On Thu, Jan 11, 2024 at 09:48:33AM +0000, Bruce Richardson wrote: > On Thu, Jan 11, 2024 at 10:38:05AM +0100, Morten Brørup wrote: > > > From: Tyler Retzlaff [mailto:roret...@linux.microsoft.com] > > > Sent: Wednesday, 10 January 2024 17.58 > > > > > > On Wed, Jan 10, 2024 at 03:01:03PM +0000, Bruce Richardson wrote: > > > > The default behaviour of "ld.lld" has changed, so it now prints out > > > > warnings about entries in the version.map file which don't exist in > > > > the current build. Since we use our version.map file simply to filter > > > > out the functions we don't want made public, we include in it all > > > > functions across all OS's and builds that we want public if present. > > > > This causes these ld warnings to be emitted, e.g. on BSD, which is > > > > missing functionality found on Linux. For example: > > > > > > > > * hpet functions in EAL > > > > * regexdev enqueue and dequeue burst > > > > * eventdev event_timer functions > > > > > > > > Easiest solution, without major rework of how we use our version.map > > > > files, and without dynamically generating them per-build, is to pass > > > > the --undefined-version flag to the linker, to restore the old > > > > behaviour. > > > > > > > > Signed-off-by: Bruce Richardson <bruce.richard...@intel.com> > > > > --- > > > > > > Acked-by: Tyler Retzlaff <roret...@linux.microsoft.com> > > > > > > i don't know if has ever been discussed but a way to achieve a similar > > > outcome would be to introduce a visibility macro allowing the data and > > > function symbols to be explicitly made visible while making the build > > > default hidden. > > > > > > https://gcc.gnu.org/wiki/Visibility > > > > This looks interesting! > > Declaring a function "public" directly in its header seems much simpler to > > manage than having to add it to the version.map file too. > > > > I wonder if function versioning is still supported if using this instead of > > version.map files? > > Of if there are other relevant reasons for continuing to use the > > version.map files instead of this? > > > > I don't see in that wiki page and details of how to mark symbols with > different ABI versions. For example, as well as listing what functions are > public, our version.map files also identify the ABI version (e.g. DPDK_24) > they belong to, or whether they are experimental or internal. Having them > all in the version file also makes it easy to see how many experimental > functions we have in each component.
you can use symver in combination with visibility default https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html anyway just food for thought, it would get me out of having to hack & enhance the .def from .map generation and unfortunately even with that there are going to be cases where i still have to annotate the actual symbol export in code (for windows). just thought a more unified approach for all might appeal. ty > > /Bruce
