uefi_std: Remove unstable features except prelude_import

Most of the unstable features are not required for building.

For panics, the only remaining detail is having an implementation of the
panic handler (`panic_handler`) itself.

- `eh_personality`: Not required with `panic=abort`
- `_Unwind_Resume`: Symbol not present with `panic=abort`
- `alloc_error_handler`: OOM triggers a panic; feature will be removed [1]

[1]: rust-lang/rust#112331

Signed-off-by: Tim Crawford <tcrawford@system76.com>

crates/uefi/src/lib.rs

@@ -1,6 +1,6 @@
+#![no_std]
 #![allow(dead_code)]
 #![allow(non_snake_case)]
-#![no_std]
 
 #[macro_use]
 pub mod macros;

crates/uefi_std/src/lib.rs

@@ -1,16 +1,5 @@
 #![no_std]
-#![feature(alloc_error_handler)]
-#![feature(concat_idents)]
-#![feature(core_intrinsics)]
-#![feature(custom_test_frameworks)]
-#![feature(format_args_nl)]
-#![feature(lang_items)]
-#![feature(log_syntax)]
 #![feature(prelude_import)]
-#![feature(prelude_2024)]
-#![feature(slice_concat_ext)]
-#![feature(test)]
-#![feature(trace_macros)]
 
 /* This section was addapted from the Rust Standard Library, and is licensed accordingly
  * https://github.com/rust-lang/rust/blob/master/src/libstd/lib.rs
@@ -60,7 +49,6 @@ pub use core::i16;
 pub use core::i32;
 pub use core::i64;
 pub use core::i8;
-pub use core::intrinsics;
 pub use core::isize;
 pub use core::iter;
 pub use core::marker;
@@ -96,28 +84,23 @@ pub use core::{
 };
 
 // Re-export built-in macros defined through libcore.
-pub use core::prelude::v1::{
+pub use core::prelude::rust_2021::{
     // Stable
     assert,
     cfg,
     column,
     compile_error,
     concat,
     // Unstable
-    concat_idents,
     env,
     file,
-    format_args,
-    format_args_nl,
     include,
     include_bytes,
     include_str,
     line,
-    log_syntax,
     module_path,
     option_env,
     stringify,
-    trace_macros,
 };
 
 /* } */

crates/uefi_std/src/prelude.rs

@@ -27,18 +27,18 @@ pub use crate::result::Result::{self, Err, Ok};
 
 // Re-exported built-in macros
 #[doc(no_inline)]
-pub use core::prelude::v1::{
-    assert, cfg, column, compile_error, concat, concat_idents, env, file, format_args,
-    format_args_nl, include, include_bytes, include_str, line, log_syntax, module_path, option_env,
-    stringify, trace_macros,
+pub use core::prelude::rust_2021::{
+    assert, cfg, column, compile_error, concat, env, file,
+    include, include_bytes, include_str, line, module_path, option_env,
+    stringify,
 };
 
 // FIXME: Attribute and derive macros are not documented because for them rustdoc generates
 // dead links which fail link checker testing.
 #[allow(deprecated)]
 #[doc(hidden)]
-pub use core::prelude::v1::{
-    bench, test, test_case, Clone, Copy, Debug, Default, Eq, Hash, Ord,
+pub use core::prelude::rust_2021::{
+    Clone, Copy, Debug, Default, Eq, Hash, Ord,
     PartialEq, PartialOrd,
 };
 

crates/uefi_std/src/rt/panic.rs

@@ -1,35 +1,6 @@
-// These functions are used by the compiler, but not
-// for a bare-bones hello world. These are normally
-// provided by libstd.
-
-use core::prelude::rust_2024::alloc_error_handler;
-
-#[lang = "eh_personality"]
-#[no_mangle]
-pub extern "C" fn rust_eh_personality() {}
-
 #[panic_handler]
-#[no_mangle]
-pub fn rust_begin_panic(pi: &::core::panic::PanicInfo) -> ! {
+pub fn panic(pi: &core::panic::PanicInfo) -> ! {
     print!("SETUP PANIC: {}", pi);
 
     loop {}
 }
-
-#[alloc_error_handler]
-#[no_mangle]
-pub fn rust_oom(layout: ::core::alloc::Layout) -> ! {
-    println!(
-        "SETUP OOM: {} bytes aligned to {} bytes\n",
-        layout.size(),
-        layout.align()
-    );
-
-    loop {}
-}
-
-#[allow(non_snake_case)]
-#[no_mangle]
-pub extern "C" fn _Unwind_Resume() {
-    loop {}
-}