Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'crates/intern/src/gc.rs')
| -rw-r--r-- | crates/intern/src/gc.rs | 44 |
1 files changed, 31 insertions, 13 deletions
diff --git a/crates/intern/src/gc.rs b/crates/intern/src/gc.rs index f4e8f75e71..596b05eb1c 100644 --- a/crates/intern/src/gc.rs +++ b/crates/intern/src/gc.rs @@ -34,9 +34,7 @@ impl<T: Internable + GcInternedVisit> Storage for InternedStorage<T> { for item in storage { let item = item.key(); let addr = Arc::as_ptr(item).addr(); - if Arc::strong_count(item) > 1 { - // The item is referenced from the outside. - gc.alive.insert(addr); + if Arc::strong_count(item) > 1 && gc.alive.insert(addr) { item.visit_with(gc); } } @@ -60,9 +58,7 @@ impl<T: SliceInternable + GcInternedSliceVisit> Storage for InternedSliceStorage for item in storage { let item = item.key(); let addr = ThinArc::as_ptr(item).addr(); - if ThinArc::strong_count(item) > 1 { - // The item is referenced from the outside. - gc.alive.insert(addr); + if ThinArc::strong_count(item) > 1 && gc.alive.insert(addr) { T::visit_header(&item.header.header, gc); T::visit_slice(&item.slice, gc); } @@ -81,7 +77,7 @@ pub trait GcInternedVisit { pub trait GcInternedSliceVisit: SliceInternable { fn visit_header(header: &Self::Header, gc: &mut GarbageCollector); - fn visit_slice(header: &[Self::SliceType], gc: &mut GarbageCollector); + fn visit_slice(slice: &[Self::SliceType], gc: &mut GarbageCollector); } #[derive(Default)] @@ -103,11 +99,13 @@ impl GarbageCollector { self.storages.push(&InternedSliceStorage::<T>(PhantomData)); } + /// Collects unreachable GC-managed interned values. + /// /// # Safety /// /// - This cannot be called if there are some not-yet-recorded type values. - /// - All relevant storages must have been added; that is, within the full graph of values, - /// the added storages must form a DAG. + /// - All storages that can contain live GC-managed values must have been added, and those + /// storages must be closed over the GC-managed values reachable from them. /// - [`GcInternedVisit`] and [`GcInternedSliceVisit`] must mark all values reachable from the node. pub unsafe fn collect(mut self) { if cfg!(feature = "prevent-gc") { @@ -136,8 +134,9 @@ impl GarbageCollector { &mut self, interned: InternedRef<'_, T>, ) -> ControlFlow<()> { + const { assert!(T::USE_GC) }; + if interned.strong_count() > 1 { - // It will be visited anyway, so short-circuit return ControlFlow::Break(()); } let addr = interned.as_raw().addr(); @@ -148,8 +147,9 @@ impl GarbageCollector { &mut self, interned: InternedSliceRef<'_, T>, ) -> ControlFlow<()> { + const { assert!(T::USE_GC) }; + if interned.strong_count() > 1 { - // It will be visited anyway, so short-circuit return ControlFlow::Break(()); } let addr = interned.as_raw().addr(); @@ -240,7 +240,7 @@ mod tests { impl GcInternedSliceVisit for StringSlice { fn visit_header(_header: &Self::Header, _gc: &mut GarbageCollector) {} - fn visit_slice(_header: &[Self::SliceType], _gc: &mut GarbageCollector) {} + fn visit_slice(_slice: &[Self::SliceType], _gc: &mut GarbageCollector) {} } let (a, d) = { @@ -276,6 +276,10 @@ mod tests { gc.add_storage::<GcString>(); unsafe { gc.collect() }; + if !cfg!(feature = "prevent-gc") { + assert_eq!(<GcString as crate::Internable>::storage().get().len(), 1); + assert_eq!(<StringSlice as crate::SliceInternable>::storage().get().len(), 1); + } assert_eq!(a.0, "abc"); assert_eq!(d.header.length, 2); assert_eq!(d.header.header, "abc"); @@ -288,6 +292,11 @@ mod tests { gc.add_slice_storage::<StringSlice>(); gc.add_storage::<GcString>(); unsafe { gc.collect() }; + + if !cfg!(feature = "prevent-gc") { + assert_eq!(<GcString as crate::Internable>::storage().get().len(), 0); + assert_eq!(<StringSlice as crate::SliceInternable>::storage().get().len(), 0); + } } #[test] @@ -309,7 +318,7 @@ mod tests { impl GcInternedSliceVisit for StringSlice { fn visit_header(_header: &Self::Header, _gc: &mut GarbageCollector) {} - fn visit_slice(_header: &[Self::SliceType], _gc: &mut GarbageCollector) {} + fn visit_slice(_slice: &[Self::SliceType], _gc: &mut GarbageCollector) {} } let outer = { @@ -322,6 +331,10 @@ mod tests { gc.add_storage::<GcInterned>(); unsafe { gc.collect() }; + if !cfg!(feature = "prevent-gc") { + assert_eq!(<GcInterned as crate::Internable>::storage().get().len(), 1); + assert_eq!(<StringSlice as crate::SliceInternable>::storage().get().len(), 1); + } assert_eq!(outer.0.header.header, "abc"); assert_eq!(outer.0.slice, [123, 456, 789]); @@ -331,5 +344,10 @@ mod tests { gc.add_slice_storage::<StringSlice>(); gc.add_storage::<GcInterned>(); unsafe { gc.collect() }; + + if !cfg!(feature = "prevent-gc") { + assert_eq!(<GcInterned as crate::Internable>::storage().get().len(), 0); + assert_eq!(<StringSlice as crate::SliceInternable>::storage().get().len(), 0); + } } } |