AVR: Cannot compile compiler_builtins in either release or debug mode with nightly 2021-08-21

[gergoerdi]

Compiling a pretty much empty project for AVR brings in compiler_builtins as a dependency, but then building that fails with a segfault (with --release) or a a ran out of registers during register allocation error message.

To reproduce, make the following files:

Cargo.toml

[package]
name = "foo"
version = "0.1.0"

.cargo/config

[build]
target = "avr-unknown-gnu-atmega328"

[unstable]
build-std = ["core"]

src/main.rs

#![no_std]
#![no_main]

#[no_mangle]
pub extern fn main() {
}

Build logs:

$ cargo build 
   Compiling core v0.0.0 (/home/cactus/sdk/rust/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core)
   Compiling compiler_builtins v0.1.49
   Compiling rustc-std-workspace-core v1.99.0 (rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/rustc-std-workspace-core)
error: ran out of registers during register allocation

error: could not compile `core` due to previous error
warning: build failed, waiting for other jobs to finish...
error: build failed

$ cargo build --release
   Compiling compiler_builtins v0.1.49
   Compiling core v0.0.0 (rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core)
   Compiling rustc-std-workspace-core v1.99.0 (rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/rustc-std-workspace-core)
rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/librustc_driver-f66b15f11dec651a.so(+0x4ffee3)[0x7f4b5705dee3]
/lib/x86_64-linux-gnu/libpthread.so.0(+0x141f0)[0x7f4b567be1f0]
rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/libLLVM-13-rust-1.56.0-nightly.so(_ZN4llvm12MachineInstr15addRegisterDeadENS_8RegisterEPKNS_18TargetRegisterInfoEb+0xe1)[0x7f4b536eb021]
rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/libLLVM-13-rust-1.56.0-nightly.so(_ZN4llvm13LiveIntervals17computeDeadValuesERNS_12LiveIntervalEPNS_15SmallVectorImplIPNS_12MachineInstrEEE+0x2ab)[0x7f4b5363bd1b]
rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/libLLVM-13-rust-1.56.0-nightly.so(_ZN4llvm13LiveIntervals12shrinkToUsesEPNS_12LiveIntervalEPNS_15SmallVectorImplIPNS_12MachineInstrEEE+0x492)[0x7f4b5363d242]
rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/libLLVM-13-rust-1.56.0-nightly.so(_ZN4llvm13LiveRangeEdit17eliminateDeadDefsERNS_15SmallVectorImplIPNS_12MachineInstrEEENS_8ArrayRefINS_8RegisterEEEPNS_9AAResultsE+0x20a)[0x7f4b5365811a]
rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/libLLVM-13-rust-1.56.0-nightly.so(+0x25af0f2)[0x7f4b536090f2]
rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/libLLVM-13-rust-1.56.0-nightly.so(_ZN4llvm12RegAllocBase16postOptimizationEv+0x17)[0x7f4b5382adf7]
rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/libLLVM-13-rust-1.56.0-nightly.so(+0x27e04ca)[0x7f4b5383a4ca]
rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/libLLVM-13-rust-1.56.0-nightly.so(_ZN4llvm19MachineFunctionPass13runOnFunctionERNS_8FunctionE+0xee)[0x7f4b536dcfde]
rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/libLLVM-13-rust-1.56.0-nightly.so(_ZN4llvm13FPPassManager13runOnFunctionERNS_8FunctionE+0x639)[0x7f4b53479429]
rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/libLLVM-13-rust-1.56.0-nightly.so(_ZN4llvm13FPPassManager11runOnModuleERNS_6ModuleE+0x33)[0x7f4b534803e3]
rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/libLLVM-13-rust-1.56.0-nightly.so(_ZN4llvm6legacy15PassManagerImpl3runERNS_6ModuleE+0x470)[0x7f4b53479c90]
rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/librustc_driver-f66b15f11dec651a.so(+0x2129268)[0x7f4b58c87268]
rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/librustc_driver-f66b15f11dec651a.so(+0x20b004f)[0x7f4b58c0e04f]
rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/librustc_driver-f66b15f11dec651a.so(+0x20b2f70)[0x7f4b58c10f70]
rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/librustc_driver-f66b15f11dec651a.so(+0x20be46b)[0x7f4b58c1c46b]
rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/librustc_driver-f66b15f11dec651a.so(+0x20b7d84)[0x7f4b58c15d84]
rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/librustc_driver-f66b15f11dec651a.so(+0x20f9d3c)[0x7f4b58c57d3c]
rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/librustc_driver-f66b15f11dec651a.so(+0x211631c)[0x7f4b58c7431c]
rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/libstd-1dd6c19f0820d51d.so(rust_metadata_std_155e9b00b45252a2+0xa9fe3)[0x7f4b5689bfe3]
/lib/x86_64-linux-gnu/libpthread.so.0(+0x9450)[0x7f4b567b3450]
/lib/x86_64-linux-gnu/libc.so.6(clone+0x43)[0x7f4b566c1d53]
error: could not compile `compiler_builtins`

Caused by:
  process didn't exit successfully: `rustc --crate-name compiler_builtins .cargo/registry/src/github.com-1ecc6299db9ec823/compiler_builtins-0.1.49/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi --crate-type lib --emit=dep-info,metadata,link -C opt-level=3 -C embed-bitcode=no --cfg 'feature="compiler-builtins"' --cfg 'feature="core"' --cfg 'feature="default"' --cfg 'feature="rustc-dep-of-std"' -C metadata=35ae16dbb58b86b3 -C extra-filename=-35ae16dbb58b86b3 --out-dir prog/rust/avr/compiler-builtins-bug/target/avr-unknown-gnu-atmega328/release/deps --target avr-unknown-gnu-atmega328 -Z force-unstable-if-unmarked -L dependency=prog/rust/avr/compiler-builtins-bug/target/avr-unknown-gnu-atmega328/release/deps -L dependency=prog/rust/avr/compiler-builtins-bug/target/release/deps --extern core=prog/rust/avr/compiler-builtins-bug/target/avr-unknown-gnu-atmega328/release/deps/librustc_std_workspace_core-feaa69e1bf1370b5.rmeta --cap-lints allow --cfg 'feature="unstable"'` (signal: 11, SIGSEGV: invalid memory reference)

[nikic]

Just to double check, this is a regression in nightly 2021-08-21 and worked fine with the previous nightly? In that case it's almost certainly an LLVM 13 regression.

[gergoerdi]

I haven't tried Rust on AVR since 2017 so can't tell how recent this regression is.

…

On Mon, Aug 23, 2021, 17:45 Nikita Popov ***@***.***> wrote: Just to double check, this is a regression in nightly 2021-08-21 and worked fine with the previous nightly? In that case it's almost certainly an LLVM 13 regression. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#88252 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAA4KKMRZHCSMU3YKAPZPO3T6IKC5ANCNFSM5CUBJHYQ> . Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&utm_campaign=notification-email> .

[gergoerdi]

OK so I just tried with some previous nightlies. On 2021-08-16 I am not getting a segfault; instead, it fails with:

LLVM ERROR: Not supported instr: <MCInst 296 <MCOperand Reg:1> <MCOperand Imm:15> <MCOperand Reg:47>>

I get the same error on 2021-05-21.

On 2021-02-22, I get:

LLVM ERROR: Not supported instr: <MCInst 258 <MCOperand Reg:1> <MCOperand Imm:15> <MCOperand Reg:45>>

[nikic]

Okay, that seems to be a long-standing issue then: rust-lang/compiler-builtins#400

[gergoerdi]

I had to go back all the way to rustc 1.47.0-nightly (2d8a3b9 2020-08-26) to get this to work, at least up to compilation (I haven't done linking yet).

[MForster]

I believe that there are two different issues at work here. I have a similar setup with a custom AVR target definition (for atmega32u4) that shows the ran out of registers issue first in nightly-2021-03-05. The previous day still works.

[gergoerdi]

So is there a particular nightly that is known to work with AVR? I can compile my program with 2d8a3b9 2020-08-26 but the resulting program is juuuust a bit wrong when executing it. I hope I won't have to re-do all the LLVM AVR backend debugging from back in 2017...

[MForster]

I was experimenting with a later version from January 2021, and it also seemed to generate wrong code. Compilation succeeded, but the resulting program didn't seem to do what it should.

I'm not 100% sure about this, because I didn't have a debugging setup, but I couldn't get even the simplest logic to execute correctly.

[linclelinkpart5]

I had to go back all the way to rustc 1.47.0-nightly (2d8a3b9 2020-08-26) to get this to work, at least up to compilation (I haven't done linking yet).

Confirming that this nightly works for me. For reference, I'm following the steps in part 6 of https://book.avr-rust.com/ (after installing all the third-party tools linked in part 2 of the same link).

[bombela]

For what is worth nightly-2021-01-07-x86_64-unknown-linux-gnu produces working machine code for me on attiny13a, attint24a and atmega328. Any version after that I get the LLVM ERROR: Not supported instr: <MCInst 312 <MCOperand Reg:1> <MCOperand Imm:15> <MCOperand Reg:47>> error.

[jeremysalwen]

I am hitting this crash with the latest nightly and https://reviews.llvm.org/D114611 applied (as well as the CONFIG-0000 and LLVM-0001 patches from https://gitlab.com/snowgoonspub/rust-avr-nightly-builder/-/tree/main/patches applied). I was able to compile rustc with debug info and get the following stack trace:

Command Line:

rustc --crate-name compiler_builtins /home/jeremy/.cargo/registry/src/github.com-1ecc6299db9ec823/compiler_builtins-0.1.66/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --crate-type lib --emit=dep-info,metadata,link -C opt-level=3 -C embed-bitcode=no --cfg 'feature="compiler-builtins"' --cfg 'feature="core"' --cfg 'feature="default"' --cfg 'feature="rustc-dep-of-std"' -C metadata=b3e737738101e8cc -C extra-filename=-b3e737738101e8cc --out-dir /home/jeremy/apechem/heapless/target/avr-atmega328p/release/deps --target /home/jeremy/apechem/heapless/avr-specs/avr-atmega328p.json -Z force-unstable-if-unmarked -L dependency=/home/jeremy/apechem/heapless/target/avr-atmega328p/release/deps -L dependency=/home/jeremy/apechem/heapless/target/release/deps --extern core=/home/jeremy/apechem/heapless/target/avr-atmega328p/release/deps/librustc_std_workspace_core-7e9ff7e977f1ead7.rmeta --cap-lints allow --cfg 'feature="unstable"'

Stack Trace:

Thread 25 "LTO compiler_bu" received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7fffe4ffe640 (LWP 27539)]
0x00007ffff1660a5a in llvm::MachineInstr::addRegisterDead(llvm::Register, llvm::TargetRegisterInfo const*, bool) ()
   from /home/jeremy/.rustup/toolchains/snowgoons/lib/librustc_driver-c81e44a66c4bb924.so
(gdb) bt
#0  0x00007ffff1660a5a in llvm::MachineInstr::addRegisterDead(llvm::Register, llvm::TargetRegisterInfo const*, bool) ()
   from /home/jeremy/.rustup/toolchains/snowgoons/lib/librustc_driver-c81e44a66c4bb924.so
#1  0x00007ffff15981d0 in llvm::LiveIntervals::computeDeadValues(llvm::LiveInterval&, llvm::SmallVectorImpl<llvm::MachineInstr*>*) [clone .localalias] () from /home/jeremy/.rustup/toolchains/snowgoons/lib/librustc_driver-c81e44a66c4bb924.so
#2  0x00007ffff159e3aa in llvm::LiveIntervals::shrinkToUses(llvm::LiveInterval*, llvm::SmallVectorImpl<llvm::MachineInstr*>*) ()
   from /home/jeremy/.rustup/toolchains/snowgoons/lib/librustc_driver-c81e44a66c4bb924.so
#3  0x00007ffff15bbd8a in llvm::LiveRangeEdit::eliminateDeadDefs(llvm::SmallVectorImpl<llvm::MachineInstr*>&, llvm::ArrayRef<llvm::Register>, llvm::AAResults*) () from /home/jeremy/.rustup/toolchains/snowgoons/lib/librustc_driver-c81e44a66c4bb924.so
#4  0x00007ffff1561b03 in (anonymous namespace)::HoistSpillHelper::hoistAllSpills() ()
   from /home/jeremy/.rustup/toolchains/snowgoons/lib/librustc_driver-c81e44a66c4bb924.so
#5  0x00007ffff17aec62 in llvm::RegAllocBase::postOptimization() [clone .localalias] ()
   from /home/jeremy/.rustup/toolchains/snowgoons/lib/librustc_driver-c81e44a66c4bb924.so
#6  0x00007ffff17cd02e in (anonymous namespace)::RAGreedy::runOnMachineFunction(llvm::MachineFunction&) ()
   from /home/jeremy/.rustup/toolchains/snowgoons/lib/librustc_driver-c81e44a66c4bb924.so
#7  0x00007ffff16526d4 in llvm::MachineFunctionPass::runOnFunction(llvm::Function&) [clone .localalias] ()
   from /home/jeremy/.rustup/toolchains/snowgoons/lib/librustc_driver-c81e44a66c4bb924.so
#8  0x00007ffff25c8d20 in llvm::FPPassManager::runOnFunction(llvm::Function&) [clone .localalias] ()
   from /home/jeremy/.rustup/toolchains/snowgoons/lib/librustc_driver-c81e44a66c4bb924.so
#9  0x00007ffff25c8e8c in llvm::FPPassManager::runOnModule(llvm::Module&) [clone .localalias] ()
   from /home/jeremy/.rustup/toolchains/snowgoons/lib/librustc_driver-c81e44a66c4bb924.so
#10 0x00007ffff25ca8b1 in llvm::legacy::PassManagerImpl::run(llvm::Module&) [clone .localalias] ()
   from /home/jeremy/.rustup/toolchains/snowgoons/lib/librustc_driver-c81e44a66c4bb924.so
#11 0x00007ffff025c5c8 in LLVMRustWriteOutputFile () from /home/jeremy/.rustup/toolchains/snowgoons/lib/librustc_driver-c81e44a66c4bb924.so
#12 0x00007ffff00b270d in _RNvNtNtCs2Hy2UJfC2YD_18rustc_codegen_llvm4back5write17write_output_file ()
    at compiler/rustc_codegen_llvm/src/back/write.rs:72
#13 0x00007ffff00b91c7 in _RNCNvNtNtCs2Hy2UJfC2YD_18rustc_codegen_llvm4back5write7codegens0_0B7_ ()
    at compiler/rustc_codegen_llvm/src/back/write.rs:914
#14 _RINvNvNtNtCs2Hy2UJfC2YD_18rustc_codegen_llvm4back5write7codegen12with_codegenNCB2_s0_0INtNtCsaEJlGfOjSyv_4core6result6ResultuNtNtCs5LBiNHwbBUs_10rustc_span11fatal_error10FatalErrorEEB8_ () at compiler/rustc_codegen_llvm/src/back/write.rs:768
#15 _RNvNtNtCs2Hy2UJfC2YD_18rustc_codegen_llvm4back5write7codegen () at compiler/rustc_codegen_llvm/src/back/write.rs:913
#16 0x00007ffff010f382 in _RNvXs1_Cs2Hy2UJfC2YD_18rustc_codegen_llvmNtB5_18LlvmCodegenBackendNtNtNtCscKPc0T4Mv2G_17rustc_codegen_ssa6traits5write19WriteBackendMethods7codegen () at compiler/rustc_codegen_llvm/src/lib.rs:215
#17 _RINvNtNtCscKPc0T4Mv2G_17rustc_codegen_ssa4back5write24finish_intra_module_workNtCs2Hy2UJfC2YD_18rustc_codegen_llvm18LlvmCodegenBackendEB1g_ () at /home/jeremy/apechem/rust-avr-nightly-builder/build/rust/compiler/rustc_codegen_ssa/src/back/write.rs:911
#18 0x00007ffff010e088 in _RINvNtNtCscKPc0T4Mv2G_17rustc_codegen_ssa4back5write21execute_lto_work_itemNtCs2Hy2UJfC2YD_18rustc_codegen_llvm18LlvmCodegenBackendEB1d_ () at /home/jeremy/apechem/rust-avr-nightly-builder/build/rust/compiler/rustc_codegen_ssa/src/back/write.rs:897
--Type <RET> for more, q to quit, c to continue without paging--
#19 _RINvNtNtCscKPc0T4Mv2G_17rustc_codegen_ssa4back5write17execute_work_itemNtCs2Hy2UJfC2YD_18rustc_codegen_llvm18LlvmCodegenBackendEB19_ ()
    at /home/jeremy/apechem/rust-avr-nightly-builder/build/rust/compiler/rustc_codegen_ssa/src/back/write.rs:749
#20 0x00007ffff01ab6c5 in _RNCINvNtNtCscKPc0T4Mv2G_17rustc_codegen_ssa4back5write10spawn_workNtCs2Hy2UJfC2YD_18rustc_codegen_llvm18LlvmCodegenBackendE0B14_ () at /home/jeremy/apechem/rust-avr-nightly-builder/build/rust/compiler/rustc_codegen_ssa/src/back/write.rs:1665
#21 _RNCINvXs0_Cs2Hy2UJfC2YD_18rustc_codegen_llvmNtB8_18LlvmCodegenBackendNtNtNtCscKPc0T4Mv2G_17rustc_codegen_ssa6traits7backend19ExtraBackendMethods18spawn_named_threadNCINvNtNtB1b_4back5write10spawn_workBG_E0uE0B8_ () at compiler/rustc_codegen_llvm/src/lib.rs:157
#22 _RINvNtNtCsiRCMJYjrQF4_3std10sys_common9backtrace28___rust_begin_short_backtraceNCINvXs0_Cs2Hy2UJfC2YD_18rustc_codegen_llvmNtB1o_18LlvmCodegenBackendNtNtNtCscKPc0T4Mv2G_17rustc_codegen_ssa6traits7backend19ExtraBackendMethods18spawn_named_threadNCINvNtNtB2s_4back5write10spawn_workB1W_E0uE0uEB1o_ () at /home/jeremy/apechem/rust-avr-nightly-builder/build/rust/library/std/src/sys_common/backtrace.rs:123
#23 0x00007ffff0228cd7 in _RNCNCINvMNtCsiRCMJYjrQF4_3std6threadNtB7_7Builder15spawn_uncheckedNCINvXs0_Cs2Hy2UJfC2YD_18rustc_codegen_llvmNtB1b_18LlvmCodegenBackendNtNtNtCscKPc0T4Mv2G_17rustc_codegen_ssa6traits7backend19ExtraBackendMethods18spawn_named_threadNCINvNtNtB2f_4back5write10spawn_workB1J_E0uE0uEs_00B1b_ () at /home/jeremy/apechem/rust-avr-nightly-builder/build/rust/library/std/src/thread/mod.rs:477
#24 _RNvXsl_NtNtCsaEJlGfOjSyv_4core5panic11unwind_safeINtB5_16AssertUnwindSafeNCNCINvMNtCsiRCMJYjrQF4_3std6threadNtB1h_7Builder15spawn_uncheckedNCINvXs0_Cs2Hy2UJfC2YD_18rustc_codegen_llvmNtB2m_18LlvmCodegenBackendNtNtNtCscKPc0T4Mv2G_17rustc_codegen_ssa6traits7backend19ExtraBackendMethods18spawn_named_threadNCINvNtNtB3q_4back5write10spawn_workB2U_E0uE0uEs_00EINtNtNtB9_3ops8function6FnOnceuE9call_onceB2m_ ()
    at /home/jeremy/apechem/rust-avr-nightly-builder/build/rust/library/core/src/panic/unwind_safe.rs:271
#25 _RINvNvNtCsiRCMJYjrQF4_3std9panicking3try7do_callINtNtNtCsaEJlGfOjSyv_4core5panic11unwind_safe16AssertUnwindSafeNCNCINvMNtB6_6threadNtB1T_7Builder15spawn_uncheckedNCINvXs0_Cs2Hy2UJfC2YD_18rustc_codegen_llvmNtB2J_18LlvmCodegenBackendNtNtNtCscKPc0T4Mv2G_17rustc_codegen_ssa6traits7backend19ExtraBackendMethods18spawn_named_threadNCINvNtNtB3N_4back5write10spawn_workB3h_E0uE0uEs_00EuEB2J_ ()
    at /home/jeremy/apechem/rust-avr-nightly-builder/build/rust/library/std/src/panicking.rs:406
#26 _RINvNtCsiRCMJYjrQF4_3std9panicking3tryuINtNtNtCsaEJlGfOjSyv_4core5panic11unwind_safe16AssertUnwindSafeNCNCINvMNtB4_6threadNtB1K_7Builder15spawn_uncheckedNCINvXs0_Cs2Hy2UJfC2YD_18rustc_codegen_llvmNtB2A_18LlvmCodegenBackendNtNtNtCscKPc0T4Mv2G_17rustc_codegen_ssa6traits7backend19ExtraBackendMethods18spawn_named_threadNCINvNtNtB3E_4back5write10spawn_workB38_E0uE0uEs_00EEB2A_ ()
    at /home/jeremy/apechem/rust-avr-nightly-builder/build/rust/library/std/src/panicking.rs:370
#27 _RINvNtCsiRCMJYjrQF4_3std5panic12catch_unwindINtNtNtCsaEJlGfOjSyv_4core5panic11unwind_safe16AssertUnwindSafeNCNCINvMNtB4_6threadNtB1P_7Builder15spawn_uncheckedNCINvXs0_Cs2Hy2UJfC2YD_18rustc_codegen_llvmNtB2F_18LlvmCodegenBackendNtNtNtCscKPc0T4Mv2G_17rustc_codegen_ssa6traits7backend19ExtraBackendMethods18spawn_named_threadNCINvNtNtB3J_4back5write10spawn_workB3d_E0uE0uEs_00EuEB2F_ ()
    at /home/jeremy/apechem/rust-avr-nightly-builder/build/rust/library/std/src/panic.rs:133
#28 _RNCINvMNtCsiRCMJYjrQF4_3std6threadNtB5_7Builder15spawn_uncheckedNCINvXs0_Cs2Hy2UJfC2YD_18rustc_codegen_llvmNtB19_18LlvmCodegenBackendNtNtNtCscKPc0T4Mv2G_17rustc_codegen_ssa6traits7backend19ExtraBackendMethods18spawn_named_threadNCINvNtNtB2d_4back5write10spawn_workB1H_E0uE0uEs_0B19_
    () at /home/jeremy/apechem/rust-avr-nightly-builder/build/rust/library/std/src/thread/mod.rs:476
#29 _RNSNvYNCINvMNtCsiRCMJYjrQF4_3std6threadNtBa_7Builder15spawn_uncheckedNCINvXs0_Cs2Hy2UJfC2YD_18rustc_codegen_llvmNtB1e_18LlvmCodegenBackendNtNtNtCscKPc0T4Mv2G_17rustc_codegen_ssa6traits7backend19ExtraBackendMethods18spawn_named_threadNCINvNtNtB2i_4back5write10spawn_workB1M_E0uE0uEs_0INtNtNtCsaEJlGfOjSyv_4core3ops8function6FnOnceuE9call_once6vtableB1e_ ()
    at /home/jeremy/apechem/rust-avr-nightly-builder/build/rust/library/core/src/ops/function.rs:227
#30 0x00007fffeefd67e3 in <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once ()
--Type <RET> for more, q to quit, c to continue without paging--
    at /home/jeremy/apechem/rust-avr-nightly-builder/build/rust/library/alloc/src/boxed.rs:1854
#31 <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once ()
    at /home/jeremy/apechem/rust-avr-nightly-builder/build/rust/library/alloc/src/boxed.rs:1854
#32 std::sys::unix::thread::Thread::new::thread_start () at library/std/src/sys/unix/thread.rs:108
#33 0x00007fffeeedbd80 in start_thread (arg=0x7fffe4ffe640) at pthread_create.c:481
#34 0x00007fffeee06b6f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95