight:white">IRBuilder::CreateAlloca</span> appears in a conditional block).<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F4E79;mso-style-textfill-fill-color:#1F4E79;mso-style-textfill-fill-alpha:100.0%">Perhaps the issue can be fixed by using indirect call via 64-bit register or replicating service routines inside jitted block.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F4E79;mso-style-textfill-fill-color:#1F4E79;mso-style-textfill-fill-alpha:100.0%"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F4E79;mso-style-textfill-fill-color:#1F4E79;mso-style-textfill-fill-alpha:100.0%">Is it known issue?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F4E79;mso-style-textfill-fill-color:#1F4E79;mso-style-textfill-fill-alpha:100.0%">Repro is available on demand, just let us know in which form you’d like to get it.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F4E79;mso-style-textfill-fill-color:#1F4E79;mso-style-textfill-fill-alpha:100.0%"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F4E79;mso-style-textfill-fill-color:#1F4E79;mso-style-textfill-fill-alpha:100.0%">Regards,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F4E79;mso-style-textfill-fill-color:#1F4E79;mso-style-textfill-fill-alpha:100.0%">Mikhail<o:p></o:p></span></p>
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