Address comments

Author: doctorn

src/librustc_mir/transform/validate.rs

@@ -11,6 +11,7 @@ use rustc_middle::{
 };
 use rustc_span::def_id::DefId;
 
+#[derive(Copy, Clone, Debug)]
 enum EdgeKind {
     Unwind,
     Normal,
@@ -54,7 +55,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
         );
     }
 
-    fn check_bb(&self, location: Location, bb: BasicBlock, edge_kind: EdgeKind) {
+    fn check_edge(&self, location: Location, bb: BasicBlock, edge_kind: EdgeKind) {
         if let Some(bb) = self.body.basic_blocks().get(bb) {
             let src = self.body.basic_blocks().get(location.block).unwrap();
             match (src.is_cleanup, bb.is_cleanup, edge_kind) {
@@ -68,7 +69,13 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                 _ => {
                     self.fail(
                         location,
-                        format!("encountered jump that does not respect unwind invariants {:?}", bb)
+                        format!(
+                            "{:?} edge to {:?} violates unwind invariants (cleanup {:?} -> {:?})",
+                            edge_kind,
+                            bb,
+                            src.is_cleanup,
+                            bb.is_cleanup,
+                        )
                     )
                 }
             }
@@ -114,7 +121,7 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
     fn visit_terminator(&mut self, terminator: &Terminator<'tcx>, location: Location) {
         match &terminator.kind {
             TerminatorKind::Goto { target } => {
-                self.check_bb(location, *target, EdgeKind::Normal);
+                self.check_edge(location, *target, EdgeKind::Normal);
             }
             TerminatorKind::SwitchInt { targets, values, .. } => {
                 if targets.len() != values.len() + 1 {
@@ -128,19 +135,19 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
                     );
                 }
                 for target in targets {
-                    self.check_bb(location, *target, EdgeKind::Normal);
+                    self.check_edge(location, *target, EdgeKind::Normal);
                 }
             }
             TerminatorKind::Drop { target, unwind, .. } => {
-                self.check_bb(location, *target, EdgeKind::Normal);
+                self.check_edge(location, *target, EdgeKind::Normal);
                 if let Some(unwind) = unwind {
-                    self.check_bb(location, *unwind, EdgeKind::Unwind);
+                    self.check_edge(location, *unwind, EdgeKind::Unwind);
                 }
             }
             TerminatorKind::DropAndReplace { target, unwind, .. } => {
-                self.check_bb(location, *target, EdgeKind::Normal);
+                self.check_edge(location, *target, EdgeKind::Normal);
                 if let Some(unwind) = unwind {
-                    self.check_bb(location, *unwind, EdgeKind::Unwind);
+                    self.check_edge(location, *unwind, EdgeKind::Unwind);
                 }
             }
             TerminatorKind::Call { func, destination, cleanup, .. } => {
@@ -153,10 +160,10 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
                     ),
                 }
                 if let Some((_, target)) = destination {
-                    self.check_bb(location, *target, EdgeKind::Normal);
+                    self.check_edge(location, *target, EdgeKind::Normal);
                 }
                 if let Some(cleanup) = cleanup {
-                    self.check_bb(location, *cleanup, EdgeKind::Unwind);
+                    self.check_edge(location, *cleanup, EdgeKind::Unwind);
                 }
             }
             TerminatorKind::Assert { cond, target, cleanup, .. } => {
@@ -170,30 +177,30 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
                         ),
                     );
                 }
-                self.check_bb(location, *target, EdgeKind::Normal);
+                self.check_edge(location, *target, EdgeKind::Normal);
                 if let Some(cleanup) = cleanup {
-                    self.check_bb(location, *cleanup, EdgeKind::Unwind);
+                    self.check_edge(location, *cleanup, EdgeKind::Unwind);
                 }
             }
             TerminatorKind::Yield { resume, drop, .. } => {
-                self.check_bb(location, *resume, EdgeKind::Normal);
+                self.check_edge(location, *resume, EdgeKind::Normal);
                 if let Some(drop) = drop {
-                    self.check_bb(location, *drop, EdgeKind::Normal);
+                    self.check_edge(location, *drop, EdgeKind::Normal);
                 }
             }
             TerminatorKind::FalseEdge { real_target, imaginary_target } => {
-                self.check_bb(location, *real_target, EdgeKind::Normal);
-                self.check_bb(location, *imaginary_target, EdgeKind::Normal);
+                self.check_edge(location, *real_target, EdgeKind::Normal);
+                self.check_edge(location, *imaginary_target, EdgeKind::Normal);
             }
             TerminatorKind::FalseUnwind { real_target, unwind } => {
-                self.check_bb(location, *real_target, EdgeKind::Normal);
+                self.check_edge(location, *real_target, EdgeKind::Normal);
                 if let Some(unwind) = unwind {
-                    self.check_bb(location, *unwind, EdgeKind::Unwind);
+                    self.check_edge(location, *unwind, EdgeKind::Unwind);
                 }
             }
             TerminatorKind::InlineAsm { destination, .. } => {
                 if let Some(destination) = destination {
-                    self.check_bb(location, *destination, EdgeKind::Normal);
+                    self.check_edge(location, *destination, EdgeKind::Normal);
                 }
             }
             // Nothing to validate for these.