Re: out of tree driver builds broken with C++

[Bruce Richardson <bruce.richardson@intel.com>]

On Mon, Feb 14, 2022 at 12:19:24PM +0100, Thomas Monjalon wrote:
> 14/02/2022 11:45, Bruce Richardson:
> > On Mon, Feb 14, 2022 at 10:22:08AM +0100, Thomas Monjalon wrote:
> > > 14/02/2022 10:13, Tyler Retzlaff:
> > > > while the driver api is "internal" we agreed some time ago that drivers
> > > > could be built external to the dpdk tree. by enabling the meson setup
> > > > option -Denable_driver_sdk=true.
> > > > 
> > > > it was agreed that the driver api was internal and would attract no
> > > > binary compatibility support which was fine.  this change has now
> > > > imposed a further restriction that out of tree drivers have to be
> > > > authored in C only as non-C++ compatible code will invariably leak into
> > > > the internal structures.
> > > > 
> > > > you won't allow us to build C++ drivers in the dpdk tree and it seems
> > > > now you are preventing building of C++ drivers outside of the tree too.
> > > 
> > > That's the problem of non-written assumptions, they are unknown or forgotten.
> > > Did we agree to support out-of-tree drivers in C++?
> > > 
> > > We really need to make things clear and written in documentation.
> > > 
> > > > could we please re-evaluate this.
> > > 
> > > Yes we can re-evaluate.
> > > What is the list of impacted files?
> > > 
> > Hacking meson files a bit, the list of SDK header files is reported as below.
> > 
> > /Bruce
> > 
> > Message: SDK headers: 
> > Message: ethdev_driver.h
> > Message: ethdev_pci.h
> > Message: ethdev_vdev.h
> > Message: cryptodev_pmd.h
> > Message: eventdev_pmd.h
> > Message: eventdev_pmd_pci.h
> > Message: eventdev_pmd_vdev.h
> > Message: eventdev_trace.h
> > Message: event_timer_adapter_pmd.h
> > Message: rte_dmadev_pmd.h
> > Message: vdpa_driver.h
> 
> I see no harm in supporting C++ include of these headers.
> Any objection?
> 
> Could we have a test in chkincs for the SDK headers?
> 
Yes. It may make things a little more complicated, though, as it seems
these headers also have a tendency to rely on some driver headers -
specifically bus driver headers.

/Bruce