AtomicU128 uses __atomic_load function on OSX #39590
Description
Last night's nightly build failed with these logs:
error: linking with `cc` failed: exit code: 1 | = note: "cc" "-m64" "-L" "/Users/rustbuild/src/rust-buildbot/slave/nightly-dist-rustc-mac/build/obj/build/x86_64-apple-darwin/stage1/lib/rustlib/x86_64-apple-darwin/lib" "/Users/rustbuild/src/rust-buildbot/slave/nightly-dist-rustc-mac/build/obj/build/x86_64-apple-darwin/stage1-std/x86_64-apple-darwin/release/deps/std-a260b5db713b337f.0.o" "-o" "/Users/rustbuild/src/rust-buildbot/slave/nightly-dist-rustc-mac/build/obj/build/x86_64-apple-darwin/stage1-std/x86_64-apple-darwin/release/deps/libstd-a260b5db713b337f.dylib" "/Users/rustbuild/src/rust-buildbot/slave/nightly-dist-rustc-mac/build/obj/build/x86_64-apple-darwin/stage1-std/x86_64-apple-darwin/release/deps/std-a260b5db713b337f.metadata.o" "-Wl,-dead_strip" "-nodefaultlibs" "-L" "/Users/rustbuild/src/rust-buildbot/slave/nightly-dist-rustc-mac/build/obj/build/x86_64-apple-darwin/stage1-std/x86_64-apple-darwin/release/deps" "-L" "/Users/rustbuild/src/rust-buildbot/slave/nightly-dist-rustc-mac/build/obj/build/x86_64-apple-darwin/stage1-std/release/deps" "-L" "/Users/rustbuild/src/rust-buildbot/slave/nightly-dist-rustc-mac/build/obj/build/x86_64-apple-darwin/native/jemalloc/lib" "-L" "/Users/rustbuild/src/rust-buildbot/slave/nightly-dist-rustc-mac/build/obj/build/x86_64-apple-darwin/stage1-std/x86_64-apple-darwin/release/build/compiler_builtins-069104501ba665d8/out" "-L" "/Users/rustbuild/src/rust-buildbot/slave/nightly-dist-rustc-mac/build/obj/build/x86_64-apple-darwin/stage1/lib/rustlib/x86_64-apple-darwin/lib" "-l" "System" "-Wl,-force_load,/tmp/rustc.K4tN3uRshYIw/libpanic_unwind-18bf5d50673f1daa.rlib" "-Wl,-force_load,/tmp/rustc.K4tN3uRshYIw/libunwind-6b24ec54aa474d14.rlib" "-Wl,-force_load,/tmp/rustc.K4tN3uRshYIw/libcollections-4e19d5a43d7fdd2c.rlib" "-Wl,-force_load,/tmp/rustc.K4tN3uRshYIw/liballoc-99e0cdfb2e11773a.rlib" "-Wl,-force_load,/tmp/rustc.K4tN3uRshYIw/liballoc_jemalloc-7b14c3e63843fe84.rlib" "-Wl,-force_load,/tmp/rustc.K4tN3uRshYIw/liblibc-109501e572ed7296.rlib" "-Wl,-force_load,/tmp/rustc.K4tN3uRshYIw/libstd_unicode-49cd3c7af2b2f27f.rlib" "-Wl,-force_load,/tmp/rustc.K4tN3uRshYIw/librand-664091cbac310259.rlib" "-Wl,-force_load,/tmp/rustc.K4tN3uRshYIw/libcore-f1125930d2c15bcd.rlib" "/tmp/rustc.K4tN3uRshYIw/libcompiler_builtins-594db3b2ae45efeb.rlib" "-l" "pthread" "-l" "c" "-l" "m" "-dynamiclib" "-Wl,-dylib" "-Wl,-install_name,@rpath/libstd-a260b5db713b337f.dylib" "-Wl,-rpath,@loader_path/../lib" = note: Undefined symbols for architecture x86_64: "___atomic_load", referenced from: _$LT$core..sync..atomic..AtomicI128$u20$as$u20$core..fmt..Debug$GT$::fmt::hc3b52e65322d95c5 in libcore-f1125930d2c15bcd.rlib(core-f1125930d2c15bcd.0.o) _$LT$core..sync..atomic..AtomicU128$u20$as$u20$core..fmt..Debug$GT$::fmt::h78335460c4fed629 in libcore-f1125930d2c15bcd.rlib(core-f1125930d2c15bcd.0.o) ld: symbol(s) not found for architecture x86_64 clang: error: linker command failed with exit code 1 (use -v to see invocation) error: aborting due to previous error error: Could not compile `std`. Notably it looks like this code:
#![feature(i128_type, i128)] use std::sync::atomic::{AtomicU128, Ordering}; #[no_mangle] pub extern fn foo(a: &AtomicU128) -> u128 { a.load(Ordering::SeqCst) }generates this assembly:
.section__TEXT,__text,regular,pure_instructions .globl _foo .p2align4, 0x90 _foo: .cfi_startproc pushq %rbp Ltmp0: .cfi_def_cfa_offset 16 Ltmp1: .cfi_offset %rbp, -16 movq%rsp, %rbp Ltmp2: .cfi_def_cfa_register %rbp subq$16, %rsp movq%rdi, %rax leaq-16(%rbp), %rdx movl$16, %edi movl$5, %ecx movq%rax, %rsi callq ___atomic_load movq-16(%rbp), %rax movq-8(%rbp), %rdx addq$16, %rsp popq %rbp retq .cfi_endproc .subsections_via_symbolsI'm going to temporarily revert #38959 to fix the nightlies while we figure out a solution