1 use rustc_index::bit_set::BitSet;
2 use rustc_middle::mir::{self, Local};
4 /// The set of locals in a MIR body that do not have `StorageLive`/`StorageDead` annotations.
6 /// These locals have fixed storage for the duration of the body.
8 // FIXME: Currently, we need to traverse the entire MIR to compute this. We should instead store it
9 // as a field in the `LocalDecl` for each `Local`.
10 #[derive(Debug, Clone)]
11 pub struct AlwaysLiveLocals(BitSet<Local>);
13 impl AlwaysLiveLocals {
14 pub fn new(body: &mir::Body<'_>) -> Self {
15 let mut always_live_locals = AlwaysLiveLocals(BitSet::new_filled(body.local_decls.len()));
17 for block in body.basic_blocks() {
18 for statement in &block.statements {
19 use mir::StatementKind::{StorageDead, StorageLive};
20 if let StorageLive(l) | StorageDead(l) = statement.kind {
21 always_live_locals.0.remove(l);
29 pub fn into_inner(self) -> BitSet<Local> {
34 impl std::ops::Deref for AlwaysLiveLocals {
35 type Target = BitSet<Local>;
38 fn deref(&self) -> &Self::Target {