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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;mso-fareast-language:EN-US">Hi Anna,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;mso-fareast-language:EN-US">thanks for the positive feedback. I am sure this analysis option will be useful for many.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;mso-fareast-language:EN-US">We will consult with Laszlo Nagy on how to integrate 2-stage analysis into scan-build-py. I assume you did not mean the perl version
of scan-build.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;mso-fareast-language:EN-US">For those who are interested in the latest version of the patch it is moved into this repo:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;mso-fareast-language:EN-US"><a href="https://github.com/Ericsson/clang/tree/ctu-os">https://github.com/Ericsson/clang/tree/ctu-os</a><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;mso-fareast-language:EN-US">An extended version of the patch including coverage measurement is available on this branch:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;mso-fareast-language:EN-US"><a href="https://github.com/Ericsson/clang/tree/ctu-master">https://github.com/Ericsson/clang/tree/ctu-master</a><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;mso-fareast-language:EN-US"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;mso-fareast-language:EN-US">Thanks for the review in advance,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;mso-fareast-language:EN-US">Daniel<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif"> ganna@apple.com [mailto:ganna@apple.com]
<br>
<b>Sent:</b> 2017. április 8. 0:04<br>
<b>To:</b> Dániel Krupp <daniel.krupp@ericsson.com><br>
<b>Cc:</b> cfe-dev@lists.llvm.org<br>
<b>Subject:</b> Re: [cfe-dev] Cross Translational Unit Analysis in Clang Static Analyzer<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Hi Daniel,<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Thank you for sending the patch! While I think that doing whole project analysis via “inlining” is not a scalable solution, this prototype could be useful for the community to experiment with. It can also serve as bases for other two stage
analysis, where we collect some data about functions in the first pass and use it in the second pass. <o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">A side benefit is that this direction exercises the ASTImporter and would benefit other uses of it such as lldb.<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 am sure there will be a few comments about the patch itself and it’s important to have the workflow integrated into scan-build, which is our user facing tool.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">For those interested in the topic, I recommend watching Gabor’s talk at LLVM Euro 2017 once the video is available:<o:p></o:p></p>
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<p class="MsoNormal"><a href="http://llvm.org/devmtg/2017-03/2017/02/20/accepted-sessions.html#7">http://llvm.org/devmtg/2017-03//2017/02/20/accepted-sessions.html#7</a><o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Thank you!<o:p></o:p></p>
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<p class="MsoNormal">Anna<o:p></o:p></p>
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<p class="MsoNormal">On Mar 31, 2017, at 8:28 AM, Dániel Krupp via cfe-dev <<a href="mailto:cfe-dev@lists.llvm.org">cfe-dev@lists.llvm.org</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">Hi All,</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif"> </span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">at the EuroLLVM’17 conference we presented our results about a new analysis mode in clang static analyzer: Cross Translational Unit analysis.</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">See patch<span class="apple-converted-space"> </span></span><a href="https://reviews.llvm.org/D30691"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:purple">https://reviews.llvm.org/D30691</span></a><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">which is based on the work of A. Sidorin et al.<span class="apple-converted-space"> </span></span><a href="http://lists.llvm.org/pipermail/cfe-dev/2015-October/045730.html" target="_blank"><span lang="EN-US" style="font-size:10.0pt;font-family:"Segoe UI",sans-serif;color:#136CB2;background:white">http://lists.llvm.org/pipermail/cfe-dev/2015-October/045730.html</span></a><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">,
but without function summaries and updated to the newest Clang.</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif"> </span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">The CTU mode allows the analyzer to “inline” function calls that are defined in another TU than the one currently analyzed.</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">So it allows to find bugs that span multiple source files.</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">Without this patch the static analyzer engine, when meets an external function call,</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">cannot reason about the return value of a function (unknown) and the pointed values, references passed to a function as parameter are invalidated.</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif"> </span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">You can find a full patched clang 4.0 (use it with llvm commit 01609a325b5f85d88e3ab5c7d470409092436cb2 )</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><a href="https://github.com/dkrupp/clang/tree/ctu-master"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:purple">https://github.com/dkrupp/clang/tree/ctu-master</span></a><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif"> </span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">We have run the analysis on some reasonably-sized (ffmpeg, curl, vim, openssl, postgresql) open source C projects and found many additional true positive reports
compared to the traditional single TU mode in all projects.</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">This indicates that this feature would give many new results on any project.</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif"> </span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">We measured the heap usage, the analysis time and the number of new findings.</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">You can find the detailed comparison results here:</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><a href="http://cc.elte.hu/clang-ctu/"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:purple">http://cc.elte.hu/clang-ctu/</span></a><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">In summary, the number of reported bugs is ~1.5-5x times the original single TU analysis, at the cost of 1.5-5x higher analysis time, 1.5-5x max heap usage (roughly
in proportion to the increase in the number of reported faults).</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif"> </span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">The design concept is described shortly in this document:<span class="apple-converted-space"> </span></span><a href="http://cc.elte.hu/clang-ctu/eurollvm17/abstract.pdf"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:purple">http://cc.elte.hu/clang-ctu/eurollvm17/abstract.pdf</span></a><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif"> </span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">If you would like to try this analysis mode on your project please find the description of the 2 new additional analyzer scripts here:</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><a href="https://github.com/dkrupp/clang/blob/ctu-master/tools/xtu-build-new/readme.md"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:purple">https://github.com/dkrupp/clang/blob/ctu-master/tools/xtu-build-new/readme.md</span></a><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif"> </span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">Would be happy to hear your opinion and experiences with this feature and would appreciate your help in reviewing the patch.</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif"> </span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">Thanks & Regards,</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">Daniel</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif"> </span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif">_______________________________________________<br>
cfe-dev mailing list<br>
</span><a href="mailto:cfe-dev@lists.llvm.org"><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif;color:purple">cfe-dev@lists.llvm.org</span></a><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif"><br>
</span><a href="http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev"><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif;color:purple">http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev</span></a><o:p></o:p></p>
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