http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47558
--- Comment #25 from Jack Howarth <howarth at nitro dot med.uc.edu> 2011-02-01 18:22:45 UTC --- Again, I would note Nick's original comments on these issues... This may be that the libgcc_s.dylib based unwinder is incompatible with the darwin unwinder. You cannot mix and match the two. One of the lines from the bugzilla comments shows: /sw/lib/gcc4.5/lib/libgcc_s.1.dylib (compatibility version 1.0.0, being used. That will not work. All of the libgcc_s.dylib functionality has been subsumed into libSystem.dylib on SnowLeopard (darwin10). The gcc compiler that shipped with SnowLeopard leaves the -lgcc_s off the link line when targeting SnowLeopard. If there is a newer libgcc_s with new functions added, then the link line needs to change to "-lSystem -lgcc_s", that way the linker will find the most routines in libSystem.dylib and only the new functions from libgcc_s.dylib. Thus all linkage units will use the same unwinder. So for compatibility with any Apple gcc built software, we should never allow the FSF gcc unwinder to become operational under any circumstances.
