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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">I should clarify that the tests I’m talking about are compile-and-execute tests, so they will still be relevant to the re-designed implementation. Unfortunately,
I don’t have them integrated with any LLVM testing mechanism. That’s something else I’ve been meaning to ask about.<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">Anyway, I think the results I’m seeing now are fairly significant, so I’d like to get these changes checked in -- especially given that it’s going to be a month
or more before an alternate approach is ready. I’d also like to talk about a transition plan so that we can minimize the backward steps taken as this is redesigned. Maybe a command line option to enable the new IR generation until an end-to-end implementation
is complete?<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’m working right now to clean up what I’ve done, but I should have it in a reviewable state today. After that, I’ll try to create some lit-based tests that
exercise the trouble spots that I am addressing.<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 don’t have any objections to turning MSVC C++ exceptions off by default, but I think it’s possible that with these changes that might not be necessary.<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> Thursday, May 14, 2015 9:12 AM<br>
<b>To:</b> Kaylor, Andrew<br>
<b>Cc:</b> David Majnemer; LLVM Developers Mailing List<br>
<b>Subject:</b> Re: [WinEH] A hiccup for the Windows C++ exception handling<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">On Wed, May 13, 2015 at 4:37 PM, Kaylor, Andrew <<a href="mailto:andrew.kaylor@intel.com" target="_blank">andrew.kaylor@intel.com</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"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">I made some progress this afternoon. I now have a set of changes in my local sandbox that allows
clang to pass all of the tests in the suite I’ve been using to exercise this code.</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">How do you feel about working these changes into trunk to establish a working baseline, even knowing
that parts of this are going to be redesigned?</span><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 I'm kind of ambivalent about continuing in the current direction. It doesn't hurt, but if it provides someone with basic functionality for now, then that's OK. On the other hand, the tests won't be particularly valuable because
Clang is going to emit new LLVM IR, so they'll need to be redone.<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 also think that, given that the rewrite will take at least a month, we should turn MSVC C++ exceptions off by default in Clang until it's ready. We need some hidden flag that isn't /EHs. I'm already tired of getting bug reports along
the lines of "clang crashed while compiling MSVC-style exceptions". Of course, the user can't tell from the crash that the workaround is just "turn off exceptions until they work". =/<o:p></o:p></p>
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