Xen devel - Aug 2008 - [PATCH] xen/Makefile: use CC --version instead of -v

Hi all,

the xen/Makefile calls 
  $(CC) $(CFLAGS) -v 2>&1 | grep -i "gcc.*version"
to get a human-readable representation of the GCC being used. However, 
this poses a problem at least in Gentoo, where as of gcc 4.3, "gcc -v"
reads:
====================================================================Using
built-in specs.
Target: x86_64-pc-linux-gnu
Configured 
with: /var/tmp/portage/sys-devel/gcc-4.3.1-r1/work/gcc-4.3.1/configure
--prefix=/usr --bindir=/usr/x86_64-pc-linux-gnu/gcc-bin/4.3.1
--includedir=/usr/lib/gcc/x86_64-pc-linux-gnu/4.3.1/include
--datadir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.3.1
--mandir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.3.1/man
--infodir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.3.1/info
--with-gxx-include-dir=/usr/lib/gcc/x86_64-pc-linux-gnu/4.3.1/include/g++-v4
--host=x86_64-pc-linux-gnu --build=x86_64-pc-linux-gnu --disable-altivec
--enable-nls --without-included-gettext --with-system-zlib --disable-checking
--disable-werror --enable-secureplt --enable-multilib --enable-libmudflap
--disable-libssp --enable-cld --enable-java-awt=gtk
--enable-languages=c,c++,java,treelang,fortran --enable-shared
--enable-threads=posix --enable-__cxa_atexit --enable-clocale=gnu
--with-bugurl=http://bugs.gentoo.org/ --with-pkgversion=''Gentoo
4.3.1-r1 p1.1''
Thread model: posix
gcc version 4.3.1 (Gentoo 4.3.1-r1 p1.1)
====================================================================(Notice the
line starting ''with'' matches "gcc.*version")

I propose to change the statement to:
  $(CC) $(CFLAGS) --version | head -n1

See the attached patch.
This is Gentoo bug #217151 [ https://bugs.gentoo.org/217151 ]

Regards,
Robert



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On 27/8/08 00:06, "Robert Buchholz" <rbu@gentoo.org> wrote:
> I propose to change the statement to:
>   $(CC) $(CFLAGS) --version | head -n1
I think we can just tighten up the grep regexp a little.

"gcc .*version " should do it.

 -- Keir



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On Wednesday 27 August 2008, Keir Fraser wrote:
> On 27/8/08 00:06, "Robert Buchholz" <rbu@gentoo.org> wrote:
> > I propose to change the statement to:
> >   $(CC) $(CFLAGS) --version | head -n1
>
> I think we can just tighten up the grep regexp a little.
>
> "gcc .*version " should do it.
That is not guaranteed to filter only the desired lines (if a configure 
parameter would end in "gcc", or there is "gcc " in the path
GCC was
compiled in).
The reason I proposed "gcc --version | head -n1" was that the output
is
only dependent on the GCC source, whereas "gcc -v | grep"  also
depends
on the system configuration.

Btw, what is the reason for ".*" in the first place?


Regards,
Robert


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On 27/8/08 11:12, "Robert Buchholz" <rbu@gentoo.org> wrote:
> Btw, what is the reason for ".*" in the first place?
Lost somewhat in the mists of time, but I think some vendor packages
(possibly Red Hat iirc) stuck something in between ''gcc'' and
''version''.

Another tactic might be ''tail -n1''. I can''t remember
if the version is
always the last line of ''gcc -v'' output though.

Hmmm... actually that is what Linux does (tail -n 1). So let''s go with
that.

 -- Keir



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On 27/8/08 11:33, "Keir Fraser" <keir.fraser@eu.citrix.com>
wrote:
> On 27/8/08 11:12, "Robert Buchholz" <rbu@gentoo.org> wrote:
> 
>> Btw, what is the reason for ".*" in the first place?
> 
> Lost somewhat in the mists of time, but I think some vendor packages
> (possibly Red Hat iirc) stuck something in between ''gcc''
and ''version''.
> 
> Another tactic might be ''tail -n1''. I can''t
remember if the version is
> always the last line of ''gcc -v'' output though.
> 
> Hmmm... actually that is what Linux does (tail -n 1). So let''s go
with that.
I''ve checked in ''tail -1'' which I think is more
portable. If that is
agreeable to everyone then I''ll backport to 3.3 and 3.2 branches.

 -- Keir



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On Wednesday 27 August 2008, Keir Fraser wrote:
> On 27/8/08 11:33, "Keir Fraser" <keir.fraser@eu.citrix.com>
wrote:
> > On 27/8/08 11:12, "Robert Buchholz" <rbu@gentoo.org>
wrote:
> >> Btw, what is the reason for ".*" in the first place?
> >
> > Lost somewhat in the mists of time, but I think some vendor
> > packages (possibly Red Hat iirc) stuck something in between
''gcc''
> > and ''version''.
> >
> > Another tactic might be ''tail -n1''. I can''t
remember if the version
> > is always the last line of ''gcc -v'' output though.
> >
> > Hmmm... actually that is what Linux does (tail -n 1). So
let''s go
> > with that.
>
> I''ve checked in ''tail -1'' which I think is more
portable. If that is
> agreeable to everyone then I''ll backport to 3.3 and 3.2 branches.
Thanks, backports are appreciated (and trivial).


Robert



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