Add process_* place hooks to improve code reutilization

Author: spastorino

src/librustc/mir/visit.rs

@@ -786,10 +786,32 @@ macro_rules! visit_place_fns {
     (mut) => (
         fn super_place(
             &mut self,
-            _place: &mut Place<'tcx>,
-            _context: PlaceContext,
-            _location: Location,
+            place: &mut Place<'tcx>,
+            context: PlaceContext,
+            location: Location,
         ) {
+            self.visit_place_base(&mut place.base, context, location);
+
+            place.projection = self.process_projection(&place.projection);
+        }
+
+        fn process_projection(
+            &mut self,
+            projection: &Box<[PlaceElem<'tcx>]>,
+        ) -> Box<[PlaceElem<'tcx>]> {
+            let new_projection: Vec<_> = projection.iter().map(|elem|
+                self.process_projection_elem(elem)
+            ).collect();
+
+            new_projection.into_boxed_slice()
+        }
+
+        fn process_projection_elem(
+            &mut self,
+            elem: &PlaceElem<'tcx>,
+        ) -> PlaceElem<'tcx> {
+            // FIXME: avoid cloning here
+            elem.clone()
         }
     );
 

src/librustc_mir/borrow_check/nll/renumber.rs

@@ -1,7 +1,7 @@
 use rustc::ty::subst::SubstsRef;
 use rustc::ty::{self, Ty, TypeFoldable};
-use rustc::mir::{Body, Location, Place, PlaceElem, Promoted};
-use rustc::mir::visit::{MutVisitor, PlaceContext, TyContext};
+use rustc::mir::{Body, Location, PlaceElem, Promoted};
+use rustc::mir::visit::{MutVisitor, TyContext};
 use rustc::infer::{InferCtxt, NLLRegionVariableOrigin};
 use rustc_index::vec::IndexVec;
 
@@ -62,23 +62,15 @@ impl<'a, 'tcx> MutVisitor<'tcx> for NLLVisitor<'a, 'tcx> {
         debug!("visit_ty: ty={:?}", ty);
     }
 
-    fn visit_place(
+    fn process_projection_elem(
         &mut self,
-        place: &mut Place<'tcx>,
-        context: PlaceContext,
-        location: Location,
-    ) {
-        self.visit_place_base(&mut place.base, context, location);
-
-        let new_projection: Vec<_> = place.projection.iter().map(|elem|
-            if let PlaceElem::Field(field, ty) = elem {
-                PlaceElem::Field(*field, self.renumber_regions(ty))
-            } else {
-                elem.clone()
-            }
-        ).collect();
-
-        place.projection = new_projection.into_boxed_slice();
+        elem: &PlaceElem<'tcx>,
+    ) -> PlaceElem<'tcx> {
+        if let PlaceElem::Field(field, ty) = elem {
+            PlaceElem::Field(*field, self.renumber_regions(ty))
+        } else {
+            elem.clone()
+        }
     }
 
     fn visit_substs(&mut self, substs: &mut SubstsRef<'tcx>, location: Location) {

src/librustc_mir/transform/erase_regions.rs

@@ -7,7 +7,7 @@
 use rustc::ty::subst::SubstsRef;
 use rustc::ty::{self, Ty, TyCtxt};
 use rustc::mir::*;
-use rustc::mir::visit::{MutVisitor, PlaceContext, TyContext};
+use rustc::mir::visit::{MutVisitor, TyContext};
 use crate::transform::{MirPass, MirSource};
 
 struct EraseRegionsVisitor<'tcx> {
@@ -39,23 +39,15 @@ impl MutVisitor<'tcx> for EraseRegionsVisitor<'tcx> {
         *substs = self.tcx.erase_regions(substs);
     }
 
-    fn visit_place(
+    fn process_projection_elem(
         &mut self,
-        place: &mut Place<'tcx>,
-        context: PlaceContext,
-        location: Location,
-    ) {
-        self.visit_place_base(&mut place.base, context, location);
-
-        let new_projection: Vec<_> = place.projection.iter().map(|elem|
-            if let PlaceElem::Field(field, ty) = elem {
-                PlaceElem::Field(*field, self.tcx.erase_regions(ty))
-            } else {
-                elem.clone()
-            }
-        ).collect();
-
-        place.projection = new_projection.into_boxed_slice();
+        elem: &PlaceElem<'tcx>,
+    ) -> PlaceElem<'tcx> {
+        if let PlaceElem::Field(field, ty) = elem {
+            PlaceElem::Field(*field, self.tcx.erase_regions(ty))
+        } else {
+            elem.clone()
+        }
     }
 }
 

src/librustc_mir/transform/inline.rs

@@ -695,21 +695,22 @@ impl<'a, 'tcx> MutVisitor<'tcx> for Integrator<'a, 'tcx> {
                 *place = self.destination.clone();
             },
             _ => {
-                self.visit_place_base(&mut place.base, context, location);
-
-                let new_projection: Vec<_> = place.projection.iter().map(|elem|
-                    if let PlaceElem::Index(local) = elem {
-                        PlaceElem::Index(self.make_integrate_local(local))
-                    } else {
-                        elem.clone()
-                    }
-                ).collect();
-
-                place.projection = new_projection.into_boxed_slice();
+                self.super_place(place, context, location);
             }
         }
     }
 
+    fn process_projection_elem(
+        &mut self,
+        elem: &PlaceElem<'tcx>,
+    ) -> PlaceElem<'tcx> {
+        if let PlaceElem::Index(local) = elem {
+            PlaceElem::Index(self.make_integrate_local(local))
+        } else {
+            elem.clone()
+        }
+    }
+
     fn visit_basic_block_data(&mut self, block: BasicBlock, data: &mut BasicBlockData<'tcx>) {
         self.in_cleanup_block = data.is_cleanup;
         self.super_basic_block_data(block, data);

src/librustc_mir/transform/promote_consts.rs

@@ -405,24 +405,16 @@ impl<'a, 'tcx> MutVisitor<'tcx> for Promoter<'a, 'tcx> {
         }
     }
 
-    fn visit_place(
+    fn process_projection_elem(
         &mut self,
-        place: &mut Place<'tcx>,
-        context: PlaceContext,
-        location: Location,
-    ) {
-        self.visit_place_base(&mut place.base, context, location);
-
-        let new_projection: Vec<_> = place.projection.iter().map(|elem|
-            match elem {
-                PlaceElem::Index(local) if self.is_temp_kind(*local) => {
-                    PlaceElem::Index(self.promote_temp(*local))
-                }
-                _ => elem.clone(),
+        elem: &PlaceElem<'tcx>,
+    ) -> PlaceElem<'tcx> {
+        match elem {
+            PlaceElem::Index(local) if self.is_temp_kind(*local) => {
+                PlaceElem::Index(self.promote_temp(*local))
             }
-        ).collect();
-
-        place.projection = new_projection.into_boxed_slice();
+            _ => elem.clone(),
+        }
     }
 }
 

src/librustc_mir/transform/simplify.rs

@@ -371,22 +371,14 @@ impl<'tcx> MutVisitor<'tcx> for LocalUpdater {
         *l = self.map[*l].unwrap();
     }
 
-    fn visit_place(
+    fn process_projection_elem(
         &mut self,
-        place: &mut Place<'tcx>,
-        context: PlaceContext,
-        location: Location,
-    ) {
-        self.visit_place_base(&mut place.base, context, location);
-
-        let new_projection: Vec<_> = place.projection.iter().map(|elem|
-            if let PlaceElem::Index(local) = elem {
-                PlaceElem::Index(self.map[*local].unwrap())
-            } else {
-                elem.clone()
-            }
-        ).collect();
-
-        place.projection = new_projection.into_boxed_slice();
+        elem: &PlaceElem<'tcx>,
+    ) -> PlaceElem<'tcx> {
+        if let PlaceElem::Index(local) = elem {
+            PlaceElem::Index(self.map[*local].unwrap())
+        } else {
+            elem.clone()
+        }
     }
 }

src/librustc_mir/util/def_use.rs

@@ -1,6 +1,6 @@
 //! Def-use analysis.
 
-use rustc::mir::{Body, Local, Location, Place, PlaceElem};
+use rustc::mir::{Body, Local, Location, PlaceElem};
 use rustc::mir::visit::{PlaceContext, MutVisitor, Visitor};
 use rustc_index::vec::IndexVec;
 use std::mem;
@@ -138,21 +138,15 @@ impl MutVisitor<'_> for MutateUseVisitor {
         }
     }
 
-    fn visit_place(&mut self,
-                    place: &mut Place<'tcx>,
-                    context: PlaceContext,
-                    location: Location) {
-        self.visit_place_base(&mut place.base, context, location);
-
-        let new_projection: Vec<_> = place.projection.iter().map(|elem|
-            match elem {
-                PlaceElem::Index(local) if *local == self.query => {
-                    PlaceElem::Index(self.new_local)
-                }
-                _ => elem.clone(),
+    fn process_projection_elem(
+        &mut self,
+        elem: &PlaceElem<'tcx>,
+    ) -> PlaceElem<'tcx> {
+        match elem {
+            PlaceElem::Index(local) if *local == self.query => {
+                PlaceElem::Index(self.new_local)
             }
-        ).collect();
-
-        place.projection = new_projection.into_boxed_slice();
+            _ => elem.clone(),
+        }
     }
 }