bjoernager/rust
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Only exclude locals if the place is not indirect.

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This commit is contained in:
Camille GILLOT 2023-01-21 21:53:26 +00:00
parent 0d59b8c997
commit cd3649b2a5
3 changed files with 24 additions and 18 deletions
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20
compiler/rustc_mir_dataflow/src/value_analysis.rs
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@ -35,6 +35,7 @@
use std::fmt::{Debug, Formatter};
use rustc_data_structures::fx::FxHashMap;
use rustc_index::bit_set::BitSet;
use rustc_index::vec::IndexVec;
use rustc_middle::mir::visit::{MutatingUseContext, PlaceContext, Visitor};
use rustc_middle::mir::*;
@ -589,7 +590,7 @@ impl Map {
) -> Self {
let mut map = Self::new();
let exclude = excluded_locals(body);
map.register_with_filter(tcx, body, filter, &exclude);
map.register_with_filter(tcx, body, filter, exclude);
debug!("registered {} places ({} nodes in total)", map.value_count, map.places.len());
map
}
@ -600,12 +601,12 @@ impl Map {
tcx: TyCtxt<'tcx>,
body: &Body<'tcx>,
mut filter: impl FnMut(Ty<'tcx>) -> bool,
exclude: &IndexVec<Local, bool>,
exclude: BitSet<Local>,
) {
// We use this vector as stack, pushing and popping projections.
let mut projection = Vec::new();
for (local, decl) in body.local_decls.iter_enumerated() {
if !exclude[local] {
if !exclude.contains(local) {
self.register_with_filter_rec(tcx, local, &mut projection, decl.ty, &mut filter);
}
}
@ -823,26 +824,27 @@ pub fn iter_fields<'tcx>(
}
/// Returns all locals with projections that have their reference or address taken.
pub fn excluded_locals(body: &Body<'_>) -> IndexVec<Local, bool> {
pub fn excluded_locals(body: &Body<'_>) -> BitSet<Local> {
struct Collector {
result: IndexVec<Local, bool>,
result: BitSet<Local>,
}
impl<'tcx> Visitor<'tcx> for Collector {
fn visit_place(&mut self, place: &Place<'tcx>, context: PlaceContext, _location: Location) {
if context.is_borrow()
if (context.is_borrow()
|| context.is_address_of()
|| context.is_drop()
|| context == PlaceContext::MutatingUse(MutatingUseContext::AsmOutput)
|| context == PlaceContext::MutatingUse(MutatingUseContext::AsmOutput))
&& !place.is_indirect()
{
// A pointer to a place could be used to access other places with the same local,
// hence we have to exclude the local completely.
self.result[place.local] = true;
self.result.insert(place.local);
}
}
}
let mut collector = Collector { result: IndexVec::from_elem(false, &body.local_decls) };
let mut collector = Collector { result: BitSet::new_empty(body.local_decls.len()) };
collector.visit_body(body);
collector.result
}