Auto merge of rust-lang#2312 - RalfJung:misc, r=RalfJung

put call to stacked borrows end_call in a more sensible place

This looks like a refactoring accident.

Author: bors

README.md

@@ -65,9 +65,9 @@ in your program, and cannot run all programs:
   not support networking. System API support varies between targets; if you run
   on Windows it is a good idea to use `--target x86_64-unknown-linux-gnu` to get
   better support.
-* Weak memory emulation may produce weak behaivours unobservable by compiled
-  programs running on real hardware when `SeqCst` fences are used, and it cannot
-  produce all behaviors possibly observable on real hardware.
+* Weak memory emulation may [produce weak behaivours](https://github.com/rust-lang/miri/issues/2301)
+  unobservable by compiled programs running on real hardware when `SeqCst` fences are used, and it
+  cannot produce all behaviors possibly observable on real hardware.
 
 [rust]: https://www.rust-lang.org/
 [mir]: https://github.com/rust-lang/rfcs/blob/master/text/1211-mir.md
@@ -192,8 +192,9 @@ randomness that is used to determine allocation base addresses. The following
 snippet calls Miri in a loop with different values for the seed:
 
 ```
-for seed in $({ echo obase=16; seq 0 255; } | bc); do
-  MIRIFLAGS=-Zmiri-seed=$seed cargo miri test || { echo "Last seed: $seed"; break; };
+for SEED in $({ echo obase=16; seq 0 255; } | bc); do
+  echo "Trying seed: $SEED"
+  MIRIFLAGS=-Zmiri-seed=$SEED cargo miri test || { echo "Failing seed: $SEED"; break; };
 done
 ```
 

src/machine.rs

@@ -930,7 +930,10 @@ impl<'mir, 'tcx> Machine<'mir, 'tcx> for Evaluator<'mir, 'tcx> {
         unwinding: bool,
     ) -> InterpResult<'tcx, StackPopJump> {
         let timing = frame.extra.timing.take();
-        let res = ecx.handle_stack_pop(frame.extra, unwinding);
+        if let Some(stacked_borrows) = &ecx.machine.stacked_borrows {
+            stacked_borrows.borrow_mut().end_call(frame.extra.call_id);
+        }
+        let res = ecx.handle_stack_pop_unwind(frame.extra, unwinding);
         if let Some(profiler) = ecx.machine.profiler.as_ref() {
             profiler.finish_recording_interval_event(timing.unwrap());
         }

src/shims/panic.rs

@@ -115,17 +115,13 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         Ok(())
     }
 
-    fn handle_stack_pop(
+    fn handle_stack_pop_unwind(
         &mut self,
         mut extra: FrameData<'tcx>,
         unwinding: bool,
     ) -> InterpResult<'tcx, StackPopJump> {
         let this = self.eval_context_mut();
-
-        trace!("handle_stack_pop(extra = {:?}, unwinding = {})", extra, unwinding);
-        if let Some(stacked_borrows) = &this.machine.stacked_borrows {
-            stacked_borrows.borrow_mut().end_call(extra.call_id);
-        }
+        trace!("handle_stack_pop_unwind(extra = {:?}, unwinding = {})", extra, unwinding);
 
         // We only care about `catch_panic` if we're unwinding - if we're doing a normal
         // return, then we don't need to do anything special.