27/05/2020 23:27, Thomas Monjalon: > 27/05/2020 22:35, Neil Horman: > > On Wed, May 27, 2020 at 02:50:07PM +0200, Thomas Monjalon wrote: > > > +Cc more people > > > > > > 27/05/2020 12:41, Fady Bader: > > > > What should we do with the ABI versioning in Windows ? > > > > > > I think there are 2 questions here: > > > > > > 1/ Do we want to maintain ABI compatibility on Windows like we do for > > > Linux and FreeBSD? > > > The decision must be clearly documented. > > > > > My first notion, without any greater thought is "why wouldn't we". ABI > > stability is OS agnostic. If a symbol is considered stable, theres no > > reason > > that I can think of that it wouldn't be stable for each OS. > > Technical reason + no need so far. > > > > > 2/ How do we implement the macros in rte_function_versioning.h for > > > Windows? > > > Something needs to be done, otherwise we cannot compile libraries having > > > some function versioning. > > > > > Can you elaborate on what exactly the issue is here? I presume by your > > comment > > above that visual studio either doesn't support symbol level versioning or > > doesn't support versioning at all? > > I don't know how to implement the macros in rte_function_versioning.h for > Windows. > > > > If thats the case, and there is a commitment to make dpdk buildable on > > windows, > > I suppose the only choice is to make a ifdef WINDOWS section of the > > rte_function_versioning.h file, and effectively turn all the macros into > > no-ops. > > Yes that's the idea. > But we still need to implement either BIND_DEFAULT_SYMBOL or MAP_STATIC_SYMBOL > to alias the latest function version to the actual function symbol.
I've just found a tip in https://sourceware.org/binutils/docs/ld/WIN32.html It suggests to create a weak symbol: void foo() __attribute__((weak, alias ("foo_latestversion"))); > > The BIND_DEFAULT_SYMBOL macro looks like it could still work, as MSVC has an > > alias linker command thats implementable via __pragma, but thats probably > > all we > > can do, unless there is some more robust versioning support that I can't > > find. > > What is this pragma? > > > > Note we will also likely need to agument the makefiles/meson files so that > > the > > link stage doesn't pass the version script to the linker > > Why not using the version script for exported symbols? > We are already doing it (.def file generated from .map).
