Add read_only fn to BodyCache<&mut...> impl, fix more Body -> (ReadOnly)BodyCache type errors

6 files changed, 48 insertions, 40 deletions

diff --git a/src/librustc/mir/cache.rs b/src/librustc/mir/cache.rs
index c0c5f77fe6e..24d1f9e373b 100644
--- a/src/librustc/mir/cache.rs
+++ b/src/librustc/mir/cache.rs
@@ -206,6 +206,15 @@ impl<'a, 'tcx> BodyCache<&'a mut Body<'tcx>> {
     }
 
     #[inline]
+    pub fn read_only(mut self) -> ReadOnlyBodyCache<'a, 'tcx> {
+        self.cache.ensure_predecessors(self.body);
+        ReadOnlyBodyCache {
+            cache: self.cache,
+            body: self.body,
+        }
+    }
+
+    #[inline]
     pub fn basic_blocks(&self) -> &IndexVec<BasicBlock, BasicBlockData<'tcx>> {
         &self.body.basic_blocks
     }
diff --git a/src/librustc_mir/borrow_check/mod.rs b/src/librustc_mir/borrow_check/mod.rs
index 0c1b0c4e14e..f8ae07aa394 100644
--- a/src/librustc_mir/borrow_check/mod.rs
+++ b/src/librustc_mir/borrow_check/mod.rs
@@ -163,13 +163,13 @@ fn do_mir_borrowck<'a, 'tcx>(
     // be modified (in place) to contain non-lexical lifetimes. It
     // will have a lifetime tied to the inference context.
     let mut body: Body<'tcx> = input_body.clone();
-    // TODO(pfaria) this very likely won't work because
-    let promoted: IndexVec<Promoted, Body<'tcx>> = input_promoted.clone();
-    let mut promoted_cache: IndexVec<Promoted, BodyCache<&mut Body<'tcx>>> = promoted.iter_mut().map(|body| BodyCache::new(body)).collect();
+    let mut promoted = input_promoted.clone();
+    let mut promoted_cache: IndexVec<Promoted, BodyCache<&mut Body<'tcx>>> = input_promoted.clone().iter_mut().map(|body| BodyCache::new(body)).collect();
     let mut body_cache = BodyCache::new(&mut body);
     let free_regions =
         nll::replace_regions_in_mir(infcx, def_id, param_env, &mut body_cache, &mut promoted_cache);
     let body_cache = BodyCache::new(&body).read_only(); // no further changes
+    let promoted: IndexVec<Promoted, ReadOnlyBodyCache<'_, 'tcx>> = promoted_cache.into_iter().map(|body_cache| body_cache.read_only()).collect();
 
     let location_table = &LocationTable::new(&body_cache);
 
diff --git a/src/librustc_mir/borrow_check/nll/mod.rs b/src/librustc_mir/borrow_check/nll/mod.rs
index dac5815fada..5fa2c6605f6 100644
--- a/src/librustc_mir/borrow_check/nll/mod.rs
+++ b/src/librustc_mir/borrow_check/nll/mod.rs
@@ -159,7 +159,7 @@ pub(in crate::borrow_check) fn compute_regions<'cx, 'tcx>(
     def_id: DefId,
     universal_regions: UniversalRegions<'tcx>,
     body_cache: &ReadOnlyBodyCache<'_, 'tcx>,
-    promoted: &IndexVec<Promoted, Body<'tcx>>,
+    promoted_cache: &IndexVec<Promoted, ReadOnlyBodyCache<'_, 'tcx>>,
     local_names: &IndexVec<Local, Option<Symbol>>,
     upvars: &[Upvar],
     location_table: &LocationTable,
@@ -191,7 +191,7 @@ pub(in crate::borrow_check) fn compute_regions<'cx, 'tcx>(
         infcx,
         param_env,
         body_cache,
-        promoted,
+        promoted_cache,
         def_id,
         &universal_regions,
         location_table,
diff --git a/src/librustc_mir/borrow_check/nll/type_check/liveness/mod.rs b/src/librustc_mir/borrow_check/nll/type_check/liveness/mod.rs
index a01b528833b..833958814af 100644
--- a/src/librustc_mir/borrow_check/nll/type_check/liveness/mod.rs
+++ b/src/librustc_mir/borrow_check/nll/type_check/liveness/mod.rs
@@ -7,7 +7,7 @@ use crate::borrow_check::nll::ToRegionVid;
 use crate::dataflow::move_paths::MoveData;
 use crate::dataflow::FlowAtLocation;
 use crate::dataflow::MaybeInitializedPlaces;
-use rustc::mir::{Body, Local};
+use rustc::mir::{Body, Local, ReadOnlyBodyCache};
 use rustc::ty::{RegionVid, TyCtxt};
 use rustc_data_structures::fx::FxHashSet;
 use std::rc::Rc;
@@ -28,7 +28,7 @@ mod trace;
 /// performed before
 pub(super) fn generate<'tcx>(
     typeck: &mut TypeChecker<'_, 'tcx>,
-    body: &Body<'tcx>,
+    body_cache: &ReadOnlyBodyCache<'_, 'tcx>,
     elements: &Rc<RegionValueElements>,
     flow_inits: &mut FlowAtLocation<'tcx, MaybeInitializedPlaces<'_, 'tcx>>,
     move_data: &MoveData<'tcx>,
@@ -41,15 +41,14 @@ pub(super) fn generate<'tcx>(
         &typeck.borrowck_context.universal_regions,
         &typeck.borrowck_context.constraints.outlives_constraints,
     );
-    let live_locals = compute_live_locals(typeck.tcx(), &free_regions, body);
+    let live_locals = compute_live_locals(typeck.tcx(), &free_regions, &body_cache);
     let facts_enabled = AllFacts::enabled(typeck.tcx());
 
-
     let polonius_drop_used = if facts_enabled {
         let mut drop_used = Vec::new();
         polonius::populate_access_facts(
             typeck,
-            body,
+            &body_cache,
             location_table,
             move_data,
             &mut drop_used,
@@ -62,7 +61,7 @@ pub(super) fn generate<'tcx>(
     if !live_locals.is_empty() || facts_enabled {
         trace::trace(
             typeck,
-            body,
+            body_cache,
             elements,
             flow_inits,
             move_data,
diff --git a/src/librustc_mir/borrow_check/nll/type_check/liveness/trace.rs b/src/librustc_mir/borrow_check/nll/type_check/liveness/trace.rs
index eacc4d084db..5929516ec4e 100644
--- a/src/librustc_mir/borrow_check/nll/type_check/liveness/trace.rs
+++ b/src/librustc_mir/borrow_check/nll/type_check/liveness/trace.rs
@@ -7,7 +7,7 @@ use crate::dataflow::indexes::MovePathIndex;
 use crate::dataflow::move_paths::MoveData;
 use crate::dataflow::{FlowAtLocation, FlowsAtLocation, MaybeInitializedPlaces};
 use rustc::infer::canonical::QueryRegionConstraints;
-use rustc::mir::{BasicBlock, Body, ConstraintCategory, Local, Location};
+use rustc::mir::{BasicBlock, ConstraintCategory, Local, Location, ReadOnlyBodyCache};
 use rustc::traits::query::dropck_outlives::DropckOutlivesResult;
 use rustc::traits::query::type_op::outlives::DropckOutlives;
 use rustc::traits::query::type_op::TypeOp;
@@ -32,7 +32,7 @@ use std::rc::Rc;
 /// this respects `#[may_dangle]` annotations).
 pub(super) fn trace(
     typeck: &mut TypeChecker<'_, 'tcx>,
-    body: &Body<'tcx>,
+    body_cache: &ReadOnlyBodyCache<'_, 'tcx>,
     elements: &Rc<RegionValueElements>,
     flow_inits: &mut FlowAtLocation<'tcx, MaybeInitializedPlaces<'_, 'tcx>>,
     move_data: &MoveData<'tcx>,
@@ -41,11 +41,11 @@ pub(super) fn trace(
 ) {
     debug!("trace()");
 
-    let local_use_map = &LocalUseMap::build(&live_locals, elements, body);
+    let local_use_map = &LocalUseMap::build(&live_locals, elements, &body_cache);
 
     let cx = LivenessContext {
         typeck,
-        body,
+        body_cache,
         flow_inits,
         elements,
         local_use_map,
@@ -71,7 +71,7 @@ struct LivenessContext<'me, 'typeck, 'flow, 'tcx> {
     elements: &'me RegionValueElements,
 
     /// MIR we are analyzing.
-    body: &'me Body<'tcx>,
+    body_cache: &'me ReadOnlyBodyCache<'me, 'tcx>,
 
     /// Mapping to/from the various indices used for initialization tracking.
     move_data: &'me MoveData<'tcx>,
@@ -135,7 +135,7 @@ impl LivenessResults<'me, 'typeck, 'flow, 'tcx> {
             self.compute_use_live_points_for(local);
             self.compute_drop_live_points_for(local);
 
-            let local_ty = self.cx.body.local_decls[local].ty;
+            let local_ty = self.cx.body_cache.local_decls[local].ty;
 
             if !self.use_live_at.is_empty() {
                 self.cx.add_use_live_facts_for(local_ty, &self.use_live_at);
@@ -165,7 +165,7 @@ impl LivenessResults<'me, 'typeck, 'flow, 'tcx> {
 
         for (local, location) in drop_used {
             if !live_locals.contains(&local) {
-                let local_ty = self.cx.body.local_decls[local].ty;
+                let local_ty = self.cx.body_cache.local_decls[local].ty;
                 if local_ty.has_free_regions() {
                     self.cx.add_drop_live_facts_for(
                         local,
@@ -211,7 +211,7 @@ impl LivenessResults<'me, 'typeck, 'flow, 'tcx> {
             }
 
             if self.use_live_at.insert(p) {
-                self.cx.elements.push_predecessors(self.cx.body, p, &mut self.stack)
+                self.cx.elements.push_predecessors(&self.cx.body_cache, p, &mut self.stack)
             }
         }
     }
@@ -234,7 +234,7 @@ impl LivenessResults<'me, 'typeck, 'flow, 'tcx> {
         // Find the drops where `local` is initialized.
         for drop_point in self.cx.local_use_map.drops(local) {
             let location = self.cx.elements.to_location(drop_point);
-            debug_assert_eq!(self.cx.body.terminator_loc(location.block), location,);
+            debug_assert_eq!(self.cx.body_cache.terminator_loc(location.block), location,);
 
             if self.cx.initialized_at_terminator(location.block, mpi) {
                 if self.drop_live_at.insert(drop_point) {
@@ -280,7 +280,7 @@ impl LivenessResults<'me, 'typeck, 'flow, 'tcx> {
         // block.  One of them may be either a definition or use
         // live point.
         let term_location = self.cx.elements.to_location(term_point);
-        debug_assert_eq!(self.cx.body.terminator_loc(term_location.block), term_location,);
+        debug_assert_eq!(self.cx.body_cache.terminator_loc(term_location.block), term_location,);
         let block = term_location.block;
         let entry_point = self.cx.elements.entry_point(term_location.block);
         for p in (entry_point..term_point).rev() {
@@ -302,7 +302,7 @@ impl LivenessResults<'me, 'typeck, 'flow, 'tcx> {
             }
         }
 
-        for &pred_block in self.cx.body.predecessors_for(block).iter() {
+        for &pred_block in self.cx.body_cache.predecessors_for(block).iter() {
             debug!("compute_drop_live_points_for_block: pred_block = {:?}", pred_block,);
 
             // Check whether the variable is (at least partially)
@@ -328,7 +328,7 @@ impl LivenessResults<'me, 'typeck, 'flow, 'tcx> {
                 continue;
             }
 
-            let pred_term_loc = self.cx.body.terminator_loc(pred_block);
+            let pred_term_loc = self.cx.body_cache.terminator_loc(pred_block);
             let pred_term_point = self.cx.elements.point_from_location(pred_term_loc);
 
             // If the terminator of this predecessor either *assigns*
@@ -399,7 +399,7 @@ impl LivenessContext<'_, '_, '_, 'tcx> {
         // the effects of all statements. This is the only way to get
         // "just ahead" of a terminator.
         self.flow_inits.reset_to_entry_of(block);
-        for statement_index in 0..self.body[block].statements.len() {
+        for statement_index in 0..self.body_cache[block].statements.len() {
             let location = Location { block, statement_index };
             self.flow_inits.reconstruct_statement_effect(location);
             self.flow_inits.apply_local_effect(location);
@@ -471,7 +471,7 @@ impl LivenessContext<'_, '_, '_, 'tcx> {
 
         drop_data.dropck_result.report_overflows(
             self.typeck.infcx.tcx,
-            self.body.source_info(*drop_locations.first().unwrap()).span,
+            self.body_cache.source_info(*drop_locations.first().unwrap()).span,
             dropped_ty,
         );
 
diff --git a/src/librustc_mir/borrow_check/nll/type_check/mod.rs b/src/librustc_mir/borrow_check/nll/type_check/mod.rs
index 2de9f0e1282..8e966033bb8 100644
--- a/src/librustc_mir/borrow_check/nll/type_check/mod.rs
+++ b/src/librustc_mir/borrow_check/nll/type_check/mod.rs
@@ -116,7 +116,7 @@ pub(crate) fn type_check<'tcx>(
     infcx: &InferCtxt<'_, 'tcx>,
     param_env: ty::ParamEnv<'tcx>,
     body_cache: &ReadOnlyBodyCache<'_, 'tcx>,
-    promoted: &IndexVec<Promoted, Body<'tcx>>,
+    promoted_cache: &IndexVec<Promoted, ReadOnlyBodyCache<'_, 'tcx>>,
     mir_def_id: DefId,
     universal_regions: &Rc<UniversalRegions<'tcx>>,
     location_table: &LocationTable,
@@ -162,7 +162,7 @@ pub(crate) fn type_check<'tcx>(
         mir_def_id,
         param_env,
         body_cache,
-        promoted,
+        promoted_cache,
         &region_bound_pairs,
         implicit_region_bound,
         &mut borrowck_context,
@@ -186,7 +186,7 @@ fn type_check_internal<'a, 'tcx, R>(
     mir_def_id: DefId,
     param_env: ty::ParamEnv<'tcx>,
     body_cache: &ReadOnlyBodyCache<'a, 'tcx>,
-    promoted: &'a IndexVec<Promoted, Body<'tcx>>,
+    promoted_cache: &'a IndexVec<Promoted, ReadOnlyBodyCache<'_, 'tcx>>,
     region_bound_pairs: &'a RegionBoundPairs<'tcx>,
     implicit_region_bound: ty::Region<'tcx>,
     borrowck_context: &'a mut BorrowCheckContext<'a, 'tcx>,
@@ -204,7 +204,7 @@ fn type_check_internal<'a, 'tcx, R>(
         universal_region_relations,
     );
     let errors_reported = {
-        let mut verifier = TypeVerifier::new(&mut checker, body_cache, promoted);
+        let mut verifier = TypeVerifier::new(&mut checker, body_cache, promoted_cache);
         verifier.visit_body(body_cache);
         verifier.errors_reported
     };
@@ -261,7 +261,7 @@ enum FieldAccessError {
 struct TypeVerifier<'a, 'b, 'tcx> {
     cx: &'a mut TypeChecker<'b, 'tcx>,
     body: &'b Body<'tcx>,
-    promoted: &'b IndexVec<Promoted, Body<'tcx>>,
+    promoted_cache: &'b IndexVec<Promoted, ReadOnlyBodyCache<'b, 'tcx>>,
     last_span: Span,
     mir_def_id: DefId,
     errors_reported: bool,
@@ -401,11 +401,11 @@ impl<'a, 'b, 'tcx> TypeVerifier<'a, 'b, 'tcx> {
     fn new(
         cx: &'a mut TypeChecker<'b, 'tcx>,
         body: &'b Body<'tcx>,
-        promoted: &'b IndexVec<Promoted, Body<'tcx>>,
+        promoted_cache: &'b IndexVec<Promoted, ReadOnlyBodyCache<'b, 'tcx>>,
     ) -> Self {
         TypeVerifier {
             body,
-            promoted,
+            promoted_cache,
             mir_def_id: cx.mir_def_id,
             cx,
             last_span: body.span,
@@ -464,10 +464,10 @@ impl<'a, 'b, 'tcx> TypeVerifier<'a, 'b, 'tcx> {
                 match kind {
                     StaticKind::Promoted(promoted, _) => {
                         if !self.errors_reported {
-                            let promoted_body = &self.promoted[*promoted];
-                            self.sanitize_promoted(promoted_body, location);
+                            let promoted_body_cache = &self.promoted_cache[*promoted];
+                            self.sanitize_promoted(promoted_body_cache, location);
 
-                            let promoted_ty = promoted_body.return_ty();
+                            let promoted_ty = promoted_body_cache.return_ty();
                             check_err(self, place, promoted_ty, san_ty);
                         }
                     }
@@ -535,12 +535,12 @@ impl<'a, 'b, 'tcx> TypeVerifier<'a, 'b, 'tcx> {
         place_ty
     }
 
-    fn sanitize_promoted(&mut self, promoted_body: &'b Body<'tcx>, location: Location) {
+    fn sanitize_promoted(&mut self, promoted_body_cache: &ReadOnlyBodyCache<'b, 'tcx>, location: Location) {
         // Determine the constraints from the promoted MIR by running the type
         // checker on the promoted MIR, then transfer the constraints back to
         // the main MIR, changing the locations to the provided location.
 
-        let parent_body = mem::replace(&mut self.body, promoted_body);
+        let parent_body = mem::replace(&mut self.body, &promoted_body_cache);
 
         // Use new sets of constraints and closure bounds so that we can
         // modify their locations.
@@ -548,7 +548,7 @@ impl<'a, 'b, 'tcx> TypeVerifier<'a, 'b, 'tcx> {
         let mut constraints = Default::default();
         let mut closure_bounds = Default::default();
         let mut liveness_constraints = LivenessValues::new(
-            Rc::new(RegionValueElements::new(promoted_body)),
+            Rc::new(RegionValueElements::new(&promoted_body_cache)),
         );
         // Don't try to add borrow_region facts for the promoted MIR
 
@@ -570,12 +570,12 @@ impl<'a, 'b, 'tcx> TypeVerifier<'a, 'b, 'tcx> {
 
         swap_constraints(self);
 
-        self.visit_body(promoted_body);
+        self.visit_body(promoted_body_cache);
 
 
         if !self.errors_reported {
             // if verifier failed, don't do further checks to avoid ICEs
-            self.cx.typeck_mir(promoted_body);
+            self.cx.typeck_mir(&promoted_body_cache);
         }
 
         self.body = parent_body;