hanging on aarch64

[Licenser]

autocfg hangs / never finishes on aarch64 rust:

   Compiling autocfg v1.0.1 (autocfg)
    Finished test [unoptimized + debuginfo] target(s) in 3.85s
     Running unittests (target/debug/deps/autocfg-f01dc8476d25cc8c)

running 16 tests
test tests::dir_does_contain_target ... ok
test tests::dir_does_contain_target_with_custom_target_dir ... ok
test tests::dir_does_not_contain_target ... ok
test tests::dir_does_not_contain_target_with_custom_target_dir ... ok
test tests::version_cmp ... ok

test tests::autocfg_version has been running for over 60 seconds
test tests::probe_add has been running for over 60 seconds
test tests::probe_alloc has been running for over 60 seconds
test tests::probe_as_ref has been running for over 60 seconds
test tests::probe_bad_sysroot_crate has been running for over 60 seconds
test tests::probe_constant has been running for over 60 seconds
test tests::probe_expression has been running for over 60 seconds
test tests::probe_i128 has been running for over 60 seconds
test tests::probe_no_std has been running for over 60 seconds
test tests::probe_std has been running for over 60 seconds
test tests::probe_sum has been running for over 60 seconds

[Licenser]

looking at the debugger the calltracek looks like this:

* thread #1, name = 'autocfg-f01dc84', stop reason = signal SIGSTOP
    frame #0: 0x0000aaaaaaad6a98 autocfg-f01dc8476d25cc8c`core::sync::atomic::atomic_add::h46e986141843397d(dst=0x0000aaaaaab7a0c0, val=1, order=Relaxed) at atomic.rs:2387:24
(lldb) bt
error: need to add support for DW_TAG_base_type '()' encoded with DW_ATE = 0x7, bit_size = 0
* thread #1, name = 'autocfg-f01dc84', stop reason = signal SIGSTOP
  * frame #0: 0x0000aaaaaaad6a98 autocfg-f01dc8476d25cc8c`core::sync::atomic::atomic_add::h46e986141843397d(dst=0x0000aaaaaab7a0c0, val=1, order=Relaxed) at atomic.rs:2387:24
    frame #1: 0x0000aaaaaaacedf8 autocfg-f01dc8476d25cc8c`core::sync::atomic::AtomicUsize::fetch_add::hac95446173d992f0(self=0x0000aaaaaab7a0c0, val=1, order=Relaxed) at atomic.rs:1740:26
    frame #2: 0x0000aaaaaaacbc04 autocfg-f01dc8476d25cc8c`autocfg::AutoCfg::probe::h91d6d047b62c4170(self=0x0000ffffffffce80, code="") at lib.rs:233:18
    frame #3: 0x0000aaaaaaacb158 autocfg-f01dc8476d25cc8c`autocfg::AutoCfg::with_dir::h07af96618be0546c(dir="target") at lib.rs:203:13
    frame #4: 0x0000aaaaaaac4a54 autocfg-f01dc8476d25cc8c`autocfg::tests::_$LT$impl$u20$autocfg..AutoCfg$GT$::for_test::hf187392a572e307d at tests.rs:21:21
    frame #5: 0x0000aaaaaaacfd04 autocfg-f01dc8476d25cc8c`autocfg::tests::autocfg_version::hf8b96c6f0671e887 at tests.rs:28:14
    frame #6: 0x0000aaaaaaac34a8 autocfg-f01dc8476d25cc8c`autocfg::tests::autocfg_version::_$u7b$$u7b$closure$u7d$$u7d$::h513763c4192f38d2((null)=0x0000ffffffffd2fe) at tests.rs:27:1
    frame #7: 0x0000aaaaaaad5024 autocfg-f01dc8476d25cc8c`core::ops::function::FnOnce::call_once::h6da51f25e97b6c65((null)=closure-0 @ 0x0000ffffffffd2fe, (null)=<unavailable>) at function.rs:227:5
    frame #8: 0x0000aaaaaaaf9174 autocfg-f01dc8476d25cc8c`test::__rust_begin_short_backtrace::h5bcd9a25efe8d634 [inlined] core::ops::function::FnOnce::call_once::h0acf993ed6146b74 at function.rs:227:5
    frame #9: 0x0000aaaaaaaf9170 autocfg-f01dc8476d25cc8c`test::__rust_begin_short_backtrace::h5bcd9a25efe8d634 at lib.rs:577
    frame #10: 0x0000aaaaaaaf813c autocfg-f01dc8476d25cc8c`test::run_test::run_test_inner::_$u7b$$u7b$closure$u7d$$u7d$::h97753dd854620227 [inlined] _$LT$alloc..boxed..Box$LT$F$C$A$GT$$u20$as$u20$core..ops..function..FnOnce$LT$Args$GT$$GT$::call_once::h51f753c3873f5fa3 at boxed.rs:1575:9
    frame #11: 0x0000aaaaaaaf8130 autocfg-f01dc8476d25cc8c`test::run_test::run_test_inner::_$u7b$$u7b$closure$u7d$$u7d$::h97753dd854620227 [inlined] _$LT$std..panic..AssertUnwindSafe$LT$F$GT$$u20$as$u20$core..ops..function..FnOnce$LT$$LP$$RP$$GT$$GT$::call_once::h5efc09572c3a7383 at panic.rs:347
    frame #12: 0x0000aaaaaaaf8130 autocfg-f01dc8476d25cc8c`test::run_test::run_test_inner::_$u7b$$u7b$closure$u7d$$u7d$::h97753dd854620227 [inlined] std::panicking::try::do_call::h3d93d2055ab96c94 at panicking.rs:401
    frame #13: 0x0000aaaaaaaf8130 autocfg-f01dc8476d25cc8c`test::run_test::run_test_inner::_$u7b$$u7b$closure$u7d$$u7d$::h97753dd854620227 [inlined] std::panicking::try::h62bb60c147376d5c at panicking.rs:365
    frame #14: 0x0000aaaaaaaf8130 autocfg-f01dc8476d25cc8c`test::run_test::run_test_inner::_$u7b$$u7b$closure$u7d$$u7d$::h97753dd854620227 [inlined] std::panic::catch_unwind::hb2faed6399cba22b at panic.rs:434
    frame #15: 0x0000aaaaaaaf8130 autocfg-f01dc8476d25cc8c`test::run_test::run_test_inner::_$u7b$$u7b$closure$u7d$$u7d$::h97753dd854620227 [inlined] test::run_test_in_process::hc72ce3f8a1782280 at lib.rs:600
    frame #16: 0x0000aaaaaaaf80ac autocfg-f01dc8476d25cc8c`test::run_test::run_test_inner::_$u7b$$u7b$closure$u7d$$u7d$::h97753dd854620227 at lib.rs:492
    frame #17: 0x0000aaaaaaaf7650 autocfg-f01dc8476d25cc8c`test::run_test::run_test_inner::h85a02fa0fb1b0fa4 at lib.rs:530:13
    frame #18: 0x0000aaaaaaaf6614 autocfg-f01dc8476d25cc8c`test::run_test::h8218e7b82137be72 at lib.rs:564:28
    frame #19: 0x0000aaaaaaaf1dbc autocfg-f01dc8476d25cc8c`test::run_tests::h7e5532b3f478e10b at lib.rs:305:17
    frame #20: 0x0000aaaaaaae5c2c autocfg-f01dc8476d25cc8c`test::console::run_tests_console::h7ce9800d0f5abe2a at console.rs:290:5
    frame #21: 0x0000aaaaaaaf0544 autocfg-f01dc8476d25cc8c`test::test_main::h8fa9ab6b79e5eccb at lib.rs:122:15
    frame #22: 0x0000aaaaaaaf1278 autocfg-f01dc8476d25cc8c`test::test_main_static::h9e81e219e9eef511 at lib.rs:141:5
    frame #23: 0x0000aaaaaaac505c autocfg-f01dc8476d25cc8c`autocfg::main::h902804c37733bec8 at lib.rs:1:1
    frame #24: 0x0000aaaaaaad534c autocfg-f01dc8476d25cc8c`core::ops::function::FnOnce::call_once::hca54486c9f7a668f((null)=(autocfg-f01dc8476d25cc8c`autocfg::main::h902804c37733bec8 at lib.rs:1), (null)=<unavailable>) at function.rs:227:5
    frame #25: 0x0000aaaaaaac2d5c autocfg-f01dc8476d25cc8c`std::sys_common::backtrace::__rust_begin_short_backtrace::h2dfc5cbea67a689d(f=(autocfg-f01dc8476d25cc8c`autocfg::main::h902804c37733bec8 at lib.rs:1)) at backtrace.rs:125:18
    frame #26: 0x0000aaaaaaac189c autocfg-f01dc8476d25cc8c`std::rt::lang_start::_$u7b$$u7b$closure$u7d$$u7d$::h19a744862809308b at rt.rs:49:18
    frame #27: 0x0000aaaaaab1e0fc autocfg-f01dc8476d25cc8c`std::rt::lang_start_internal::hbc0bc990d09d4f94 [inlined] core::ops::function::impls::_$LT$impl$u20$core..ops..function..FnOnce$LT$A$GT$$u20$for$u20$$RF$F$GT$::call_once::h99be496e2711d3b7 at function.rs:259:13
    frame #28: 0x0000aaaaaab1e0f0 autocfg-f01dc8476d25cc8c`std::rt::lang_start_internal::hbc0bc990d09d4f94 [inlined] std::panicking::try::do_call::ha870bafb774bdd40 at panicking.rs:401
    frame #29: 0x0000aaaaaab1e0f0 autocfg-f01dc8476d25cc8c`std::rt::lang_start_internal::hbc0bc990d09d4f94 [inlined] std::panicking::try::h46a214daad8fddae at panicking.rs:365
    frame #30: 0x0000aaaaaab1e0f0 autocfg-f01dc8476d25cc8c`std::rt::lang_start_internal::hbc0bc990d09d4f94 [inlined] std::panic::catch_unwind::hc48118c52f11bbeb at panic.rs:434
    frame #31: 0x0000aaaaaab1e0f0 autocfg-f01dc8476d25cc8c`std::rt::lang_start_internal::hbc0bc990d09d4f94 at rt.rs:34
    frame #32: 0x0000aaaaaaac1874 autocfg-f01dc8476d25cc8c`std::rt::lang_start::he326385d099c7ebc(main=(autocfg-f01dc8476d25cc8c`autocfg::main::h902804c37733bec8 at lib.rs:1), argc=3, argv=0x0000fffffffff228) at rt.rs:48:5
    frame #33: 0x0000aaaaaaac508c autocfg-f01dc8476d25cc8c`main + 40
    frame #34: 0x0000fffff7e14090 libc.so.6`__libc_start_main + 232
    frame #35: 0x0000aaaaaaabf760 autocfg-f01dc8476d25cc8c`_start + 52

[cuviper]

If atomic_add is hanging, that seems like a compiler codegen issue. Can you reproduce this separately? Something like:

use std::sync::atomic::{AtomicUsize, Ordering};

static ID: AtomicUsize = AtomicUsize::new(0);

#[test]
fn test1() {
    for _ in 0..1_000_000 {
        ID.fetch_add(1, Ordering::Relaxed);
    }
}

#[test]
fn test2() {
    for _ in 0..1_000_000 {
        ID.fetch_add(1, Ordering::Relaxed);
    }
}

[Licenser]

Oh that's a good call!

You are right, this fails as well :) (I really shouldn't add a smiley here ... )

going down this rout I could reduce the failure to:

use std::sync::atomic::{AtomicUsize, Ordering};

static ID: AtomicUsize = AtomicUsize::new(0);

#[test]
fn test1() {
        ID.fetch_add(1, Ordering::Relaxed);
}

which quite clearly isn't a autocfg issue! I'll open a rust bug and close this one. Thank you for helping to track this down!