On Sun, 2012-10-28 at 11:35 +0100, Bernhard R. Link wrote: > * Philip Ashmore <contact@philipashmore.com> [121028 09:12]: > > Yeah, in (cough)Fedora, kdbg even offers to download and install > > debug packages for you. > > Debug packages also make back-traces more than useless, and > > (cough)Ubuntu offers to download debug packages which it installs > > and re-examines the back-trace to see if more are needed. > > While having some way to get the stripped debug info from the installed > packages is nice to more easily get some debug information or to > retroactively make a backtrace a bit more verbose, it is still not > enough for all cases of debugging. Ideal debugging information you get > by locally rebuilding the needed libraries with > DEB_BUILD_OPTIONS="noopt nostrip" and installing those. > (Sadly not all libraries support noopt, but it's getting much better as a > side effect of the current hardening effords). There are plenty of bugs that involve 'undefined behaviour' that in practice depends on whether optimisation is enabled. Unless you have a good idea what's going wrong, how do you know that 'noopt' won't hide the bug? Also, gdb and the GNU toolchain have recently got a lot better at handling highly optimised code (tracking variables in registers, treating inlined functions as logically separate functions, etc.). Ben. -- Ben Hutchings Reality is just a crutch for people who can't handle science fiction.
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