Extend Polonius fact generation for (some) move tracking

Cargo.lock

@@ -2324,9 +2324,9 @@ checksum = "676e8eb2b1b4c9043511a9b7bea0915320d7e502b0a079fb03f9635a5252b18c"
 
 [[package]]
 name = "polonius-engine"
-version = "0.9.0"
+version = "0.10.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f6b8a5defa2aef9ba4999aaa745fbc01c622ecea35964a306adc3e44be4f3b5b"
+checksum = "50fa9dbfd0d3d60594da338cfe6f94028433eecae4b11b7e83fd99759227bbfe"
 dependencies = [
  "datafrog",
  "log",

src/librustc/Cargo.toml

@@ -21,7 +21,7 @@ scoped-tls = "1.0"
 log = { version = "0.4", features = ["release_max_level_info", "std"] }
 rustc-rayon = "0.2.0"
 rustc-rayon-core = "0.2.0"
-polonius-engine  = "0.9.0"
+polonius-engine  = "0.10.0"
 rustc_apfloat = { path = "../librustc_apfloat" }
 rustc_target = { path = "../librustc_target" }
 rustc_macros = { path = "../librustc_macros" }

src/librustc_mir/Cargo.toml

@@ -15,7 +15,7 @@ either = "1.5.0"
 dot = { path = "../libgraphviz", package = "graphviz" }
 log = "0.4"
 log_settings = "0.1.1"
-polonius-engine  = "0.9.0"
+polonius-engine  = "0.10.0"
 rustc = { path = "../librustc" }
 rustc_target = { path = "../librustc_target" }
 rustc_data_structures = { path = "../librustc_data_structures" }

src/librustc_mir/borrow_check/flows.rs

@@ -12,7 +12,7 @@ use crate::borrow_check::location::LocationIndex;
 use polonius_engine::Output;
 
 use crate::dataflow::indexes::BorrowIndex;
-use crate::dataflow::move_paths::HasMoveData;
+use crate::dataflow::move_paths::{HasMoveData, MovePathIndex};
 use crate::dataflow::Borrows;
 use crate::dataflow::EverInitializedPlaces;
 use crate::dataflow::MaybeUninitializedPlaces;
@@ -21,7 +21,7 @@ use either::Either;
 use std::fmt;
 use std::rc::Rc;
 
-crate type PoloniusOutput = Output<RegionVid, BorrowIndex, LocationIndex, Local>;
+crate type PoloniusOutput = Output<RegionVid, BorrowIndex, LocationIndex, Local, MovePathIndex>;
 
 // (forced to be `pub` due to its use as an associated type below.)
 crate struct Flows<'b, 'tcx> {

src/librustc_mir/borrow_check/nll/facts.rs

@@ -1,5 +1,5 @@
 use crate::borrow_check::location::{LocationIndex, LocationTable};
-use crate::dataflow::indexes::BorrowIndex;
+use crate::dataflow::indexes::{BorrowIndex, MovePathIndex};
 use polonius_engine::AllFacts as PoloniusAllFacts;
 use polonius_engine::Atom;
 use rustc::mir::Local;
@@ -11,7 +11,7 @@ use std::fs::{self, File};
 use std::io::Write;
 use std::path::Path;
 
-crate type AllFacts = PoloniusAllFacts<RegionVid, BorrowIndex, LocationIndex, Local>;
+crate type AllFacts = PoloniusAllFacts<RegionVid, BorrowIndex, LocationIndex, Local, MovePathIndex>;
 
 crate trait AllFactsExt {
     /// Returns `true` if there is a need to gather `AllFacts` given the
@@ -58,14 +58,17 @@ impl AllFactsExt for AllFacts {
                 cfg_edge,
                 killed,
                 outlives,
-                region_live_at,
                 invalidates,
                 var_used,
                 var_defined,
                 var_drop_used,
                 var_uses_region,
                 var_drops_region,
-                var_initialized_on_exit,
+                child,
+                path_belongs_to_var,
+                initialized_at,
+                moved_out_at,
+                path_accessed_at,
             ])
         }
         Ok(())
@@ -84,6 +87,12 @@ impl Atom for LocationIndex {
     }
 }
 
+impl Atom for MovePathIndex {
+    fn index(self) -> usize {
+        Idx::index(self)
+    }
+}
+
 struct FactWriter<'w> {
     location_table: &'w LocationTable,
     dir: &'w Path,

src/librustc_mir/borrow_check/nll/mod.rs

@@ -4,14 +4,15 @@ use crate::borrow_check::nll::facts::AllFactsExt;
 use crate::borrow_check::nll::type_check::{MirTypeckResults, MirTypeckRegionConstraints};
 use crate::borrow_check::nll::region_infer::values::RegionValueElements;
 use crate::dataflow::indexes::BorrowIndex;
-use crate::dataflow::move_paths::MoveData;
+use crate::dataflow::move_paths::{InitLocation, MoveData, MovePathIndex, InitKind};
 use crate::dataflow::FlowAtLocation;
 use crate::dataflow::MaybeInitializedPlaces;
 use crate::transform::MirSource;
 use crate::borrow_check::Upvar;
 use rustc::hir::def_id::DefId;
 use rustc::infer::InferCtxt;
-use rustc::mir::{ClosureOutlivesSubject, ClosureRegionRequirements, Local, Body, Promoted};
+use rustc::mir::{ClosureOutlivesSubject, ClosureRegionRequirements,
+                 Local, Location, Body, LocalKind, BasicBlock, Promoted};
 use rustc::ty::{self, RegionKind, RegionVid};
 use rustc_data_structures::indexed_vec::IndexVec;
 use rustc_errors::Diagnostic;
@@ -69,6 +70,85 @@ pub(in crate::borrow_check) fn replace_regions_in_mir<'cx, 'tcx>(
     universal_regions
 }
 
+
+// This function populates an AllFacts instance with base facts related to
+// MovePaths and needed for the move analysis.
+fn populate_polonius_move_facts(
+    all_facts: &mut AllFacts,
+    move_data: &MoveData<'_>,
+    location_table: &LocationTable,
+    body: &Body<'_>) {
+    all_facts
+        .path_belongs_to_var
+        .extend(
+            move_data
+                .rev_lookup
+                .iter_locals_enumerated()
+                .map(|(v, &m)| (m, v)));
+
+    for (child, move_path) in move_data.move_paths.iter_enumerated() {
+        all_facts
+            .child
+            .extend(
+                move_path
+                    .parents(&move_data.move_paths)
+                    .iter()
+                    .map(|&parent| (child, parent)));
+    }
+
+    // initialized_at
+    for init in move_data.inits.iter() {
+
+        match init.location {
+            InitLocation::Statement(location) => {
+                let block_data = &body[location.block];
+                let is_terminator = location.statement_index == block_data.statements.len();
+
+                if is_terminator && init.kind == InitKind::NonPanicPathOnly {
+                    // We are at the terminator of an init that has a panic path,
+                    // and where the init should not happen on panic
+
+                    for &successor in block_data.terminator().successors() {
+                        if body[successor].is_cleanup {
+                            continue;
+                        }
+
+                        // The initialization happened in (or rather, when arriving at)
+                        // the successors, but not in the unwind block.
+                        let first_statement = Location { block: successor, statement_index: 0};
+                        all_facts
+                            .initialized_at
+                            .push((init.path, location_table.start_index(first_statement)));
+                    }
+
+                } else {
+                    // In all other cases, the initialization just happens at the
+                    // midpoint, like any other effect.
+                    all_facts.initialized_at.push((init.path, location_table.mid_index(location)));
+                }
+            },
+            // Arguments are initialized on function entry
+            InitLocation::Argument(local) => {
+                assert!(body.local_kind(local) == LocalKind::Arg);
+                let fn_entry = Location {block: BasicBlock::from_u32(0u32), statement_index: 0 };
+                all_facts.initialized_at.push((init.path, location_table.start_index(fn_entry)));
+
+            }
+        }
+    }
+
+
+    // moved_out_at
+    // deinitialisation is assumed to always happen!
+    all_facts
+        .moved_out_at
+        .extend(
+            move_data
+                .moves
+                .iter()
+                .map(|mo| (mo.path, location_table.mid_index(mo.source))));
+}
+
 /// Computes the (non-lexical) regions from the input MIR.
 ///
 /// This may result in errors being reported.
@@ -87,7 +167,7 @@ pub(in crate::borrow_check) fn compute_regions<'cx, 'tcx>(
     errors_buffer: &mut Vec<Diagnostic>,
 ) -> (
     RegionInferenceContext<'tcx>,
-    Option<Rc<Output<RegionVid, BorrowIndex, LocationIndex, Local>>>,
+    Option<Rc<Output<RegionVid, BorrowIndex, LocationIndex, Local, MovePathIndex>>>,
     Option<ClosureRegionRequirements<'tcx>>,
 ) {
     let mut all_facts = if AllFacts::enabled(infcx.tcx) {
@@ -123,6 +203,7 @@ pub(in crate::borrow_check) fn compute_regions<'cx, 'tcx>(
         all_facts
             .universal_region
             .extend(universal_regions.universal_regions());
+        populate_polonius_move_facts(all_facts, move_data, location_table, body);
     }
 
     // Create the region inference context, taking ownership of the

src/librustc_mir/borrow_check/nll/type_check/liveness/local_use_map.rs

@@ -1,7 +1,7 @@
 use crate::borrow_check::nll::region_infer::values::{PointIndex, RegionValueElements};
 use crate::util::liveness::{categorize, DefUse};
 use rustc::mir::visit::{PlaceContext, Visitor};
-use rustc::mir::{Local, Location, Body};
+use rustc::mir::{Body, Local, Location};
 use rustc_data_structures::indexed_vec::{Idx, IndexVec};
 use rustc_data_structures::vec_linked_list as vll;
 
@@ -72,16 +72,10 @@ impl LocalUseMap {
 
         let mut locals_with_use_data: IndexVec<Local, bool> =
             IndexVec::from_elem_n(false, body.local_decls.len());
-        live_locals
-            .iter()
-            .for_each(|&local| locals_with_use_data[local] = true);
-
-        LocalUseMapBuild {
-            local_use_map: &mut local_use_map,
-            elements,
-            locals_with_use_data,
-        }
-        .visit_body(body);
+        live_locals.iter().for_each(|&local| locals_with_use_data[local] = true);
+
+        LocalUseMapBuild { local_use_map: &mut local_use_map, elements, locals_with_use_data }
+            .visit_body(body);
 
         local_use_map
     }
@@ -151,10 +145,8 @@ impl LocalUseMapBuild<'_> {
         location: Location,
     ) {
         let point_index = elements.point_from_location(location);
-        let appearance_index = appearances.push(Appearance {
-            point_index,
-            next: *first_appearance,
-        });
+        let appearance_index =
+            appearances.push(Appearance { point_index, next: *first_appearance });
         *first_appearance = Some(appearance_index);
     }
 }

src/librustc_mir/borrow_check/nll/type_check/liveness/mod.rs

@@ -58,9 +58,9 @@ pub(super) fn generate<'tcx>(
     };
 
     if !live_locals.is_empty() {
-        trace::trace(typeck, body, elements, flow_inits, move_data, live_locals, location_table);
+        trace::trace(typeck, body, elements, flow_inits, move_data, live_locals);
 
-        polonius::populate_var_liveness_facts(typeck, body, location_table);
+        polonius::populate_access_facts(typeck, body, location_table, move_data);
     }
 }
 

src/librustc_mir/borrow_check/nll/type_check/liveness/polonius.rs

@@ -1,22 +1,28 @@
 use crate::borrow_check::location::{LocationIndex, LocationTable};
+use crate::dataflow::indexes::MovePathIndex;
+use crate::dataflow::move_paths::{LookupResult, MoveData};
 use crate::util::liveness::{categorize, DefUse};
-use rustc::mir::visit::{PlaceContext, Visitor};
-use rustc::mir::{Body, Local, Location};
+use rustc::mir::visit::{MutatingUseContext, PlaceContext, Visitor};
+use rustc::mir::{Body, Local, Location, Place};
 use rustc::ty::subst::Kind;
 use rustc::ty::Ty;
 
 use super::TypeChecker;
 
 type VarPointRelations = Vec<(Local, LocationIndex)>;
+type MovePathPointRelations = Vec<(MovePathIndex, LocationIndex)>;
 
-struct LivenessPointFactsExtractor<'me> {
+struct UseFactsExtractor<'me> {
     var_defined: &'me mut VarPointRelations,
     var_used: &'me mut VarPointRelations,
     location_table: &'me LocationTable,
+    var_drop_used: &'me mut VarPointRelations,
+    move_data: &'me MoveData<'me>,
+    path_accessed_at: &'me mut MovePathPointRelations,
 }
 
 // A Visitor to walk through the MIR and extract point-wise facts
-impl LivenessPointFactsExtractor<'_> {
+impl UseFactsExtractor<'_> {
     fn location_to_index(&self, location: Location) -> LocationIndex {
         self.location_table.mid_index(location)
     }
@@ -30,15 +36,50 @@ impl LivenessPointFactsExtractor<'_> {
         debug!("LivenessFactsExtractor::insert_use()");
         self.var_used.push((local, self.location_to_index(location)));
     }
+
+    fn insert_drop_use(&mut self, local: Local, location: Location) {
+        debug!("LivenessFactsExtractor::insert_drop_use()");
+        self.var_drop_used.push((local, self.location_to_index(location)));
+    }
+
+    fn insert_path_access(&mut self, path: MovePathIndex, location: Location) {
+        debug!("LivenessFactsExtractor::insert_path_access({:?}, {:?})", path, location);
+        self.path_accessed_at.push((path, self.location_to_index(location)));
+    }
+
+    fn place_to_mpi(&self, place: &Place<'_>) -> Option<MovePathIndex> {
+        match self.move_data.rev_lookup.find(place.as_ref()) {
+            LookupResult::Exact(mpi) => Some(mpi),
+            LookupResult::Parent(mmpi) => mmpi,
+        }
+    }
 }
 
-impl Visitor<'tcx> for LivenessPointFactsExtractor<'_> {
+impl Visitor<'tcx> for UseFactsExtractor<'_> {
     fn visit_local(&mut self, &local: &Local, context: PlaceContext, location: Location) {
         match categorize(context) {
             Some(DefUse::Def) => self.insert_def(local, location),
             Some(DefUse::Use) => self.insert_use(local, location),
+            Some(DefUse::Drop) => self.insert_drop_use(local, location),
+            _ => (),
+        }
+    }
+
+    fn visit_place(&mut self, place: &Place<'tcx>, context: PlaceContext, location: Location) {
+        self.super_place(place, context, location);
+        match context {
+            PlaceContext::NonMutatingUse(_) => {
+                if let Some(mpi) = self.place_to_mpi(place) {
+                    self.insert_path_access(mpi, location);
+                }
+            }
+
+            PlaceContext::MutatingUse(MutatingUseContext::Borrow) => {
+                if let Some(mpi) = self.place_to_mpi(place) {
+                    self.insert_path_access(mpi, location);
+                }
+            }
             _ => (),
-            // NOTE: Drop handling is now done in trace()
         }
     }
 }
@@ -54,23 +95,27 @@ fn add_var_uses_regions(typeck: &mut TypeChecker<'_, 'tcx>, local: Local, ty: Ty
     });
 }
 
-pub(super) fn populate_var_liveness_facts(
+pub(super) fn populate_access_facts(
     typeck: &mut TypeChecker<'_, 'tcx>,
-    mir: &Body<'tcx>,
+    body: &Body<'tcx>,
     location_table: &LocationTable,
+    move_data: &MoveData<'_>,
 ) {
     debug!("populate_var_liveness_facts()");
 
     if let Some(facts) = typeck.borrowck_context.all_facts.as_mut() {
-        LivenessPointFactsExtractor {
+        UseFactsExtractor {
             var_defined: &mut facts.var_defined,
             var_used: &mut facts.var_used,
+            var_drop_used: &mut facts.var_drop_used,
+            path_accessed_at: &mut facts.path_accessed_at,
             location_table,
+            move_data,
         }
-        .visit_body(mir);
+        .visit_body(body);
     }
 
-    for (local, local_decl) in mir.local_decls.iter_enumerated() {
+    for (local, local_decl) in body.local_decls.iter_enumerated() {
         add_var_uses_regions(typeck, local, local_decl.ty);
     }
 }