Re: 64 bit codes

[Simon Wright <simon@pushface.org>]

Simon Wright <simon@pushface.org> writes:

> I built an x86_64 compiler for Darwin using an i386 (32-bit) compiler;
> no trouble at all.

That would be exaggerating. I had quite a few problems, though my log
seems to indicate that things were worse when I said
--target=x86_64-apple-darwin10.2.0 (for cross-compilation) rather than
just --build=x86_64-apple-darwin10.2.0.

I see I built a 32-bit GNAT GPL 2009 for the GNU Ada Sourceforge project
as well as a 64-bit one; I can't now recall why I did the first (I
suspect because Tk was only supported in 32-bit), and I think I did the
second because AdaCore's didn't work on Snow Leopard because of an Apple
change to exception unwinding.

So I just now d/l'd the 2009 32-bit compiler and used it to build GCC
4.6.1, configuring like so:

  ./gcc-4.6.1/configure \
    CC="gcc -D_FORTIFY_SOURCE=0" \
    --prefix=/opt/gcc-4.6.1 \
    --disable-multilib \
    --enable-languages=c,ada \
    --build=x86_64-apple-darwin11

(gmp, mpfr, mpc are symlinked from the GCC tree; the setting of CC is
because of http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50342)

and sure enough pointers are now 64-bit, as expected.

I'm pretty sure this only works because Apple's binutils are 32- and
64-bit capable.