Rename some Analysis and ResultsVisitor methods.

The words "before" and "after" have an obvious temporal meaning, e.g.
`seek_before_primary_effect`,
`visit_statement_{before,after}_primary_effect`. But "before" is also
used to name the effect that occurs before the primary effect of a
statement/terminator; this is `Effect::Before`. This leads to the
confusing possibility of talking about things happening "before/after
the before event".

This commit removes this awkward overloading of "before" by renaming
`Effect::Before` as `Effect::Early`. It also renames some of the
`Analysis` and `ResultsVisitor` methods to be more consistent.

Here are the before and after names:

- `Effect::{Before,Primary}`              -> `Effect::{Early,Primary}`
- `apply_before_statement_effect`         -> `apply_early_statement_effect`
- `apply_statement_effect`                -> `apply_primary_statement_effect`
- `visit_statement_before_primary_effect` -> `visit_after_early_statement_effect`
- `visit_statement_after_primary_effect`  -> `visit_after_primary_statement_effect`

(And s/statement/terminator/ for all the terminator events.)

Author: nnethercote

Diff for: compiler/rustc_borrowck/src/dataflow.rs

@@ -44,48 +44,48 @@ impl<'a, 'tcx> Analysis<'tcx> for Borrowck<'a, 'tcx> {
         unreachable!();
     }
 
-    fn apply_before_statement_effect(
+    fn apply_early_statement_effect(
         &mut self,
         state: &mut Self::Domain,
         stmt: &mir::Statement<'tcx>,
         loc: Location,
     ) {
-        self.borrows.apply_before_statement_effect(&mut state.borrows, stmt, loc);
-        self.uninits.apply_before_statement_effect(&mut state.uninits, stmt, loc);
-        self.ever_inits.apply_before_statement_effect(&mut state.ever_inits, stmt, loc);
+        self.borrows.apply_early_statement_effect(&mut state.borrows, stmt, loc);
+        self.uninits.apply_early_statement_effect(&mut state.uninits, stmt, loc);
+        self.ever_inits.apply_early_statement_effect(&mut state.ever_inits, stmt, loc);
     }
 
-    fn apply_statement_effect(
+    fn apply_primary_statement_effect(
         &mut self,
         state: &mut Self::Domain,
         stmt: &mir::Statement<'tcx>,
         loc: Location,
     ) {
-        self.borrows.apply_statement_effect(&mut state.borrows, stmt, loc);
-        self.uninits.apply_statement_effect(&mut state.uninits, stmt, loc);
-        self.ever_inits.apply_statement_effect(&mut state.ever_inits, stmt, loc);
+        self.borrows.apply_primary_statement_effect(&mut state.borrows, stmt, loc);
+        self.uninits.apply_primary_statement_effect(&mut state.uninits, stmt, loc);
+        self.ever_inits.apply_primary_statement_effect(&mut state.ever_inits, stmt, loc);
     }
 
-    fn apply_before_terminator_effect(
+    fn apply_early_terminator_effect(
         &mut self,
         state: &mut Self::Domain,
         term: &mir::Terminator<'tcx>,
         loc: Location,
     ) {
-        self.borrows.apply_before_terminator_effect(&mut state.borrows, term, loc);
-        self.uninits.apply_before_terminator_effect(&mut state.uninits, term, loc);
-        self.ever_inits.apply_before_terminator_effect(&mut state.ever_inits, term, loc);
+        self.borrows.apply_early_terminator_effect(&mut state.borrows, term, loc);
+        self.uninits.apply_early_terminator_effect(&mut state.uninits, term, loc);
+        self.ever_inits.apply_early_terminator_effect(&mut state.ever_inits, term, loc);
     }
 
-    fn apply_terminator_effect<'mir>(
+    fn apply_primary_terminator_effect<'mir>(
         &mut self,
         state: &mut Self::Domain,
         term: &'mir mir::Terminator<'tcx>,
         loc: Location,
     ) -> TerminatorEdges<'mir, 'tcx> {
-        self.borrows.apply_terminator_effect(&mut state.borrows, term, loc);
-        self.uninits.apply_terminator_effect(&mut state.uninits, term, loc);
-        self.ever_inits.apply_terminator_effect(&mut state.ever_inits, term, loc);
+        self.borrows.apply_primary_terminator_effect(&mut state.borrows, term, loc);
+        self.uninits.apply_primary_terminator_effect(&mut state.uninits, term, loc);
+        self.ever_inits.apply_primary_terminator_effect(&mut state.ever_inits, term, loc);
 
         // This return value doesn't matter. It's only used by `iterate_to_fixpoint`, which this
         // analysis doesn't use.
@@ -593,7 +593,7 @@ impl<'tcx> rustc_mir_dataflow::Analysis<'tcx> for Borrows<'_, 'tcx> {
         // function execution, so this method has no effect.
     }
 
-    fn apply_before_statement_effect(
+    fn apply_early_statement_effect(
         &mut self,
         state: &mut Self::Domain,
         _statement: &mir::Statement<'tcx>,
@@ -602,7 +602,7 @@ impl<'tcx> rustc_mir_dataflow::Analysis<'tcx> for Borrows<'_, 'tcx> {
         self.kill_loans_out_of_scope_at_location(state, location);
     }
 
-    fn apply_statement_effect(
+    fn apply_primary_statement_effect(
         &mut self,
         state: &mut Self::Domain,
         stmt: &mir::Statement<'tcx>,
@@ -651,7 +651,7 @@ impl<'tcx> rustc_mir_dataflow::Analysis<'tcx> for Borrows<'_, 'tcx> {
         }
     }
 
-    fn apply_before_terminator_effect(
+    fn apply_early_terminator_effect(
         &mut self,
         state: &mut Self::Domain,
         _terminator: &mir::Terminator<'tcx>,
@@ -660,7 +660,7 @@ impl<'tcx> rustc_mir_dataflow::Analysis<'tcx> for Borrows<'_, 'tcx> {
         self.kill_loans_out_of_scope_at_location(state, location);
     }
 
-    fn apply_terminator_effect<'mir>(
+    fn apply_primary_terminator_effect<'mir>(
         &mut self,
         state: &mut Self::Domain,
         terminator: &'mir mir::Terminator<'tcx>,

Diff for: compiler/rustc_borrowck/src/lib.rs

@@ -600,7 +600,7 @@ struct MirBorrowckCtxt<'a, 'infcx, 'tcx> {
 // 3. assignments do not affect things loaned out as immutable
 // 4. moves do not affect things loaned out in any way
 impl<'a, 'tcx> ResultsVisitor<'a, 'tcx, Borrowck<'a, 'tcx>> for MirBorrowckCtxt<'a, '_, 'tcx> {
-    fn visit_statement_before_primary_effect(
+    fn visit_after_early_statement_effect(
         &mut self,
         _results: &mut Results<'tcx, Borrowck<'a, 'tcx>>,
         state: &BorrowckDomain,
@@ -674,7 +674,7 @@ impl<'a, 'tcx> ResultsVisitor<'a, 'tcx, Borrowck<'a, 'tcx>> for MirBorrowckCtxt<
         }
     }
 
-    fn visit_terminator_before_primary_effect(
+    fn visit_after_early_terminator_effect(
         &mut self,
         _results: &mut Results<'tcx, Borrowck<'a, 'tcx>>,
         state: &BorrowckDomain,
@@ -787,7 +787,7 @@ impl<'a, 'tcx> ResultsVisitor<'a, 'tcx, Borrowck<'a, 'tcx>> for MirBorrowckCtxt<
         }
     }
 
-    fn visit_terminator_after_primary_effect(
+    fn visit_after_primary_terminator_effect(
         &mut self,
         _results: &mut Results<'tcx, Borrowck<'a, 'tcx>>,
         state: &BorrowckDomain,

Diff for: compiler/rustc_const_eval/src/check_consts/resolver.rs

@@ -329,7 +329,7 @@ where
         self.transfer_function(state).initialize_state();
     }
 
-    fn apply_statement_effect(
+    fn apply_primary_statement_effect(
         &mut self,
         state: &mut Self::Domain,
         statement: &mir::Statement<'tcx>,
@@ -338,7 +338,7 @@ where
         self.transfer_function(state).visit_statement(statement, location);
     }
 
-    fn apply_terminator_effect<'mir>(
+    fn apply_primary_terminator_effect<'mir>(
         &mut self,
         state: &mut Self::Domain,
         terminator: &'mir mir::Terminator<'tcx>,

Diff for: compiler/rustc_mir_dataflow/src/framework/cursor.rs

@@ -179,15 +179,15 @@ where
     /// Advances the cursor to hold the dataflow state at `target` before its "primary" effect is
     /// applied.
     ///
-    /// The "before" effect at the target location *will be* applied.
+    /// The "early" effect at the target location *will be* applied.
     pub fn seek_before_primary_effect(&mut self, target: Location) {
-        self.seek_after(target, Effect::Before)
+        self.seek_after(target, Effect::Early)
     }
 
     /// Advances the cursor to hold the dataflow state at `target` after its "primary" effect is
     /// applied.
     ///
-    /// The "before" effect at the target location will be applied as well.
+    /// The "early" effect at the target location will be applied as well.
     pub fn seek_after_primary_effect(&mut self, target: Location) {
         self.seek_after(target, Effect::Primary)
     }
@@ -222,12 +222,12 @@ where
         #[rustfmt::skip]
         let next_effect = if A::Direction::IS_FORWARD {
             self.pos.curr_effect_index.map_or_else(
-                || Effect::Before.at_index(0),
+                || Effect::Early.at_index(0),
                 EffectIndex::next_in_forward_order,
             )
         } else {
             self.pos.curr_effect_index.map_or_else(
-                || Effect::Before.at_index(block_data.statements.len()),
+                || Effect::Early.at_index(block_data.statements.len()),
                 EffectIndex::next_in_backward_order,
             )
         };

Diff for: compiler/rustc_mir_dataflow/src/framework/direction.rs

@@ -66,12 +66,12 @@ impl Direction for Backward {
     {
         let terminator = block_data.terminator();
         let location = Location { block, statement_index: block_data.statements.len() };
-        analysis.apply_before_terminator_effect(state, terminator, location);
-        analysis.apply_terminator_effect(state, terminator, location);
+        analysis.apply_early_terminator_effect(state, terminator, location);
+        analysis.apply_primary_terminator_effect(state, terminator, location);
         for (statement_index, statement) in block_data.statements.iter().enumerate().rev() {
             let location = Location { block, statement_index };
-            analysis.apply_before_statement_effect(state, statement, location);
-            analysis.apply_statement_effect(state, statement, location);
+            analysis.apply_early_statement_effect(state, statement, location);
+            analysis.apply_primary_statement_effect(state, statement, location);
         }
 
         let exit_state = state;
@@ -159,14 +159,14 @@ impl Direction for Backward {
                 let location = Location { block, statement_index: from.statement_index };
                 let terminator = block_data.terminator();
 
-                if from.effect == Effect::Before {
-                    analysis.apply_before_terminator_effect(state, terminator, location);
-                    if to == Effect::Before.at_index(terminator_index) {
+                if from.effect == Effect::Early {
+                    analysis.apply_early_terminator_effect(state, terminator, location);
+                    if to == Effect::Early.at_index(terminator_index) {
                         return;
                     }
                 }
 
-                analysis.apply_terminator_effect(state, terminator, location);
+                analysis.apply_primary_terminator_effect(state, terminator, location);
                 if to == Effect::Primary.at_index(terminator_index) {
                     return;
                 }
@@ -180,37 +180,37 @@ impl Direction for Backward {
                 let location = Location { block, statement_index: from.statement_index };
                 let statement = &block_data.statements[from.statement_index];
 
-                analysis.apply_statement_effect(state, statement, location);
+                analysis.apply_primary_statement_effect(state, statement, location);
                 if to == Effect::Primary.at_index(from.statement_index) {
                     return;
                 }
 
                 from.statement_index - 1
             }
 
-            Effect::Before => from.statement_index,
+            Effect::Early => from.statement_index,
         };
 
         // Handle all statements between `first_unapplied_idx` and `to.statement_index`.
 
         for statement_index in (to.statement_index..next_effect).rev().map(|i| i + 1) {
             let location = Location { block, statement_index };
             let statement = &block_data.statements[statement_index];
-            analysis.apply_before_statement_effect(state, statement, location);
-            analysis.apply_statement_effect(state, statement, location);
+            analysis.apply_early_statement_effect(state, statement, location);
+            analysis.apply_primary_statement_effect(state, statement, location);
         }
 
         // Handle the statement at `to`.
 
         let location = Location { block, statement_index: to.statement_index };
         let statement = &block_data.statements[to.statement_index];
-        analysis.apply_before_statement_effect(state, statement, location);
+        analysis.apply_early_statement_effect(state, statement, location);
 
-        if to.effect == Effect::Before {
+        if to.effect == Effect::Early {
             return;
         }
 
-        analysis.apply_statement_effect(state, statement, location);
+        analysis.apply_primary_statement_effect(state, statement, location);
     }
 
     fn visit_results_in_block<'mir, 'tcx, A>(
@@ -228,17 +228,17 @@ impl Direction for Backward {
 
         let loc = Location { block, statement_index: block_data.statements.len() };
         let term = block_data.terminator();
-        results.analysis.apply_before_terminator_effect(state, term, loc);
-        vis.visit_terminator_before_primary_effect(results, state, term, loc);
-        results.analysis.apply_terminator_effect(state, term, loc);
-        vis.visit_terminator_after_primary_effect(results, state, term, loc);
+        results.analysis.apply_early_terminator_effect(state, term, loc);
+        vis.visit_after_early_terminator_effect(results, state, term, loc);
+        results.analysis.apply_primary_terminator_effect(state, term, loc);
+        vis.visit_after_primary_terminator_effect(results, state, term, loc);
 
         for (statement_index, stmt) in block_data.statements.iter().enumerate().rev() {
             let loc = Location { block, statement_index };
-            results.analysis.apply_before_statement_effect(state, stmt, loc);
-            vis.visit_statement_before_primary_effect(results, state, stmt, loc);
-            results.analysis.apply_statement_effect(state, stmt, loc);
-            vis.visit_statement_after_primary_effect(results, state, stmt, loc);
+            results.analysis.apply_early_statement_effect(state, stmt, loc);
+            vis.visit_after_early_statement_effect(results, state, stmt, loc);
+            results.analysis.apply_primary_statement_effect(state, stmt, loc);
+            vis.visit_after_primary_statement_effect(results, state, stmt, loc);
         }
 
         vis.visit_block_start(state);
@@ -294,13 +294,13 @@ impl Direction for Forward {
     {
         for (statement_index, statement) in block_data.statements.iter().enumerate() {
             let location = Location { block, statement_index };
-            analysis.apply_before_statement_effect(state, statement, location);
-            analysis.apply_statement_effect(state, statement, location);
+            analysis.apply_early_statement_effect(state, statement, location);
+            analysis.apply_primary_statement_effect(state, statement, location);
         }
         let terminator = block_data.terminator();
         let location = Location { block, statement_index: block_data.statements.len() };
-        analysis.apply_before_terminator_effect(state, terminator, location);
-        let edges = analysis.apply_terminator_effect(state, terminator, location);
+        analysis.apply_early_terminator_effect(state, terminator, location);
+        let edges = analysis.apply_primary_terminator_effect(state, terminator, location);
 
         let exit_state = state;
         match edges {
@@ -368,21 +368,21 @@ impl Direction for Forward {
         // after effect, do so now and start the loop below from the next statement.
 
         let first_unapplied_index = match from.effect {
-            Effect::Before => from.statement_index,
+            Effect::Early => from.statement_index,
 
             Effect::Primary if from.statement_index == terminator_index => {
                 debug_assert_eq!(from, to);
 
                 let location = Location { block, statement_index: terminator_index };
                 let terminator = block_data.terminator();
-                analysis.apply_terminator_effect(state, terminator, location);
+                analysis.apply_primary_terminator_effect(state, terminator, location);
                 return;
             }
 
             Effect::Primary => {
                 let location = Location { block, statement_index: from.statement_index };
                 let statement = &block_data.statements[from.statement_index];
-                analysis.apply_statement_effect(state, statement, location);
+                analysis.apply_primary_statement_effect(state, statement, location);
 
                 // If we only needed to apply the after effect of the statement at `idx`, we are
                 // done.
@@ -399,26 +399,26 @@ impl Direction for Forward {
         for statement_index in first_unapplied_index..to.statement_index {
             let location = Location { block, statement_index };
             let statement = &block_data.statements[statement_index];
-            analysis.apply_before_statement_effect(state, statement, location);
-            analysis.apply_statement_effect(state, statement, location);
+            analysis.apply_early_statement_effect(state, statement, location);
+            analysis.apply_primary_statement_effect(state, statement, location);
         }
 
         // Handle the statement or terminator at `to`.
 
         let location = Location { block, statement_index: to.statement_index };
         if to.statement_index == terminator_index {
             let terminator = block_data.terminator();
-            analysis.apply_before_terminator_effect(state, terminator, location);
+            analysis.apply_early_terminator_effect(state, terminator, location);
 
             if to.effect == Effect::Primary {
-                analysis.apply_terminator_effect(state, terminator, location);
+                analysis.apply_primary_terminator_effect(state, terminator, location);
             }
         } else {
             let statement = &block_data.statements[to.statement_index];
-            analysis.apply_before_statement_effect(state, statement, location);
+            analysis.apply_early_statement_effect(state, statement, location);
 
             if to.effect == Effect::Primary {
-                analysis.apply_statement_effect(state, statement, location);
+                analysis.apply_primary_statement_effect(state, statement, location);
             }
         }
     }
@@ -438,18 +438,18 @@ impl Direction for Forward {
 
         for (statement_index, stmt) in block_data.statements.iter().enumerate() {
             let loc = Location { block, statement_index };
-            results.analysis.apply_before_statement_effect(state, stmt, loc);
-            vis.visit_statement_before_primary_effect(results, state, stmt, loc);
-            results.analysis.apply_statement_effect(state, stmt, loc);
-            vis.visit_statement_after_primary_effect(results, state, stmt, loc);
+            results.analysis.apply_early_statement_effect(state, stmt, loc);
+            vis.visit_after_early_statement_effect(results, state, stmt, loc);
+            results.analysis.apply_primary_statement_effect(state, stmt, loc);
+            vis.visit_after_primary_statement_effect(results, state, stmt, loc);
         }
 
         let loc = Location { block, statement_index: block_data.statements.len() };
         let term = block_data.terminator();
-        results.analysis.apply_before_terminator_effect(state, term, loc);
-        vis.visit_terminator_before_primary_effect(results, state, term, loc);
-        results.analysis.apply_terminator_effect(state, term, loc);
-        vis.visit_terminator_after_primary_effect(results, state, term, loc);
+        results.analysis.apply_early_terminator_effect(state, term, loc);
+        vis.visit_after_early_terminator_effect(results, state, term, loc);
+        results.analysis.apply_primary_terminator_effect(state, term, loc);
+        vis.visit_after_primary_terminator_effect(results, state, term, loc);
 
         vis.visit_block_end(state);
     }