[Bug libbacktrace/96973] No backtrace for cc1 on x86_64-apple-darwin

[fxcoudert at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96973

--- Comment #3 from Francois-Xavier Coudert <fxcoudert at gcc dot gnu.org> ---
In macho_add_fat(), the code correctly identifies 2 archs, with the right types
(first i386, then x86_64). It's then calling macho_add() for the x86_64 arch,
with an foffset of 0x0000b00000000000, which looks very weird to me.

That code has a FIXME, so maybe that's the issue?

          /* FIXME: What about cpusubtype?  */
          foffset = fat_arch.offset;
          if (swapped)
            foffset = __builtin_bswap64 (foffset);
          backtrace_release_view (state, &arch_view, error_callback, data);
          return macho_add (state, filename, descriptor, foffset, match_uuid,
                            base_address, skip_symtab, error_callback, data,
                            fileline_fn, found_sym);