Re: [dpdk-dev] [PATCH v1] build: ccache support for cross build

["Stanisław Kardach" <kda@semihalf.com>]

On Wed, Jun 8, 2022 at 7:17 PM Jerin Jacob <jerinjacobk@gmail.com> wrote:
>
> On Wed, Jun 8, 2022 at 2:00 PM Thomas Monjalon <thomas@monjalon.net> wrote:
> >
> > 08/06/2022 10:22, Jerin Jacob:
> > > On Thu, Jun 2, 2022 at 5:30 PM Jerin Jacob <jerinjacobk@gmail.com> wrote:
> > > >
> > > > On Thu, Jun 2, 2022 at 4:25 PM Thomas Monjalon <thomas@monjalon.net> wrote:
> > > > >
> > > > > 02/06/2022 11:43, Jerin Jacob:
> > > > > > On Thu, Jun 2, 2022 at 3:11 PM Bruce Richardson
> > > > > > <bruce.richardson@intel.com> wrote:
> > > > > > >
> > > > > > > On Thu, Jun 02, 2022 at 02:53:55PM +0530, jerinj@marvell.com wrote:
> > > > > > > > From: Jerin Jacob <jerinj@marvell.com>
> > > > > > > >
> > > > > > > > By default, ccache is not used for cross build[1].
> > > > > > > > Update all cross files to use ccache if it is available
> > > > > > > > in build machine.
> > > > > > > >
> > > > > > > > [1]
> > > > > > > > https://mesonbuild.com/Machine-files.html
> > > > > > > >
> > > > > > > > Signed-off-by: Jerin Jacob <jerinj@marvell.com>
> > > > > > >
> > > > > > > Does this still work even if ccache is not available? That's not fully
> > > > > >
> > > > > > Yes.
> > > > > >
> > > > > > > clear from the docs, but it seems to be that if an array is passed the
> > > > > > > whole array is used as the command, rather than just one element of the
> > > > > > > array. That would imply that cross-builds now require ccache. Is that
> > > > > > > acceptable?
> > > > > >
> > > > > > I have removed ccache from the build machine still it works.
> > > > >
> > > > > I don't understand why it works without ccache.
> > > >
> > > > Meson is detecting valid compiler prefix. ccache is one of them.
> > > >
> > > > See
> > > > https://github.com/fabio-porcedda/meson/commit/44db495f5ece43645ca3994dc95895c76a828530
> > > > https://github.com/mesonbuild/meson/issues/1392
> > >
> > > I hope there are no other review comments to fix it for this patch.
> > > Since it is improving the build time for cross-build. If there is no
> > > objection to this patch, Please merge it.
> >
> > I've tested it now and I see a big blocker.
> > This patch is breaking the use of devtools/test-meson-builds.sh
> > so I cannot merge it as-is, sorry.
>
> I assume you are referring to fixing the DPDK_TARGET update due to the
> cross-file update.
> If so, it is fixed in v2 at
> http://patches.dpdk.org/project/dpdk/patch/20220608171304.945454-1-jerinj@marvell.com/

I've just tested it on a clean Ubuntu 20.04 docker with only RISC-V
toolchain, no ccache and indeed compilation works. Both directly with
meson and via test-meson-builds.sh.
Seems like ccache is parsed in special way by meson as using any other
unknown command just fails meson configuration.
Also setting CC/CXX env variable makes meson bail (even if I use the
cross-file value), so I'm not sure if there is a better way to do it.

Acked-by: Stanislaw Kardach <kda@semihalf.com>