Move ever_borrowed_locals to utilities

Author: tmiasko

compiler/rustc_mir/src/transform/dest_prop.rs

@@ -100,7 +100,7 @@ use crate::dataflow::impls::{MaybeInitializedLocals, MaybeLiveLocals};
 use crate::dataflow::Analysis;
 use crate::{
     transform::MirPass,
-    util::{dump_mir, PassWhere},
+    util::{dump_mir, ever_borrowed_locals, PassWhere},
 };
 use itertools::Itertools;
 use rustc_data_structures::unify::{InPlaceUnificationTable, UnifyKey};
@@ -946,68 +946,6 @@ fn is_local_required(local: Local, body: &Body<'_>) -> bool {
     }
 }
 
-/// Walks MIR to find all locals that have their address taken anywhere.
-fn ever_borrowed_locals(body: &Body<'_>) -> BitSet<Local> {
-    let mut visitor = BorrowCollector { locals: BitSet::new_empty(body.local_decls.len()) };
-    visitor.visit_body(body);
-    visitor.locals
-}
-
-struct BorrowCollector {
-    locals: BitSet<Local>,
-}
-
-impl<'tcx> Visitor<'tcx> for BorrowCollector {
-    fn visit_rvalue(&mut self, rvalue: &Rvalue<'tcx>, location: Location) {
-        self.super_rvalue(rvalue, location);
-
-        match rvalue {
-            Rvalue::AddressOf(_, borrowed_place) | Rvalue::Ref(_, _, borrowed_place) => {
-                if !borrowed_place.is_indirect() {
-                    self.locals.insert(borrowed_place.local);
-                }
-            }
-
-            Rvalue::Cast(..)
-            | Rvalue::Use(..)
-            | Rvalue::Repeat(..)
-            | Rvalue::Len(..)
-            | Rvalue::BinaryOp(..)
-            | Rvalue::CheckedBinaryOp(..)
-            | Rvalue::NullaryOp(..)
-            | Rvalue::UnaryOp(..)
-            | Rvalue::Discriminant(..)
-            | Rvalue::Aggregate(..)
-            | Rvalue::ThreadLocalRef(..) => {}
-        }
-    }
-
-    fn visit_terminator(&mut self, terminator: &Terminator<'tcx>, location: Location) {
-        self.super_terminator(terminator, location);
-
-        match terminator.kind {
-            TerminatorKind::Drop { place: dropped_place, .. }
-            | TerminatorKind::DropAndReplace { place: dropped_place, .. } => {
-                self.locals.insert(dropped_place.local);
-            }
-
-            TerminatorKind::Abort
-            | TerminatorKind::Assert { .. }
-            | TerminatorKind::Call { .. }
-            | TerminatorKind::FalseEdge { .. }
-            | TerminatorKind::FalseUnwind { .. }
-            | TerminatorKind::GeneratorDrop
-            | TerminatorKind::Goto { .. }
-            | TerminatorKind::Resume
-            | TerminatorKind::Return
-            | TerminatorKind::SwitchInt { .. }
-            | TerminatorKind::Unreachable
-            | TerminatorKind::Yield { .. }
-            | TerminatorKind::InlineAsm { .. } => {}
-        }
-    }
-}
-
 /// `PlaceElem::Index` only stores a `Local`, so we can't replace that with a full `Place`.
 ///
 /// Collect locals used as indices so we don't generate candidates that are impossible to apply

compiler/rustc_mir/src/util/borrowed.rs

@@ -0,0 +1,65 @@
+use rustc_index::bit_set::BitSet;
+use rustc_middle::mir::visit::Visitor;
+use rustc_middle::mir::*;
+
+/// Walks MIR to find all locals that have their address taken anywhere.
+pub fn ever_borrowed_locals(body: &Body<'_>) -> BitSet<Local> {
+    let mut visitor = BorrowCollector { locals: BitSet::new_empty(body.local_decls.len()) };
+    for (block, data) in body.basic_blocks().iter_enumerated() {
+        visitor.visit_basic_block_data(block, data);
+    }
+    visitor.locals
+}
+
+struct BorrowCollector {
+    locals: BitSet<Local>,
+}
+
+impl<'tcx> Visitor<'tcx> for BorrowCollector {
+    fn visit_rvalue(&mut self, rvalue: &Rvalue<'tcx>, _location: Location) {
+        match rvalue {
+            Rvalue::AddressOf(_, borrowed_place) | Rvalue::Ref(_, _, borrowed_place) => {
+                if !borrowed_place.is_indirect() {
+                    self.locals.insert(borrowed_place.local);
+                }
+            }
+
+            Rvalue::Cast(..)
+            | Rvalue::Use(..)
+            | Rvalue::Repeat(..)
+            | Rvalue::Len(..)
+            | Rvalue::BinaryOp(..)
+            | Rvalue::CheckedBinaryOp(..)
+            | Rvalue::NullaryOp(..)
+            | Rvalue::UnaryOp(..)
+            | Rvalue::Discriminant(..)
+            | Rvalue::Aggregate(..)
+            | Rvalue::ThreadLocalRef(..) => {}
+        }
+    }
+
+    fn visit_terminator(&mut self, terminator: &Terminator<'tcx>, location: Location) {
+        self.super_terminator(terminator, location);
+
+        match terminator.kind {
+            TerminatorKind::Drop { place: dropped_place, .. }
+            | TerminatorKind::DropAndReplace { place: dropped_place, .. } => {
+                self.locals.insert(dropped_place.local);
+            }
+
+            TerminatorKind::Abort
+            | TerminatorKind::Assert { .. }
+            | TerminatorKind::Call { .. }
+            | TerminatorKind::FalseEdge { .. }
+            | TerminatorKind::FalseUnwind { .. }
+            | TerminatorKind::GeneratorDrop
+            | TerminatorKind::Goto { .. }
+            | TerminatorKind::Resume
+            | TerminatorKind::Return
+            | TerminatorKind::SwitchInt { .. }
+            | TerminatorKind::Unreachable
+            | TerminatorKind::Yield { .. }
+            | TerminatorKind::InlineAsm { .. } => {}
+        }
+    }
+}

compiler/rustc_mir/src/util/mod.rs

@@ -5,6 +5,7 @@ pub mod patch;
 pub mod storage;
 
 mod alignment;
+mod borrowed;
 pub mod collect_writes;
 mod find_self_call;
 mod generic_graph;
@@ -15,6 +16,7 @@ pub(crate) mod spanview;
 
 pub use self::aggregate::expand_aggregate;
 pub use self::alignment::is_disaligned;
+pub use self::borrowed::ever_borrowed_locals;
 pub use self::find_self_call::find_self_call;
 pub use self::generic_graph::graphviz_safe_def_name;
 pub use self::graphviz::write_mir_graphviz;