http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48835
--- Comment #10 from Mikael Pettersson <mikpe at it dot uu.se> 2011-06-14 08:12:54 UTC --- (In reply to comment #9) > > - __gnat_malloc is defined in Ada to return Address (integer, so in d0), but > > it's called from a couple of places via fake "extern" declarations that > > pretend > > it returns void* (pointer, so in a0). The attached patch fixes the two call > > sites affected (in Interfaces.C.Strings and build_call_alloc_dealloc), as > > well > > as the internal fake prototype (init_gigi_decls). > > - Source code inspection showed that get_jmpbuf_address probably suffers > > from > > the same issue (mismatching decl and use via wrong intermediate fake > > prototype) > > so I fixed that too. > > I don't think that we want __gnat_malloc to return anything else than a > pointer > in the GCC representation. Its DECL node is DECL_IS_MALLOC and had better > mimic a canonical malloc as much as possible. In that case the Ada side of __gnat_malloc has to be changed to use a pointer type rather than Address. Is Interfaces.C.Strings.chars_ptr acceptible, or is there a better approximation for void* somewhere? > Andreas mentioned a compatibility trick in comment #6. How is it implemented? The effect is that a pointer-valued callee returns its value in both %a0 and %d0. A caller that has seen the pointer-valued prototype picks up the value from %a0, but a caller that hasn't seen that prototype picks it up from %d0. The actual implementation is in m68k_function_value.
