diff options
Diffstat (limited to 'compiler/rustc_mir_dataflow/src/framework/lattice.rs')
-rw-r--r-- | compiler/rustc_mir_dataflow/src/framework/lattice.rs | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/compiler/rustc_mir_dataflow/src/framework/lattice.rs b/compiler/rustc_mir_dataflow/src/framework/lattice.rs index d6b89eb82..f0e75c53e 100644 --- a/compiler/rustc_mir_dataflow/src/framework/lattice.rs +++ b/compiler/rustc_mir_dataflow/src/framework/lattice.rs @@ -73,6 +73,16 @@ pub trait MeetSemiLattice: Eq { fn meet(&mut self, other: &Self) -> bool; } +/// A set that has a "bottom" element, which is less than or equal to any other element. +pub trait HasBottom { + fn bottom() -> Self; +} + +/// A set that has a "top" element, which is greater than or equal to any other element. +pub trait HasTop { + fn top() -> Self; +} + /// A `bool` is a "two-point" lattice with `true` as the top element and `false` as the bottom: /// /// ```text @@ -102,6 +112,18 @@ impl MeetSemiLattice for bool { } } +impl HasBottom for bool { + fn bottom() -> Self { + false + } +} + +impl HasTop for bool { + fn top() -> Self { + true + } +} + /// A tuple (or list) of lattices is itself a lattice whose least upper bound is the concatenation /// of the least upper bounds of each element of the tuple (or list). /// @@ -250,3 +272,15 @@ impl<T: Clone + Eq> MeetSemiLattice for FlatSet<T> { true } } + +impl<T> HasBottom for FlatSet<T> { + fn bottom() -> Self { + Self::Bottom + } +} + +impl<T> HasTop for FlatSet<T> { + fn top() -> Self { + Self::Top + } +} |