Does anyone know what it would take to get the slow unwinder to work on Darwin?
thanks, vedant > On Apr 13, 2017, at 6:59 PM, Vedant Kumar via cfe-commits > <cfe-commits@lists.llvm.org> wrote: > > Author: vedantk > Date: Thu Apr 13 20:59:44 2017 > New Revision: 300295 > > URL: http://llvm.org/viewvc/llvm-project?rev=300295&view=rev > Log: > [docs] UBSan: Mention that print_stacktrace=1 is unsupported on Darwin > > Printing out stack traces along with UBSan diagnostics is unsupported on > Darwin. That's because it isn't possible to use the fast unwinder or the > slow unwinder. > > Apparently, it's inappropriate to use the fast unwinder for UBSan > issues. I'm not exactly sure why (see the comment in ubsan_diag.cc). > Forcing use of the fast unwinder produces decent results, AFAICT. > > Darwin also does not appear to have a slow unwinder suitable for use > with the sanitizers. Apparently that's because of PR20800 [1][2]. But > that bug has been fixed. I'm not sure if there is anything preventing > use of the slow unwinder now. > > Currently, passing UBSAN_OPTIONS=print_stacktrace=1 does nothing on > Darwin. This isn't good, but it might be a while before we can fix the > situation, so we should at least document it. > > [1] https://github.com/google/sanitizers/issues/137 > "We can't use the slow unwinder on OSX now, because Clang produces > incorrect unwind info for the ASan runtime functions on OSX > (http://llvm.org/PR20800)." > > [2] https://bugs.llvm.org/show_bug.cgi?id=20800 > Bug 20800 - Invalid compact unwind info generated for a function without > frame pointers on OSX > > Modified: > cfe/trunk/docs/UndefinedBehaviorSanitizer.rst > > Modified: cfe/trunk/docs/UndefinedBehaviorSanitizer.rst > URL: > http://llvm.org/viewvc/llvm-project/cfe/trunk/docs/UndefinedBehaviorSanitizer.rst?rev=300295&r1=300294&r2=300295&view=diff > ============================================================================== > --- cfe/trunk/docs/UndefinedBehaviorSanitizer.rst (original) > +++ cfe/trunk/docs/UndefinedBehaviorSanitizer.rst Thu Apr 13 20:59:44 2017 > @@ -157,6 +157,8 @@ will need to: > ``UBSAN_OPTIONS=print_stacktrace=1``. > #. Make sure ``llvm-symbolizer`` binary is in ``PATH``. > > +Stacktrace printing for UBSan issues is currently not supported on Darwin. > + > Issue Suppression > ================= > > > > _______________________________________________ > cfe-commits mailing list > cfe-commits@lists.llvm.org > http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
