Streamlining exception handling macros a little bit.

* eval.c (op_unwind_protect): Use uw_simple_catch_begin,
and remove the uw_catch (exsym, exvals) clause. Put
explicit braces around the unwind code even though it
is only one statement.

* match.c (do_txeval): Got rid of empty uw_unwind clause.
This is not needed any longer.
(v_try): Got rid of explicit uw_do_unwind calls.

* unwind.h (uw_simple_catch_begin): New macro.
(uw_do_unwind): Macro removed.
(uw_catch): Added goto uw_unwind_label at the front.
This way if the previous clause falls through,
control goes to the unwind logic.
(uw_unwind): Got rid of initial break. Previous
clause should fall through to unwind logic,
whether it is the main clause, or one of the catches.
(uw_catch_end): Default case aborts, because
we don't expect this.

1 files changed, 10 insertions, 5 deletions

diff --git a/unwind.h b/unwind.h
index 4dea9469..98b965e7 100644
--- a/unwind.h
+++ b/unwind.h
@@ -133,6 +133,13 @@ noreturn val type_mismatch(val, ...);
     uw_pop_frame(&uw_env);              \
   } while (0)
 
+#define uw_simple_catch_begin           \
+  do {                                  \
+    uw_frame_t uw_catch;                \
+    uw_push_catch(&uw_catch, nil);      \
+    switch (setjmp(uw_catch.ca.jb)) {   \
+    case 0:
+
 #define uw_catch_begin(MATCHES, SYMVAR, \
                        EXCVAR)          \
   obj_t *SYMVAR = nil;                  \
@@ -143,23 +150,21 @@ noreturn val type_mismatch(val, ...);
     switch (setjmp(uw_catch.ca.jb)) {   \
     case 0:
 
-#define uw_do_unwind                    \
-      goto uw_unwind_label
-
 #define uw_catch(SYMVAR, EXCVAR)        \
+    goto uw_unwind_label;               \
       break;                            \
     case 2:                             \
       EXCVAR = uw_catch.ca.exception;   \
       SYMVAR = uw_catch.ca.sym;
 
 #define uw_unwind                       \
-      break;                            \
     uw_unwind_label:                    \
     case 1:
 
 #define uw_catch_end                    \
-    default:                            \
       break;                            \
+    default:                            \
+      abort();                          \
     }                                   \
     if (uw_catch.ca.cont)               \
       uw_continue(&uw_catch,            \