9d7c8edd6c
Print a helpful message if unwinding aborts when it reaches a nounwind function This is implemented by routing `TerminatorKind::Abort` back through the panic handler, but with a special flag in the `PanicInfo` which indicates that the panic handler should *not* attempt to unwind the stack and should instead abort immediately. This is useful for the planned change in https://github.com/rust-lang/lang-team/issues/97 which would make `Drop` impls `nounwind` by default. ### Code ```rust #![feature(c_unwind)] fn panic() { panic!() } extern "C" fn nounwind() { panic(); } fn main() { nounwind(); } ``` ### Before ``` $ ./test thread 'main' panicked at 'explicit panic', test.rs:4:5 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace Illegal instruction (core dumped) ``` ### After ``` $ ./test thread 'main' panicked at 'explicit panic', test.rs:4:5 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace thread 'main' panicked at 'panic in a function that cannot unwind', test.rs:7:1 stack backtrace: 0: 0x556f8f86ec9b - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::hdccefe11a6ac4396 1: 0x556f8f88ac6c - core::fmt::write::he152b28c41466ebb 2: 0x556f8f85d6e2 - std::io::Write::write_fmt::h0c261480ab86f3d3 3: 0x556f8f8654fa - std::panicking::default_hook::{{closure}}::h5d7346f3ff7f6c1b 4: 0x556f8f86512b - std::panicking::default_hook::hd85803a1376cac7f 5: 0x556f8f865a91 - std::panicking::rust_panic_with_hook::h4dc1c5a3036257ac 6: 0x556f8f86f079 - std::panicking::begin_panic_handler::{{closure}}::hdda1d83c7a9d34d2 7: 0x556f8f86edc4 - std::sys_common::backtrace::__rust_end_short_backtrace::h5b70ed0cce71e95f 8: 0x556f8f865592 - rust_begin_unwind 9: 0x556f8f85a764 - core::panicking::panic_no_unwind::h2606ab3d78c87899 10: 0x556f8f85b910 - test::nounwind::hade6c7ee65050347 11: 0x556f8f85b936 - test::main::hdc6e02cb36343525 12: 0x556f8f85b7e3 - core::ops::function::FnOnce::call_once::h4d02663acfc7597f 13: 0x556f8f85b739 - std::sys_common::backtrace::__rust_begin_short_backtrace::h071d40135adb0101 14: 0x556f8f85c149 - std::rt::lang_start::{{closure}}::h70dbfbf38b685e93 15: 0x556f8f85c791 - std::rt::lang_start_internal::h798f1c0268d525aa 16: 0x556f8f85c131 - std::rt::lang_start::h476a7ee0a0bb663f 17: 0x556f8f85b963 - main 18: 0x7f64c0822b25 - __libc_start_main 19: 0x556f8f85ae8e - _start 20: 0x0 - <unknown> thread panicked while panicking. aborting. Aborted (core dumped) ``` |
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|---|---|---|
| .. | ||
| alloc | ||
| backtrace@b02ed04a7e | ||
| core | ||
| panic_abort | ||
| panic_unwind | ||
| portable-simd | ||
| proc_macro | ||
| profiler_builtins | ||
| rtstartup | ||
| rustc-std-workspace-alloc | ||
| rustc-std-workspace-core | ||
| rustc-std-workspace-std | ||
| std | ||
| stdarch@11c98f6eb9 | ||
| test | ||
| unwind | ||