Bug #35137

* unwind.c (uw_unwind_to_exit_point): When jumping to a catch frame,
do not mark it invisible.

* unwind.h (uw_catch): Flip the matches to nil so that this catch
frame can no longer be identified as an unwind point by uw_throw,
and thus will not be re-entered for the purposes of handling
an exception. It remains visible for the purposes of running the
clean up code.
(uw_unwind): Prior to executing cleanup forms, flip the visibility
to 0. This means that the frame will no longer be re-entered
for any reason.

1 files changed, 8 insertions, 2 deletions

diff --git a/unwind.h b/unwind.h
index 98b965e7..03e43982 100644
--- a/unwind.h
+++ b/unwind.h
@@ -155,11 +155,17 @@ noreturn val type_mismatch(val, ...);
       break;                            \
     case 2:                             \
       EXCVAR = uw_catch.ca.exception;   \
-      SYMVAR = uw_catch.ca.sym;
+      SYMVAR = uw_catch.ca.sym;         \
+      /* prevent looping */             \
+      uw_catch.ca.matches = nil;
 
 #define uw_unwind                       \
+    /* suppress unused label warning */ \
+    goto uw_unwind_label;               \
     uw_unwind_label:                    \
-    case 1:
+    case 1:                             \
+      /* prevent looping */             \
+      uw_catch.ca.visible = 0;
 
 #define uw_catch_end                    \
       break;                            \