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<p class="MsoNormal"><span lang="EN-US">Hello Vedant,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal">> What's not clear to me is why dso-specific .profraw files are helpful for code coverage, since merged .profraw's should work just as well.<o:p></o:p></p>
<p class="MsoNormal"><span style="color:black">> Have you encountered issues using merged .profraws? </span>Could you clarify what's meant by backtracking and instrumenting [the] final binary?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span lang="EN-US">There were problems when decoding merged profraw files. Couldn’t recall exactly error messages. But symbols in the profraws could not at all be matched to their definitions in the .so files.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Also tried %m which worked, except that we had no way to know which .so file corresponded to which .profraw file when decoding them.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Hence we added %n.<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thank you.<o:p></o:p></p>
<p class="MsoNormal">-Hiral<span lang="EN-US"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span lang="EN-US">From:</span></b><span lang="EN-US"> Vedant Kumar <vsk@apple.com>
<br>
<b>Sent:</b> Friday, 24 September, 2021 00:01<br>
<b>To:</b> Oza, Hiral <Hiral.Oza@netapp.com><br>
<b>Cc:</b> llvm-dev@lists.llvm.org; cfe-dev@lists.llvm.org<br>
<b>Subject:</b> Re: [cfe-dev] compiler-rt RFE to support creating profraw for each Shared Library<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<b><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:yellow">NetApp Security WARNING</span></b><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:yellow">: This is an external email. Do not click links or open attachments unless
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<p class="MsoNormal">Hi Oza, <o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">The mechanics of the patch are clear. What's not clear to me is why dso-specific .profraw files are helpful for code coverage, since merged .profraw's should work just as well.<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 style="color:black">Have you encountered issues using merged .profraws? </span>Could you clarify what's meant by backtracking and instrumenting [the] final binary?<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">thanks,<o:p></o:p></p>
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<p class="MsoNormal">vedant<o:p></o:p></p>
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<p class="MsoNormal">On Sep 22, 2021, at 9:36 PM, Oza, Hiral <<a href="mailto:Hiral.Oza@netapp.com">Hiral.Oza@netapp.com</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">Hello Vedant,<o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<p class="MsoNormal">> could you share some of the use cases for this feature? > What were the pros/cons of any alternatives you considered (e.g. the %m/%c modes)?<o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<p class="MsoNormal">We are taking coverage of shared libraries (i.e. Linux .so) and dumping coverage into files corresponding to SO’s filename.<o:p></o:p></p>
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<p class="MsoNormal">With this proposed patch, will get coverage as below for sample code (pls refer<span class="apple-converted-space"> </span><span class="diff-banner-path">compiler-rt/test/profile/Linux/</span><span class="diff-banner-file">instrprof-shared-nProfraws.test)</span>:<o:p></o:p></p>
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<p class="MsoNormal" style="text-indent:36.0pt">libhi.so -> will dump into libhi.so.profraw<o:p></o:p></p>
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<p class="MsoNormal" style="text-indent:36.0pt">libhello.so -> will dump into libhellp.so.profraw<o:p></o:p></p>
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<p class="MsoNormal" style="text-indent:36.0pt">main.out -> will dump into main.out.profraw<o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<p class="MsoNormal">Regarding ‘%m or %c: (from<span class="apple-converted-space"> </span><a href="https://clang.llvm.org/docs/SourceBasedCodeCoverage.html"><span style="color:#0563C1">https://clang.llvm.org/docs/SourceBasedCodeCoverage.html</span></a>): %m
is expands instrumented binary’s signature (and with “%Nm” dumps into poll of N profraws) and %c seems very different from proposed “%n”.<o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<p class="MsoNormal">Basically with proposed patch (i.e. using “%n”) one can get one-to-one mapping of Shared Library and generated .profraw.<o:p></o:p></p>
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<p class="MsoNormal">This makes backtracking and instrumenting final-binary based on feedback easy.<o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<p class="MsoNormal">Please let me know in case of further queries or any changes in proposed patch.<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">-Hiral<o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<p class="MsoNormal"><b><span lang="EN-US">From:</span></b><span class="apple-converted-space"><span lang="EN-US"> </span></span><span lang="EN-US">cfe-dev <<a href="mailto:cfe-dev-bounces@lists.llvm.org"><span style="color:#0563C1">cfe-dev-bounces@lists.llvm.org</span></a>><span class="apple-converted-space"> </span><b>On
Behalf Of<span class="apple-converted-space"> </span></b>Oza, Hiral via cfe-dev<br>
<b>Sent:</b><span class="apple-converted-space"> </span>Wednesday, 22 September, 2021 18:56<br>
<b>To:</b><span class="apple-converted-space"> </span><a href="mailto:cfe-dev@lists.llvm.org"><span style="color:#0563C1">cfe-dev@lists.llvm.org</span></a>; llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org"><span style="color:#0563C1">llvm-dev@lists.llvm.org</span></a>><br>
<b>Subject:</b><span class="apple-converted-space"> </span>[cfe-dev] compiler-rt RFE to support creating profraw for each Shared Library</span><o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<b><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:yellow">NetApp Security WARNING</span></b><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:yellow">: This is an external email. Do not click links or open attachments unless
you recognize the sender and know the content is safe.</span><o:p></o:p></p>
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<p class="MsoNormal">Greetings!<o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<p class="MsoNormal">Please review our patch compiler-rt RFE patch here --<span class="apple-converted-space"> </span><a href="https://reviews.llvm.org/D110232"><span style="color:#0563C1">https://reviews.llvm.org/D110232</span></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">This patch is about creating profraw for each Shared Library.<o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<p class="MsoNormal"><patch_info><o:p></o:p></p>
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<pre><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">SBCC RFE: Support SBCC for Shared Library</span><o:p></o:p></pre>
<pre><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> </span><o:p></o:p></pre>
<pre><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">SBCC RFE: Support SBCC for Shared Library</span><o:p></o:p></pre>
<pre><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Using '%n' format parameter for profile name templates, to insert the full</span><o:p></o:p></pre>
<pre><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">path of the current shared object into profile file names.</span><o:p></o:p></pre>
<pre><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> </span><o:p></o:p></pre>
<pre><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Internally using a linked list to gather all profile dumping functions</span><o:p></o:p></pre>
<pre><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">(there is one defined in each shared object) so they can be invoked with a</span><o:p></o:p></pre>
<pre><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">single function call. Ensure the resulting directory paths are created</span><o:p></o:p></pre>
<pre><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">prior to dumping.</span><o:p></o:p></pre>
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<p class="MsoNormal"></patch_info><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 in advance for your kind review.<o:p></o:p></p>
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<p class="MsoNormal">-Hiral<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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