[Mesa-dev] [PATCH 1/2] mesa: bump required GCC version to 4.4.0

[Jonathan Gray]

On Tue, Jan 26, 2016 at 07:51:06PM -0500, Ilia Mirkin wrote:
> On Tue, Jan 26, 2016 at 7:35 PM, Jonathan Gray <jsg at jsg.id.au> wrote:
> > I would be interested to hear specifics as to what post gcc 4.2.1
> > extensions/changes people are interested in using.
> 
> Lack of C++11 has been a bit of an annoyance in nouveau - I've been
> using tr1 versions of things, but that apparently causes problems for
> Android. I guess since no one has been interested in nouveau on the
> BSD's I could just up the nouveau requirement to a later gcc version.
> 
>   -ilia

NetBSD seems to have at least attempted it but perhaps it isn't useable there
http://permalink.gmane.org/gmane.os.netbsd.devel.x11/3630
According to http://www.netbsd.org/releases/formal-7/NetBSD-7.0.html
they have intel and radeon, but they also ship gcc 4.8.4.

With the high amount of code churn, it is quite a lot of work to keep
porting the i915 and radeon kernel code as it is.  I don't believe there
is any interest on the OpenBSD side to port nouveau's kernel code which
seems to be on the order of 800 files and 150,000 lines of code.

So from that point of view I'd be fine with a nouveau specific check.
There is already a clover specific gcc 4.7 check.

One thing to keep in mind though is that even recent versions of
clang with full c++11 such as 3.7.1, still claim to be gcc 4.2.1.

$ clang -dM -E - < /dev/null | fgrep GNUC
#define __GNUC_MINOR__ 2
#define __GNUC_PATCHLEVEL__ 1
#define __GNUC_STDC_INLINE__ 1
#define __GNUC__ 4

$ clang -dM -E - < /dev/null | fgrep clang
#define __clang__ 1
#define __clang_major__ 3
#define __clang_minor__ 7
#define __clang_patchlevel__ 1
#define __clang_version__ "3.7.1 (tags/RELEASE_371/final)"

So perhaps a configure check for --std=c++11 would be better.  I recently
built Mesa with this version of clang, including the nouveau driver
without problem.