So you tracked down these unitialized values down to the strxxx functions defined in ld.so and Valgrind normally intercepts these calls because Memcheck can't handle the sorts of code that is generated for these routines? Is it possible to teach Memcheck to deal with these optimizations?
Steve Munroe, the author of those optimized strxxx functions, tells me that the kinds of optimizations done for these routines are going to start appearing in other library routines, and possibly in generated object code so the problem is going to become more pervasive. Julian Seward wrote: > On Monday 12 November 2007 03:28, Paul Mackerras wrote: > >> It's now used as the TLS pointer. [...] >> > > Thanks for the info. > > After hours of frustratingly chasing undefined values around vast > nameless blocks of machine code, I discovered the large numbers of > uninitialised values are a result of having /lib/ld-2.6.1.so being > almost completely devoid of symbol table info. > > On ppc32, ld.so has its own strlen/strcmp/strchr functions, which do > strange things with carry bits that fool Memcheck. (or something > that it can't handle - I can't remember). > > For glibc <= 2.5 V simply supplied its own non-optimised replacements > for these functions in ld.so, and used them. That worked fine, but > now fails because the strlen/strcmp/strchr symbols on ld.so are no > longer present. Installing the debuginfo package provides that info, > so V's replacements kick in, and the problem goes away. > > Result is that on ppc32-linux and ppc64-linux, for glibc 2.6 and later, > Valgrind will be unusable unless glibc-2.6-debuginfo.rpm is installed. > > J > > ------------------------------------------------------------------------- > This SF.net email is sponsored by: Splunk Inc. > Still grepping through log files to find problems? Stop. > Now Search log events and configuration files using AJAX and a browser. > Download your FREE copy of Splunk now >> http://get.splunk.com/ > _______________________________________________ > Valgrind-developers mailing list > Valgrind-developers@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/valgrind-developers > -- Dave Nomura LTC Linux Power Toolchain ------------------------------------------------------------------------- SF.Net email is sponsored by: The Future of Linux Business White Paper from Novell. From the desktop to the data center, Linux is going mainstream. Let it simplify your IT future. http://altfarm.mediaplex.com/ad/ck/8857-50307-18918-4 _______________________________________________ Valgrind-developers mailing list Valgrind-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/valgrind-developers
