On Tue, Jan 19 2021, Charlene Wendling <[email protected]> wrote: > Hi, > >> http://build-failures.rhaalovely.net/mips64/2021-01-12/devel/fmt.log > (and the same in the current bulk for the other clang+ld.bfd arch, > macppc) > > As often '-Wl,--as-needed' causes undefined reference errors with > ld.bfd. Surprisingly gcc archs are not impacted. > > target_link_libraries() takes precedence over our LDFLAGS, so i could > not use them. > > Sadly cmake has not meson's 'b_asneeded' out of the box, so i've added > an AS_NEEDED option, which is ON by default, bringing no change > to clang+ld.lld archs, and turn it OFF on clang+ld.bfd archs. > > That also means no REVISION bump is needed (fmt has never been built on > impacted archs). > > With the below diff i can build fmt and pass its tests on macppc [0]. > mips64 seems to have further problems, i'm not 100% positive it would > fix the build there. > > I would be happy to upstream this, but it seems they preferred an OS > centric approach which doesn't play nice with our situation. > > Comments and feedback are welcome,
IIRC this is a bug in binutils, and it's not likely to be fixed soon. cmake itself provides https://cmake.org/cmake/help/latest/prop_tgt/LINK_WHAT_YOU_USE.html but I doubt that it would help us autodetect that --as-needed doesn't work. An alternative would be to just strip --as-needed on all archs and keep that as a local patch (we probably don't care about the improvements from --as-needed). But your approach makes sense too. ok jca@ fwiw -- jca | PGP : 0x1524E7EE / 5135 92C1 AD36 5293 2BDF DDCC 0DFA 74AE 1524 E7EE
