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Description
auto-reduced (treereduce-rust):
//@compile-flags: -Zsanitizer=kcfi -Cpanic=abort
//
#![feature(abi_custom)]
use std::arch::{asm, global_asm, naked_asm};
#[unsafe(naked)]
unsafe extern "custom" fn double() {
naked_asm!("add rax, rax", "ret");
}
unsafe extern "custom" {}
struct Thing(u64);
trait BitwiseNot {
#[unsafe(naked)]
unsafe extern "custom" fn bitwise_not() {
naked_asm!("\0\x00\u{0}\u{0}", "ret");
}
}
impl BitwiseNot for Thing {}
#[unsafe(naked)]
unsafe extern "C" fn const_generic<const N: u64>() {
naked_asm!(
"mov rax, {}",
"ret",
const N,
);
}
pub fn main() {
let mut x: u64 = 42;
unsafe { asm!("call {}", sym Thing::bitwise_not, inout("rax") x) };
}
original code
original:
// Test that `extern "custom"` functions can be called from assembly, and defined using a naked
// function, and `global_asm!` with an `extern "custom"` block.
//
//@ run-pass
//@ only-x86_64
#![feature(abi_custom)]
use std::arch::{asm, global_asm, naked_asm};
#[unsafe(naked)]
unsafe extern "custom" fn double() {
naked_asm!("add rax, rax", "ret");
}
global_asm!(
// work around macOS prefixing symbols with _
" .globl {0}",
"{0}:",
" add rax, 1",
" ret",
sym increment,
);
unsafe extern "custom" {
fn increment();
}
#[repr(transparent)]
struct Thing(u64);
impl Thing {
#[unsafe(naked)]
unsafe extern "custom" fn is_even() {
naked_asm!("test al, 1", "sete al", "ret");
}
}
trait BitwiseNot {
#[unsafe(naked)]
unsafe extern "custom" fn bitwise_not() {
naked_asm!("\0\x00\u{0}\u{0}", "ret");
}
}
impl BitwiseNot for Thing {}
#[unsafe(naked)]
unsafe extern "C" fn const_generic<const N: u64>() {
naked_asm!(
"mov rax, {}",
"ret",
const N,
);
}
pub fn main() {
let mut x: u64 = 21;
unsafe { asm!("call {}", sym double, inout("rax") x) };
assert_eq!(x, 42);
let mut x: u64 = 41;
unsafe { asm!("call {}", sym increment, inout("rax") x) };
assert_eq!(x, 42);
let mut x: u8;
unsafe { asm!("call {}", sym Thing::is_even, inout("al") 42u8 => x) };
assert!(x != 0);
let mut x: u64 = 42;
unsafe { asm!("call {}", sym Thing::bitwise_not, inout("rax") x) };
assert_eq!(x, !42);
// Create and call in `asm!` an `extern "custom"` function pointer.
fn caller(f: unsafe extern "custom" fn(), mut x: u64) -> u64 {
unsafe { asm!("call {}", in(reg) f, inout("rax") x) };
x
}
assert_eq!(caller(double, 2), 4);
let x: u64;
unsafe { asm!("call {}", sym const_generic::<42>, out("rax") x) };
assert_eq!(x, 42);
let x: u64;
unsafe { asm!("call {}", sym const_generic::<84>, out("rax") x) };
assert_eq!(x, 84);
}
Version information
rustc 1.90.0-nightly (f26e58023 2025-06-30)
binary: rustc
commit-hash: f26e58023071e71636a3c72ac3a2bf89b1f76706
commit-date: 2025-06-30
host: x86_64-unknown-linux-gnu
release: 1.90.0-nightly
LLVM version: 20.1.7
Command:
/home/matthias/.rustup/toolchains/master/bin/rustc -Zsanitizer=kcfi -Cpanic=abort
Program output
warning: unused import: `global_asm`
--> /tmp/icemaker_global_tempdir.L3dNdrnvcGlo/rustc_testrunner_tmpdir_reporting.8ehK9SvmHkij/mvce.rs:5:22
|
5 | use std::arch::{asm, global_asm, naked_asm};
| ^^^^^^^^^^
|
= note: `#[warn(unused_imports)]` on by default
warning: value assigned to `x` is never read
--> /tmp/icemaker_global_tempdir.L3dNdrnvcGlo/rustc_testrunner_tmpdir_reporting.8ehK9SvmHkij/mvce.rs:37:67
|
37 | unsafe { asm!("call {}", sym Thing::bitwise_not, inout("rax") x) };
| ^
|
= help: maybe it is overwritten before being read?
= note: `#[warn(unused_assignments)]` on by default
warning: function `double` is never used
--> /tmp/icemaker_global_tempdir.L3dNdrnvcGlo/rustc_testrunner_tmpdir_reporting.8ehK9SvmHkij/mvce.rs:8:27
|
8 | unsafe extern "custom" fn double() {
| ^^^^^^
|
= note: `#[warn(dead_code)]` on by default
warning: field `0` is never read
--> /tmp/icemaker_global_tempdir.L3dNdrnvcGlo/rustc_testrunner_tmpdir_reporting.8ehK9SvmHkij/mvce.rs:14:14
|
14 | struct Thing(u64);
| ----- ^^^
| |
| field in this struct
|
= help: consider removing this field
warning: function `const_generic` is never used
--> /tmp/icemaker_global_tempdir.L3dNdrnvcGlo/rustc_testrunner_tmpdir_reporting.8ehK9SvmHkij/mvce.rs:26:22
|
26 | unsafe extern "C" fn const_generic<const N: u64>() {
| ^^^^^^^^^^^^^
error: internal compiler error: /rustc-dev/f26e58023071e71636a3c72ac3a2bf89b1f76706/compiler/rustc_codegen_ssa/src/mir/naked_asm.rs:40:9: #[naked] functions should always terminate with an asm! block
thread 'rustc' panicked at /rustc-dev/f26e58023071e71636a3c72ac3a2bf89b1f76706/compiler/rustc_codegen_ssa/src/mir/naked_asm.rs:40:9:
Box<dyn Any>
stack backtrace:
0: 0x773530f2e243 - <std::sys::backtrace::BacktraceLock::print::DisplayBacktrace as core::fmt::Display>::fmt::h5d4004938ff2c5de
1: 0x77353160277f - core::fmt::write::he40d39caeedce22d
2: 0x773530f23e83 - std::io::Write::write_fmt::h6b481595dd1fc53f
3: 0x773530f2e0a2 - std::sys::backtrace::BacktraceLock::print::h6122e56851fd7e04
4: 0x773530f31b9a - std::panicking::default_hook::{{closure}}::h5da9a6ee005a6c0c
5: 0x773530f3171f - std::panicking::default_hook::he77158b4319b132a
6: 0x7735300095d3 - std[abb3b870cf4d8027]::panicking::update_hook::<alloc[3b9c56f51ca07bea]::boxed::Box<rustc_driver_impl[7eb6cf164257341f]::install_ice_hook::{closure#1}>>::{closure#0}
7: 0x773530f323eb - std::panicking::rust_panic_with_hook::hbc48a4f07e431d11
8: 0x773530043861 - std[abb3b870cf4d8027]::panicking::begin_panic::<rustc_errors[3b19c8b340e0e702]::ExplicitBug>::{closure#0}
9: 0x773530037d86 - std[abb3b870cf4d8027]::sys::backtrace::__rust_end_short_backtrace::<std[abb3b870cf4d8027]::panicking::begin_panic<rustc_errors[3b19c8b340e0e702]::ExplicitBug>::{closure#0}, !>
10: 0x773530037c17 - std[abb3b870cf4d8027]::panicking::begin_panic::<rustc_errors[3b19c8b340e0e702]::ExplicitBug>
11: 0x77353004d341 - <rustc_errors[3b19c8b340e0e702]::diagnostic::BugAbort as rustc_errors[3b19c8b340e0e702]::diagnostic::EmissionGuarantee>::emit_producing_guarantee
12: 0x77353061900a - rustc_middle[6ca7f7d3ce556234]::util::bug::opt_span_bug_fmt::<rustc_span[376a63540bfd47fc]::span_encoding::Span>::{closure#0}
13: 0x7735305f8bea - rustc_middle[6ca7f7d3ce556234]::ty::context::tls::with_opt::<rustc_middle[6ca7f7d3ce556234]::util::bug::opt_span_bug_fmt<rustc_span[376a63540bfd47fc]::span_encoding::Span>::{closure#0}, !>::{closure#0}
14: 0x7735305f8a5b - rustc_middle[6ca7f7d3ce556234]::ty::context::tls::with_context_opt::<rustc_middle[6ca7f7d3ce556234]::ty::context::tls::with_opt<rustc_middle[6ca7f7d3ce556234]::util::bug::opt_span_bug_fmt<rustc_span[376a63540bfd47fc]::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
15: 0x77352d6a7e90 - rustc_middle[6ca7f7d3ce556234]::util::bug::bug_fmt
16: 0x7735327519a9 - rustc_codegen_llvm[5e38973cde8d21c0]::base::compile_codegen_unit::module_codegen
17: 0x773532714c4d - <rustc_codegen_llvm[5e38973cde8d21c0]::LlvmCodegenBackend as rustc_codegen_ssa[87a67ccac236a82e]::traits::backend::ExtraBackendMethods>::compile_codegen_unit
18: 0x7735327129b3 - rustc_codegen_ssa[87a67ccac236a82e]::base::codegen_crate::<rustc_codegen_llvm[5e38973cde8d21c0]::LlvmCodegenBackend>
19: 0x773532837083 - <rustc_codegen_llvm[5e38973cde8d21c0]::LlvmCodegenBackend as rustc_codegen_ssa[87a67ccac236a82e]::traits::backend::CodegenBackend>::codegen_crate
20: 0x773532836732 - <rustc_interface[f681bac94ac292a9]::queries::Linker>::codegen_and_build_linker
21: 0x77353282ca87 - rustc_interface[f681bac94ac292a9]::passes::create_and_enter_global_ctxt::<core[7243450d3d38063e]::option::Option<rustc_interface[f681bac94ac292a9]::queries::Linker>, rustc_driver_impl[7eb6cf164257341f]::run_compiler::{closure#0}::{closure#2}>::{closure#2}::{closure#0}
22: 0x77353286756f - rustc_interface[f681bac94ac292a9]::interface::run_compiler::<(), rustc_driver_impl[7eb6cf164257341f]::run_compiler::{closure#0}>::{closure#1}
23: 0x773532807e38 - std[abb3b870cf4d8027]::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface[f681bac94ac292a9]::util::run_in_thread_with_globals<rustc_interface[f681bac94ac292a9]::util::run_in_thread_pool_with_globals<rustc_interface[f681bac94ac292a9]::interface::run_compiler<(), rustc_driver_impl[7eb6cf164257341f]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>
24: 0x773532807b16 - <<std[abb3b870cf4d8027]::thread::Builder>::spawn_unchecked_<rustc_interface[f681bac94ac292a9]::util::run_in_thread_with_globals<rustc_interface[f681bac94ac292a9]::util::run_in_thread_pool_with_globals<rustc_interface[f681bac94ac292a9]::interface::run_compiler<(), rustc_driver_impl[7eb6cf164257341f]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1} as core[7243450d3d38063e]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
25: 0x77353280ddfd - std::sys::pal::unix::thread::Thread::new::thread_start::h277742a54d34f956
26: 0x77352c2a57eb - <unknown>
27: 0x77352c32918c - <unknown>
28: 0x0 - <unknown>
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 1.90.0-nightly (f26e58023 2025-06-30) running on x86_64-unknown-linux-gnu
note: compiler flags: -Z sanitizer=kcfi -C panic=abort -Z dump-mir-dir=dir
query stack during panic:
end of query stack
error: aborting due to 1 previous error; 5 warnings emitted
@rustbot label +F-abi_custom
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Area: Control Flow Integrity (CFI) security mitigationArea: `#[naked]`, prologue and epilogue-free, functions, https://git.io/vAzzSCategory: This is a bug.Issue: The compiler panicked, giving an Internal Compilation Error (ICE) ❄️Project group: Exploit mitigationsRelevant to the compiler team, which will review and decide on the PR/issue.