Unable to find long double symbols on aarch64-apple-darwin

[tgross35]

I am working on rust-lang/rust#114607 and unfortunately can't build on my system due to linker errors:

  = note: ld: warning: ignoring duplicate libraries: '-lSystem'
          ld: Undefined symbols:
            ___addtf3, referenced from:
                std::num::test_num::h83194c034ce7125a in std-a7f7c4c812353510.std.3e4ab7aa3f61e492-cgu.12.rcgu.o
            ___divtf3, referenced from:
                std::num::test_num::h83194c034ce7125a in std-a7f7c4c812353510.std.3e4ab7aa3f61e492-cgu.12.rcgu.o
            ___multf3, referenced from:
                std::num::test_num::h83194c034ce7125a in std-a7f7c4c812353510.std.3e4ab7aa3f61e492-cgu.12.rcgu.o
            ___subtf3, referenced from:
                std::num::test_num::h83194c034ce7125a in std-a7f7c4c812353510.std.3e4ab7aa3f61e492-cgu.12.rcgu.o
            ___trunctfdf2, referenced from:
                _$LT$$RF$T$u20$as$u20$core..fmt..Debug$GT$::fmt::h8dd8a3b2b4bc54ac in std-a7f7c4c812353510.std.3e4ab7aa3f61e492-cgu.06.rcgu.o
                core::fmt::float::_$LT$impl$u20$core..fmt..Debug$u20$for$u20$f128$GT$::fmt::h0686fe3ef7164d45 in std-a7f7c4c812353510.std.3e4ab7aa3f61e492-cgu.10.rcgu.o
            ___unordtf2, referenced from:
                std::num::test_num::h83194c034ce7125a in std-a7f7c4c812353510.std.3e4ab7aa3f61e492-cgu.12.rcgu.o
                std::num::test_num::h83194c034ce7125a in std-a7f7c4c812353510.std.3e4ab7aa3f61e492-cgu.12.rcgu.o
                std::num::test_num::h83194c034ce7125a in std-a7f7c4c812353510.std.3e4ab7aa3f61e492-cgu.12.rcgu.o
                std::num::test_num::h83194c034ce7125a in std-a7f7c4c812353510.std.3e4ab7aa3f61e492-cgu.12.rcgu.o
                std::num::test_num::h83194c034ce7125a in std-a7f7c4c812353510.std.3e4ab7aa3f61e492-cgu.12.rcgu.o
          clang: error: linker command failed with exit code 1 (use -v to see invocation)
---
          ld: Undefined symbols:
            ___extenddftf2, referenced from:
                __RNvNtCsgSq1suy33ib_12clippy_utils6consts19lit_to_mir_constant in libclippy_utils-52261686d0193f09.rlib[10](clippy_utils-52261686d0193f09.clippy_utils.c495e003dc0e053d-cgu.07.rcgu.o)
            ___trunctfdf2, referenced from:
                __RINvXs1_NtCsgSq1suy33ib_12clippy_utils6constsNtB6_8ConstantNtNtCsdSdPP26wXhD_4core4hash4Hash4hashNtCsgzWzvnNrs6k_10rustc_hash8FxHasherEB8_ in libclippy_utils-52261686d0193f09.rlib[10](clippy_utils-52261686d0193f09.clippy_utils.c495e003dc0e053d-cgu.07.rcgu.o)

It seems like a fix similar to rust-lang/libc#1034 may work, I can submit a PR if this seems correct. @Amanieu

[Amanieu]

If we are supporting these types directly in Rust then we should add these intrinsics to compiler-builtins. For now you can just change the compiler-builtins build script to include the versions from compiler-rt, but eventually we will want to have these fully implemented in Rust.

[tgross35]

@Amanieu are you able to move this issue to compiler-builtins?

It seems like they should be getting included already, so I'm not sure what is going on https://github.com/rust-lang/compiler-builtins/blob/47e64bfa0a387c811e4c409959a4d2668f0b1c37/build.rs#L506C20-L512. This is on aarch64-apple-darwin, I don't have any reason to think +nofp is set

[Amanieu]

Are you building with the "c" feature of compiler-builtins? We only enable this when building with x.py but not for -Zbuild-std.

[tgross35]

This should be fixed by #593, #606, and others that are listed in the readme