[PATCH v3 11/11] telemetry: avoid expanding versioned symbol macros on msvc

[Tyler Retzlaff]

On Tue, Apr 11, 2023 at 11:24:07AM +0100, Bruce Richardson wrote:
> On Wed, Apr 05, 2023 at 05:45:19PM -0700, Tyler Retzlaff wrote:
> > Windows does not support versioned symbols. Fortunately Windows also
> > doesn't have an exported stable ABI.
> > 
> > Export rte_tel_data_add_array_int -> rte_tel_data_add_array_int_24
> > and rte_tel_data_add_dict_int -> rte_tel_data_add_dict_int_v24
> > functions.
> > 
> > Windows does have a way to achieve similar versioning for symbols but it
> > is not a simple #define so it will be done as a work package later.
> > 
> > Signed-off-by: Tyler Retzlaff <roretzla at linux.microsoft.com>
> > ---
> >  lib/telemetry/telemetry_data.c | 16 ++++++++++++++++
> >  1 file changed, 16 insertions(+)
> > 
> > diff --git a/lib/telemetry/telemetry_data.c b/lib/telemetry/telemetry_data.c
> > index 2bac2de..284c16e 100644
> > --- a/lib/telemetry/telemetry_data.c
> > +++ b/lib/telemetry/telemetry_data.c
> > @@ -82,8 +82,16 @@
> >  /* mark the v23 function as the older version, and v24 as the default version */
> >  VERSION_SYMBOL(rte_tel_data_add_array_int, _v23, 23);
> >  BIND_DEFAULT_SYMBOL(rte_tel_data_add_array_int, _v24, 24);
> > +#ifndef RTE_TOOLCHAIN_MSVC
> >  MAP_STATIC_SYMBOL(int rte_tel_data_add_array_int(struct rte_tel_data *d,
> >  		int64_t x), rte_tel_data_add_array_int_v24);
> > +#else
> > +int
> > +rte_tel_data_add_array_int(struct rte_tel_data *d, int64_t x)
> > +{
> > +	return rte_tel_data_add_array_int_v24(d, x);
> > +}
> > +#endif
> >  
> 
> Can't see any general way to do this from the versioning header file, so
> agree that we need some changes here. Rather than defining a public
> funcion, we could keep the diff reduced by just using a macro alias here,
> right? For example:
> 
> #ifdef RTE_TOOLCHAIN_MSVC
> #define rte_tel_data_add_array_int rte_tel_data_add_array_int_v24
> #else
> MAP_STATIC_SYMBOL(int rte_tel_data_add_array_int(struct rte_tel_data *d,
> 		int64_t x), rte_tel_data_add_array_int_v24);
> #endif
> 
> If this is a temporary measure, I'd tend towards the shortest solution that
> can work. However, no strong opinions, so, either using functions as you
> have it, or macros:

so i have to leave it as it is the reason being the version.map ->
exports.def generation does not handle this. the .def only contains the
rte_tel_data_add_array_int symbol. if we expand it away to the _v24 name
the link will fail.

let's consume the change as-is for now and i will work on the
generalized solution when changes are integrated that actually make the
windows dso/dll functional.

> 
> Acked-by: Bruce Richardson <bruce.richardson at intel.com>