Move PointIndex to mir_dataflow.

Author: cjgillot

compiler/rustc_borrowck/src/constraint_generation.rs

@@ -10,11 +10,9 @@ use rustc_middle::mir::{
 use rustc_middle::ty::visit::TypeVisitable;
 use rustc_middle::ty::GenericArgsRef;
 use rustc_middle::ty::{self, RegionVid, Ty, TyCtxt};
+use rustc_mir_dataflow::points::LivenessValues;
 
-use crate::{
-    borrow_set::BorrowSet, facts::AllFacts, location::LocationTable, places_conflict,
-    region_infer::values::LivenessValues,
-};
+use crate::{borrow_set::BorrowSet, facts::AllFacts, location::LocationTable, places_conflict};
 
 pub(super) fn generate_constraints<'tcx>(
     infcx: &InferCtxt<'tcx>,

compiler/rustc_borrowck/src/nll.rs

@@ -11,6 +11,7 @@ use rustc_middle::mir::{
     START_BLOCK,
 };
 use rustc_middle::ty::{self, OpaqueHiddenType, TyCtxt};
+use rustc_mir_dataflow::points::DenseLocationMap;
 use rustc_span::symbol::sym;
 use std::env;
 use std::io;
@@ -32,7 +33,7 @@ use crate::{
     facts::{AllFacts, AllFactsExt, RustcFacts},
     invalidation,
     location::LocationTable,
-    region_infer::{values::RegionValueElements, RegionInferenceContext},
+    region_infer::RegionInferenceContext,
     renumber,
     type_check::{self, MirTypeckRegionConstraints, MirTypeckResults},
     universal_regions::UniversalRegions,
@@ -177,7 +178,7 @@ pub(crate) fn compute_regions<'cx, 'tcx>(
 
     let universal_regions = Rc::new(universal_regions);
 
-    let elements = &Rc::new(RegionValueElements::new(&body));
+    let elements = &Rc::new(DenseLocationMap::new(&body));
 
     // Run the MIR type-checker.
     let MirTypeckResults { constraints, universal_region_relations, opaque_type_values } =

compiler/rustc_borrowck/src/region_infer/dump_mir.rs

@@ -67,7 +67,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         with_msg: &mut dyn FnMut(&str) -> io::Result<()>,
     ) -> io::Result<()> {
         for region in self.definitions.indices() {
-            let value = self.liveness_constraints.region_value_str(region);
+            let value = self.region_value_str(region);
             if value != "{}" {
                 with_msg(&format!("{region:?} live at {value}"))?;
             }

compiler/rustc_borrowck/src/region_infer/mod.rs

@@ -19,6 +19,7 @@ use rustc_middle::mir::{
 use rustc_middle::traits::ObligationCause;
 use rustc_middle::traits::ObligationCauseCode;
 use rustc_middle::ty::{self, RegionVid, Ty, TyCtxt, TypeFoldable, TypeVisitableExt};
+use rustc_mir_dataflow::points::{DenseLocationMap, LivenessValues};
 use rustc_span::Span;
 
 use crate::{
@@ -29,10 +30,7 @@ use crate::{
     member_constraints::{MemberConstraintSet, NllMemberConstraintIndex},
     nll::PoloniusOutput,
     region_infer::reverse_sccs::ReverseSccGraph,
-    region_infer::values::{
-        LivenessValues, PlaceholderIndices, RegionElement, RegionValueElements, RegionValues,
-        ToElementIndex,
-    },
+    region_infer::values::{PlaceholderIndices, RegionElement, RegionValues, ToElementIndex},
     type_check::{free_region_relations::UniversalRegionRelations, Locations},
     universal_regions::UniversalRegions,
     BorrowckInferCtxt,
@@ -329,7 +327,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         universe_causes: FxIndexMap<ty::UniverseIndex, UniverseInfo<'tcx>>,
         type_tests: Vec<TypeTest<'tcx>>,
         liveness_constraints: LivenessValues<RegionVid>,
-        elements: &Rc<RegionValueElements>,
+        elements: &Rc<DenseLocationMap>,
     ) -> Self {
         debug!("universal_regions: {:#?}", universal_regions);
         debug!("outlives constraints: {:#?}", outlives_constraints);
@@ -1963,7 +1961,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         trace!(universe = ?self.scc_universes[self.constraint_sccs.scc(fr1)]);
         self.find_constraint_paths_between_regions(fr1, |r| {
             // First look for some `r` such that `fr1: r` and `r` is live at `elem`
-            trace!(?r, liveness_constraints=?self.liveness_constraints.region_value_str(r));
+            trace!(?r, liveness_constraints=?self.region_value_str(r));
             self.liveness_constraints.contains(r, elem)
         })
         .or_else(|| {

compiler/rustc_borrowck/src/region_infer/values.rs

@@ -2,98 +2,14 @@
 #![deny(rustc::diagnostic_outside_of_impl)]
 use rustc_data_structures::fx::FxIndexSet;
 use rustc_index::bit_set::SparseBitMatrix;
-use rustc_index::interval::IntervalSet;
 use rustc_index::interval::SparseIntervalMatrix;
 use rustc_index::Idx;
-use rustc_index::IndexVec;
-use rustc_middle::mir::{BasicBlock, Body, Location};
+use rustc_middle::mir::{BasicBlock, Location};
 use rustc_middle::ty::{self, RegionVid};
+use rustc_mir_dataflow::points::{DenseLocationMap, LivenessValues, PointIndex};
 use std::fmt::Debug;
 use std::rc::Rc;
 
-/// Maps between a `Location` and a `PointIndex` (and vice versa).
-pub(crate) struct RegionValueElements {
-    /// For each basic block, how many points are contained within?
-    statements_before_block: IndexVec<BasicBlock, usize>,
-
-    /// Map backward from each point to the basic block that it
-    /// belongs to.
-    basic_blocks: IndexVec<PointIndex, BasicBlock>,
-
-    num_points: usize,
-}
-
-impl RegionValueElements {
-    pub(crate) fn new(body: &Body<'_>) -> Self {
-        let mut num_points = 0;
-        let statements_before_block: IndexVec<BasicBlock, usize> = body
-            .basic_blocks
-            .iter()
-            .map(|block_data| {
-                let v = num_points;
-                num_points += block_data.statements.len() + 1;
-                v
-            })
-            .collect();
-        debug!("RegionValueElements: statements_before_block={:#?}", statements_before_block);
-        debug!("RegionValueElements: num_points={:#?}", num_points);
-
-        let mut basic_blocks = IndexVec::with_capacity(num_points);
-        for (bb, bb_data) in body.basic_blocks.iter_enumerated() {
-            basic_blocks.extend((0..=bb_data.statements.len()).map(|_| bb));
-        }
-
-        Self { statements_before_block, basic_blocks, num_points }
-    }
-
-    /// Total number of point indices
-    pub(crate) fn num_points(&self) -> usize {
-        self.num_points
-    }
-
-    /// Converts a `Location` into a `PointIndex`. O(1).
-    pub(crate) fn point_from_location(&self, location: Location) -> PointIndex {
-        let Location { block, statement_index } = location;
-        let start_index = self.statements_before_block[block];
-        PointIndex::new(start_index + statement_index)
-    }
-
-    /// Converts a `Location` into a `PointIndex`. O(1).
-    pub(crate) fn entry_point(&self, block: BasicBlock) -> PointIndex {
-        let start_index = self.statements_before_block[block];
-        PointIndex::new(start_index)
-    }
-
-    /// Return the PointIndex for the block start of this index.
-    pub(crate) fn to_block_start(&self, index: PointIndex) -> PointIndex {
-        PointIndex::new(self.statements_before_block[self.basic_blocks[index]])
-    }
-
-    /// Converts a `PointIndex` back to a location. O(1).
-    pub(crate) fn to_location(&self, index: PointIndex) -> Location {
-        assert!(index.index() < self.num_points);
-        let block = self.basic_blocks[index];
-        let start_index = self.statements_before_block[block];
-        let statement_index = index.index() - start_index;
-        Location { block, statement_index }
-    }
-
-    /// Sometimes we get point-indices back from bitsets that may be
-    /// out of range (because they round up to the nearest 2^N number
-    /// of bits). Use this function to filter such points out if you
-    /// like.
-    pub(crate) fn point_in_range(&self, index: PointIndex) -> bool {
-        index.index() < self.num_points
-    }
-}
-
-rustc_index::newtype_index! {
-    /// A single integer representing a `Location` in the MIR control-flow
-    /// graph. Constructed efficiently from `RegionValueElements`.
-    #[debug_format = "PointIndex({})"]
-    pub struct PointIndex {}
-}
-
 rustc_index::newtype_index! {
     /// A single integer representing a `ty::Placeholder`.
     #[debug_format = "PlaceholderIndex({})"]
@@ -116,68 +32,6 @@ pub(crate) enum RegionElement {
     PlaceholderRegion(ty::PlaceholderRegion),
 }
 
-/// When we initially compute liveness, we use an interval matrix storing
-/// liveness ranges for each region-vid.
-pub(crate) struct LivenessValues<N: Idx> {
-    elements: Rc<RegionValueElements>,
-    points: SparseIntervalMatrix<N, PointIndex>,
-}
-
-impl<N: Idx> LivenessValues<N> {
-    /// Creates a new set of "region values" that tracks causal information.
-    /// Each of the regions in num_region_variables will be initialized with an
-    /// empty set of points and no causal information.
-    pub(crate) fn new(elements: Rc<RegionValueElements>) -> Self {
-        Self { points: SparseIntervalMatrix::new(elements.num_points), elements }
-    }
-
-    /// Iterate through each region that has a value in this set.
-    pub(crate) fn rows(&self) -> impl Iterator<Item = N> {
-        self.points.rows()
-    }
-
-    /// Adds the given element to the value for the given region. Returns whether
-    /// the element is newly added (i.e., was not already present).
-    pub(crate) fn add_element(&mut self, row: N, location: Location) -> bool {
-        debug!("LivenessValues::add(r={:?}, location={:?})", row, location);
-        let index = self.elements.point_from_location(location);
-        self.points.insert(row, index)
-    }
-
-    /// Adds all the elements in the given bit array into the given
-    /// region. Returns whether any of them are newly added.
-    pub(crate) fn add_elements(&mut self, row: N, locations: &IntervalSet<PointIndex>) -> bool {
-        debug!("LivenessValues::add_elements(row={:?}, locations={:?})", row, locations);
-        self.points.union_row(row, locations)
-    }
-
-    /// Adds all the control-flow points to the values for `r`.
-    pub(crate) fn add_all_points(&mut self, row: N) {
-        self.points.insert_all_into_row(row);
-    }
-
-    /// Returns `true` if the region `r` contains the given element.
-    pub(crate) fn contains(&self, row: N, location: Location) -> bool {
-        let index = self.elements.point_from_location(location);
-        self.points.row(row).is_some_and(|r| r.contains(index))
-    }
-
-    /// Returns an iterator of all the elements contained by the region `r`
-    pub(crate) fn get_elements(&self, row: N) -> impl Iterator<Item = Location> + '_ {
-        self.points
-            .row(row)
-            .into_iter()
-            .flat_map(|set| set.iter())
-            .take_while(move |&p| self.elements.point_in_range(p))
-            .map(move |p| self.elements.to_location(p))
-    }
-
-    /// Returns a "pretty" string value of the region. Meant for debugging.
-    pub(crate) fn region_value_str(&self, r: N) -> String {
-        region_value_str(self.get_elements(r).map(RegionElement::Location))
-    }
-}
-
 /// Maps from `ty::PlaceholderRegion` values that are used in the rest of
 /// rustc to the internal `PlaceholderIndex` values that are used in
 /// NLL.
@@ -229,7 +83,7 @@ impl PlaceholderIndices {
 /// it would also contain various points from within the function.
 #[derive(Clone)]
 pub(crate) struct RegionValues<N: Idx> {
-    elements: Rc<RegionValueElements>,
+    elements: Rc<DenseLocationMap>,
     placeholder_indices: Rc<PlaceholderIndices>,
     points: SparseIntervalMatrix<N, PointIndex>,
     free_regions: SparseBitMatrix<N, RegionVid>,
@@ -244,14 +98,14 @@ impl<N: Idx> RegionValues<N> {
     /// Each of the regions in num_region_variables will be initialized with an
     /// empty set of points and no causal information.
     pub(crate) fn new(
-        elements: &Rc<RegionValueElements>,
+        elements: &Rc<DenseLocationMap>,
         num_universal_regions: usize,
         placeholder_indices: &Rc<PlaceholderIndices>,
     ) -> Self {
         let num_placeholders = placeholder_indices.len();
         Self {
             elements: elements.clone(),
-            points: SparseIntervalMatrix::new(elements.num_points),
+            points: SparseIntervalMatrix::new(elements.num_points()),
             placeholder_indices: placeholder_indices.clone(),
             free_regions: SparseBitMatrix::new(num_universal_regions),
             placeholders: SparseBitMatrix::new(num_placeholders),
@@ -303,7 +157,7 @@ impl<N: Idx> RegionValues<N> {
     /// elements for the region `from` from `values` and add them to
     /// the region `to` in `self`.
     pub(crate) fn merge_liveness<M: Idx>(&mut self, to: N, from: M, values: &LivenessValues<M>) {
-        if let Some(set) = values.points.row(from) {
+        if let Some(set) = values.get_intervals(from) {
             self.points.union_row(to, set);
         }
     }
@@ -416,7 +270,7 @@ impl ToElementIndex for ty::PlaceholderRegion {
 }
 
 pub(crate) fn location_set_str(
-    elements: &RegionValueElements,
+    elements: &DenseLocationMap,
     points: impl IntoIterator<Item = PointIndex>,
 ) -> String {
     region_value_str(

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

@@ -2,9 +2,9 @@ use rustc_data_structures::vec_linked_list as vll;
 use rustc_index::IndexVec;
 use rustc_middle::mir::visit::{PlaceContext, Visitor};
 use rustc_middle::mir::{Body, Local, Location};
+use rustc_mir_dataflow::points::{DenseLocationMap, PointIndex};
 
 use crate::def_use::{self, DefUse};
-use crate::region_infer::values::{PointIndex, RegionValueElements};
 
 /// A map that cross references each local with the locations where it
 /// is defined (assigned), used, or dropped. Used during liveness
@@ -60,7 +60,7 @@ impl vll::LinkElem for Appearance {
 impl LocalUseMap {
     pub(crate) fn build(
         live_locals: &[Local],
-        elements: &RegionValueElements,
+        elements: &DenseLocationMap,
         body: &Body<'_>,
     ) -> Self {
         let nones = IndexVec::from_elem(None, &body.local_decls);
@@ -103,7 +103,7 @@ impl LocalUseMap {
 
 struct LocalUseMapBuild<'me> {
     local_use_map: &'me mut LocalUseMap,
-    elements: &'me RegionValueElements,
+    elements: &'me DenseLocationMap,
 
     // Vector used in `visit_local` to signal which `Local`s do we need
     // def/use/drop information on, constructed from `live_locals` (that
@@ -144,7 +144,7 @@ impl LocalUseMapBuild<'_> {
     }
 
     fn insert(
-        elements: &RegionValueElements,
+        elements: &DenseLocationMap,
         first_appearance: &mut Option<AppearanceIndex>,
         appearances: &mut IndexVec<AppearanceIndex, Appearance>,
         location: Location,

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

@@ -4,14 +4,14 @@ use rustc_middle::mir::{Body, Local};
 use rustc_middle::ty::{RegionVid, TyCtxt};
 use rustc_mir_dataflow::impls::MaybeInitializedPlaces;
 use rustc_mir_dataflow::move_paths::MoveData;
+use rustc_mir_dataflow::points::DenseLocationMap;
 use rustc_mir_dataflow::ResultsCursor;
 use std::rc::Rc;
 
 use crate::{
     constraints::OutlivesConstraintSet,
     facts::{AllFacts, AllFactsExt},
     location::LocationTable,
-    region_infer::values::RegionValueElements,
     universal_regions::UniversalRegions,
 };
 
@@ -32,7 +32,7 @@ mod trace;
 pub(super) fn generate<'mir, 'tcx>(
     typeck: &mut TypeChecker<'_, 'tcx>,
     body: &Body<'tcx>,
-    elements: &Rc<RegionValueElements>,
+    elements: &Rc<DenseLocationMap>,
     flow_inits: &mut ResultsCursor<'mir, 'tcx, MaybeInitializedPlaces<'mir, 'tcx>>,
     move_data: &MoveData<'tcx>,
     location_table: &LocationTable,