rust: report file and line number that caused a panic.

[wedsonaf]

At the moment we get a mangled call stack. This prints a message that
allows us to pinpoint the source of the panic.

Signed-off-by: Wedson Almeida Filho wedsonaf@google.com

[nbdd0121]

Well, I guess a better approach is to move the panic handler to kernel::print and just call pr_emerg!. I don't think this needs to be in the compiler_builtin crate.

[nbdd0121]

Using pr_emerg!("{}", info) would also be more helpful since it will print the panic message as well.

[wedsonaf]

You're right, it doesn't have to have to be in the compiler_builtins crate. Moving it to the kernel crate allows to use pr_*.

Updated the code.

[wedsonaf]

rusttest is failing. Pinging @ojeda -- is there a way to fix this?

  RUSTC T  rust/kernel/lib.rs
error[E0152]: found duplicate lang item `panic_impl`
   --> rust/kernel/lib.rs:231:1
    |
231 | fn panic(info: &core::panic::PanicInfo<'_>) -> ! {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: the lang item is first defined in crate `std` (which `test` depends on)
    = note: first definition in `std` loaded from /home/runner/work/linux/linux/rust/test/sysroot/lib/rustlib/x86_64-unknown-linux-gnu/lib/libstd-4bf57c4df90bbdf9.rlib, /home/runner/work/linux/linux/rust/test/sysroot/lib/rustlib/x86_64-unknown-linux-gnu/lib/libstd-4bf57c4df90bbdf9.rmeta
    = note: second definition in the local crate (`kernel`)

error: aborting due to previous error

[nbdd0121]

#[cfg(not(testlib))]

[wedsonaf]

#[cfg(not(testlib))]

I'm still getting the same error even with this.

[nbdd0121]

Maybe #[cfg(not(any(testlib,doctest)))]?

[wedsonaf]

Maybe #[cfg(not(any(testlib,doctest)))]?

Doesn't work either.

I'm reverting back to the previous implementation. I'll open a bug to move it to the kernel crate and use pr_emerg.

[nbdd0121]

#[cfg(not(any(testlib,test,doctest)))] seems to be working for me.

[wedsonaf]

#[cfg(not(any(testlib,test,doctest)))] seems to be working for me.

Thanks, Gary! It looks like it's sufficient to exclude it on testlib and test.