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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">What I’m seeing is that a landing pad instruction using __gcc_personality_v0 is generated for the CodeGen/X86/GC/alloc_loop.ll test case. The landing pad instruction
is in the gc_cleanup block after the (GCStrategy.cpp) LowerIntrinsics pass. My outlining patch adds the MSVCEHPrepare pass, which was flagging the presence of this personality function as an error.<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">If I just ignore the landing pad containing that personality function (or if my pass is never called), the gc_cleanup block eventually gets removed by the UnreachableBlockElim
pass.<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">So I can easily avoid the test failure, but it seems like something is wrong here.<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>
<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""> Reid Kleckner [mailto:rnk@google.com]
<br>
<b>Sent:</b> Tuesday, January 13, 2015 4:56 PM<br>
<b>To:</b> Kaylor, Andrew<br>
<b>Cc:</b> Reid Kleckner; llvm-commits@cs.uiuc.edu<br>
<b>Subject:</b> Re: [llvm] r224625 - Add the ExceptionHandling::MSVC enumeration<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">On Fri, Jan 9, 2015 at 11:02 AM, Kaylor, Andrew <<a href="mailto:andrew.kaylor@intel.com" target="_blank">andrew.kaylor@intel.com</a>> wrote:<o:p></o:p></p>
<p class="MsoNormal">Hi Reid,<br>
<br>
I just discovered that ShadowStackGC inserts landing pad instructions that use __gcc_personality_v0 without checking the exception handling type setting. It seems clear that ShadowStackGC needs to be updated, and I wonder if as a result of your changes below
GC isn't in a broken state on Windows with the MSVC environment. I'm not sure if that's even a supported combination right now, but it seems like we should at least include something in our planning to get this fixed.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">I guess ShadowStackGC crashes now rather than silently referencing a personality function that doesn't generally exist on the target? We should try not to crash, but that never would have worked.<o:p></o:p></p>
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