Unify GOSTART and GOSUB

GOSTART is a special case of GOSUB, we can remove a lot of offset twiddling,
and other special casing by unifying them, at pretty much no cost.

GOSUB has 2 arguments, ARG() and ARG2L(), which are interpreted as
a U32 and an I32 respectively. ARG() holds the "parno" we will recurse
into. ARG2L() holds a signed offset to the relevant start node for the
recursion.

Prior to this patch the argument to GOSUB would always be >=, and unlike
other parts of our logic we would not use 0 to represent "start/end" of
pattern, as GOSTART would be used for "recurse to beginning of pattern",
after this patch we use 0 to represent "start/end", and a lot of
complexity "goes away" along with GOSTART regops.

1 files changed, 10 insertions, 4 deletions

diff --git a/regexp.h b/regexp.h
index ff44df27e7..02258fe176 100644
--- a/regexp.h
+++ b/regexp.h
@@ -833,13 +833,19 @@ typedef struct regmatch_state {
     } u;
 } regmatch_state;
 
-#define EVAL_CLOSE_PAREN_IS(cur_eval,expr) \
+#define EVAL_CLOSE_PAREN_IS(st,expr) \
 (\
-    ( ( cur_eval )                                         ) && \
-    ( ( cur_eval )->u.eval.close_paren                     ) && \
-    ( ( ( cur_eval )->u.eval.close_paren - 1 ) == ( expr ) ) \
+    ( ( st )                                         ) && \
+    ( ( st )->u.eval.close_paren                     ) && \
+    ( ( ( st )->u.eval.close_paren - 1 ) == ( expr ) ) \
 )
 
+#define EVAL_CLOSE_PAREN_SET(st,expr) \
+    (st)->u.eval.close_paren = (expr) + 1
+
+#define EVAL_CLOSE_PAREN_CLEAR(st) \
+    (st)->u.eval.close_paren = 0
+
 /* how many regmatch_state structs to allocate as a single slab.
  * We do it in 4K blocks for efficiency. The "3" is 2 for the next/prev
  * pointers, plus 1 for any mythical malloc overhead. */