Function stw_trace

crates/vm/src/vm/mod.rs:533–572

(msg: core::fmt::Arguments<'_>)

#[cfg(all(unix, feature = "threading"))]
pub(super) fn stw_trace(msg: core::fmt::Arguments<'_>) {
    if stw_trace_enabled() {
        use core::fmt::Write as _;

        // Avoid stdio locking here: this path runs around fork where a child
        // may inherit a borrowed stderr lock and panic on eprintln!/stderr.
        struct FixedBuf {
            buf: [u8; 512],
            len: usize,
        }

        impl core::fmt::Write for FixedBuf {
            fn write_str(&mut self, s: &str) -> core::fmt::Result {
                if self.len >= self.buf.len() {
                    return Ok(());
                }
                let remain = self.buf.len() - self.len;
                let src = s.as_bytes();
                let n = src.len().min(remain);
                self.buf[self.len..self.len + n].copy_from_slice(&src[..n]);
                self.len += n;
                Ok(())
            }
        }

        let mut out = FixedBuf {
            buf: [0u8; 512],
            len: 0,
        };
        let _ = writeln!(
            &mut out,
            "[rp-stw tid={}] {}",
            crate::stdlib::_thread::get_ident(),
            msg
        );
        unsafe {
            let _ = libc::write(libc::STDERR_FILENO, out.buf.as_ptr().cast(), out.len);
        }
    }
}

#[derive(Clone, Debug, Default)]
pub(crate) struct CallableCache {