Auto merge of #116152 - cjgillot:unchunck, r=<try>

Experiment: only use dense bitsets

r? `@ghost`

compiler/rustc_borrowck/src/lib.rs

@@ -24,7 +24,7 @@ use rustc_errors::{Diagnostic, DiagnosticBuilder, DiagnosticMessage, Subdiagnost
 use rustc_fluent_macro::fluent_messages;
 use rustc_hir as hir;
 use rustc_hir::def_id::LocalDefId;
-use rustc_index::bit_set::{BitSet, ChunkedBitSet};
+use rustc_index::bit_set::BitSet;
 use rustc_index::{IndexSlice, IndexVec};
 use rustc_infer::infer::{
     InferCtxt, NllRegionVariableOrigin, RegionVariableOrigin, TyCtxtInferExt,
@@ -1657,7 +1657,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         location: Location,
         desired_action: InitializationRequiringAction,
         place_span: (PlaceRef<'tcx>, Span),
-        maybe_uninits: &ChunkedBitSet<MovePathIndex>,
+        maybe_uninits: &BitSet<MovePathIndex>,
         from: u64,
         to: u64,
     ) {

compiler/rustc_borrowck/src/type_check/liveness/trace.rs

@@ -1,5 +1,5 @@
 use rustc_data_structures::fx::{FxIndexMap, FxIndexSet};
-use rustc_index::bit_set::HybridBitSet;
+use rustc_index::bit_set::BitSet;
 use rustc_index::interval::IntervalSet;
 use rustc_infer::infer::canonical::QueryRegionConstraints;
 use rustc_middle::mir::{BasicBlock, Body, ConstraintCategory, Local, Location};
@@ -106,7 +106,7 @@ struct LivenessResults<'me, 'typeck, 'flow, 'tcx> {
     cx: LivenessContext<'me, 'typeck, 'flow, 'tcx>,
 
     /// Set of points that define the current local.
-    defs: HybridBitSet<PointIndex>,
+    defs: BitSet<PointIndex>,
 
     /// Points where the current variable is "use live" -- meaning
     /// that there is a future "full use" that may use its value.
@@ -129,7 +129,7 @@ impl<'me, 'typeck, 'flow, 'tcx> LivenessResults<'me, 'typeck, 'flow, 'tcx> {
         let num_points = cx.elements.num_points();
         LivenessResults {
             cx,
-            defs: HybridBitSet::new_empty(num_points),
+            defs: BitSet::new_empty(num_points),
             use_live_at: IntervalSet::new(num_points),
             drop_live_at: IntervalSet::new(num_points),
             drop_locations: vec![],

compiler/rustc_index/src/bit_set.rs

@@ -293,7 +293,7 @@ impl<T: Idx> BitSet<T> {
         not_already
     }
 
-    fn last_set_in(&self, range: impl RangeBounds<T>) -> Option<T> {
+    pub fn last_set_in(&self, range: impl RangeBounds<T>) -> Option<T> {
         let (start, end) = inclusive_start_end(range, self.domain_size)?;
         let (start_word_index, _) = word_index_and_mask(start);
         let (end_word_index, end_mask) = word_index_and_mask(end);
@@ -1278,7 +1278,7 @@ impl<T: Idx> SparseBitSet<T> {
 }
 
 impl<T: Idx + Ord> SparseBitSet<T> {
-    fn last_set_in(&self, range: impl RangeBounds<T>) -> Option<T> {
+    pub fn last_set_in(&self, range: impl RangeBounds<T>) -> Option<T> {
         let mut last_leq = None;
         for e in self.iter() {
             if range.contains(e) {

compiler/rustc_mir_dataflow/src/impls/initialized.rs

@@ -1,4 +1,4 @@
-use rustc_index::bit_set::{BitSet, ChunkedBitSet};
+use rustc_index::bit_set::BitSet;
 use rustc_index::Idx;
 use rustc_middle::mir::{self, Body, CallReturnPlaces, Location, TerminatorEdges};
 use rustc_middle::ty::{self, TyCtxt};
@@ -68,7 +68,7 @@ impl<'a, 'tcx> MaybeInitializedPlaces<'a, 'tcx> {
     pub fn is_unwind_dead(
         &self,
         place: mir::Place<'tcx>,
-        state: &MaybeReachable<ChunkedBitSet<MovePathIndex>>,
+        state: &MaybeReachable<BitSet<MovePathIndex>>,
     ) -> bool {
         if let LookupResult::Exact(path) = self.move_data().rev_lookup.find(place.as_ref()) {
             let mut maybe_live = false;
@@ -308,7 +308,7 @@ impl<'a, 'tcx> DefinitelyInitializedPlaces<'a, 'tcx> {
 }
 
 impl<'tcx> AnalysisDomain<'tcx> for MaybeInitializedPlaces<'_, 'tcx> {
-    type Domain = MaybeReachable<ChunkedBitSet<MovePathIndex>>;
+    type Domain = MaybeReachable<BitSet<MovePathIndex>>;
     const NAME: &'static str = "maybe_init";
 
     fn bottom_value(&self, _: &mir::Body<'tcx>) -> Self::Domain {
@@ -317,8 +317,7 @@ impl<'tcx> AnalysisDomain<'tcx> for MaybeInitializedPlaces<'_, 'tcx> {
     }
 
     fn initialize_start_block(&self, _: &mir::Body<'tcx>, state: &mut Self::Domain) {
-        *state =
-            MaybeReachable::Reachable(ChunkedBitSet::new_empty(self.move_data().move_paths.len()));
+        *state = MaybeReachable::Reachable(BitSet::new_empty(self.move_data().move_paths.len()));
         drop_flag_effects_for_function_entry(self.tcx, self.body, self.mdpe, |path, s| {
             assert!(s == DropFlagState::Present);
             state.gen(path);
@@ -444,13 +443,13 @@ impl<'tcx> GenKillAnalysis<'tcx> for MaybeInitializedPlaces<'_, 'tcx> {
 }
 
 impl<'tcx> AnalysisDomain<'tcx> for MaybeUninitializedPlaces<'_, 'tcx> {
-    type Domain = ChunkedBitSet<MovePathIndex>;
+    type Domain = BitSet<MovePathIndex>;
 
     const NAME: &'static str = "maybe_uninit";
 
     fn bottom_value(&self, _: &mir::Body<'tcx>) -> Self::Domain {
         // bottom = initialized (start_block_effect counters this at outset)
-        ChunkedBitSet::new_empty(self.move_data().move_paths.len())
+        BitSet::new_empty(self.move_data().move_paths.len())
     }
 
     // sets on_entry bits for Arg places
@@ -649,13 +648,13 @@ impl<'tcx> GenKillAnalysis<'tcx> for DefinitelyInitializedPlaces<'_, 'tcx> {
 }
 
 impl<'tcx> AnalysisDomain<'tcx> for EverInitializedPlaces<'_, 'tcx> {
-    type Domain = ChunkedBitSet<InitIndex>;
+    type Domain = BitSet<InitIndex>;
 
     const NAME: &'static str = "ever_init";
 
     fn bottom_value(&self, _: &mir::Body<'tcx>) -> Self::Domain {
         // bottom = no initialized variables by default
-        ChunkedBitSet::new_empty(self.move_data().inits.len())
+        BitSet::new_empty(self.move_data().inits.len())
     }
 
     fn initialize_start_block(&self, body: &mir::Body<'tcx>, state: &mut Self::Domain) {

compiler/rustc_mir_dataflow/src/impls/liveness.rs

@@ -1,4 +1,4 @@
-use rustc_index::bit_set::{BitSet, ChunkedBitSet};
+use rustc_index::bit_set::BitSet;
 use rustc_middle::mir::visit::{MutatingUseContext, NonMutatingUseContext, PlaceContext, Visitor};
 use rustc_middle::mir::{
     self, CallReturnPlaces, Local, Location, Place, StatementKind, TerminatorEdges,
@@ -27,14 +27,14 @@ use crate::{Analysis, AnalysisDomain, Backward, GenKill, GenKillAnalysis};
 pub struct MaybeLiveLocals;
 
 impl<'tcx> AnalysisDomain<'tcx> for MaybeLiveLocals {
-    type Domain = ChunkedBitSet<Local>;
+    type Domain = BitSet<Local>;
     type Direction = Backward;
 
     const NAME: &'static str = "liveness";
 
     fn bottom_value(&self, body: &mir::Body<'tcx>) -> Self::Domain {
         // bottom = not live
-        ChunkedBitSet::new_empty(body.local_decls.len())
+        BitSet::new_empty(body.local_decls.len())
     }
 
     fn initialize_start_block(&self, _: &mir::Body<'tcx>, _: &mut Self::Domain) {
@@ -234,14 +234,14 @@ impl<'a> MaybeTransitiveLiveLocals<'a> {
 }
 
 impl<'a, 'tcx> AnalysisDomain<'tcx> for MaybeTransitiveLiveLocals<'a> {
-    type Domain = ChunkedBitSet<Local>;
+    type Domain = BitSet<Local>;
     type Direction = Backward;
 
     const NAME: &'static str = "transitive liveness";
 
     fn bottom_value(&self, body: &mir::Body<'tcx>) -> Self::Domain {
         // bottom = not live
-        ChunkedBitSet::new_empty(body.local_decls.len())
+        BitSet::new_empty(body.local_decls.len())
     }
 
     fn initialize_start_block(&self, _: &mir::Body<'tcx>, _: &mut Self::Domain) {

compiler/rustc_mir_dataflow/src/rustc_peek.rs

@@ -1,7 +1,7 @@
 use rustc_span::symbol::sym;
 use rustc_span::Span;
 
-use rustc_index::bit_set::ChunkedBitSet;
+use rustc_index::bit_set::BitSet;
 use rustc_middle::mir::MirPass;
 use rustc_middle::mir::{self, Body, Local, Location};
 use rustc_middle::ty::{self, Ty, TyCtxt};
@@ -264,7 +264,7 @@ impl<'tcx> RustcPeekAt<'tcx> for MaybeLiveLocals {
         &self,
         tcx: TyCtxt<'tcx>,
         place: mir::Place<'tcx>,
-        flow_state: &ChunkedBitSet<Local>,
+        flow_state: &BitSet<Local>,
         call: PeekCall,
     ) {
         info!(?place, "peek_at");

compiler/rustc_mir_transform/src/nrvo.rs

@@ -1,7 +1,7 @@
 //! See the docs for [`RenameReturnPlace`].
 
 use rustc_hir::Mutability;
-use rustc_index::bit_set::HybridBitSet;
+use rustc_index::bit_set::BitSet;
 use rustc_middle::mir::visit::{MutVisitor, NonUseContext, PlaceContext, Visitor};
 use rustc_middle::mir::{self, BasicBlock, Local, Location};
 use rustc_middle::ty::TyCtxt;
@@ -123,7 +123,7 @@ fn find_local_assigned_to_return_place(
     body: &mut mir::Body<'_>,
 ) -> Option<Local> {
     let mut block = start;
-    let mut seen = HybridBitSet::new_empty(body.basic_blocks.len());
+    let mut seen = BitSet::new_empty(body.basic_blocks.len());
 
     // Iterate as long as `block` has exactly one predecessor that we have not yet visited.
     while seen.insert(block) {

compiler/rustc_mir_transform/src/remove_uninit_drops.rs

@@ -1,4 +1,4 @@
-use rustc_index::bit_set::ChunkedBitSet;
+use rustc_index::bit_set::BitSet;
 use rustc_middle::mir::{Body, TerminatorKind};
 use rustc_middle::ty::GenericArgsRef;
 use rustc_middle::ty::{self, ParamEnv, Ty, TyCtxt, VariantDef};
@@ -79,7 +79,7 @@ impl<'tcx> MirPass<'tcx> for RemoveUninitDrops {
 fn is_needs_drop_and_init<'tcx>(
     tcx: TyCtxt<'tcx>,
     param_env: ParamEnv<'tcx>,
-    maybe_inits: &ChunkedBitSet<MovePathIndex>,
+    maybe_inits: &BitSet<MovePathIndex>,
     move_data: &MoveData<'tcx>,
     ty: Ty<'tcx>,
     mpi: MovePathIndex,