Take MIR dataflow analyses by mutable reference.

4 files changed, 74 insertions, 66 deletions

diff --git a/compiler/rustc_mir_dataflow/src/impls/borrowed_locals.rs b/compiler/rustc_mir_dataflow/src/impls/borrowed_locals.rs
index 92d30f254a6..b88ed32b687 100644
--- a/compiler/rustc_mir_dataflow/src/impls/borrowed_locals.rs
+++ b/compiler/rustc_mir_dataflow/src/impls/borrowed_locals.rs
@@ -10,6 +10,7 @@ use rustc_middle::mir::*;
 /// At present, this is used as a very limited form of alias analysis. For example,
 /// `MaybeBorrowedLocals` is used to compute which locals are live during a yield expression for
 /// immovable generators.
+#[derive(Clone, Copy)]
 pub struct MaybeBorrowedLocals;
 
 impl MaybeBorrowedLocals {
@@ -36,7 +37,7 @@ impl<'tcx> GenKillAnalysis<'tcx> for MaybeBorrowedLocals {
     type Idx = Local;
 
     fn statement_effect(
-        &self,
+        &mut self,
         trans: &mut impl GenKill<Self::Idx>,
         statement: &mir::Statement<'tcx>,
         location: Location,
@@ -45,7 +46,7 @@ impl<'tcx> GenKillAnalysis<'tcx> for MaybeBorrowedLocals {
     }
 
     fn terminator_effect(
-        &self,
+        &mut self,
         trans: &mut impl GenKill<Self::Idx>,
         terminator: &mir::Terminator<'tcx>,
         location: Location,
@@ -54,7 +55,7 @@ impl<'tcx> GenKillAnalysis<'tcx> for MaybeBorrowedLocals {
     }
 
     fn call_return_effect(
-        &self,
+        &mut self,
         _trans: &mut impl GenKill<Self::Idx>,
         _block: mir::BasicBlock,
         _return_places: CallReturnPlaces<'_, 'tcx>,
diff --git a/compiler/rustc_mir_dataflow/src/impls/liveness.rs b/compiler/rustc_mir_dataflow/src/impls/liveness.rs
index aeca0073304..56cd18cf711 100644
--- a/compiler/rustc_mir_dataflow/src/impls/liveness.rs
+++ b/compiler/rustc_mir_dataflow/src/impls/liveness.rs
@@ -21,6 +21,7 @@ use crate::{Analysis, AnalysisDomain, Backward, CallReturnPlaces, GenKill, GenKi
 /// [`MaybeBorrowedLocals`]: super::MaybeBorrowedLocals
 /// [flow-test]: https://github.com/rust-lang/rust/blob/a08c47310c7d49cbdc5d7afb38408ba519967ecd/src/test/ui/mir-dataflow/liveness-ptr.rs
 /// [liveness]: https://en.wikipedia.org/wiki/Live_variable_analysis
+#[derive(Clone, Copy)]
 pub struct MaybeLiveLocals;
 
 impl<'tcx> AnalysisDomain<'tcx> for MaybeLiveLocals {
@@ -43,7 +44,7 @@ impl<'tcx> GenKillAnalysis<'tcx> for MaybeLiveLocals {
     type Idx = Local;
 
     fn statement_effect(
-        &self,
+        &mut self,
         trans: &mut impl GenKill<Self::Idx>,
         statement: &mir::Statement<'tcx>,
         location: Location,
@@ -52,7 +53,7 @@ impl<'tcx> GenKillAnalysis<'tcx> for MaybeLiveLocals {
     }
 
     fn terminator_effect(
-        &self,
+        &mut self,
         trans: &mut impl GenKill<Self::Idx>,
         terminator: &mir::Terminator<'tcx>,
         location: Location,
@@ -61,7 +62,7 @@ impl<'tcx> GenKillAnalysis<'tcx> for MaybeLiveLocals {
     }
 
     fn call_return_effect(
-        &self,
+        &mut self,
         trans: &mut impl GenKill<Self::Idx>,
         _block: mir::BasicBlock,
         return_places: CallReturnPlaces<'_, 'tcx>,
@@ -74,7 +75,7 @@ impl<'tcx> GenKillAnalysis<'tcx> for MaybeLiveLocals {
     }
 
     fn yield_resume_effect(
-        &self,
+        &mut self,
         trans: &mut impl GenKill<Self::Idx>,
         _resume_block: mir::BasicBlock,
         resume_place: mir::Place<'tcx>,
@@ -216,6 +217,7 @@ impl DefUse {
 /// This is basically written for dead store elimination and nothing else.
 ///
 /// All of the caveats of `MaybeLiveLocals` apply.
+#[derive(Clone, Copy)]
 pub struct MaybeTransitiveLiveLocals<'a> {
     always_live: &'a BitSet<Local>,
 }
@@ -248,7 +250,7 @@ impl<'a, 'tcx> AnalysisDomain<'tcx> for MaybeTransitiveLiveLocals<'a> {
 
 impl<'a, 'tcx> Analysis<'tcx> for MaybeTransitiveLiveLocals<'a> {
     fn apply_statement_effect(
-        &self,
+        &mut self,
         trans: &mut Self::Domain,
         statement: &mir::Statement<'tcx>,
         location: Location,
@@ -283,7 +285,7 @@ impl<'a, 'tcx> Analysis<'tcx> for MaybeTransitiveLiveLocals<'a> {
     }
 
     fn apply_terminator_effect(
-        &self,
+        &mut self,
         trans: &mut Self::Domain,
         terminator: &mir::Terminator<'tcx>,
         location: Location,
@@ -292,7 +294,7 @@ impl<'a, 'tcx> Analysis<'tcx> for MaybeTransitiveLiveLocals<'a> {
     }
 
     fn apply_call_return_effect(
-        &self,
+        &mut self,
         trans: &mut Self::Domain,
         _block: mir::BasicBlock,
         return_places: CallReturnPlaces<'_, 'tcx>,
@@ -305,7 +307,7 @@ impl<'a, 'tcx> Analysis<'tcx> for MaybeTransitiveLiveLocals<'a> {
     }
 
     fn apply_yield_resume_effect(
-        &self,
+        &mut self,
         trans: &mut Self::Domain,
         _resume_block: mir::BasicBlock,
         resume_place: mir::Place<'tcx>,
diff --git a/compiler/rustc_mir_dataflow/src/impls/mod.rs b/compiler/rustc_mir_dataflow/src/impls/mod.rs
index 171db6965ac..98cec1c6760 100644
--- a/compiler/rustc_mir_dataflow/src/impls/mod.rs
+++ b/compiler/rustc_mir_dataflow/src/impls/mod.rs
@@ -306,7 +306,7 @@ impl<'tcx> GenKillAnalysis<'tcx> for MaybeInitializedPlaces<'_, 'tcx> {
     type Idx = MovePathIndex;
 
     fn statement_effect(
-        &self,
+        &mut self,
         trans: &mut impl GenKill<Self::Idx>,
         statement: &mir::Statement<'tcx>,
         location: Location,
@@ -329,7 +329,7 @@ impl<'tcx> GenKillAnalysis<'tcx> for MaybeInitializedPlaces<'_, 'tcx> {
     }
 
     fn terminator_effect(
-        &self,
+        &mut self,
         trans: &mut impl GenKill<Self::Idx>,
         terminator: &mir::Terminator<'tcx>,
         location: Location,
@@ -351,7 +351,7 @@ impl<'tcx> GenKillAnalysis<'tcx> for MaybeInitializedPlaces<'_, 'tcx> {
     }
 
     fn call_return_effect(
-        &self,
+        &mut self,
         trans: &mut impl GenKill<Self::Idx>,
         _block: mir::BasicBlock,
         return_places: CallReturnPlaces<'_, 'tcx>,
@@ -372,7 +372,7 @@ impl<'tcx> GenKillAnalysis<'tcx> for MaybeInitializedPlaces<'_, 'tcx> {
     }
 
     fn switch_int_edge_effects<G: GenKill<Self::Idx>>(
-        &self,
+        &mut self,
         block: mir::BasicBlock,
         discr: &mir::Operand<'tcx>,
         edge_effects: &mut impl SwitchIntEdgeEffects<G>,
@@ -442,7 +442,7 @@ impl<'tcx> GenKillAnalysis<'tcx> for MaybeUninitializedPlaces<'_, 'tcx> {
     type Idx = MovePathIndex;
 
     fn statement_effect(
-        &self,
+        &mut self,
         trans: &mut impl GenKill<Self::Idx>,
         _statement: &mir::Statement<'tcx>,
         location: Location,
@@ -456,7 +456,7 @@ impl<'tcx> GenKillAnalysis<'tcx> for MaybeUninitializedPlaces<'_, 'tcx> {
     }
 
     fn terminator_effect(
-        &self,
+        &mut self,
         trans: &mut impl GenKill<Self::Idx>,
         _terminator: &mir::Terminator<'tcx>,
         location: Location,
@@ -467,7 +467,7 @@ impl<'tcx> GenKillAnalysis<'tcx> for MaybeUninitializedPlaces<'_, 'tcx> {
     }
 
     fn call_return_effect(
-        &self,
+        &mut self,
         trans: &mut impl GenKill<Self::Idx>,
         _block: mir::BasicBlock,
         return_places: CallReturnPlaces<'_, 'tcx>,
@@ -488,7 +488,7 @@ impl<'tcx> GenKillAnalysis<'tcx> for MaybeUninitializedPlaces<'_, 'tcx> {
     }
 
     fn switch_int_edge_effects<G: GenKill<Self::Idx>>(
-        &self,
+        &mut self,
         block: mir::BasicBlock,
         discr: &mir::Operand<'tcx>,
         edge_effects: &mut impl SwitchIntEdgeEffects<G>,
@@ -562,7 +562,7 @@ impl<'tcx> GenKillAnalysis<'tcx> for DefinitelyInitializedPlaces<'_, 'tcx> {
     type Idx = MovePathIndex;
 
     fn statement_effect(
-        &self,
+        &mut self,
         trans: &mut impl GenKill<Self::Idx>,
         _statement: &mir::Statement<'tcx>,
         location: Location,
@@ -573,7 +573,7 @@ impl<'tcx> GenKillAnalysis<'tcx> for DefinitelyInitializedPlaces<'_, 'tcx> {
     }
 
     fn terminator_effect(
-        &self,
+        &mut self,
         trans: &mut impl GenKill<Self::Idx>,
         _terminator: &mir::Terminator<'tcx>,
         location: Location,
@@ -584,7 +584,7 @@ impl<'tcx> GenKillAnalysis<'tcx> for DefinitelyInitializedPlaces<'_, 'tcx> {
     }
 
     fn call_return_effect(
-        &self,
+        &mut self,
         trans: &mut impl GenKill<Self::Idx>,
         _block: mir::BasicBlock,
         return_places: CallReturnPlaces<'_, 'tcx>,
@@ -627,7 +627,7 @@ impl<'tcx> GenKillAnalysis<'tcx> for EverInitializedPlaces<'_, 'tcx> {
 
     #[instrument(skip(self, trans), level = "debug")]
     fn statement_effect(
-        &self,
+        &mut self,
         trans: &mut impl GenKill<Self::Idx>,
         stmt: &mir::Statement<'tcx>,
         location: Location,
@@ -651,7 +651,7 @@ impl<'tcx> GenKillAnalysis<'tcx> for EverInitializedPlaces<'_, 'tcx> {
 
     #[instrument(skip(self, trans, _terminator), level = "debug")]
     fn terminator_effect(
-        &self,
+        &mut self,
         trans: &mut impl GenKill<Self::Idx>,
         _terminator: &mir::Terminator<'tcx>,
         location: Location,
@@ -672,7 +672,7 @@ impl<'tcx> GenKillAnalysis<'tcx> for EverInitializedPlaces<'_, 'tcx> {
     }
 
     fn call_return_effect(
-        &self,
+        &mut self,
         trans: &mut impl GenKill<Self::Idx>,
         block: mir::BasicBlock,
         _return_places: CallReturnPlaces<'_, 'tcx>,
diff --git a/compiler/rustc_mir_dataflow/src/impls/storage_liveness.rs b/compiler/rustc_mir_dataflow/src/impls/storage_liveness.rs
index 463ce083a64..666c8d50a8a 100644
--- a/compiler/rustc_mir_dataflow/src/impls/storage_liveness.rs
+++ b/compiler/rustc_mir_dataflow/src/impls/storage_liveness.rs
@@ -1,10 +1,9 @@
 pub use super::*;
 
-use crate::{CallReturnPlaces, GenKill, Results, ResultsRefCursor};
+use crate::{CallReturnPlaces, GenKill, ResultsClonedCursor};
 use rustc_middle::mir::visit::{NonMutatingUseContext, PlaceContext, Visitor};
 use rustc_middle::mir::*;
 use std::borrow::Cow;
-use std::cell::RefCell;
 
 #[derive(Clone)]
 pub struct MaybeStorageLive<'a> {
@@ -17,6 +16,12 @@ impl<'a> MaybeStorageLive<'a> {
     }
 }
 
+impl crate::CloneAnalysis for MaybeStorageLive<'_> {
+    fn clone_analysis(&self) -> Self {
+        self.clone()
+    }
+}
+
 impl<'tcx, 'a> crate::AnalysisDomain<'tcx> for MaybeStorageLive<'a> {
     type Domain = BitSet<Local>;
 
@@ -43,7 +48,7 @@ impl<'tcx, 'a> crate::GenKillAnalysis<'tcx> for MaybeStorageLive<'a> {
     type Idx = Local;
 
     fn statement_effect(
-        &self,
+        &mut self,
         trans: &mut impl GenKill<Self::Idx>,
         stmt: &mir::Statement<'tcx>,
         _: Location,
@@ -56,7 +61,7 @@ impl<'tcx, 'a> crate::GenKillAnalysis<'tcx> for MaybeStorageLive<'a> {
     }
 
     fn terminator_effect(
-        &self,
+        &mut self,
         _trans: &mut impl GenKill<Self::Idx>,
         _: &mir::Terminator<'tcx>,
         _: Location,
@@ -65,7 +70,7 @@ impl<'tcx, 'a> crate::GenKillAnalysis<'tcx> for MaybeStorageLive<'a> {
     }
 
     fn call_return_effect(
-        &self,
+        &mut self,
         _trans: &mut impl GenKill<Self::Idx>,
         _block: BasicBlock,
         _return_places: CallReturnPlaces<'_, 'tcx>,
@@ -110,7 +115,7 @@ impl<'tcx> crate::GenKillAnalysis<'tcx> for MaybeStorageDead {
     type Idx = Local;
 
     fn statement_effect(
-        &self,
+        &mut self,
         trans: &mut impl GenKill<Self::Idx>,
         stmt: &mir::Statement<'tcx>,
         _: Location,
@@ -123,7 +128,7 @@ impl<'tcx> crate::GenKillAnalysis<'tcx> for MaybeStorageDead {
     }
 
     fn terminator_effect(
-        &self,
+        &mut self,
         _trans: &mut impl GenKill<Self::Idx>,
         _: &mir::Terminator<'tcx>,
         _: Location,
@@ -132,7 +137,7 @@ impl<'tcx> crate::GenKillAnalysis<'tcx> for MaybeStorageDead {
     }
 
     fn call_return_effect(
-        &self,
+        &mut self,
         _trans: &mut impl GenKill<Self::Idx>,
         _block: BasicBlock,
         _return_places: CallReturnPlaces<'_, 'tcx>,
@@ -141,28 +146,28 @@ impl<'tcx> crate::GenKillAnalysis<'tcx> for MaybeStorageDead {
     }
 }
 
-type BorrowedLocalsResults<'a, 'tcx> = ResultsRefCursor<'a, 'a, 'tcx, MaybeBorrowedLocals>;
+type BorrowedLocalsResults<'res, 'mir, 'tcx> =
+    ResultsClonedCursor<'res, '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<'mir, 'tcx> {
-    body: &'mir Body<'tcx>,
-    borrowed_locals: RefCell<BorrowedLocalsResults<'mir, 'tcx>>,
+pub struct MaybeRequiresStorage<'res, 'mir, 'tcx> {
+    borrowed_locals: BorrowedLocalsResults<'res, 'mir, 'tcx>,
 }
 
-impl<'mir, 'tcx> MaybeRequiresStorage<'mir, 'tcx> {
-    pub fn new(
-        body: &'mir Body<'tcx>,
-        borrowed_locals: &'mir Results<'tcx, MaybeBorrowedLocals>,
-    ) -> Self {
-        MaybeRequiresStorage {
-            body,
-            borrowed_locals: RefCell::new(ResultsRefCursor::new(&body, borrowed_locals)),
-        }
+impl<'res, 'mir, 'tcx> MaybeRequiresStorage<'res, 'mir, 'tcx> {
+    pub fn new(borrowed_locals: BorrowedLocalsResults<'res, 'mir, 'tcx>) -> Self {
+        MaybeRequiresStorage { borrowed_locals }
+    }
+}
+
+impl crate::CloneAnalysis for MaybeRequiresStorage<'_, '_, '_> {
+    fn clone_analysis(&self) -> Self {
+        Self { borrowed_locals: self.borrowed_locals.new_cursor() }
     }
 }
 
-impl<'mir, 'tcx> crate::AnalysisDomain<'tcx> for MaybeRequiresStorage<'mir, 'tcx> {
+impl<'tcx> crate::AnalysisDomain<'tcx> for MaybeRequiresStorage<'_, '_, 'tcx> {
     type Domain = BitSet<Local>;
 
     const NAME: &'static str = "requires_storage";
@@ -181,17 +186,17 @@ impl<'mir, 'tcx> crate::AnalysisDomain<'tcx> for MaybeRequiresStorage<'mir, 'tcx
     }
 }
 
-impl<'mir, 'tcx> crate::GenKillAnalysis<'tcx> for MaybeRequiresStorage<'mir, 'tcx> {
+impl<'tcx> crate::GenKillAnalysis<'tcx> for MaybeRequiresStorage<'_, '_, 'tcx> {
     type Idx = Local;
 
     fn before_statement_effect(
-        &self,
+        &mut self,
         trans: &mut impl GenKill<Self::Idx>,
         stmt: &mir::Statement<'tcx>,
         loc: Location,
     ) {
         // If a place is borrowed in a statement, it needs storage for that statement.
-        self.borrowed_locals.borrow().analysis().statement_effect(trans, stmt, loc);
+        self.borrowed_locals.mut_analysis().statement_effect(trans, stmt, loc);
 
         match &stmt.kind {
             StatementKind::StorageDead(l) => trans.kill(*l),
@@ -218,7 +223,7 @@ impl<'mir, 'tcx> crate::GenKillAnalysis<'tcx> for MaybeRequiresStorage<'mir, 'tc
     }
 
     fn statement_effect(
-        &self,
+        &mut self,
         trans: &mut impl GenKill<Self::Idx>,
         _: &mir::Statement<'tcx>,
         loc: Location,
@@ -229,13 +234,13 @@ impl<'mir, 'tcx> crate::GenKillAnalysis<'tcx> for MaybeRequiresStorage<'mir, 'tc
     }
 
     fn before_terminator_effect(
-        &self,
+        &mut self,
         trans: &mut impl GenKill<Self::Idx>,
         terminator: &mir::Terminator<'tcx>,
         loc: Location,
     ) {
         // If a place is borrowed in a terminator, it needs storage for that terminator.
-        self.borrowed_locals.borrow().analysis().terminator_effect(trans, terminator, loc);
+        self.borrowed_locals.mut_analysis().terminator_effect(trans, terminator, loc);
 
         match &terminator.kind {
             TerminatorKind::Call { destination, .. } => {
@@ -282,7 +287,7 @@ impl<'mir, 'tcx> crate::GenKillAnalysis<'tcx> for MaybeRequiresStorage<'mir, 'tc
     }
 
     fn terminator_effect(
-        &self,
+        &mut self,
         trans: &mut impl GenKill<Self::Idx>,
         terminator: &mir::Terminator<'tcx>,
         loc: Location,
@@ -321,7 +326,7 @@ impl<'mir, 'tcx> crate::GenKillAnalysis<'tcx> for MaybeRequiresStorage<'mir, 'tc
     }
 
     fn call_return_effect(
-        &self,
+        &mut self,
         trans: &mut impl GenKill<Self::Idx>,
         _block: BasicBlock,
         return_places: CallReturnPlaces<'_, 'tcx>,
@@ -330,7 +335,7 @@ impl<'mir, 'tcx> crate::GenKillAnalysis<'tcx> for MaybeRequiresStorage<'mir, 'tc
     }
 
     fn yield_resume_effect(
-        &self,
+        &mut self,
         trans: &mut impl GenKill<Self::Idx>,
         _resume_block: BasicBlock,
         resume_place: mir::Place<'tcx>,
@@ -339,28 +344,28 @@ impl<'mir, 'tcx> crate::GenKillAnalysis<'tcx> for MaybeRequiresStorage<'mir, 'tc
     }
 }
 
-impl<'mir, 'tcx> MaybeRequiresStorage<'mir, 'tcx> {
+impl<'tcx> MaybeRequiresStorage<'_, '_, 'tcx> {
     /// Kill locals that are fully moved and have not been borrowed.
-    fn check_for_move(&self, trans: &mut impl GenKill<Local>, loc: Location) {
-        let mut visitor = MoveVisitor { trans, borrowed_locals: &self.borrowed_locals };
-        visitor.visit_location(&self.body, loc);
+    fn check_for_move(&mut self, trans: &mut impl GenKill<Local>, loc: Location) {
+        let body = self.borrowed_locals.body();
+        let mut visitor = MoveVisitor { trans, borrowed_locals: &mut self.borrowed_locals };
+        visitor.visit_location(body, loc);
     }
 }
 
-struct MoveVisitor<'a, 'mir, 'tcx, T> {
-    borrowed_locals: &'a RefCell<BorrowedLocalsResults<'mir, 'tcx>>,
+struct MoveVisitor<'a, 'res, 'mir, 'tcx, T> {
+    borrowed_locals: &'a mut BorrowedLocalsResults<'res, 'mir, 'tcx>,
     trans: &'a mut T,
 }
 
-impl<'a, 'mir, 'tcx, T> Visitor<'tcx> for MoveVisitor<'a, 'mir, 'tcx, T>
+impl<'tcx, T> Visitor<'tcx> for MoveVisitor<'_, '_, '_, 'tcx, T>
 where
     T: GenKill<Local>,
 {
     fn visit_local(&mut self, local: Local, context: PlaceContext, loc: Location) {
         if PlaceContext::NonMutatingUse(NonMutatingUseContext::Move) == context {
-            let mut borrowed_locals = self.borrowed_locals.borrow_mut();
-            borrowed_locals.seek_before_primary_effect(loc);
-            if !borrowed_locals.contains(local) {
+            self.borrowed_locals.seek_before_primary_effect(loc);
+            if !self.borrowed_locals.contains(local) {
                 self.trans.kill(local);
             }
         }