Re: [PATCH] meson: Work around too strict lld

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(a)redhat.com&gt; > --- > > 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 = &#39;@0(a)/src/libvirt_qemu.syms&#39;.format(meson.project_source_root()) > + version_script_flags = '' > if cc.has_link_argument(&#39;-Wl,--version-script=@0(a)&#39;.format(test_file)) > version_script_flags = '-Wl,--version-script=' > - else > + elif cc.has_multi_link_arguments('-Wl,--undefined-version', &#39;-Wl,--version-script=@0(a)&#39;.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 = &#39;@0(a)/src/libvirt_qemu.syms&#39;.format(meson.project_source_root()) if cc.has_link_argument(&#39;-Wl,--version-script=@0(a)&#39;.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 ?