Hi!
On Mon, 05 Nov 2012 07:09:43 +0100, I wrote:
> On Fri, 28 Sep 2012 09:56:41 +0200, Samuel Thibault <samuel.thibault@gnu.org> wrote:
> > Thomas Schwinge, le Thu 27 Sep 2012 09:15:23 +0200, a écrit :
> > > On Wed, 26 Sep 2012 16:02:29 +0200, Svante Signell <svante.signell@telia.com> wrote:
> > > > gdb does not build from source any longer since gdb-multiarch packages
> > > > was enabled in 7.4.1-1. The build problems are due to two reasons:
> > >
> > > I also once had a look and came to the same conclusion.
> > >
> > > > First the reserved keyword MACH is defined in include/objcode/h8300.h
> > > > causing problems since gcc defines it for GNU/Hurd.
> > >
> > > Correct. And I wonder if that isn't a name-space violation? This is
> > > what I meant to look up when working on this two months ago, but then it
> > > seems I again got distracted by other issues. Roland, do you have any
> > > comments regarding that?
> > >
> > > [GCC]/gcc/config/gnu.h:
> > > [...]
> > > #undef GNU_USER_TARGET_OS_CPP_BUILTINS
> > > #define GNU_USER_TARGET_OS_CPP_BUILTINS() \
> > > do { \
> > > builtin_define ("__gnu_hurd__"); \
> > > builtin_define ("__GNU__"); \
> > > builtin_define_std ("unix"); \
> > > builtin_define_std ("MACH"); \
> > > builtin_assert ("system=gnu"); \
> > > builtin_assert ("system=mach"); \
> > > builtin_assert ("system=unix"); \
> > > builtin_assert ("system=posix"); \
> > > } while (0)
> > >
> > > $ gcc -dM -E -x c - < /dev/null | grep -i mach
> > > #define __MACH 1
> > > #define __MACH__ 1
> > > #define MACH 1
> >
> > On Linux i386, both "linux" and "i386" macros are defined, which poses
> > its own problems too.
>
> (Let's pause for a moment in remembrance of the »glibc vs. i686 defined«
> issue that would nearly have seen its 10th anniversary these days.)
>
> > I'd indeed tend to say that defining a non-underscored macro is only a
> > way for troubles.
> >
> > > Could we/should we remove the latter one? Though, I have no idea how
> > > much user code is relying on MACH being #defined. I had a colleague
> > > check, and Apple/Darwin systems do *only* #define __MACH__ (as well as
> > > __APPLE__).
>
> Here is the straightforward patch. With it, only the __MACH__ built-in
> preprocessor macro remains, and we get:
>
> [...]
> Fixing headers into /home/thomas/tmp/gnu-0/obj/gcc/gcc/include-fixed for
> i686-pc-gnu target
> -Forbidden identifiers: MACH i386 unix
> +Forbidden identifiers: i386 unix
> [...]
>
> These two are to remain.
>
> diff --git gcc/config/gnu.h gcc/config/gnu.h
> index dddbcbf..4d9449e 100644
> --- gcc/config/gnu.h
> +++ gcc/config/gnu.h
> @@ -34,7 +34,7 @@ along with GCC. If not, see <http://www.gnu.org/licenses/>.
> builtin_define ("__gnu_hurd__"); \
> builtin_define ("__GNU__"); \
> builtin_define_std ("unix"); \
> - builtin_define_std ("MACH"); \
> + builtin_define ("__MACH__"); \
> builtin_assert ("system=gnu"); \
> builtin_assert ("system=mach"); \
> builtin_assert ("system=unix"); \
Committed to trunk as r195826. Samuel, please port to active Debian GCC
branches.
Grüße,
Thomas
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