unwind is no longer Option<BasicBlock>

rust-version

@@ -1 +1 @@
-0f8cd43ee8c3614e04b5c624dd8a45758d7023da
+ce0d64e03ef9875e0935bb60e989542b7ec29579

src/machine.rs

@@ -356,7 +356,7 @@ impl<'mir, 'tcx> Machine<'mir, 'tcx> for Evaluator<'mir, 'tcx> {
         abi: Abi,
         args: &[OpTy<'tcx, Tag>],
         ret: Option<(&PlaceTy<'tcx, Tag>, mir::BasicBlock)>,
-        unwind: Option<mir::BasicBlock>,
+        unwind: StackPopUnwind,
     ) -> InterpResult<'tcx, Option<&'mir mir::Body<'tcx>>> {
         ecx.find_mir_or_eval_fn(instance, abi, args, ret, unwind)
     }
@@ -368,7 +368,7 @@ impl<'mir, 'tcx> Machine<'mir, 'tcx> for Evaluator<'mir, 'tcx> {
         abi: Abi,
         args: &[OpTy<'tcx, Tag>],
         ret: Option<(&PlaceTy<'tcx, Tag>, mir::BasicBlock)>,
-        _unwind: Option<mir::BasicBlock>,
+        _unwind: StackPopUnwind,
     ) -> InterpResult<'tcx> {
         ecx.call_dlsym(fn_val, abi, args, ret)
     }
@@ -379,7 +379,7 @@ impl<'mir, 'tcx> Machine<'mir, 'tcx> for Evaluator<'mir, 'tcx> {
         instance: ty::Instance<'tcx>,
         args: &[OpTy<'tcx, Tag>],
         ret: Option<(&PlaceTy<'tcx, Tag>, mir::BasicBlock)>,
-        unwind: Option<mir::BasicBlock>,
+        unwind: StackPopUnwind,
     ) -> InterpResult<'tcx> {
         ecx.call_intrinsic(instance, args, ret, unwind)
     }

src/shims/foreign_items.rs

@@ -120,7 +120,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         abi: Abi,
         args: &[OpTy<'tcx, Tag>],
         ret: Option<(&PlaceTy<'tcx, Tag>, mir::BasicBlock)>,
-        unwind: Option<mir::BasicBlock>,
+        unwind: StackPopUnwind,
     ) -> InterpResult<'tcx, Option<&'mir mir::Body<'tcx>>> {
         let this = self.eval_context_mut();
         let attrs = this.tcx.get_attrs(def_id);

src/shims/intrinsics.rs

@@ -23,7 +23,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         instance: ty::Instance<'tcx>,
         args: &[OpTy<'tcx, Tag>],
         ret: Option<(&PlaceTy<'tcx, Tag>, mir::BasicBlock)>,
-        _unwind: Option<mir::BasicBlock>,
+        _unwind: StackPopUnwind,
     ) -> InterpResult<'tcx> {
         let this = self.eval_context_mut();
 

src/shims/mod.rs

@@ -29,7 +29,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         abi: Abi,
         args: &[OpTy<'tcx, Tag>],
         ret: Option<(&PlaceTy<'tcx, Tag>, mir::BasicBlock)>,
-        unwind: Option<mir::BasicBlock>,
+        unwind: StackPopUnwind,
     ) -> InterpResult<'tcx, Option<&'mir mir::Body<'tcx>>> {
         let this = self.eval_context_mut();
         trace!("eval_fn_call: {:#?}, {:?}", instance, ret.map(|p| p.0));
@@ -64,7 +64,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         ptr_op: &OpTy<'tcx, Tag>,
         align_op: &OpTy<'tcx, Tag>,
         ret: Option<(&PlaceTy<'tcx, Tag>, mir::BasicBlock)>,
-        unwind: Option<mir::BasicBlock>,
+        unwind: StackPopUnwind,
     ) -> InterpResult<'tcx, bool> {
         let this = self.eval_context_mut();
         let (dest, ret) = ret.unwrap();

src/shims/panic.rs

@@ -41,15 +41,11 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
     fn handle_miri_start_panic(
         &mut self,
         args: &[OpTy<'tcx, Tag>],
-        unwind: Option<mir::BasicBlock>,
+        unwind: StackPopUnwind,
     ) -> InterpResult<'tcx> {
         let this = self.eval_context_mut();
 
         trace!("miri_start_panic: {:?}", this.frame().instance);
-        // Make sure we only start unwinding when this matches our panic strategy.
-        if this.tcx.sess.panic_strategy() != PanicStrategy::Unwind {
-            throw_ub_format!("unwinding despite panic=abort");
-        }
 
         // Get the raw pointer stored in arg[0] (the panic payload).
         let &[ref payload] = check_arg_count(args)?;
@@ -59,7 +55,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         thread.panic_payload = Some(payload);
 
         // Jump to the unwind block to begin unwinding.
-        this.unwind_to_block(unwind);
+        this.unwind_to_block(unwind)?;
         return Ok(());
     }
 
@@ -99,7 +95,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
             &[data.into()],
             Some(&ret_place),
             // Directly return to caller.
-            StackPopCleanup::Goto { ret: Some(ret), unwind: None },
+            StackPopCleanup::Goto { ret: Some(ret), unwind: StackPopUnwind::Skip },
         )?;
 
         // We ourselves will return `0`, eventually (will be overwritten if we catch a panic).
@@ -155,7 +151,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
                 &[catch_unwind.data.into(), payload.into()],
                 Some(&ret_place),
                 // Directly return to caller of `try`.
-                StackPopCleanup::Goto { ret: Some(catch_unwind.ret), unwind: None },
+                StackPopCleanup::Goto { ret: Some(catch_unwind.ret), unwind: StackPopUnwind::Skip },
             )?;
 
             // We pushed a new stack frame, the engine should not do any jumping now!
@@ -166,7 +162,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
     }
 
     /// Starta a panic in the interpreter with the given message as payload.
-    fn start_panic(&mut self, msg: &str, unwind: Option<mir::BasicBlock>) -> InterpResult<'tcx> {
+    fn start_panic(&mut self, msg: &str, unwind: StackPopUnwind) -> InterpResult<'tcx> {
         let this = self.eval_context_mut();
 
         // First arg: message.
@@ -209,12 +205,24 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
                     Abi::Rust,
                     &[index.into(), len.into()],
                     None,
-                    StackPopCleanup::Goto { ret: None, unwind },
+                    StackPopCleanup::Goto {
+                        ret: None,
+                        unwind: match unwind {
+                            Some(cleanup) => StackPopUnwind::Cleanup(cleanup),
+                            None => StackPopUnwind::Skip,
+                        },
+                    },
                 )?;
             }
             _ => {
                 // Forward everything else to `panic` lang item.
-                this.start_panic(msg.description(), unwind)?;
+                this.start_panic(
+                    msg.description(),
+                    match unwind {
+                        Some(cleanup) => StackPopUnwind::Cleanup(cleanup),
+                        None => StackPopUnwind::Skip,
+                    },
+                )?;
             }
         }
         Ok(())

tests/compile-fail/panic/unwind_panic_abort.rs

@@ -7,5 +7,5 @@ extern "Rust" {
 }
 
 fn main() {
-    unsafe { miri_start_panic(&mut 0); } //~ ERROR unwinding despite panic=abort
+    unsafe { miri_start_panic(&mut 0); } //~ ERROR unwinding past a stack frame that does not allow unwinding
 }