Move find_use stuff to it's own file

Author: spastorino

src/librustc_mir/borrow_check/nll/explain_borrow/find_use.rs

@@ -0,0 +1,142 @@
+// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use borrow_check::borrow_set::BorrowData;
+use borrow_check::nll::region_infer::RegionInferenceContext;
+use rustc::mir::visit::{MirVisitable, PlaceContext, Visitor};
+use rustc::mir::{Local, Location, Mir};
+use rustc_data_structures::fx::FxHashSet;
+use util::liveness::{self, DefUse, LivenessMode};
+
+crate fn regular_use<'gcx, 'tcx>(
+    mir: &'gcx Mir,
+    regioncx: &'tcx RegionInferenceContext,
+    borrow: &'tcx BorrowData,
+    start_point: Location,
+    local: Local,
+) -> Option<Location> {
+    let mut uf = UseFinder {
+        mir,
+        regioncx,
+        borrow,
+        start_point,
+        local,
+        liveness_mode: LivenessMode {
+            include_regular_use: true,
+            include_drops: false,
+        },
+    };
+
+    uf.find()
+}
+
+crate fn drop_use<'gcx, 'tcx>(
+    mir: &'gcx Mir,
+    regioncx: &'tcx RegionInferenceContext,
+    borrow: &'tcx BorrowData,
+    start_point: Location,
+    local: Local,
+) -> Option<Location> {
+    let mut uf = UseFinder {
+        mir,
+        regioncx,
+        borrow,
+        start_point,
+        local,
+        liveness_mode: LivenessMode {
+            include_regular_use: false,
+            include_drops: true,
+        },
+    };
+
+    uf.find()
+}
+
+struct UseFinder<'gcx, 'tcx> {
+    mir: &'gcx Mir<'gcx>,
+    regioncx: &'tcx RegionInferenceContext<'tcx>,
+    borrow: &'tcx BorrowData<'tcx>,
+    start_point: Location,
+    local: Local,
+    liveness_mode: LivenessMode,
+}
+
+impl<'gcx, 'tcx> UseFinder<'gcx, 'tcx> {
+    fn find(&mut self) -> Option<Location> {
+        let mut stack = vec![];
+        let mut visited = FxHashSet();
+
+        stack.push(self.start_point);
+        while let Some(p) = stack.pop() {
+            if !self.regioncx.region_contains_point(self.borrow.region, p) {
+                continue;
+            }
+
+            if !visited.insert(p) {
+                continue;
+            }
+
+            let block_data = &self.mir[p.block];
+            let (defined, used) = self.def_use(p, block_data.visitable(p.statement_index));
+
+            if used {
+                return Some(p);
+            } else if !defined {
+                if p.statement_index < block_data.statements.len() {
+                    stack.push(Location {
+                        statement_index: p.statement_index + 1,
+                        ..p
+                    });
+                } else {
+                    stack.extend(block_data.terminator().successors().map(|&basic_block| {
+                        Location {
+                            statement_index: 0,
+                            block: basic_block,
+                        }
+                    }));
+                }
+            }
+        }
+
+        None
+    }
+
+    fn def_use(&self, location: Location, thing: &dyn MirVisitable<'tcx>) -> (bool, bool) {
+        let mut visitor = DefUseVisitor {
+            defined: false,
+            used: false,
+            local: self.local,
+            liveness_mode: self.liveness_mode,
+        };
+
+        thing.apply(location, &mut visitor);
+
+        (visitor.defined, visitor.used)
+    }
+}
+
+struct DefUseVisitor {
+    defined: bool,
+    used: bool,
+    local: Local,
+    liveness_mode: LivenessMode,
+}
+
+impl<'tcx> Visitor<'tcx> for DefUseVisitor {
+    fn visit_local(&mut self, &local: &Local, context: PlaceContext<'tcx>, _: Location) {
+        if local == self.local {
+            match liveness::categorize(context, self.liveness_mode) {
+                Some(DefUse::Def) => self.defined = true,
+                Some(DefUse::Use) => self.used = true,
+                None => (),
+            }
+        }
+    }
+}

src/librustc_mir/borrow_check/nll/explain_borrow/mod.rs

@@ -9,13 +9,12 @@
 // except according to those terms.
 
 use borrow_check::borrow_set::BorrowData;
-use borrow_check::nll::region_infer::{Cause, RegionInferenceContext};
+use borrow_check::nll::region_infer::Cause;
 use borrow_check::{Context, MirBorrowckCtxt, WriteKind};
-use rustc::mir::visit::{MirVisitable, PlaceContext, Visitor};
-use rustc::mir::{Local, Location, Mir, Place};
-use rustc_data_structures::fx::FxHashSet;
+use rustc::mir::Place;
 use rustc_errors::DiagnosticBuilder;
-use util::liveness::{self, DefUse, LivenessMode};
+
+mod find_use;
 
 impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> {
     /// Adds annotations to `err` explaining *why* the borrow contains the
@@ -45,7 +44,7 @@ impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> {
         let borrow_region_vid = regioncx.to_region_vid(borrow.region);
         if let Some(cause) = regioncx.why_region_contains_point(borrow_region_vid, context.loc) {
             match cause {
-                Cause::LiveVar(local, location) => match find_regular_use(
+                Cause::LiveVar(local, location) => match find_use::regular_use(
                     mir, regioncx, borrow, location, local,
                 ) {
                     Some(p) => {
@@ -60,7 +59,7 @@ impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> {
                     }
                 },
 
-                Cause::DropVar(local, location) => match find_drop_use(
+                Cause::DropVar(local, location) => match find_use::drop_use(
                     mir, regioncx, borrow, location, local,
                 ) {
                     Some(p) => match &mir.local_decls[local].name {
@@ -124,129 +123,3 @@ impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> {
         }
     }
 }
-
-fn find_regular_use<'gcx, 'tcx>(
-    mir: &'gcx Mir,
-    regioncx: &'tcx RegionInferenceContext,
-    borrow: &'tcx BorrowData,
-    start_point: Location,
-    local: Local,
-) -> Option<Location> {
-    let mut uf = UseFinder {
-        mir,
-        regioncx,
-        borrow,
-        start_point,
-        local,
-        liveness_mode: LivenessMode {
-            include_regular_use: true,
-            include_drops: false,
-        },
-    };
-
-    uf.find()
-}
-
-fn find_drop_use<'gcx, 'tcx>(
-    mir: &'gcx Mir,
-    regioncx: &'tcx RegionInferenceContext,
-    borrow: &'tcx BorrowData,
-    start_point: Location,
-    local: Local,
-) -> Option<Location> {
-    let mut uf = UseFinder {
-        mir,
-        regioncx,
-        borrow,
-        start_point,
-        local,
-        liveness_mode: LivenessMode {
-            include_regular_use: false,
-            include_drops: true,
-        },
-    };
-
-    uf.find()
-}
-
-struct UseFinder<'gcx, 'tcx> {
-    mir: &'gcx Mir<'gcx>,
-    regioncx: &'tcx RegionInferenceContext<'tcx>,
-    borrow: &'tcx BorrowData<'tcx>,
-    start_point: Location,
-    local: Local,
-    liveness_mode: LivenessMode,
-}
-
-impl<'gcx, 'tcx> UseFinder<'gcx, 'tcx> {
-    fn find(&mut self) -> Option<Location> {
-        let mut stack = vec![];
-        let mut visited = FxHashSet();
-
-        stack.push(self.start_point);
-        while let Some(p) = stack.pop() {
-            if !self.regioncx.region_contains_point(self.borrow.region, p) {
-                continue;
-            }
-
-            if !visited.insert(p) {
-                continue;
-            }
-
-            let block_data = &self.mir[p.block];
-            let (defined, used) = self.def_use(p, block_data.visitable(p.statement_index));
-
-            if used {
-                return Some(p);
-            } else if !defined {
-                if p.statement_index < block_data.statements.len() {
-                    stack.push(Location {
-                        statement_index: p.statement_index + 1,
-                        ..p
-                    });
-                } else {
-                    stack.extend(block_data.terminator().successors().map(|&basic_block| {
-                        Location {
-                            statement_index: 0,
-                            block: basic_block,
-                        }
-                    }));
-                }
-            }
-        }
-
-        None
-    }
-
-    fn def_use(&self, location: Location, thing: &dyn MirVisitable<'tcx>) -> (bool, bool) {
-        let mut visitor = DefUseVisitor {
-            defined: false,
-            used: false,
-            local: self.local,
-            liveness_mode: self.liveness_mode,
-        };
-
-        thing.apply(location, &mut visitor);
-
-        (visitor.defined, visitor.used)
-    }
-}
-
-struct DefUseVisitor {
-    defined: bool,
-    used: bool,
-    local: Local,
-    liveness_mode: LivenessMode,
-}
-
-impl<'tcx> Visitor<'tcx> for DefUseVisitor {
-    fn visit_local(&mut self, &local: &Local, context: PlaceContext<'tcx>, _: Location) {
-        if local == self.local {
-            match liveness::categorize(context, self.liveness_mode) {
-                Some(DefUse::Def) => self.defined = true,
-                Some(DefUse::Use) => self.used = true,
-                None => (),
-            }
-        }
-    }
-}