Auto merge of #115045 - RalfJung:unwind-terminate-reason, r=davidtwco
when terminating during unwinding, show the reason why
With this, the output on double-panic becomes something like that:
```
thread 'main' panicked at src/tools/miri/tests/fail/panic/double_panic.rs:15:5:
first
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
thread 'main' panicked at src/tools/miri/tests/fail/panic/double_panic.rs:10:9:
second
stack backtrace:
0: 0xbe273a - std::backtrace_rs::backtrace::miri::trace_unsynchronized::<&mut [closure@std::sys_common::backtrace::_print_fmt::{closure#1}]>
at /home/r/src/rust/rustc.3/library/std/src/../../backtrace/src/backtrace/miri.rs:99:5
1: 0xbe22e6 - std::backtrace_rs::backtrace::miri::trace::<&mut [closure@std::sys_common::backtrace::_print_fmt::{closure#1}]>
at /home/r/src/rust/rustc.3/library/std/src/../../backtrace/src/backtrace/miri.rs:62:14
2: 0xbe1086 - std::backtrace_rs::backtrace::trace_unsynchronized::<[closure@std::sys_common::backtrace::_print_fmt::{closure#1}]>
at /home/r/src/rust/rustc.3/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
3: 0xba3afd - std::sys_common::backtrace::_print_fmt
at /home/r/src/rust/rustc.3/library/std/src/sys_common/backtrace.rs:67:5
4: 0xba2471 - <std::sys_common::backtrace::_print::DisplayBacktrace as std::fmt::Display>::fmt
at /home/r/src/rust/rustc.3/library/std/src/sys_common/backtrace.rs:44:22
5: 0xbcf754 - core::fmt::rt::Argument::<'_>::fmt
at /home/r/src/rust/rustc.3/library/core/src/fmt/rt.rs:138:9
6: 0x9b8f81 - std::fmt::write
at /home/r/src/rust/rustc.3/library/core/src/fmt/mod.rs:1094:17
7: 0x21391d - <std::sys::unix::stdio::Stderr as std::io::Write>::write_fmt
at /home/r/src/rust/rustc.3/library/std/src/io/mod.rs:1714:15
8: 0xba37b1 - std::sys_common::backtrace::_print
at /home/r/src/rust/rustc.3/library/std/src/sys_common/backtrace.rs:47:5
9: 0xba365b - std::sys_common::backtrace::print
at /home/r/src/rust/rustc.3/library/std/src/sys_common/backtrace.rs:34:9
10: 0x143c67 - std::panic_hook_with_disk_dump::{closure#1}
at /home/r/src/rust/rustc.3/library/std/src/panicking.rs:278:22
11: 0x144187 - std::panic_hook_with_disk_dump
at /home/r/src/rust/rustc.3/library/std/src/panicking.rs:312:9
12: 0x143659 - std::panicking::default_hook
at /home/r/src/rust/rustc.3/library/std/src/panicking.rs:239:5
13: 0x1482a7 - std::panicking::rust_panic_with_hook
at /home/r/src/rust/rustc.3/library/std/src/panicking.rs:729:13
14: 0x1475d5 - std::rt::begin_panic::<&str>::{closure#0}
at /home/r/src/rust/rustc.3/library/std/src/panicking.rs:650:9
15: 0xba496a - std::sys_common::backtrace::__rust_end_short_backtrace::<[closure@std::rt::begin_panic<&str>::{closure#0}], !>
at /home/r/src/rust/rustc.3/library/std/src/sys_common/backtrace.rs:170:18
16: 0x147599 - std::rt::begin_panic::<&str>
at /home/r/src/rust/rustc.3/library/std/src/panicking.rs:649:12
17: 0x31916 - <Foo as std::ops::Drop>::drop
at src/tools/miri/tests/fail/panic/double_panic.rs:10:9
18: 0x1a2b5e - std::ptr::drop_in_place::<Foo> - shim(Some(Foo))
at /home/r/src/rust/rustc.3/library/core/src/ptr/mod.rs:497:1
19: 0x202bf - main
at src/tools/miri/tests/fail/panic/double_panic.rs:16:1
20: 0xcc6a8 - <fn() as std::ops::FnOnce<()>>::call_once - shim(fn())
at /home/r/src/rust/rustc.3/library/core/src/ops/function.rs:250:5
21: 0xba47d9 - std::sys_common::backtrace::__rust_begin_short_backtrace::<fn(), ()>
at /home/r/src/rust/rustc.3/library/std/src/sys_common/backtrace.rs:154:18
22: 0x141a6a - std::rt::lang_start::<()>::{closure#0}
at /home/r/src/rust/rustc.3/library/std/src/rt.rs:166:18
23: 0xcca18 - std::ops::function::impls::<impl std::ops::FnOnce<()> for &dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe>::call_once
at /home/r/src/rust/rustc.3/library/core/src/ops/function.rs:284:13
24: 0x146469 - std::panicking::try::do_call::<&dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe, i32>
at /home/r/src/rust/rustc.3/library/std/src/panicking.rs:524:40
25: 0x145e09 - std::panicking::try::<i32, &dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe>
at /home/r/src/rust/rustc.3/library/std/src/panicking.rs:488:19
26: 0x7b0ac - std::panic::catch_unwind::<&dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe, i32>
at /home/r/src/rust/rustc.3/library/std/src/panic.rs:142:14
27: 0x14189b - std::rt::lang_start_internal::{closure#2}
at /home/r/src/rust/rustc.3/library/std/src/rt.rs:148:48
28: 0x146481 - std::panicking::try::do_call::<[closure@std::rt::lang_start_internal::{closure#2}], isize>
at /home/r/src/rust/rustc.3/library/std/src/panicking.rs:524:40
29: 0x145e2c - std::panicking::try::<isize, [closure@std::rt::lang_start_internal::{closure#2}]>
at /home/r/src/rust/rustc.3/library/std/src/panicking.rs:488:19
30: 0x7b0d5 - std::panic::catch_unwind::<[closure@std::rt::lang_start_internal::{closure#2}], isize>
at /home/r/src/rust/rustc.3/library/std/src/panic.rs:142:14
31: 0x1418b0 - std::rt::lang_start_internal
at /home/r/src/rust/rustc.3/library/std/src/rt.rs:148:20
32: 0x141a97 - std::rt::lang_start::<()>
at /home/r/src/rust/rustc.3/library/std/src/rt.rs:165:17
thread 'main' panicked at /home/r/src/rust/rustc.3/library/core/src/panicking.rs:126:5:
panic in a destructor during cleanup
stack backtrace:
0: 0xe9f6d7 - std::backtrace_rs::backtrace::miri::trace_unsynchronized::<&mut [closure@std::sys_common::backtrace::_print_fmt::{closure#1}]>
at /home/r/src/rust/rustc.3/library/std/src/../../backtrace/src/backtrace/miri.rs:99:5
1: 0xe9f27d - std::backtrace_rs::backtrace::miri::trace::<&mut [closure@std::sys_common::backtrace::_print_fmt::{closure#1}]>
at /home/r/src/rust/rustc.3/library/std/src/../../backtrace/src/backtrace/miri.rs:62:14
2: 0xe9e016 - std::backtrace_rs::backtrace::trace_unsynchronized::<[closure@std::sys_common::backtrace::_print_fmt::{closure#1}]>
at /home/r/src/rust/rustc.3/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
3: 0xba3afd - std::sys_common::backtrace::_print_fmt
at /home/r/src/rust/rustc.3/library/std/src/sys_common/backtrace.rs:67:5
4: 0xba2471 - <std::sys_common::backtrace::_print::DisplayBacktrace as std::fmt::Display>::fmt
at /home/r/src/rust/rustc.3/library/std/src/sys_common/backtrace.rs:44:22
5: 0xbcf754 - core::fmt::rt::Argument::<'_>::fmt
at /home/r/src/rust/rustc.3/library/core/src/fmt/rt.rs:138:9
6: 0x9b8f81 - std::fmt::write
at /home/r/src/rust/rustc.3/library/core/src/fmt/mod.rs:1094:17
7: 0x4d0895 - <std::sys::unix::stdio::Stderr as std::io::Write>::write_fmt
at /home/r/src/rust/rustc.3/library/std/src/io/mod.rs:1714:15
8: 0xba37b1 - std::sys_common::backtrace::_print
at /home/r/src/rust/rustc.3/library/std/src/sys_common/backtrace.rs:47:5
9: 0xba365b - std::sys_common::backtrace::print
at /home/r/src/rust/rustc.3/library/std/src/sys_common/backtrace.rs:34:9
10: 0x400bd4 - std::panic_hook_with_disk_dump::{closure#1}
at /home/r/src/rust/rustc.3/library/std/src/panicking.rs:278:22
11: 0x144187 - std::panic_hook_with_disk_dump
at /home/r/src/rust/rustc.3/library/std/src/panicking.rs:312:9
12: 0x143659 - std::panicking::default_hook
at /home/r/src/rust/rustc.3/library/std/src/panicking.rs:239:5
13: 0x1482a7 - std::panicking::rust_panic_with_hook
at /home/r/src/rust/rustc.3/library/std/src/panicking.rs:729:13
14: 0x40403b - std::panicking::begin_panic_handler::{closure#0}
at /home/r/src/rust/rustc.3/library/std/src/panicking.rs:619:13
15: 0xe618b3 - std::sys_common::backtrace::__rust_end_short_backtrace::<[closure@std::panicking::begin_panic_handler::{closure#0}], !>
at /home/r/src/rust/rustc.3/library/std/src/sys_common/backtrace.rs:170:18
16: 0x403fc8 - std::panicking::begin_panic_handler
at /home/r/src/rust/rustc.3/library/std/src/panicking.rs:617:5
17: 0xee23e9 - core::panicking::panic_nounwind_fmt
at /home/r/src/rust/rustc.3/library/core/src/panicking.rs:96:14
18: 0xee29e6 - core::panicking::panic_nounwind
at /home/r/src/rust/rustc.3/library/core/src/panicking.rs:126:5
19: 0xee365e - core::panicking::panic_in_cleanup
at /home/r/src/rust/rustc.3/library/core/src/panicking.rs:206:5
20: 0x2028a - main
at src/tools/miri/tests/fail/panic/double_panic.rs:13:1
21: 0x3895ee - <fn() as std::ops::FnOnce<()>>::call_once - shim(fn())
at /home/r/src/rust/rustc.3/library/core/src/ops/function.rs:250:5
22: 0xe61725 - std::sys_common::backtrace::__rust_begin_short_backtrace::<fn(), ()>
at /home/r/src/rust/rustc.3/library/std/src/sys_common/backtrace.rs:154:18
23: 0x3fe9aa - std::rt::lang_start::<()>::{closure#0}
at /home/r/src/rust/rustc.3/library/std/src/rt.rs:166:18
24: 0x389962 - std::ops::function::impls::<impl std::ops::FnOnce<()> for &dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe>::call_once
at /home/r/src/rust/rustc.3/library/core/src/ops/function.rs:284:13
25: 0x4033b9 - std::panicking::try::do_call::<&dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe, i32>
at /home/r/src/rust/rustc.3/library/std/src/panicking.rs:524:40
26: 0x402d58 - std::panicking::try::<i32, &dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe>
at /home/r/src/rust/rustc.3/library/std/src/panicking.rs:488:19
27: 0x337ff7 - std::panic::catch_unwind::<&dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe, i32>
at /home/r/src/rust/rustc.3/library/std/src/panic.rs:142:14
28: 0x3fe7e7 - std::rt::lang_start_internal::{closure#2}
at /home/r/src/rust/rustc.3/library/std/src/rt.rs:148:48
29: 0x4033d6 - std::panicking::try::do_call::<[closure@std::rt::lang_start_internal::{closure#2}], isize>
at /home/r/src/rust/rustc.3/library/std/src/panicking.rs:524:40
30: 0x402d7f - std::panicking::try::<isize, [closure@std::rt::lang_start_internal::{closure#2}]>
at /home/r/src/rust/rustc.3/library/std/src/panicking.rs:488:19
31: 0x338028 - std::panic::catch_unwind::<[closure@std::rt::lang_start_internal::{closure#2}], isize>
at /home/r/src/rust/rustc.3/library/std/src/panic.rs:142:14
32: 0x1418b0 - std::rt::lang_start_internal
at /home/r/src/rust/rustc.3/library/std/src/rt.rs:148:20
33: 0x3fe9dc - std::rt::lang_start::<()>
at /home/r/src/rust/rustc.3/library/std/src/rt.rs:165:17
thread caused non-unwinding panic. aborting.
```
If we also land https://github.com/rust-lang/rust/pull/115020, the 2nd backtrace disappears, hopefully making the "panic in a destructor during cleanup" easier to see.
Fixes https://github.com/rust-lang/rust/issues/114954.
b60f7b51a2