[Bug ada/48835] Porting GNAT to GNU/Linux/m68k

["mikpe at it dot uu.se" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48835

--- Comment #21 from Mikael Pettersson <mikpe at it dot uu.se> 2011-07-12 15:42:35 UTC ---
The problem is that LIBGNAT_TARGET_PAIRS is applied too late, and stage 1, 2,
and 3 gnat1 etc are built out of a fixed set of source files that your target
fragment in gcc/ada/gcc-interface/Makefile.in cannot influence (AFAIK).

You can observe this easily with a bootstrap on e.g. i686-linux.  On that
platform system.ads should be replaced by system-linux-x86.ads, but the build
log clearly shows stage 1, 2, 3 compiling the default gcc/ada/system.ads from
the gcc source dir and linking that .o file into gnat1 etc.  It's not until
some time after stage 3 that the build directory's gcc/ada/rts/ is populated
according to LIBGNAT_TARGET_PAIRS, allowing system-linux-x86.ads to get used.
But that's too late for m68k, since the type-incorrect s-memory.ad{b,s} have
already been compiled and linked into the intermediate gnat1 etc, which then
crash in stage 2.

So I'm now patching s-memory.ad{b,s} instead.  Assuming the current bootstrap
succeeds (sometime late tomorrow) I'll post my full patch for 4.5.3.