[oe] [meta-oe][PATCH v1 3/4] BCC: Add build recipe

[Leo Yan]

Hi Khem,

On Tue, Feb 18, 2020 at 03:27:26PM +0800, Leo Yan wrote:
> Hi Khem,
> 
> On Mon, Feb 17, 2020 at 10:30:46PM -0800, Khem Raj wrote:
> 
> [...]
> 
> > > +DEPENDS += "bison-native \
> > > +            ninja-native \
> > > +            elfutils-native \
> > > +            flex-native \
> > > +            ${MLPREFIX}elfutils \
> > > +            ${MLPREFIX}binutils \
> > > +            ${MLPREFIX}flex \
> > > +            luajit \
> > > +            clang \
> > > +            "
> > > +
> > 
> > this will add meta-clang dependency directly into meta-oe, which is not desired
> > is it possible to make it optional or perhaps marked when meta-clang
> > is not in BBLAYERS
> 
> Thanks a lot for reviewing.  clang is mandotory for BCC to compile
> eBPF programs, so I think we cannot build clang as optional for BCC.
> 
> For marking the recipe when meta-clang is not in BBLAYERS, I searched
> with google but seems 'LAYERDEPENDS' and 'BBMASK' both are not suitable
> for this case.  Could you give more detailed info for how to do this?

Just want to ask a following question.

Since BCC and bpftrace both are heavily relying on LLVM/Clang for their
tracing, do you think it's a good idea to merge BCC and bpftrace into
meta-clang layer, e.g. place into /meta-clang/recipes-devtools/?
If so, we can easily resolve the dependency issue and avoid to introduce
mess between meta-oe and meta-clang.

For the tool ply, it's simple and doesn't depend on Clang.  So should
keep it into meta-oe/recipes-devtools/ folder?  Also welcome any
suggestion for this.

Thanks,
Leo Yan