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<p class="MsoNormal">Hello everyone,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span lang="EN-CA">I was wondering what is the status regarding exceptions for the windows-msvc target? The corresponding part of the documentation (llvm/decs/ExceptionHandling.rst) hasn’t been updated since 2015, was there any progress
since?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA">This is most likely known, but there’s significant divergence between the behavior of MSVC cl.exe and clang-cl.exe:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA">Consider:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA"><o:p> </o:p></span></p>
<p class="MsoNormal" style="margin-left:35.4pt;text-autospace:none"><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:blue">void</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:#880000">crash</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:black">() {<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:35.4pt;text-autospace:none"><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:blue"> struct</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:blue">A</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:black"> {<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:35.4pt;text-autospace:none"><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:black"> ~</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:blue">A</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:black">()
{}<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:35.4pt;text-autospace:none"><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:black"> } Obj;<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:35.4pt;text-autospace:none"><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:black"> *(</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:blue">volatile</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:blue">int</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:black"> *)0x11 = 0;<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:35.4pt;text-autospace:none"><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:black">}<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:35.4pt;text-autospace:none"><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:black"><o:p> </o:p></span></p>
<p class="MsoNormal" style="margin-left:35.4pt;text-autospace:none"><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:gray">#ifdef</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:#A000A0">SEH</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:black"><o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:35.4pt;text-autospace:none"><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:gray"> #define</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:#A000A0">TRY</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:blue">__try</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:black"><o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:35.4pt;text-autospace:none"><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:gray"> #define</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:#A000A0">CATCH_ALL</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:blue">__except</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:black"> (1)<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:35.4pt;text-autospace:none"><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:gray">#else</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:black"><o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:35.4pt;text-autospace:none"><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:gray"> #define</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:#A000A0">TRY</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:blue">try</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:black"><o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:35.4pt;text-autospace:none"><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:gray"> #define</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:#A000A0">CATCH_ALL</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:blue">catch</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:black"> (...)<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:35.4pt;text-autospace:none"><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:gray">#endif</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:black"><o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:35.4pt;text-autospace:none"><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:black"><o:p> </o:p></span></p>
<p class="MsoNormal" style="margin-left:35.4pt;text-autospace:none"><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:blue">int</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:black">
</span><i><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:#880000">main</span></i><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:black">() {<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:35.4pt;text-autospace:none"><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:#A000A0">TRY</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:black"> {
</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:#880000">crash</span><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:black">(); }<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:35.4pt;text-autospace:none"><span lang="EN-CA" style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span style="font-size:9.5pt;font-family:Consolas;color:#A000A0">CATCH_ALL</span><span style="font-size:9.5pt;font-family:Consolas;color:black"> {}<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:35.4pt;text-autospace:none"><span style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span style="font-size:9.5pt;font-family:Consolas;color:blue">return</span><span style="font-size:9.5pt;font-family:Consolas;color:black"> 0;<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:35.4pt"><span style="font-size:9.5pt;font-family:Consolas;color:black">}<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:35.4pt"><span style="font-size:9.5pt;font-family:Consolas;color:black"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA">using try/catch (SEH not defined):<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA" style="font-size:10.0pt;font-family:"Courier New""> | (default) | /EHa | /EHs |<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA" style="font-size:10.0pt;font-family:"Courier New"">--------------------------------------------------------------------------------------------------------<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA" style="font-size:10.0pt;font-family:"Courier New"">MSVC cl | warning [1], no unwind, crash catched | unwind, crash catched | crash unhandled |<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA" style="font-size:10.0pt;font-family:"Courier New"">clang-cl | compilation error [2] | crash unhandled | crash unhandled |<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA">using __try/__except (SEH defined):<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA" style="font-size:10.0pt;font-family:"Courier New""> | (default) | /EHa | /EHs |<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA" style="font-size:10.0pt;font-family:"Courier New"">--------------------------------------------------------------------------------------------------------<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA" style="font-size:10.0pt;font-family:"Courier New"">MSVC cl | no unwind, crash catched | unwind, crash catched | crash unhandled |<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA" style="font-size:10.0pt;font-family:"Courier New"">clang-cl | no unwind, crash catched | no unwind, crash catched | no unwind, crash catched |<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA" style="font-size:10.0pt;font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA">According to Microsoft’s documentation [3],<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA"> (default) means: async exceptions + C++ exceptions, but no unwinding<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA"> /EHa means: async exceptions + C++ exceptions, with unwinding in both cases<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA"> /EHs means: C++ exceptions only, with unwinding<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA">I’m using MSVC VS2017 15.9.16 and clang-cl from github at HEAD. In both cases I’m targeting x64.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA">Using _set_se_translator [4] and /EHa does not help with clang-cl.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA" style="font-size:9.0pt;font-family:"Courier New";color:black"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA">Are there any plans to improve the async exceptions unwinding in the short term?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA">Thanks!<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA">Alex.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA" style="font-size:9.0pt;font-family:"Courier New";color:black"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA" style="font-size:9.0pt;font-family:"Courier New";color:black"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA" style="font-size:10.0pt;font-family:"Courier New"">[1] warning C4530: C++ exception handler used, but unwind semantics are not enabled. Specify /EHsc<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA" style="font-size:10.0pt;font-family:"Courier New"">[2] error: cannot use 'try' with exceptions disabled<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA" style="font-size:10.0pt;font-family:"Courier New";color:black">[3]
</span><span style="font-size:10.0pt;font-family:"Courier New""><a href="https://docs.microsoft.com/en-us/cpp/build/reference/eh-exception-handling-model?view=vs-2019"><span lang="EN-CA">https://docs.microsoft.com/en-us/cpp/build/reference/eh-exception-handling-model?view=vs-2019</span></a><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Courier New"">[4]
<a href="https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/set-se-translator?view=vs-2019">
https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/set-se-translator?view=vs-2019</a><span style="color:black"><o:p></o:p></span></span></p>
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