1 use crate::borrow_check::location::{LocationIndex, LocationTable};
2 use crate::dataflow::indexes::MovePathIndex;
3 use crate::dataflow::move_paths::{LookupResult, MoveData};
4 use crate::util::liveness::{categorize, DefUse};
5 use rustc::mir::visit::{MutatingUseContext, PlaceContext, Visitor};
6 use rustc::mir::{Local, Location, Place, ReadOnlyBodyAndCache};
7 use rustc::ty::subst::GenericArg;
9 use super::TypeChecker;
11 type VarPointRelation = Vec<(Local, LocationIndex)>;
12 type PathPointRelation = Vec<(MovePathIndex, LocationIndex)>;
14 struct UseFactsExtractor<'me> {
15 var_defined_at: &'me mut VarPointRelation,
16 var_used_at: &'me mut VarPointRelation,
17 location_table: &'me LocationTable,
18 var_dropped_at: &'me mut VarPointRelation,
19 move_data: &'me MoveData<'me>,
20 path_accessed_at_base: &'me mut PathPointRelation,
23 // A Visitor to walk through the MIR and extract point-wise facts
24 impl UseFactsExtractor<'_> {
25 fn location_to_index(&self, location: Location) -> LocationIndex {
26 self.location_table.mid_index(location)
29 fn insert_def(&mut self, local: Local, location: Location) {
30 debug!("UseFactsExtractor::insert_def()");
31 self.var_defined_at.push((local, self.location_to_index(location)));
34 fn insert_use(&mut self, local: Local, location: Location) {
35 debug!("UseFactsExtractor::insert_use()");
36 self.var_used_at.push((local, self.location_to_index(location)));
39 fn insert_drop_use(&mut self, local: Local, location: Location) {
40 debug!("UseFactsExtractor::insert_drop_use()");
41 self.var_dropped_at.push((local, self.location_to_index(location)));
44 fn insert_path_access(&mut self, path: MovePathIndex, location: Location) {
45 debug!("UseFactsExtractor::insert_path_access({:?}, {:?})", path, location);
46 self.path_accessed_at_base.push((path, self.location_table.start_index(location)));
49 fn place_to_mpi(&self, place: &Place<'_>) -> Option<MovePathIndex> {
50 match self.move_data.rev_lookup.find(place.as_ref()) {
51 LookupResult::Exact(mpi) => Some(mpi),
52 LookupResult::Parent(mmpi) => mmpi,
57 impl Visitor<'tcx> for UseFactsExtractor<'_> {
58 fn visit_local(&mut self, &local: &Local, context: PlaceContext, location: Location) {
59 match categorize(context) {
60 Some(DefUse::Def) => self.insert_def(local, location),
61 Some(DefUse::Use) => self.insert_use(local, location),
62 Some(DefUse::Drop) => self.insert_drop_use(local, location),
67 fn visit_place(&mut self, place: &Place<'tcx>, context: PlaceContext, location: Location) {
68 self.super_place(place, context, location);
70 PlaceContext::NonMutatingUse(_) => {
71 if let Some(mpi) = self.place_to_mpi(place) {
72 self.insert_path_access(mpi, location);
76 PlaceContext::MutatingUse(MutatingUseContext::Borrow) => {
77 if let Some(mpi) = self.place_to_mpi(place) {
78 self.insert_path_access(mpi, location);
86 pub(super) fn populate_access_facts(
87 typeck: &mut TypeChecker<'_, 'tcx>,
88 body: ReadOnlyBodyAndCache<'_, 'tcx>,
89 location_table: &LocationTable,
90 move_data: &MoveData<'_>,
91 dropped_at: &mut Vec<(Local, Location)>,
93 debug!("populate_access_facts()");
95 if let Some(facts) = typeck.borrowck_context.all_facts.as_mut() {
96 let mut extractor = UseFactsExtractor {
97 var_defined_at: &mut facts.var_defined_at,
98 var_used_at: &mut facts.var_used_at,
99 var_dropped_at: &mut facts.var_dropped_at,
100 path_accessed_at_base: &mut facts.path_accessed_at_base,
104 extractor.visit_body(body);
106 facts.var_dropped_at.extend(
107 dropped_at.iter().map(|&(local, location)| (local, location_table.mid_index(location))),
110 for (local, local_decl) in body.local_decls.iter_enumerated() {
112 "add use_of_var_derefs_origin facts - local={:?}, type={:?}",
115 let _prof_timer = typeck.infcx.tcx.prof.generic_activity("polonius_fact_generation");
116 let universal_regions = &typeck.borrowck_context.universal_regions;
117 typeck.infcx.tcx.for_each_free_region(&local_decl.ty, |region| {
118 let region_vid = universal_regions.to_region_vid(region);
119 facts.use_of_var_derefs_origin.push((local, region_vid));
125 // For every potentially drop()-touched region `region` in `local`'s type
126 // (`kind`), emit a Polonius `use_of_var_derefs_origin(local, origin)` fact.
127 pub(super) fn add_drop_of_var_derefs_origin(
128 typeck: &mut TypeChecker<'_, 'tcx>,
130 kind: &GenericArg<'tcx>,
132 debug!("add_drop_of_var_derefs_origin(local={:?}, kind={:?}", local, kind);
133 if let Some(facts) = typeck.borrowck_context.all_facts.as_mut() {
134 let _prof_timer = typeck.infcx.tcx.prof.generic_activity("polonius_fact_generation");
135 let universal_regions = &typeck.borrowck_context.universal_regions;
136 typeck.infcx.tcx.for_each_free_region(kind, |drop_live_region| {
137 let region_vid = universal_regions.to_region_vid(drop_live_region);
138 facts.drop_of_var_derefs_origin.push((local, region_vid));