On Wed, May 27, 2020 at 11:43:49PM +0200, Thomas Monjalon wrote: > 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"))); > Ahh, you're using mingw, which appears to support versioning. If the windows equivalent of ld.so honors those versions, I would think the versioning bits should almost just work (assuming that mingw supports all the used __attirbutes__)
Neil > > > > 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). > > > >
