Remove uses of ResultsClonedCursor.

By just cloning the entire `Results` in the one place where
`ResultsClonedCursor` was used. This is extra allocations but the
performance effect is negligible.

Author: nnethercote

Diff for: compiler/rustc_mir_dataflow/src/framework/engine.rs

@@ -31,6 +31,7 @@ use super::{
 pub type EntrySets<'tcx, A> = IndexVec<BasicBlock, <A as AnalysisDomain<'tcx>>::Domain>;
 
 /// A dataflow analysis that has converged to fixpoint.
+#[derive(Clone)]
 pub struct Results<'tcx, A, E = EntrySets<'tcx, A>>
 where
     A: Analysis<'tcx>,

Diff for: compiler/rustc_mir_dataflow/src/impls/storage_liveness.rs

@@ -5,7 +5,7 @@ use rustc_middle::mir::*;
 use std::borrow::Cow;
 
 use super::MaybeBorrowedLocals;
-use crate::{GenKill, ResultsClonedCursor};
+use crate::{GenKill, ResultsCursor};
 
 #[derive(Clone)]
 pub struct MaybeStorageLive<'a> {
@@ -152,22 +152,21 @@ impl<'tcx> crate::GenKillAnalysis<'tcx> for MaybeStorageDead {
     }
 }
 
-type BorrowedLocalsResults<'res, 'mir, 'tcx> =
-    ResultsClonedCursor<'res, 'mir, 'tcx, MaybeBorrowedLocals>;
+type BorrowedLocalsResults<'mir, 'tcx> = ResultsCursor<'mir, 'tcx, MaybeBorrowedLocals>;
 
 /// Dataflow analysis that determines whether each local requires storage at a
 /// given location; i.e. whether its storage can go away without being observed.
-pub struct MaybeRequiresStorage<'res, 'mir, 'tcx> {
-    borrowed_locals: BorrowedLocalsResults<'res, 'mir, 'tcx>,
+pub struct MaybeRequiresStorage<'mir, 'tcx> {
+    borrowed_locals: BorrowedLocalsResults<'mir, 'tcx>,
 }
 
-impl<'res, 'mir, 'tcx> MaybeRequiresStorage<'res, 'mir, 'tcx> {
-    pub fn new(borrowed_locals: BorrowedLocalsResults<'res, 'mir, 'tcx>) -> Self {
+impl<'mir, 'tcx> MaybeRequiresStorage<'mir, 'tcx> {
+    pub fn new(borrowed_locals: BorrowedLocalsResults<'mir, 'tcx>) -> Self {
         MaybeRequiresStorage { borrowed_locals }
     }
 }
 
-impl<'tcx> crate::AnalysisDomain<'tcx> for MaybeRequiresStorage<'_, '_, 'tcx> {
+impl<'tcx> crate::AnalysisDomain<'tcx> for MaybeRequiresStorage<'_, 'tcx> {
     type Domain = BitSet<Local>;
 
     const NAME: &'static str = "requires_storage";
@@ -186,7 +185,7 @@ impl<'tcx> crate::AnalysisDomain<'tcx> for MaybeRequiresStorage<'_, '_, 'tcx> {
     }
 }
 
-impl<'tcx> crate::GenKillAnalysis<'tcx> for MaybeRequiresStorage<'_, '_, 'tcx> {
+impl<'tcx> crate::GenKillAnalysis<'tcx> for MaybeRequiresStorage<'_, 'tcx> {
     type Idx = Local;
 
     fn domain_size(&self, body: &Body<'tcx>) -> usize {
@@ -343,7 +342,7 @@ impl<'tcx> crate::GenKillAnalysis<'tcx> for MaybeRequiresStorage<'_, '_, 'tcx> {
     }
 }
 
-impl<'tcx> MaybeRequiresStorage<'_, '_, 'tcx> {
+impl<'tcx> MaybeRequiresStorage<'_, 'tcx> {
     /// Kill locals that are fully moved and have not been borrowed.
     fn check_for_move(&mut self, trans: &mut impl GenKill<Local>, loc: Location) {
         let body = self.borrowed_locals.body();
@@ -352,12 +351,12 @@ impl<'tcx> MaybeRequiresStorage<'_, '_, 'tcx> {
     }
 }
 
-struct MoveVisitor<'a, 'res, 'mir, 'tcx, T> {
-    borrowed_locals: &'a mut BorrowedLocalsResults<'res, 'mir, 'tcx>,
+struct MoveVisitor<'a, 'mir, 'tcx, T> {
+    borrowed_locals: &'a mut BorrowedLocalsResults<'mir, 'tcx>,
     trans: &'a mut T,
 }
 
-impl<'tcx, T> Visitor<'tcx> for MoveVisitor<'_, '_, '_, 'tcx, T>
+impl<'tcx, T> Visitor<'tcx> for MoveVisitor<'_, '_, 'tcx, T>
 where
     T: GenKill<Local>,
 {

Diff for: compiler/rustc_mir_dataflow/src/lib.rs

@@ -24,7 +24,7 @@ pub use self::framework::{
     fmt, lattice, visit_results, Analysis, AnalysisDomain, Direction, GenKill, GenKillAnalysis,
     JoinSemiLattice, MaybeReachable, Results, ResultsCursor, ResultsVisitable, ResultsVisitor,
 };
-use self::framework::{Backward, ResultsClonedCursor, SwitchIntEdgeEffects};
+use self::framework::{Backward, SwitchIntEdgeEffects};
 use self::move_paths::MoveData;
 
 pub mod debuginfo;

Diff for: compiler/rustc_mir_transform/src/coroutine.rs

@@ -680,12 +680,12 @@ fn locals_live_across_suspend_points<'tcx>(
     let borrowed_locals_results =
         MaybeBorrowedLocals.into_engine(tcx, body).pass_name("coroutine").iterate_to_fixpoint();
 
-    let mut borrowed_locals_cursor = borrowed_locals_results.cloned_results_cursor(body);
+    let mut borrowed_locals_cursor = borrowed_locals_results.clone().into_results_cursor(body);
 
     // Calculate the MIR locals that we actually need to keep storage around
     // for.
     let mut requires_storage_cursor =
-        MaybeRequiresStorage::new(borrowed_locals_results.cloned_results_cursor(body))
+        MaybeRequiresStorage::new(borrowed_locals_results.into_results_cursor(body))
             .into_engine(tcx, body)
             .iterate_to_fixpoint()
             .into_results_cursor(body);
@@ -829,7 +829,7 @@ fn compute_storage_conflicts<'mir, 'tcx>(
     body: &'mir Body<'tcx>,
     saved_locals: &CoroutineSavedLocals,
     always_live_locals: BitSet<Local>,
-    mut requires_storage: rustc_mir_dataflow::Results<'tcx, MaybeRequiresStorage<'_, 'mir, 'tcx>>,
+    mut requires_storage: rustc_mir_dataflow::Results<'tcx, MaybeRequiresStorage<'mir, 'tcx>>,
 ) -> BitMatrix<CoroutineSavedLocal, CoroutineSavedLocal> {
     assert_eq!(body.local_decls.len(), saved_locals.domain_size());