[dpdk-dev] [PATCHv4 3/5] Makefiles: Add experimental tag check and warnings to trigger on use

[Neil Horman]

On Thu, Jan 11, 2018 at 08:06:43PM +0000, Ferruh Yigit wrote:
> On 12/13/2017 3:17 PM, Neil Horman wrote:
> > Add checks during build to ensure that all symbols in the EXPERIMENTAL
> > version map section have __experimental tags on their definitions, and
> > enable the warnings needed to announce their use.  Also add an
> > ALLOW_EXPERIMENTAL_APIS define to allow individual libraries and files
> > to declare the acceptability of experimental api usage
> > 
> > Signed-off-by: Neil Horman <nhorman at tuxdriver.com>
> > CC: Thomas Monjalon <thomas at monjalon.net>
> > CC: "Mcnamara, John" <john.mcnamara at intel.com>
> > CC: Bruce Richardson <bruce.richardson at intel.com>
> > ---
> >  app/test-eventdev/Makefile                 | 1 +
> >  app/test-pmd/Makefile                      | 1 +
> >  drivers/event/sw/Makefile                  | 1 +
> >  drivers/net/failsafe/Makefile              | 1 +
> >  drivers/net/ixgbe/Makefile                 | 1 +
> >  examples/eventdev_pipeline_sw_pmd/Makefile | 1 +
> >  examples/flow_classify/Makefile            | 1 +
> >  examples/ipsec-secgw/Makefile              | 1 +
> >  examples/service_cores/Makefile            | 1 +
> >  lib/librte_eal/bsdapp/eal/Makefile         | 1 +
> >  lib/librte_eal/linuxapp/Makefile           | 2 ++
> >  lib/librte_eal/linuxapp/eal/Makefile       | 2 ++
> >  lib/librte_eventdev/Makefile               | 1 +
> >  lib/librte_security/Makefile               | 1 +
> >  mk/internal/rte.compile-pre.mk             | 4 ++++
> >  mk/toolchain/clang/rte.vars.mk             | 2 +-
> >  mk/toolchain/gcc/rte.vars.mk               | 2 +-
> >  mk/toolchain/icc/rte.vars.mk               | 2 +-
> >  18 files changed, 23 insertions(+), 3 deletions(-)
> > 
> > diff --git a/app/test-eventdev/Makefile b/app/test-eventdev/Makefile
> > index dcb2ac476..78bae7633 100644
> > --- a/app/test-eventdev/Makefile
> > +++ b/app/test-eventdev/Makefile
> > @@ -32,6 +32,7 @@ include $(RTE_SDK)/mk/rte.vars.mk
> >  
> >  APP = dpdk-test-eventdev
> >  
> > +CFLAGS += -DALLOW_EXPERIMENTAL_APIS
> 
> Do we need this internally in DPDK? For application developers this is great,
> they will get warning unless explicitly stated that they are OK with it.
> 
I'm not sure what you're asking here.  As I mentioned in the initial post, I
think we should give blanket permission to any in-tree dpdk library to allow the
use of experimental API's, but that doesn't really imply that all developers
would wan't it disabled all the time.  That is to say, I could envision a
library author who, early in development would want to get a warning issued if
they used an unstable API, and, only once they were happy with their design and
choice of API usage, turn the warning off.

> Do we have any option than allowing them in DPDK library? And when experimental
> API modified the users in the DPDK library internally guaranteed to be updated.
> Why not globally allow this for all DPDK internally?
> 
For the reason I gave above.  We certainly could enable this in a more top-level
makefile so that for in-library systems it was opt-in rather than opt-out, but I
chose a more granular approach because I could envision newer libraries wanting
it on.  I also felt, generally speaking, that where warning flags were
concerned, it generally desireous to have them on by default, and make people
explicitly choose to turn them off.

Regards
Neil


> >  CFLAGS += -O3
> >  CFLAGS += $(WERROR_FLAGS)
> >  
> 
> <...>
> 
>