use rustc_index::bit_set::BitSet;
-use rustc_middle::mir::{self, Local};
+use rustc_middle::mir::visit::Visitor;
+use rustc_middle::mir::{self, Local, Location};
/// The set of locals in a MIR body that do not have `StorageLive`/`StorageDead` annotations.
///
impl AlwaysLiveLocals {
pub fn new(body: &mir::Body<'tcx>) -> Self {
- let mut locals = BitSet::new_filled(body.local_decls.len());
-
- // FIXME: Use a visitor for this when `visit_body` can take a plain `Body`.
- for block in body.basic_blocks().iter() {
- for stmt in &block.statements {
- if let mir::StatementKind::StorageLive(l) | mir::StatementKind::StorageDead(l) =
- stmt.kind
- {
- locals.remove(l);
- }
- }
- }
+ let mut ret = AlwaysLiveLocals(BitSet::new_filled(body.local_decls.len()));
+
+ let mut vis = StorageAnnotationVisitor(&mut ret);
+ vis.visit_body(body);
- AlwaysLiveLocals(locals)
+ ret
}
pub fn into_inner(self) -> BitSet<Local> {
&self.0
}
}
+
+/// Removes locals that have `Storage*` annotations from `AlwaysLiveLocals`.
+struct StorageAnnotationVisitor<'a>(&'a mut AlwaysLiveLocals);
+
+impl Visitor<'tcx> for StorageAnnotationVisitor<'_> {
+ fn visit_statement(&mut self, statement: &mir::Statement<'tcx>, _location: Location) {
+ use mir::StatementKind::{StorageDead, StorageLive};
+ if let StorageLive(l) | StorageDead(l) = statement.kind {
+ (self.0).0.remove(l);
+ }
+ }
+}