use std::cell::Cell;
use std::iter;
+#[cfg(debug_assertions)]
+use std::ops::BitXor;
+#[cfg(debug_assertions)]
+use std::sync::atomic::{AtomicU32, Ordering};
pub struct MarkedAttrs(GrowableBitSet<AttrId>);
pub struct AttrIdGenerator(WorkerLocal<Cell<u32>>);
+#[cfg(debug_assertions)]
+static MAX_ATTR_ID: AtomicU32 = AtomicU32::new(u32::MAX);
+
impl AttrIdGenerator {
pub fn new() -> Self {
// We use `(index as u32).reverse_bits()` to initialize the
// starting value of AttrId in each worker thread.
// The `index` is the index of the worker thread.
// This ensures that the AttrId generated in each thread is unique.
- AttrIdGenerator(WorkerLocal::new(|index| Cell::new((index as u32).reverse_bits())))
+ AttrIdGenerator(WorkerLocal::new(|index| {
+ let index: u32 = index.try_into().unwrap();
+
+ #[cfg(debug_assertions)]
+ {
+ let max_id = ((index + 1).next_power_of_two() - 1).bitxor(u32::MAX).reverse_bits();
+ MAX_ATTR_ID.fetch_min(max_id, Ordering::Release);
+ }
+
+ Cell::new(index.reverse_bits())
+ }))
}
pub fn mk_attr_id(&self) -> AttrId {
let id = self.0.get();
+
+ // Ensure the assigned attr_id does not overlap the bits
+ // representing the number of threads.
+ #[cfg(debug_assertions)]
+ assert!(id <= MAX_ATTR_ID.load(Ordering::Acquire));
+
self.0.set(id + 1);
AttrId::from_u32(id)
}