bjoernager/rust
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Remove duplicated implementations of borrowed locals analysis

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This commit is contained in:
Tomasz Miąsko 2022-06-06 00:00:00 +00:00
parent 37a42258ff
commit 915f091819
4 changed files with 29 additions and 133 deletions
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67
compiler/rustc_mir_transform/src/dest_prop.rs
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@ -104,7 +104,7 @@ use rustc_middle::mir::{
Rvalue, Statement, StatementKind, Terminator, TerminatorKind,
};
use rustc_middle::ty::TyCtxt;
use rustc_mir_dataflow::impls::{MaybeInitializedLocals, MaybeLiveLocals};
use rustc_mir_dataflow::impls::{borrowed_locals, MaybeInitializedLocals, MaybeLiveLocals};
use rustc_mir_dataflow::Analysis;
// Empirical measurements have resulted in some observations:
@ -805,7 +805,7 @@ fn find_candidates<'tcx>(body: &Body<'tcx>) -> Vec<CandidateAssignment<'tcx>> {
let mut visitor = FindAssignments {
body,
candidates: Vec::new(),
ever_borrowed_locals: ever_borrowed_locals(body),
ever_borrowed_locals: borrowed_locals(body),
locals_used_as_array_index: locals_used_as_array_index(body),
};
visitor.visit_body(body);
@ -886,69 +886,6 @@ fn is_local_required(local: Local, body: &Body<'_>) -> bool {
}
}
/// Walks MIR to find all locals that have their address taken anywhere.
fn ever_borrowed_locals(body: &Body<'_>) -> BitSet<Local> {
let mut visitor = BorrowCollector { locals: BitSet::new_empty(body.local_decls.len()) };
visitor.visit_body(body);
visitor.locals
}
struct BorrowCollector {
locals: BitSet<Local>,
}
impl<'tcx> Visitor<'tcx> for BorrowCollector {
fn visit_rvalue(&mut self, rvalue: &Rvalue<'tcx>, location: Location) {
self.super_rvalue(rvalue, location);
match rvalue {
Rvalue::AddressOf(_, borrowed_place) | Rvalue::Ref(_, _, borrowed_place) => {
if !borrowed_place.is_indirect() {
self.locals.insert(borrowed_place.local);
}
}
Rvalue::Cast(..)
| Rvalue::ShallowInitBox(..)
| Rvalue::Use(..)
| Rvalue::Repeat(..)
| Rvalue::Len(..)
| Rvalue::BinaryOp(..)
| Rvalue::CheckedBinaryOp(..)
| Rvalue::NullaryOp(..)
| Rvalue::UnaryOp(..)
| Rvalue::Discriminant(..)
| Rvalue::Aggregate(..)
| Rvalue::ThreadLocalRef(..) => {}
}
}
fn visit_terminator(&mut self, terminator: &Terminator<'tcx>, location: Location) {
self.super_terminator(terminator, location);
match terminator.kind {
TerminatorKind::Drop { place: dropped_place, .. }
| TerminatorKind::DropAndReplace { place: dropped_place, .. } => {
self.locals.insert(dropped_place.local);
}
TerminatorKind::Abort
| TerminatorKind::Assert { .. }
| TerminatorKind::Call { .. }
| TerminatorKind::FalseEdge { .. }
| TerminatorKind::FalseUnwind { .. }
| TerminatorKind::GeneratorDrop
| TerminatorKind::Goto { .. }
| TerminatorKind::Resume
| TerminatorKind::Return
| TerminatorKind::SwitchInt { .. }
| TerminatorKind::Unreachable
| TerminatorKind::Yield { .. }
| TerminatorKind::InlineAsm { .. } => {}
}
}
}
/// `PlaceElem::Index` only stores a `Local`, so we can't replace that with a full `Place`.
///
/// Collect locals used as indices so we don't generate candidates that are impossible to apply