[BUG] Compile fail on aarch64 musl when setting -Zfmt-debug=none

[qinghon]

env:
arch: aarch64
os: alpine 3.20
version: 0.1.160

code:

use std::sync::atomic::AtomicU32;
use std::sync::atomic::Ordering;

static data: AtomicU32 = AtomicU32::new(1);

#[must_use]
fn read_data() -> u32 {
	data.load(Ordering::Relaxed)
}
fn write_data() -> u32 {
	data.fetch_add(1, Ordering::Relaxed)
}

fn main() {
    println!("Hello, world! {}", read_data());
}

build flag:

RUSTFLAGS="-Zfmt-debug=none " cargo +nightly build -Z build-std=std,panic_abort    -Z unstable-options 

build error log:

note: while trying to match meta-variable `$ordering:ident`
   --> /root/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/compiler_builtins-0.1.160/src/aarch64_linux.rs:260:6
    |
260 |     ($ordering:ident, $bytes:tt, $name:ident) => {
    |      ^^^^^^^^^^^^^^^
    = note: this error originates in the macro `foreach_ldset` (in Nightly builds, run with -Z macro-backtrace for more info)

error: no rules expected `,`
   --> /tmp/test_atomic/target/debug/build/compiler_builtins-f849036744b13993/out/outlined_atomics.rs:89:10
    |
89  | $macro!( , 8, __aarch64_ldset8_acq_rel );
    |          ^ no rules expected this token in macro call
    |
   ::: /root/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/compiler_builtins-0.1.160/src/aarch64_linux.rs:259:1
    |
259 | macro_rules! or {
    | --------------- when calling this macro
...
273 | foreach_ldset!(or);
    | ------------------ in this macro invocation
    |
note: while trying to match meta-variable `$ordering:ident`
   --> /root/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/compiler_builtins-0.1.160/src/aarch64_linux.rs:260:6
    |
260 |     ($ordering:ident, $bytes:tt, $name:ident) => {
    |      ^^^^^^^^^^^^^^^
    = note: this error originates in the macro `foreach_ldset` (in Nightly builds, run with -Z macro-backtrace for more info)

After some troubleshooting, it turns out that compiler_builtins depends on the Debug trait in the build.rs

compiler-builtins/compiler-builtins/build.rs

Lines 173 to 177 in cd0f202

	writeln!(macro_, "$macro!( {ordering:?}, {size}, {name} );").unwrap();
	}
	}
	let name = format!("__aarch64_cas16_{sym_ordering}");
	writeln!(cas16, "$macro!( {ordering:?}, {name} );").unwrap();

[tgross35]

It's really weird that config options gets applied to build scripts - that seems like a bug with build-std.

That being said, we may as well change the function since it's a hack anyway. Would you be open to putting up a PR? This part of the build script can be replaced by a macro in the actual source that uses ${concat(...)} since that now works and can create identifiers.

[qinghon]

I tried to fix and turn on a PR, but not quite sure if it's the ${concat(...)} you hinted at way @tgross35