On Tue, Jul 15, 2025 at 8:47 AM 'Florian Weimer' via X86-64 System V Application Binary Interface <x86-64-...@googlegroups.com> wrote: > > * H. J. Lu: > > > Compilers will never know since the build-time glibc is independent of > > the run-time glibc. If compilers want to be 100% sure that the run-time > > is GNU2 TLS bug-free, they can require linkers which generate the > > GLIBC_ABI_GNU2_TLS dependency. > > (Such a linker requirement could be enforced by requiring that the > linker recognizes a command option specific to GLIBC_ABI_GNU2_TLS, and > that current linkers treat as an error.) > > Would such an unconditional requirement be acceptable to GCC 16? I > don't think so. So we'd still have to design a configure option for it. > And that requires further compiler changes. It's also not entirely > clear how this would interact with -fuse-ld. > > I just don't think option (b) is trivial from a compiler perspective. >
It depends on what we want. If we want 100% guarantee of glibc run-time GNU2 TLS bug-free, GCC can pass -z gnu2-tls to linker whenever GNU2 TLS is used with glibc. It is an error if the linker doesn't support -z gnu2-tls. We can provide a GCC option to disable -z gnu2-tls. -- H.J.
