ICE: `used byval ABI for unsized layout`

[matthiaskrgr]

auto-reduced (treereduce-rust):

#![feature(abi_x86_interrupt)]
#![feature(unsized_fn_params)]
struct Test;

impl Test {
    pub extern "x86-interrupt" fn test(_a: str) {}
}

original:

struct Test;

impl Test {
    pub extern "x86-interrupt" fn test(_a: str) {

    }
}

Version information

rustc 1.80.0-nightly (25e3949aa 2024-05-06)
binary: rustc
commit-hash: 25e3949aa1b24b3f62a72c1f713830aa1d1efcd4
commit-date: 2024-05-06
host: x86_64-unknown-linux-gnu
release: 1.80.0-nightly
LLVM version: 18.1.4

Command:
/home/matthias/.rustup/toolchains/master/bin/rustc -Zcrate-attr=feature(abi_x86_interrupt) -Zcrate-attr=feature(unsized_fn_params) -Clink-dead-code=true --crate-type=lib

Program output

warning: struct `Test` is never constructed
 --> /tmp/icemaker_global_tempdir.cFeBgsJNprxL/rustc_testrunner_tmpdir_reporting.zx6V8PkPVkHF/mvce.rs:1:8
  |
1 | struct Test;
  |        ^^^^
  |
  = note: `#[warn(dead_code)]` on by default

warning: associated function `test` is never used
 --> /tmp/icemaker_global_tempdir.cFeBgsJNprxL/rustc_testrunner_tmpdir_reporting.zx6V8PkPVkHF/mvce.rs:4:35
  |
3 | impl Test {
  | --------- associated function in this implementation
4 |     pub extern "x86-interrupt" fn test(_a: str) {}
  |                                   ^^^^

warning: `extern` fn uses type `str`, which is not FFI-safe
 --> /tmp/icemaker_global_tempdir.cFeBgsJNprxL/rustc_testrunner_tmpdir_reporting.zx6V8PkPVkHF/mvce.rs:4:44
  |
4 |     pub extern "x86-interrupt" fn test(_a: str) {}
  |                                            ^^^ not FFI-safe
  |
  = help: consider using `*const u8` and a length instead
  = note: string slices have no C equivalent
  = note: `#[warn(improper_ctypes_definitions)]` on by default

thread 'rustc' panicked at /rustc/25e3949aa1b24b3f62a72c1f713830aa1d1efcd4/compiler/rustc_target/src/abi/call/mod.rs:662:9:
used byval ABI for unsized layout
stack backtrace:
   0:     0x7520ddde0b35 - std::backtrace_rs::backtrace::libunwind::trace::h0237a9d37919b3ec
                               at /rustc/25e3949aa1b24b3f62a72c1f713830aa1d1efcd4/library/std/src/../../backtrace/src/backtrace/libunwind.rs:105:5
   1:     0x7520ddde0b35 - std::backtrace_rs::backtrace::trace_unsynchronized::h4c8f70ef1acfdb78
                               at /rustc/25e3949aa1b24b3f62a72c1f713830aa1d1efcd4/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7520ddde0b35 - std::sys_common::backtrace::_print_fmt::h5b738224e75de754
                               at /rustc/25e3949aa1b24b3f62a72c1f713830aa1d1efcd4/library/std/src/sys_common/backtrace.rs:68:5
   3:     0x7520ddde0b35 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::hf9f7d71c4c529ad8
                               at /rustc/25e3949aa1b24b3f62a72c1f713830aa1d1efcd4/library/std/src/sys_common/backtrace.rs:44:22
   4:     0x7520dde2fcfb - core::fmt::rt::Argument::fmt::h03b0e1b7a27ddedf
                               at /rustc/25e3949aa1b24b3f62a72c1f713830aa1d1efcd4/library/core/src/fmt/rt.rs:165:63
   5:     0x7520dde2fcfb - core::fmt::write::h248446ba3e345fa4
                               at /rustc/25e3949aa1b24b3f62a72c1f713830aa1d1efcd4/library/core/src/fmt/mod.rs:1157:21
   6:     0x7520dddd58ff - std::io::Write::write_fmt::hac9e4b182ba2857c
                               at /rustc/25e3949aa1b24b3f62a72c1f713830aa1d1efcd4/library/std/src/io/mod.rs:1835:15
   7:     0x7520ddde090e - std::sys_common::backtrace::_print::h54e0c4dd786df1a7
                               at /rustc/25e3949aa1b24b3f62a72c1f713830aa1d1efcd4/library/std/src/sys_common/backtrace.rs:47:5
   8:     0x7520ddde090e - std::sys_common::backtrace::print::h18113f9dcd919587
                               at /rustc/25e3949aa1b24b3f62a72c1f713830aa1d1efcd4/library/std/src/sys_common/backtrace.rs:34:9
   9:     0x7520ddde3279 - std::panicking::default_hook::{{closure}}::hebc9d09f9aaaef06
  10:     0x7520ddde2fbd - std::panicking::default_hook::h2248d0b2ea6d5c7c
                               at /rustc/25e3949aa1b24b3f62a72c1f713830aa1d1efcd4/library/std/src/panicking.rs:298:9
  11:     0x7520da6b6c00 - std[b086d9f741814aa7]::panicking::update_hook::<alloc[9e77a608ae7548d9]::boxed::Box<rustc_driver_impl[cd242fc3f331fee7]::install_ice_hook::{closure#0}>>::{closure#0}
  12:     0x7520ddde3976 - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::hebac1653221b3ca4
                               at /rustc/25e3949aa1b24b3f62a72c1f713830aa1d1efcd4/library/alloc/src/boxed.rs:2036:9
  13:     0x7520ddde3976 - std::panicking::rust_panic_with_hook::h2753b01180f345fa
                               at /rustc/25e3949aa1b24b3f62a72c1f713830aa1d1efcd4/library/std/src/panicking.rs:799:13
  14:     0x7520ddde36eb - std::panicking::begin_panic_handler::{{closure}}::h59aac591d532bbdd
                               at /rustc/25e3949aa1b24b3f62a72c1f713830aa1d1efcd4/library/std/src/panicking.rs:656:13
  15:     0x7520ddde0ff9 - std::sys_common::backtrace::__rust_end_short_backtrace::h80dab8854c18c59d
                               at /rustc/25e3949aa1b24b3f62a72c1f713830aa1d1efcd4/library/std/src/sys_common/backtrace.rs:171:18
  16:     0x7520ddde3457 - rust_begin_unwind
                               at /rustc/25e3949aa1b24b3f62a72c1f713830aa1d1efcd4/library/std/src/panicking.rs:652:5
  17:     0x7520dde2c2c3 - core::panicking::panic_fmt::hb8f3ed7d1c2faf0e
                               at /rustc/25e3949aa1b24b3f62a72c1f713830aa1d1efcd4/library/core/src/panicking.rs:72:14
  18:     0x7520d935c141 - <rustc_target[184f43d5e0345301]::abi::call::ArgAbi<rustc_middle[dafa6f84b775271f]::ty::Ty>>::make_indirect_byval
  19:     0x7520dc7255a2 - rustc_ty_utils[d072b78cb198a2f9]::abi::fn_abi_new_uncached
  20:     0x7520dbc77faa - rustc_ty_utils[d072b78cb198a2f9]::abi::fn_abi_of_instance
  21:     0x7520dbc76877 - rustc_query_impl[bc46c06982da3aa2]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[bc46c06982da3aa2]::query_impl::fn_abi_of_instance::dynamic_query::{closure#2}::{closure#0}, rustc_middle[dafa6f84b775271f]::query::erase::Erased<[u8; 16usize]>>
  22:     0x7520dbc7480f - rustc_query_system[9914171e3cd4e2f]::query::plumbing::try_execute_query::<rustc_query_impl[bc46c06982da3aa2]::DynamicConfig<rustc_query_system[9914171e3cd4e2f]::query::caches::DefaultCache<rustc_middle[dafa6f84b775271f]::ty::ParamEnvAnd<(rustc_middle[dafa6f84b775271f]::ty::instance::Instance, &rustc_middle[dafa6f84b775271f]::ty::list::RawList<(), rustc_middle[dafa6f84b775271f]::ty::Ty>)>, rustc_middle[dafa6f84b775271f]::query::erase::Erased<[u8; 16usize]>>, false, false, false>, rustc_query_impl[bc46c06982da3aa2]::plumbing::QueryCtxt, false>
  23:     0x7520dbc74469 - rustc_query_impl[bc46c06982da3aa2]::query_impl::fn_abi_of_instance::get_query_non_incr::__rust_end_short_backtrace
  24:     0x7520d8b44005 - <rustc_codegen_llvm[b4dd3527c9c5b42e]::context::CodegenCx as rustc_codegen_ssa[d63ee8fd2fa91707]::traits::declare::PreDefineMethods>::predefine_fn
  25:     0x7520dc6d2a13 - rustc_codegen_llvm[b4dd3527c9c5b42e]::base::compile_codegen_unit::module_codegen
  26:     0x7520dc6ced16 - <rustc_codegen_llvm[b4dd3527c9c5b42e]::LlvmCodegenBackend as rustc_codegen_ssa[d63ee8fd2fa91707]::traits::backend::ExtraBackendMethods>::compile_codegen_unit
  27:     0x7520dc927fdd - rustc_codegen_ssa[d63ee8fd2fa91707]::base::codegen_crate::<rustc_codegen_llvm[b4dd3527c9c5b42e]::LlvmCodegenBackend>
  28:     0x7520dc8214cc - <rustc_codegen_llvm[b4dd3527c9c5b42e]::LlvmCodegenBackend as rustc_codegen_ssa[d63ee8fd2fa91707]::traits::backend::CodegenBackend>::codegen_crate
  29:     0x7520dc820e5f - rustc_interface[5201622961cc16ec]::passes::start_codegen
  30:     0x7520dc8204da - <rustc_interface[5201622961cc16ec]::queries::Queries>::codegen_and_build_linker
  31:     0x7520dc62522e - rustc_interface[5201622961cc16ec]::interface::run_compiler::<core[9c1df39db662c9eb]::result::Result<(), rustc_span[6cb8761197abd2a5]::ErrorGuaranteed>, rustc_driver_impl[cd242fc3f331fee7]::run_compiler::{closure#0}>::{closure#1}
  32:     0x7520dc60f989 - std[b086d9f741814aa7]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[5201622961cc16ec]::util::run_in_thread_with_globals<rustc_interface[5201622961cc16ec]::util::run_in_thread_pool_with_globals<rustc_interface[5201622961cc16ec]::interface::run_compiler<core[9c1df39db662c9eb]::result::Result<(), rustc_span[6cb8761197abd2a5]::ErrorGuaranteed>, rustc_driver_impl[cd242fc3f331fee7]::run_compiler::{closure#0}>::{closure#1}, core[9c1df39db662c9eb]::result::Result<(), rustc_span[6cb8761197abd2a5]::ErrorGuaranteed>>::{closure#0}, core[9c1df39db662c9eb]::result::Result<(), rustc_span[6cb8761197abd2a5]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[9c1df39db662c9eb]::result::Result<(), rustc_span[6cb8761197abd2a5]::ErrorGuaranteed>>
  33:     0x7520dc60f736 - <<std[b086d9f741814aa7]::thread::Builder>::spawn_unchecked_<rustc_interface[5201622961cc16ec]::util::run_in_thread_with_globals<rustc_interface[5201622961cc16ec]::util::run_in_thread_pool_with_globals<rustc_interface[5201622961cc16ec]::interface::run_compiler<core[9c1df39db662c9eb]::result::Result<(), rustc_span[6cb8761197abd2a5]::ErrorGuaranteed>, rustc_driver_impl[cd242fc3f331fee7]::run_compiler::{closure#0}>::{closure#1}, core[9c1df39db662c9eb]::result::Result<(), rustc_span[6cb8761197abd2a5]::ErrorGuaranteed>>::{closure#0}, core[9c1df39db662c9eb]::result::Result<(), rustc_span[6cb8761197abd2a5]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[9c1df39db662c9eb]::result::Result<(), rustc_span[6cb8761197abd2a5]::ErrorGuaranteed>>::{closure#2} as core[9c1df39db662c9eb]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  34:     0x7520ddded7bb - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::ha0c4bf88c896ff7b
                               at /rustc/25e3949aa1b24b3f62a72c1f713830aa1d1efcd4/library/alloc/src/boxed.rs:2022:9
  35:     0x7520ddded7bb - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::had08bec978f53e77
                               at /rustc/25e3949aa1b24b3f62a72c1f713830aa1d1efcd4/library/alloc/src/boxed.rs:2022:9
  36:     0x7520ddded7bb - std::sys::pal::unix::thread::Thread::new::thread_start::haa511dd1bba6b653
                               at /rustc/25e3949aa1b24b3f62a72c1f713830aa1d1efcd4/library/std/src/sys/pal/unix/thread.rs:108:17
  37:     0x7520ddb8c55a - <unknown>
  38:     0x7520ddc09a3c - <unknown>
  39:                0x0 - <unknown>

error: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: https://github.com/rust-lang/rust/issues/new?labels=C-bug%2C+I-ICE%2C+T-compiler&template=ice.md

note: please make sure that you have updated to the latest nightly

note: rustc 1.80.0-nightly (25e3949aa 2024-05-06) running on x86_64-unknown-linux-gnu

note: compiler flags: -Z crate-attr=feature(abi_x86_interrupt) -Z crate-attr=feature(unsized_fn_params) -C link-dead-code=true --crate-type lib -Z dump-mir-dir=dir

query stack during panic:
#0 [fn_abi_of_instance] computing call ABI of `<impl at /tmp/icemaker_global_tempdir.cFeBgsJNprxL/rustc_testrunner_tmpdir_reporting.zx6V8PkPVkHF/mvce.rs:3:1: 3:10>::test`
end of query stack
warning: 3 warnings emitted

@rustbot label +F-abi_x86_interrupt +F-unsized_fn_params

[JoverZhang]

@rustbot claim

[JoverZhang]

I think I need more help with this.

I'm not sure if this is a ui bug or a missing feature. I may need a direction. :(

rust/compiler/rustc_target/src/abi/call/mod.rs

Lines 837 to 843 in 1fef152

	if abi == spec::abi::Abi::X86Interrupt {
	if let Some(arg) = self.args.first_mut() {
	// FIXME(pcwalton): This probably should use the x86 `byval` ABI...
	arg.make_indirect_byval(None);
	}
	return Ok(());
	}

[workingjubilee]

cc @phil-opp