<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class="">Hi Kirill,</div><div class=""><br class=""></div><div class="">The checkPreStmt callback should be used by checkers that require symbolic execution. Check out the video of our talk for introduction into how that works <a href="http://llvm.org/devmtg/2012-11/videos/Zaks-Rose-Checker24Hours.mp4" class="">http://llvm.org/devmtg/2012-11/videos/Zaks-Rose-Checker24Hours.mp4</a>. Looks like this checker is only performing a syntactic check, so using an AST visitor would be more appropriate <a href="http://clang-analyzer.llvm.org/checker_dev_manual.html#ast" class="">http://clang-analyzer.llvm.org/checker_dev_manual.html#ast</a>.</div><div class=""><br class=""></div><div class="">However, most importantly, similar functionality is already implemented in the compiler (see -Wfloat-equal)! Looks like it does not work when comparing against a constant. I am not sure what the reason for that is; was it a a source of false positives or just an oversight.</div><div class=""><br class=""></div><div class="">Since the warning is in place, we should remove this from the list of checkers to be implemented.</div><div class=""><br class=""></div><div class="">Thank you,</div><div class="">Anna.</div><div class=""><br class=""><div><blockquote type="cite" class=""><div class="">On Sep 2, 2015, at 2:58 PM, Kirill Bobyrev via cfe-dev <<a href="mailto:cfe-dev@lists.llvm.org" class="">cfe-dev@lists.llvm.org</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class="">
<div bgcolor="#FFFFFF" text="#000000" class="">
I've started implementing different.FloatingCompare checker from the
<a href="http://clang-analyzer.llvm.org/potential_checkers.html" class="">list of potential checkers</a>. I'd like to gather some feedback and do some improvements in order to push the code to the upstream in the near future.</div><div bgcolor="#FFFFFF" text="#000000" class=""><br class=""></div><div bgcolor="#FFFFFF" text="#000000" class="">Vassil Vassilev mentioned it might be reasonable if the checker could detect that there is division which might yield precision loss and then detect a check against a 'constant' values.</div><div bgcolor="#FFFFFF" text="#000000" class=""><br class=""></div><div bgcolor="#FFFFFF" text="#000000" class="">What do you think? What should be the checker's default behavior?</div><div bgcolor="#FFFFFF" text="#000000" class=""><br class=""></div><div bgcolor="#FFFFFF" text="#000000" class="">The first version of checker is attached.</div><div bgcolor="#FFFFFF" text="#000000" class="">
<br class="">
--<br class="">
Kirill Bobyrev<br class="">
<a href="https://github.com/omtcyf0" target="_blank" class="">https://github.com/omtcyf0</a><br class="">
</div>
</div>
<span id="cid:2A870EB9-86D3-4EB0-9FA5-635750006BF6"><FloatingCompareChecker.patch></span>_______________________________________________<br class="">cfe-dev mailing list<br class=""><a href="mailto:cfe-dev@lists.llvm.org" class="">cfe-dev@lists.llvm.org</a><br class="">http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev<br class=""></div></blockquote></div><br class=""></div></body></html>