libgcc_s and libgcj contain a hack which renames _Unwind_FindEnclosingFunction to _darwin10_Unwind_FindEnclosingFunction on darwin targets. It appears this was introduced to work around an issue in OS X 10.6 where the _Unwind_FindEnclosingFunction was implemented as a stub which called abort(). see: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41991
This has since been fixed in OS X 10.7+, and the system's _Unwind_FindEnclosingFunction now works. In Mac OS X 10.7 and 10.8, libgcc_s is installed as a symlink to libSystem: $ ls -l /usr/lib/libgcc_s.1.dylib lrwxr-xr-x 1 root wheel 17 Jun 19 13:16 /usr/lib/libgcc_s.1.dylib -> libSystem.B.dylib Unfortunately this means that libgcj does not work on a standard Mac OS X installation, because dyld will see the symlink and resolve libgcc_s to libSystem before it checks anywhere else: $ gcj Hello.class --main=Hello $ ./a.out dyld: _dyld_bind_fully_image_containing_address() error dyld: Symbol not found: __darwin10_Unwind_FindEnclosingFunction Referenced from: /usr/local/lib/libgcj.13.dylib Expected in: /usr/lib/libSystem.B.dylib in /usr/local/lib/libgcj.13.dylib Trace/BPT trap: 5 This can be worked around by adjusting the system library path, or forcing libgcc_s to be loaded with DYLD_INSERT_LIBRARIES, but libgcj should work out-of-the-box for without having to hack the dyld configuration - so clearly we should not be renaming _Unwind_FindEnclosingFunction on OS X 10.7+ configurations. But I'm not convinced that this solution was ever really right to begin with. Even on a 10.6 system, things ought to work so long as you ensure libgcc_s is loaded before libSystem. Shouldn't the _darwin10_Unwind_FindEnclosingFunction rename be removed entirely? Bryce
