Add predecessors fn to ReadOnlyBodyCache, fix more Body -> (ReadOnly)BodyCache type errors

10 files changed, 52 insertions, 47 deletions

diff --git a/src/librustc/mir/cache.rs b/src/librustc/mir/cache.rs
index 24d1f9e373b..b6682470606 100644
--- a/src/librustc/mir/cache.rs
+++ b/src/librustc/mir/cache.rs
@@ -14,7 +14,6 @@ pub struct Cache {
     predecessors: Option<IndexVec<BasicBlock, Vec<BasicBlock>>>,
 }
 
-
 //impl<'tcx, T> rustc_serialize::Encodable for Cache<'tcx, T> {
 //    fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
 //        Encodable::encode(&(), s)
@@ -262,6 +261,11 @@ pub struct ReadOnlyBodyCache<'a, 'tcx> {
 
 impl ReadOnlyBodyCache<'a, 'tcx> {
     #[inline]
+    pub fn predecessors(&self) -> &IndexVec<BasicBlock, Vec<BasicBlock>> {
+        self.cache.predecessors.as_ref().unwrap()
+    }
+
+    #[inline]
     pub fn predecessors_for(&self, bb: BasicBlock) -> &[BasicBlock] {
         self.cache.unwrap_predecessors_for(bb)
     }
diff --git a/src/librustc/mir/visit.rs b/src/librustc/mir/visit.rs
index 7877466fbf6..c464247c4b4 100644
--- a/src/librustc/mir/visit.rs
+++ b/src/librustc/mir/visit.rs
@@ -812,7 +812,7 @@ macro_rules! make_mir_visitor {
 
             fn visit_location(
                 &mut self,
-                body_cache: & $($mutability)? BodyCache<&'_ $($mutability)? Body<'tcx>>,
+                body_cache: body_cache_type!($($mutability)? '_, 'tcx),
                 location: Location
             ) {
                 let basic_block = & $($mutability)? body_cache[location.block];
diff --git a/src/librustc_mir/borrow_check/mutability_errors.rs b/src/librustc_mir/borrow_check/mutability_errors.rs
index 654666882cc..44e139889c9 100644
--- a/src/librustc_mir/borrow_check/mutability_errors.rs
+++ b/src/librustc_mir/borrow_check/mutability_errors.rs
@@ -1,6 +1,6 @@
 use rustc::hir;
 use rustc::hir::Node;
-use rustc::mir::{self, Body, ClearCrossCrate, Local, LocalInfo, Location};
+use rustc::mir::{self, ClearCrossCrate, Local, LocalInfo, Location, ReadOnlyBodyCache};
 use rustc::mir::{Mutability, Place, PlaceRef, PlaceBase, ProjectionElem};
 use rustc::ty::{self, Ty, TyCtxt};
 use rustc_index::vec::Idx;
@@ -529,14 +529,14 @@ fn suggest_ampmut_self<'tcx>(
 // by trying (3.), then (2.) and finally falling back on (1.).
 fn suggest_ampmut<'tcx>(
     tcx: TyCtxt<'tcx>,
-    body: &Body<'tcx>,
+    body_cache: &ReadOnlyBodyCache<'_, 'tcx>,
     local: Local,
     local_decl: &mir::LocalDecl<'tcx>,
     opt_ty_info: Option<Span>,
 ) -> (Span, String) {
-    let locations = body.find_assignments(local);
+    let locations = body_cache.find_assignments(local);
     if !locations.is_empty() {
-        let assignment_rhs_span = body.source_info(locations[0]).span;
+        let assignment_rhs_span = body_cache.source_info(locations[0]).span;
         if let Ok(src) = tcx.sess.source_map().span_to_snippet(assignment_rhs_span) {
             if let (true, Some(ws_pos)) = (
                 src.starts_with("&'"),
diff --git a/src/librustc_mir/borrow_check/nll/type_check/liveness/local_use_map.rs b/src/librustc_mir/borrow_check/nll/type_check/liveness/local_use_map.rs
index 7dee00b3eca..181508a983a 100644
--- a/src/librustc_mir/borrow_check/nll/type_check/liveness/local_use_map.rs
+++ b/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::{Body, Local, Location};
+use rustc::mir::{Local, Location, ReadOnlyBodyCache};
 use rustc_index::vec::{Idx, IndexVec};
 use rustc_data_structures::vec_linked_list as vll;
 
@@ -60,9 +60,9 @@ impl LocalUseMap {
     crate fn build(
         live_locals: &Vec<Local>,
         elements: &RegionValueElements,
-        body: &Body<'_>,
+        body_cache: &ReadOnlyBodyCache<'_, '_>,
     ) -> Self {
-        let nones = IndexVec::from_elem_n(None, body.local_decls.len());
+        let nones = IndexVec::from_elem_n(None, body_cache.local_decls.len());
         let mut local_use_map = LocalUseMap {
             first_def_at: nones.clone(),
             first_use_at: nones.clone(),
@@ -75,11 +75,11 @@ impl LocalUseMap {
         }
 
         let mut locals_with_use_data: IndexVec<Local, bool> =
-            IndexVec::from_elem_n(false, body.local_decls.len());
+            IndexVec::from_elem_n(false, body_cache.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);
+            .visit_body(body_cache);
 
         local_use_map
     }
diff --git a/src/librustc_mir/borrow_check/nll/type_check/liveness/polonius.rs b/src/librustc_mir/borrow_check/nll/type_check/liveness/polonius.rs
index 526ad7fb905..3320815688f 100644
--- a/src/librustc_mir/borrow_check/nll/type_check/liveness/polonius.rs
+++ b/src/librustc_mir/borrow_check/nll/type_check/liveness/polonius.rs
@@ -3,7 +3,7 @@ use crate::dataflow::indexes::MovePathIndex;
 use crate::dataflow::move_paths::{LookupResult, MoveData};
 use crate::util::liveness::{categorize, DefUse};
 use rustc::mir::visit::{MutatingUseContext, PlaceContext, Visitor};
-use rustc::mir::{Body, Local, Location, Place};
+use rustc::mir::{Local, Location, Place, ReadOnlyBodyCache};
 use rustc::ty::subst::GenericArg;
 use rustc::ty::Ty;
 
@@ -97,7 +97,7 @@ fn add_var_uses_regions(typeck: &mut TypeChecker<'_, 'tcx>, local: Local, ty: Ty
 
 pub(super) fn populate_access_facts(
     typeck: &mut TypeChecker<'_, 'tcx>,
-    body: &Body<'tcx>,
+    body_cache: &ReadOnlyBodyCache<'_, 'tcx>,
     location_table: &LocationTable,
     move_data: &MoveData<'_>,
     drop_used: &mut Vec<(Local, Location)>,
@@ -113,14 +113,14 @@ pub(super) fn populate_access_facts(
             location_table,
             move_data,
         }
-        .visit_body(body);
+        .visit_body(body_cache);
 
         facts.var_drop_used.extend(drop_used.iter().map(|&(local, location)| {
             (local, location_table.mid_index(location))
         }));
     }
 
-    for (local, local_decl) in body.local_decls.iter_enumerated() {
+    for (local, local_decl) in body_cache.local_decls.iter_enumerated() {
         add_var_uses_regions(typeck, local, local_decl.ty);
     }
 }
diff --git a/src/librustc_mir/dataflow/impls/storage_liveness.rs b/src/librustc_mir/dataflow/impls/storage_liveness.rs
index 1b81032bfe6..2e164765043 100644
--- a/src/librustc_mir/dataflow/impls/storage_liveness.rs
+++ b/src/librustc_mir/dataflow/impls/storage_liveness.rs
@@ -75,24 +75,24 @@ impl<'a, 'tcx> BottomValue for MaybeStorageLive<'a, 'tcx> {
 /// Dataflow analysis that determines whether each local requires storage at a
 /// given location; i.e. whether its storage can go away without being observed.
 pub struct RequiresStorage<'mir, 'tcx> {
-    body: &'mir Body<'tcx>,
+    body_cache: &'mir ReadOnlyBodyCache<'mir, 'tcx>,
     borrowed_locals:
         RefCell<DataflowResultsRefCursor<'mir, 'tcx, HaveBeenBorrowedLocals<'mir, 'tcx>>>,
 }
 
 impl<'mir, 'tcx: 'mir> RequiresStorage<'mir, 'tcx> {
     pub fn new(
-        body: &'mir Body<'tcx>,
+        body_cache: &'mir ReadOnlyBodyCache<'mir, 'tcx>,
         borrowed_locals: &'mir DataflowResults<'tcx, HaveBeenBorrowedLocals<'mir, 'tcx>>,
     ) -> Self {
         RequiresStorage {
-            body,
-            borrowed_locals: RefCell::new(DataflowResultsCursor::new(borrowed_locals, body)),
+            body_cache,
+            borrowed_locals: RefCell::new(DataflowResultsCursor::new(borrowed_locals, body_cache)),
         }
     }
 
     pub fn body(&self) -> &Body<'tcx> {
-        self.body
+        &self.body_cache
     }
 }
 
@@ -100,13 +100,13 @@ impl<'mir, 'tcx> BitDenotation<'tcx> for RequiresStorage<'mir, 'tcx> {
     type Idx = Local;
     fn name() -> &'static str { "requires_storage" }
     fn bits_per_block(&self) -> usize {
-        self.body.local_decls.len()
+        self.body_cache.local_decls.len()
     }
 
     fn start_block_effect(&self, _sets: &mut BitSet<Local>) {
         // Nothing is live on function entry (generators only have a self
         // argument, and we don't care about that)
-        assert_eq!(1, self.body.arg_count);
+        assert_eq!(1, self.body_cache.arg_count);
     }
 
     fn before_statement_effect(&self, sets: &mut GenKillSet<Self::Idx>, loc: Location) {
@@ -114,7 +114,7 @@ impl<'mir, 'tcx> BitDenotation<'tcx> for RequiresStorage<'mir, 'tcx> {
         // statement.
         self.check_for_borrow(sets, loc);
 
-        let stmt = &self.body[loc.block].statements[loc.statement_index];
+        let stmt = &self.body_cache[loc.block].statements[loc.statement_index];
         match stmt.kind {
             StatementKind::StorageDead(l) => sets.kill(l),
             StatementKind::Assign(box(ref place, _))
@@ -146,7 +146,7 @@ impl<'mir, 'tcx> BitDenotation<'tcx> for RequiresStorage<'mir, 'tcx> {
         if let TerminatorKind::Call {
             destination: Some((Place { base: PlaceBase::Local(local), .. }, _)),
             ..
-        } = self.body[loc.block].terminator().kind {
+        } = self.body_cache[loc.block].terminator().kind {
             sets.gen(local);
         }
     }
@@ -159,7 +159,7 @@ impl<'mir, 'tcx> BitDenotation<'tcx> for RequiresStorage<'mir, 'tcx> {
         if let TerminatorKind::Call {
             destination: Some((ref place, _)),
             ..
-        } = self.body[loc.block].terminator().kind {
+        } = self.body_cache[loc.block].terminator().kind {
             if let Some(local) = place.as_local() {
                 sets.kill(local);
             }
@@ -187,7 +187,7 @@ impl<'mir, 'tcx> RequiresStorage<'mir, 'tcx> {
             sets,
             borrowed_locals: &self.borrowed_locals,
         };
-        visitor.visit_location(self.body, loc);
+        visitor.visit_location(&self.body_cache, loc);
     }
 
     /// Gen locals that are newly borrowed. This includes borrowing any part of
diff --git a/src/librustc_mir/monomorphize/collector.rs b/src/librustc_mir/monomorphize/collector.rs
index a4c4c7ff616..285bdf50d4a 100644
--- a/src/librustc_mir/monomorphize/collector.rs
+++ b/src/librustc_mir/monomorphize/collector.rs
@@ -186,7 +186,7 @@ use rustc::ty::{self, TypeFoldable, Ty, TyCtxt, GenericParamDefKind, Instance};
 use rustc::ty::print::obsolete::DefPathBasedNames;
 use rustc::ty::adjustment::{CustomCoerceUnsized, PointerCast};
 use rustc::session::config::EntryFnType;
-use rustc::mir::{self, Location, PlaceBase, Static, StaticKind};
+use rustc::mir::{self, BodyCache, Location, PlaceBase, Static, StaticKind};
 use rustc::mir::visit::Visitor as MirVisitor;
 use rustc::mir::mono::{MonoItem, InstantiationMode};
 use rustc::mir::interpret::{Scalar, GlobalId, GlobalAlloc, ErrorHandled};
@@ -1249,13 +1249,14 @@ fn collect_neighbours<'tcx>(
 ) {
     debug!("collect_neighbours: {:?}", instance.def_id());
     let body = tcx.instance_mir(instance.def);
+    let body_cache = BodyCache::new(body).read_only();
 
     MirNeighborCollector {
         tcx,
         body: &body,
         output,
         param_substs: instance.substs,
-    }.visit_body(&body);
+    }.visit_body(&body_cache);
 }
 
 fn def_id_to_string(tcx: TyCtxt<'_>, def_id: DefId) -> String {
diff --git a/src/librustc_mir/util/collect_writes.rs b/src/librustc_mir/util/collect_writes.rs
index c8804dfbaf2..0092c3c86d7 100644
--- a/src/librustc_mir/util/collect_writes.rs
+++ b/src/librustc_mir/util/collect_writes.rs
@@ -1,5 +1,5 @@
 use rustc::mir::{Local, Location};
-use rustc::mir::Body;
+use rustc::mir::ReadOnlyBodyCache;
 use rustc::mir::visit::PlaceContext;
 use rustc::mir::visit::Visitor;
 
@@ -9,7 +9,7 @@ crate trait FindAssignments {
     fn find_assignments(&self, local: Local) -> Vec<Location>;
 }
 
-impl<'tcx> FindAssignments for Body<'tcx>{
+impl<'a, 'tcx> FindAssignments for ReadOnlyBodyCache<'a, 'tcx>{
     fn find_assignments(&self, local: Local) -> Vec<Location>{
             let mut visitor = FindLocalAssignmentVisitor{ needle: local, locations: vec![]};
             visitor.visit_body(self);
diff --git a/src/librustc_mir/util/liveness.rs b/src/librustc_mir/util/liveness.rs
index d313cba6bdf..87e6291a454 100644
--- a/src/librustc_mir/util/liveness.rs
+++ b/src/librustc_mir/util/liveness.rs
@@ -57,17 +57,17 @@ pub struct LivenessResult {
 /// Computes which local variables are live within the given function
 /// `mir`, including drops.
 pub fn liveness_of_locals(
-    body: &Body<'_>,
+    body_cache: &ReadOnlyBodyCache<'_, '_>,
 ) -> LivenessResult {
-    let num_live_vars = body.local_decls.len();
+    let num_live_vars = body_cache.local_decls.len();
 
-    let def_use: IndexVec<_, DefsUses> = body
+    let def_use: IndexVec<_, DefsUses> = body_cache
         .basic_blocks()
         .iter()
         .map(|b| block(b, num_live_vars))
         .collect();
 
-    let mut outs: IndexVec<_, LiveVarSet> = body
+    let mut outs: IndexVec<_, LiveVarSet> = body_cache
         .basic_blocks()
         .indices()
         .map(|_| LiveVarSet::new_empty(num_live_vars))
@@ -83,18 +83,18 @@ pub fn liveness_of_locals(
     // FIXME(ecstaticmorse): Reverse post-order on the reverse CFG may generate a better iteration
     // order when cycles are present, but the overhead of computing the reverse CFG may outweigh
     // any benefits. Benchmark this and find out.
-    let mut dirty_queue: WorkQueue<BasicBlock> = WorkQueue::with_none(body.basic_blocks().len());
-    for (bb, _) in traversal::postorder(body) {
+    let mut dirty_queue: WorkQueue<BasicBlock> = WorkQueue::with_none(body_cache.basic_blocks().len());
+    for (bb, _) in traversal::postorder(body_cache) {
         dirty_queue.insert(bb);
     }
 
     // Add blocks which are not reachable from START_BLOCK to the work queue. These blocks will
     // be processed after the ones added above.
-    for bb in body.basic_blocks().indices() {
+    for bb in body_cache.basic_blocks().indices() {
         dirty_queue.insert(bb);
     }
 
-    let predecessors = body.unwrap_predecessors();
+    let predecessors = body_cache.predecessors();
 
     while let Some(bb) = dirty_queue.pop() {
         // bits = use ∪ (bits - def)
diff --git a/src/librustc_mir/util/patch.rs b/src/librustc_mir/util/patch.rs
index a5f7e540157..01be0f598ed 100644
--- a/src/librustc_mir/util/patch.rs
+++ b/src/librustc_mir/util/patch.rs
@@ -127,21 +127,21 @@ impl<'tcx> MirPatch<'tcx> {
         self.make_nop.push(loc);
     }
 
-    pub fn apply(self, body: &mut Body<'tcx>) {
+    pub fn apply(self, body_cache: &mut BodyCache<&'_ mut Body<'tcx>>) {
         debug!("MirPatch: make nops at: {:?}", self.make_nop);
         for loc in self.make_nop {
-            body.make_statement_nop(loc);
+            body_cache.make_statement_nop(loc);
         }
         debug!("MirPatch: {:?} new temps, starting from index {}: {:?}",
-               self.new_locals.len(), body.local_decls.len(), self.new_locals);
+               self.new_locals.len(), body_cache.local_decls.len(), self.new_locals);
         debug!("MirPatch: {} new blocks, starting from index {}",
-               self.new_blocks.len(), body.basic_blocks().len());
-        body.basic_blocks_mut().extend(self.new_blocks);
-        body.local_decls.extend(self.new_locals);
+               self.new_blocks.len(), body_cache.basic_blocks().len());
+        body_cache.basic_blocks_mut().extend(self.new_blocks);
+        body_cache.local_decls.extend(self.new_locals);
         for (src, patch) in self.patch_map.into_iter_enumerated() {
             if let Some(patch) = patch {
                 debug!("MirPatch: patching block {:?}", src);
-                body[src].terminator_mut().kind = patch;
+                body_cache[src].terminator_mut().kind = patch;
             }
         }
 
@@ -159,9 +159,9 @@ impl<'tcx> MirPatch<'tcx> {
                    stmt, loc, delta);
             loc.statement_index += delta;
             let source_info = Self::source_info_for_index(
-                &body[loc.block], loc
+                &body_cache[loc.block], loc
             );
-            body[loc.block].statements.insert(
+            body_cache[loc.block].statements.insert(
                 loc.statement_index, Statement {
                     source_info,
                     kind: stmt