Mir: Add Terminatorkind::Abort

The Abort Terminatorkind will cause an llvm.trap function call to be
emitted.

Signed-off-by: David Henningsson <diwic@ubuntu.com>

Author: diwic

src/librustc/ich/impls_mir.rs

@@ -150,6 +150,7 @@ for mir::TerminatorKind<'gcx> {
                 targets.hash_stable(hcx, hasher);
             }
             mir::TerminatorKind::Resume |
+            mir::TerminatorKind::Abort |
             mir::TerminatorKind::Return |
             mir::TerminatorKind::GeneratorDrop |
             mir::TerminatorKind::Unreachable => {}

src/librustc/mir/mod.rs

@@ -637,6 +637,10 @@ pub enum TerminatorKind<'tcx> {
     /// continue. Emitted by build::scope::diverge_cleanup.
     Resume,
 
+    /// Indicates that the landing pad is finished and that the process
+    /// should abort. Used to prevent unwinding for foreign items.
+    Abort,
+
     /// Indicates a normal return. The return place should have
     /// been filled in by now. This should occur at most once.
     Return,
@@ -759,7 +763,7 @@ impl<'tcx> TerminatorKind<'tcx> {
         match *self {
             Goto { target: ref b } => slice::from_ref(b).into_cow(),
             SwitchInt { targets: ref b, .. } => b[..].into_cow(),
-            Resume | GeneratorDrop => (&[]).into_cow(),
+            Resume | Abort | GeneratorDrop => (&[]).into_cow(),
             Return => (&[]).into_cow(),
             Unreachable => (&[]).into_cow(),
             Call { destination: Some((_, t)), cleanup: Some(c), .. } => vec![t, c].into_cow(),
@@ -794,7 +798,7 @@ impl<'tcx> TerminatorKind<'tcx> {
         match *self {
             Goto { target: ref mut b } => vec![b],
             SwitchInt { targets: ref mut b, .. } => b.iter_mut().collect(),
-            Resume | GeneratorDrop => Vec::new(),
+            Resume | Abort | GeneratorDrop => Vec::new(),
             Return => Vec::new(),
             Unreachable => Vec::new(),
             Call { destination: Some((_, ref mut t)), cleanup: Some(ref mut c), .. } => vec![t, c],
@@ -823,6 +827,7 @@ impl<'tcx> TerminatorKind<'tcx> {
         match *self {
             TerminatorKind::Goto { .. } |
             TerminatorKind::Resume |
+            TerminatorKind::Abort |
             TerminatorKind::Return |
             TerminatorKind::Unreachable |
             TerminatorKind::GeneratorDrop |
@@ -918,6 +923,7 @@ impl<'tcx> TerminatorKind<'tcx> {
             Return => write!(fmt, "return"),
             GeneratorDrop => write!(fmt, "generator_drop"),
             Resume => write!(fmt, "resume"),
+            Abort => write!(fmt, "abort"),
             Yield { ref value, .. } => write!(fmt, "_1 = suspend({:?})", value),
             Unreachable => write!(fmt, "unreachable"),
             Drop { ref location, .. } => write!(fmt, "drop({:?})", location),
@@ -970,7 +976,7 @@ impl<'tcx> TerminatorKind<'tcx> {
     pub fn fmt_successor_labels(&self) -> Vec<Cow<'static, str>> {
         use self::TerminatorKind::*;
         match *self {
-            Return | Resume | Unreachable | GeneratorDrop => vec![],
+            Return | Resume | Abort | Unreachable | GeneratorDrop => vec![],
             Goto { .. } => vec!["".into()],
             SwitchInt { ref values, .. } => {
                 values.iter()
@@ -2102,6 +2108,7 @@ impl<'tcx> TypeFoldable<'tcx> for Terminator<'tcx> {
             },
             GeneratorDrop => GeneratorDrop,
             Resume => Resume,
+            Abort => Abort,
             Return => Return,
             Unreachable => Unreachable,
             FalseEdges { real_target, ref imaginary_targets } =>
@@ -2143,6 +2150,7 @@ impl<'tcx> TypeFoldable<'tcx> for Terminator<'tcx> {
             },
             Goto { .. } |
             Resume |
+            Abort |
             Return |
             GeneratorDrop |
             Unreachable |

src/librustc/mir/visit.rs

@@ -432,6 +432,7 @@ macro_rules! make_mir_visitor {
                     }
 
                     TerminatorKind::Resume |
+                    TerminatorKind::Abort |
                     TerminatorKind::Return |
                     TerminatorKind::GeneratorDrop |
                     TerminatorKind::Unreachable => {

src/librustc_mir/borrow_check/mod.rs

@@ -557,6 +557,7 @@ impl<'cx, 'gcx, 'tcx> DataflowResultsConsumer<'cx, 'tcx> for MirBorrowckCtxt<'cx
                 });
             }
             TerminatorKind::Goto { target: _ }
+            | TerminatorKind::Abort
             | TerminatorKind::Unreachable
             | TerminatorKind::FalseEdges { .. } => {
                 // no data used, thus irrelevant to borrowck

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

@@ -780,6 +780,7 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
         match term.kind {
             TerminatorKind::Goto { .. }
             | TerminatorKind::Resume
+            | TerminatorKind::Abort
             | TerminatorKind::Return
             | TerminatorKind::GeneratorDrop
             | TerminatorKind::Unreachable
@@ -1082,6 +1083,9 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
             TerminatorKind::Resume => if !is_cleanup {
                 span_mirbug!(self, block_data, "resume on non-cleanup block!")
             },
+            TerminatorKind::Abort => if !is_cleanup {
+                span_mirbug!(self, block_data, "abort on non-cleanup block!")
+            },
             TerminatorKind::Return => if is_cleanup {
                 span_mirbug!(self, block_data, "return on cleanup block")
             },

src/librustc_mir/dataflow/impls/borrows.rs

@@ -465,6 +465,7 @@ impl<'a, 'gcx, 'tcx> Borrows<'a, 'gcx, 'tcx> {
                     }
                 }
             }
+            mir::TerminatorKind::Abort |
             mir::TerminatorKind::SwitchInt {..} |
             mir::TerminatorKind::Drop {..} |
             mir::TerminatorKind::DropAndReplace {..} |

src/librustc_mir/dataflow/mod.rs

@@ -771,6 +771,7 @@ impl<'a, 'tcx: 'a, D> DataflowAnalysis<'a, 'tcx, D> where D: BitDenotation
         match bb_data.terminator().kind {
             mir::TerminatorKind::Return |
             mir::TerminatorKind::Resume |
+            mir::TerminatorKind::Abort |
             mir::TerminatorKind::GeneratorDrop |
             mir::TerminatorKind::Unreachable => {}
             mir::TerminatorKind::Goto { ref target } |

src/librustc_mir/dataflow/move_paths/builder.rs

@@ -334,6 +334,7 @@ impl<'b, 'a, 'gcx, 'tcx> Gatherer<'b, 'a, 'gcx, 'tcx> {
         match term.kind {
             TerminatorKind::Goto { target: _ } |
             TerminatorKind::Resume |
+            TerminatorKind::Abort |
             TerminatorKind::GeneratorDrop |
             TerminatorKind::FalseEdges { .. } |
             TerminatorKind::Unreachable => { }

src/librustc_mir/interpret/terminator/mod.rs

@@ -163,6 +163,7 @@ impl<'a, 'tcx, M: Machine<'tcx>> EvalContext<'a, 'tcx, M> {
             GeneratorDrop => unimplemented!(),
             DropAndReplace { .. } => unimplemented!(),
             Resume => unimplemented!(),
+            Abort => unimplemented!(),
             FalseEdges { .. } => bug!("should have been eliminated by `simplify_branches` mir pass"),
             Unreachable => return err!(Unreachable),
         }

src/librustc_mir/monomorphize/collector.rs

@@ -625,6 +625,7 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirNeighborCollector<'a, 'tcx> {
             mir::TerminatorKind::Goto { .. } |
             mir::TerminatorKind::SwitchInt { .. } |
             mir::TerminatorKind::Resume |
+            mir::TerminatorKind::Abort |
             mir::TerminatorKind::Return |
             mir::TerminatorKind::Unreachable |
             mir::TerminatorKind::Assert { .. } => {}