clean up emit_access_facts

- remove dependency on `TypeChecker`
- move to legacy fact generation module

Author: lqd

compiler/rustc_borrowck/src/polonius/legacy/accesses.rs

@@ -0,0 +1,106 @@
+use rustc_middle::mir::visit::{MutatingUseContext, PlaceContext, Visitor};
+use rustc_middle::mir::{Body, Local, Location, Place};
+use rustc_middle::ty::TyCtxt;
+use rustc_mir_dataflow::move_paths::{LookupResult, MoveData, MovePathIndex};
+use tracing::debug;
+
+use crate::def_use::{self, DefUse};
+use crate::facts::AllFacts;
+use crate::location::{LocationIndex, LocationTable};
+use crate::universal_regions::UniversalRegions;
+
+type VarPointRelation = Vec<(Local, LocationIndex)>;
+type PathPointRelation = Vec<(MovePathIndex, LocationIndex)>;
+
+/// Emit polonius facts for variable defs, uses, drops, and path accesses.
+pub(crate) fn emit_access_facts<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    body: &Body<'tcx>,
+    move_data: &MoveData<'tcx>,
+    universal_regions: &UniversalRegions<'tcx>,
+    location_table: &LocationTable,
+    all_facts: &mut Option<AllFacts>,
+) {
+    if let Some(facts) = all_facts.as_mut() {
+        debug!("emit_access_facts()");
+
+        let _prof_timer = tcx.prof.generic_activity("polonius_fact_generation");
+        let mut extractor = AccessFactsExtractor {
+            var_defined_at: &mut facts.var_defined_at,
+            var_used_at: &mut facts.var_used_at,
+            var_dropped_at: &mut facts.var_dropped_at,
+            path_accessed_at_base: &mut facts.path_accessed_at_base,
+            location_table,
+            move_data,
+        };
+        extractor.visit_body(body);
+
+        for (local, local_decl) in body.local_decls.iter_enumerated() {
+            debug!(
+                "add use_of_var_derefs_origin facts - local={:?}, type={:?}",
+                local, local_decl.ty
+            );
+            tcx.for_each_free_region(&local_decl.ty, |region| {
+                let region_vid = universal_regions.to_region_vid(region);
+                facts.use_of_var_derefs_origin.push((local, region_vid.into()));
+            });
+        }
+    }
+}
+
+/// MIR visitor extracting point-wise facts about accesses.
+struct AccessFactsExtractor<'a, 'tcx> {
+    var_defined_at: &'a mut VarPointRelation,
+    var_used_at: &'a mut VarPointRelation,
+    location_table: &'a LocationTable,
+    var_dropped_at: &'a mut VarPointRelation,
+    move_data: &'a MoveData<'tcx>,
+    path_accessed_at_base: &'a mut PathPointRelation,
+}
+
+impl<'tcx> AccessFactsExtractor<'_, 'tcx> {
+    fn location_to_index(&self, location: Location) -> LocationIndex {
+        self.location_table.mid_index(location)
+    }
+}
+
+impl<'a, 'tcx> Visitor<'tcx> for AccessFactsExtractor<'a, 'tcx> {
+    fn visit_local(&mut self, local: Local, context: PlaceContext, location: Location) {
+        match def_use::categorize(context) {
+            Some(DefUse::Def) => {
+                debug!("AccessFactsExtractor - emit def");
+                self.var_defined_at.push((local, self.location_to_index(location)));
+            }
+            Some(DefUse::Use) => {
+                debug!("AccessFactsExtractor - emit use");
+                self.var_used_at.push((local, self.location_to_index(location)));
+            }
+            Some(DefUse::Drop) => {
+                debug!("AccessFactsExtractor - emit drop");
+                self.var_dropped_at.push((local, self.location_to_index(location)));
+            }
+            _ => (),
+        }
+    }
+
+    fn visit_place(&mut self, place: &Place<'tcx>, context: PlaceContext, location: Location) {
+        self.super_place(place, context, location);
+
+        match context {
+            PlaceContext::NonMutatingUse(_)
+            | PlaceContext::MutatingUse(MutatingUseContext::Borrow) => {
+                let path = match self.move_data.rev_lookup.find(place.as_ref()) {
+                    LookupResult::Exact(path) | LookupResult::Parent(Some(path)) => path,
+                    _ => {
+                        // There's no path access to emit.
+                        return;
+                    }
+                };
+                debug!("AccessFactsExtractor - emit path access ({path:?}, {location:?})");
+                self.path_accessed_at_base.push((path, self.location_to_index(location)));
+            }
+
+            _ => {}
+        }
+    }
+}

compiler/rustc_borrowck/src/polonius/legacy/mod.rs

@@ -13,9 +13,12 @@ use crate::facts::{AllFacts, PoloniusRegionVid};
 use crate::location::LocationTable;
 use crate::type_check::free_region_relations::UniversalRegionRelations;
 
+mod accesses;
 mod loan_invalidations;
 mod loan_kills;
 
+pub(crate) use accesses::emit_access_facts;
+
 /// When requested, emit most of the facts needed by polonius:
 /// - moves and assignments
 /// - universal regions and their relations

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

@@ -45,7 +45,14 @@ pub(super) fn generate<'a, 'tcx>(
     let (relevant_live_locals, boring_locals) =
         compute_relevant_live_locals(typeck.tcx(), &free_regions, body);
 
-    polonius::emit_access_facts(typeck, body, move_data);
+    crate::polonius::legacy::emit_access_facts(
+        typeck.tcx(),
+        body,
+        move_data,
+        typeck.universal_regions,
+        typeck.location_table,
+        typeck.all_facts,
+    );
 
     trace::trace(
         typeck,

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

@@ -1,54 +1,11 @@
-use rustc_middle::mir::visit::{MutatingUseContext, PlaceContext, Visitor};
-use rustc_middle::mir::{Body, Local, Location, Place};
+use rustc_middle::mir::Local;
 use rustc_middle::ty::GenericArg;
-use rustc_mir_dataflow::move_paths::{LookupResult, MoveData, MovePathIndex};
 use tracing::debug;
 
-use super::TypeChecker;
-use crate::def_use::{self, DefUse};
-use crate::location::{LocationIndex, LocationTable};
-
-type VarPointRelation = Vec<(Local, LocationIndex)>;
-type PathPointRelation = Vec<(MovePathIndex, LocationIndex)>;
-
-/// Emit polonius facts for variable defs, uses, drops, and path accesses.
-pub(super) fn emit_access_facts<'a, 'tcx>(
-    typeck: &mut TypeChecker<'a, 'tcx>,
-    body: &Body<'tcx>,
-    move_data: &MoveData<'tcx>,
-) {
-    if let Some(facts) = typeck.all_facts.as_mut() {
-        debug!("emit_access_facts()");
-
-        let _prof_timer = typeck.infcx.tcx.prof.generic_activity("polonius_fact_generation");
-        let location_table = typeck.location_table;
-
-        let mut extractor = AccessFactsExtractor {
-            var_defined_at: &mut facts.var_defined_at,
-            var_used_at: &mut facts.var_used_at,
-            var_dropped_at: &mut facts.var_dropped_at,
-            path_accessed_at_base: &mut facts.path_accessed_at_base,
-            location_table,
-            move_data,
-        };
-        extractor.visit_body(body);
-
-        for (local, local_decl) in body.local_decls.iter_enumerated() {
-            debug!(
-                "add use_of_var_derefs_origin facts - local={:?}, type={:?}",
-                local, local_decl.ty
-            );
-            let universal_regions = &typeck.universal_regions;
-            typeck.infcx.tcx.for_each_free_region(&local_decl.ty, |region| {
-                let region_vid = universal_regions.to_region_vid(region);
-                facts.use_of_var_derefs_origin.push((local, region_vid.into()));
-            });
-        }
-    }
-}
+use crate::type_check::TypeChecker;
 
 /// For every potentially drop()-touched region `region` in `local`'s type
-/// (`kind`), emit a Polonius `use_of_var_derefs_origin(local, origin)` fact.
+/// (`kind`), emit a Polonius `drop_of_var_derefs_origin(local, origin)` fact.
 pub(super) fn emit_drop_facts<'tcx>(
     typeck: &mut TypeChecker<'_, 'tcx>,
     local: Local,
@@ -64,60 +21,3 @@ pub(super) fn emit_drop_facts<'tcx>(
         });
     }
 }
-
-/// MIR visitor extracting point-wise facts about accesses.
-struct AccessFactsExtractor<'a, 'tcx> {
-    var_defined_at: &'a mut VarPointRelation,
-    var_used_at: &'a mut VarPointRelation,
-    location_table: &'a LocationTable,
-    var_dropped_at: &'a mut VarPointRelation,
-    move_data: &'a MoveData<'tcx>,
-    path_accessed_at_base: &'a mut PathPointRelation,
-}
-
-impl<'tcx> AccessFactsExtractor<'_, 'tcx> {
-    fn location_to_index(&self, location: Location) -> LocationIndex {
-        self.location_table.mid_index(location)
-    }
-}
-
-impl<'a, 'tcx> Visitor<'tcx> for AccessFactsExtractor<'a, 'tcx> {
-    fn visit_local(&mut self, local: Local, context: PlaceContext, location: Location) {
-        match def_use::categorize(context) {
-            Some(DefUse::Def) => {
-                debug!("AccessFactsExtractor - emit def");
-                self.var_defined_at.push((local, self.location_to_index(location)));
-            }
-            Some(DefUse::Use) => {
-                debug!("AccessFactsExtractor - emit use");
-                self.var_used_at.push((local, self.location_to_index(location)));
-            }
-            Some(DefUse::Drop) => {
-                debug!("AccessFactsExtractor - emit drop");
-                self.var_dropped_at.push((local, self.location_to_index(location)));
-            }
-            _ => (),
-        }
-    }
-
-    fn visit_place(&mut self, place: &Place<'tcx>, context: PlaceContext, location: Location) {
-        self.super_place(place, context, location);
-
-        match context {
-            PlaceContext::NonMutatingUse(_)
-            | PlaceContext::MutatingUse(MutatingUseContext::Borrow) => {
-                let path = match self.move_data.rev_lookup.find(place.as_ref()) {
-                    LookupResult::Exact(path) | LookupResult::Parent(Some(path)) => path,
-                    _ => {
-                        // There's no path access to emit.
-                        return;
-                    }
-                };
-                debug!("AccessFactsExtractor - emit path access ({path:?}, {location:?})");
-                self.path_accessed_at_base.push((path, self.location_to_index(location)));
-            }
-
-            _ => {}
-        }
-    }
-}