[gobolinux-users] Re: Firefox up to date

[Michael Homer]

On 8/3/06, Lucas C. Villa Real <lucasvr at gobolinux.org> wrote:
> On 8/3/06, Michael Homer <gobo-users-dufus at wotfun.com> wrote:
> > On 8/3/06, Jonas Karlsson <jonka750 at student.liu.se> wrote:
> > > I forgot to turn on my primary build computer before I went to work,
> > > so an updated recipe and build will have to wait until tonight (CEST).
> >
> > Is Gobo using/supporting ccache? It really does save time on those big
> > builds at the expense of a little disk space. It would solve a lot of
> > the problem about compiling the big packages.
>
> I use it in my personal computer, but I was told by Hisham some time
> ago that potential bugs could appear when switching compiler versions
> (at least on previous ccache releases); doing that would make objects
> compiled with a previous gcc version to be used to link with those
> compiled with the new one (it wasn't smart at the point of recompiling
> the cached files).
>
> If you can test that and assert that it doesn't happen anymore I'd be
> very happy to start using it again :-)
It certainly doesn't happen on my Gentoo box - it doesn't appear to
clear the cache on GCC upgrades either, so that must be done
transparently if there is any problem. I have wondered about it
myself, but I haven't ever noticed significantly slower compiles after
GCC upgrades, and they're fairly frequent. So it seems at least that
that problem is fixed - I believe it automatically recompiles any
files that cause errors, at least from the statistics it shows
("compile failed" is never a symptom, so it has to be internal):
# ccache -s
cache hit                          41607
cache miss                        113375
called for link                    12256
multiple source files                 58
compile failed                      2666
preprocessor error                  1063
not a C/C++ file                    5663
autoconf compile/link              23986
unsupported compiler option         3601
no input file                      14692
files in cache                    159996
cache size                           1.8 Gbytes
max cache size                       2.0 Gbytes

A Firefox compile takes under half an hour, so does GCC or Evolution.
-Michael