Visit only terminators when removing landing pads

No functional changes intended

Author: tmiasko

compiler/rustc_mir/src/shim.rs

@@ -81,7 +81,7 @@ fn make_shim<'tcx>(tcx: TyCtxt<'tcx>, instance: ty::InstanceDef<'tcx>) -> Body<'
         MirPhase::Const,
         &[&[
             &add_moves_for_packed_drops::AddMovesForPackedDrops,
-            &no_landing_pads::NoLandingPads::new(tcx),
+            &no_landing_pads::NoLandingPads,
             &remove_noop_landing_pads::RemoveNoopLandingPads,
             &simplify::SimplifyCfg::new("make_shim"),
             &add_call_guards::CriticalCallEdges,

compiler/rustc_mir/src/transform/mod.rs

@@ -433,15 +433,15 @@ fn run_post_borrowck_cleanup_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tc
 
     let post_borrowck_cleanup: &[&dyn MirPass<'tcx>] = &[
         // Remove all things only needed by analysis
-        &no_landing_pads::NoLandingPads::new(tcx),
+        &no_landing_pads::NoLandingPads,
         &simplify_branches::SimplifyBranches::new("initial"),
         &remove_noop_landing_pads::RemoveNoopLandingPads,
         &cleanup_post_borrowck::CleanupNonCodegenStatements,
         &simplify::SimplifyCfg::new("early-opt"),
         // These next passes must be executed together
         &add_call_guards::CriticalCallEdges,
         &elaborate_drops::ElaborateDrops,
-        &no_landing_pads::NoLandingPads::new(tcx),
+        &no_landing_pads::NoLandingPads,
         // AddMovesForPackedDrops needs to run after drop
         // elaboration.
         &add_moves_for_packed_drops::AddMovesForPackedDrops,

compiler/rustc_mir/src/transform/no_landing_pads.rs

@@ -2,42 +2,27 @@
 //! specified.
 
 use crate::transform::MirPass;
-use rustc_middle::mir::visit::MutVisitor;
 use rustc_middle::mir::*;
 use rustc_middle::ty::TyCtxt;
 use rustc_target::spec::PanicStrategy;
 
-pub struct NoLandingPads<'tcx> {
-    tcx: TyCtxt<'tcx>,
-}
-
-impl<'tcx> NoLandingPads<'tcx> {
-    pub fn new(tcx: TyCtxt<'tcx>) -> Self {
-        NoLandingPads { tcx }
-    }
-}
+pub struct NoLandingPads;
 
-impl<'tcx> MirPass<'tcx> for NoLandingPads<'tcx> {
+impl<'tcx> MirPass<'tcx> for NoLandingPads {
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         no_landing_pads(tcx, body)
     }
 }
 
 pub fn no_landing_pads<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
-    if tcx.sess.panic_strategy() == PanicStrategy::Abort {
-        NoLandingPads::new(tcx).visit_body(body);
-    }
-}
-
-impl<'tcx> MutVisitor<'tcx> for NoLandingPads<'tcx> {
-    fn tcx(&self) -> TyCtxt<'tcx> {
-        self.tcx
+    if tcx.sess.panic_strategy() != PanicStrategy::Abort {
+        return;
     }
 
-    fn visit_terminator(&mut self, terminator: &mut Terminator<'tcx>, location: Location) {
+    for block in body.basic_blocks_mut() {
+        let terminator = block.terminator_mut();
         if let Some(unwind) = terminator.kind.unwind_mut() {
             unwind.take();
         }
-        self.super_terminator(terminator, location);
     }
 }