Add comments to interpret_cs_action

Author: Amanieu

src/libpanic_unwind/dwarf/eh.rs

@@ -129,10 +129,15 @@ pub unsafe fn find_eh_action(lsda: *const u8, context: &EHContext<'_>, foreign_e
 
 fn interpret_cs_action(cs_action: u64, lpad: usize, foreign_exception: bool) -> EHAction {
     if cs_action == 0 {
+        // If cs_action is 0 then this is a cleanup (Drop::drop). We run these
+        // for both Rust panics and foriegn exceptions.
         EHAction::Cleanup(lpad)
     } else if foreign_exception {
+        // catch_unwind should not catch foreign exceptions, only Rust panics.
+        // Instead just continue unwinding.
         EHAction::None
     } else {
+        // Stop unwinding Rust panics at catch_unwind.
         EHAction::Catch(lpad)
     }
 }