On 3/20/23 15:19, Daniel P. Berrangé wrote: > On Mon, Mar 20, 2023 at 02:54:11PM +0100, Michal Privoznik wrote: >> With its version 16.0, the LLVM's linker turned on >> --no-undefined-version by default [1]. This breaks how we detect >> --version-script= detection, because at the compile time there's >> no library built yet that we can use to make --version-script= >> happy. To cancel their choice of defaults, pass >> --undefined-version. Unfortunately, this flag is LLVM's invention >> and is not supported by GNU's ld. >> >> This all could be avoided if meson provided proper detection of >> supported linker arguments, but we are far away from that [2]. >> >> 1: https://reviews.llvm.org/D135402 >> 2: https://github.com/mesonbuild/meson/issues/3047 >> >> Resolves: https://bugs.gentoo.org/902211 >> Signed-off-by: Michal Privoznik <mprivozn@xxxxxxxxxx> >> --- >> >> Compile Libvirt? Absolutely Not Gonna. >> >> The choice of defaults for LLVM and related subprojects continues >> to surprise me. >> >> meson.build | 6 +++++- >> 1 file changed, 5 insertions(+), 1 deletion(-) >> >> diff --git a/meson.build b/meson.build >> index c35823a79a..df0d75449a 100644 >> --- a/meson.build >> +++ b/meson.build >> @@ -535,9 +535,13 @@ elif host_machine.system() == 'darwin' >> version_script_flags = '' >> else >> test_file = '@0@/src/libvirt_qemu.syms'.format(meson.project_source_root()) >> + version_script_flags = '' >> if cc.has_link_argument('-Wl,--version-script=@0@'.format(test_file)) >> version_script_flags = '-Wl,--version-script=' >> - else >> + elif cc.has_multi_link_arguments('-Wl,--undefined-version', '-Wl,--version-script=@0@'.format(test_file)) >> + version_script_flags = '-Wl,--version-script=' >> + endif >> + if version_script_flags == '' >> error('No supported version script link argument found.') >> endif >> endif > > Should we bother probing for the argument at all ? > > if host_machine.system() == 'windows' > version_script_flags = '-Wl,' > elif host_machine.system() == 'darwin' > # macOS libraries don't support symbol versioning > version_script_flags = '' > else > test_file = '@0@/src/libvirt_qemu.syms'.format(meson.project_source_root()) > if cc.has_link_argument('-Wl,--version-script=@0@'.format(test_file)) > version_script_flags = '-Wl,--version-script=' > else > error('No supported version script link argument found.') > endif > endif > > > In terms of our platforms, the 'else' clause is only impacting Linux and > FreeBSD. Don't both of those platforms support -Wl,--version-script= > since they both use ELF ? Yeah, I think we can drop the check completely and went with what you suggests. V2 on its way. Michal
