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Insert a compiler_fence after initialization #25

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13 changes: 13 additions & 0 deletions src/lib.rs
Original file line number Diff line number Diff line change
Expand Up @@ -73,6 +73,7 @@
#[cfg(test)]
mod test;

use core::sync::atomic::{compiler_fence, Ordering};
use core::{mem, ptr};

mod sealed {
Expand Down Expand Up @@ -133,6 +134,12 @@ where
sdata = sdata.offset(1);
sidata = sidata.offset(1);
}

// Ensure that any accesses of `static`s are not reordered before the `.data` section is
// initialized.
// We use `SeqCst`, because `Acquire` only prevents later accesses from being reordered before
// *reads*, but this method only *writes* to the locations.
compiler_fence(Ordering::SeqCst);
}

/// Zeroes the `.bss` section.
Expand All @@ -158,4 +165,10 @@ where
ptr::write_volatile(sbss, mem::zeroed());
sbss = sbss.offset(1);
}

// Ensure that any accesses of `static`s are not reordered before the `.bss` section is
// initialized.
// We use `SeqCst`, because `Acquire` only prevents later accesses from being reordered before
// *reads*, but this method only *writes* to the locations.
compiler_fence(Ordering::SeqCst);
}