Filter: Implement direct recursion

Direct recursion almost worked, just crashed on function signature check.
Split function parsing such that function signature is saved before
function body is processed. Recursive calls are marked so they can be
avoided during f_same() and similar code walking.

Also, include tower of hanoi solver as a test case.

1 files changed, 7 insertions, 2 deletions

diff --git a/filter/f-inst.c b/filter/f-inst.c
index 500732c6..e75b5e01 100644
--- a/filter/f-inst.c
+++ b/filter/f-inst.c
@@ -1165,11 +1165,16 @@
     whati->fvar = tmp;
     what->size += tmp->size;
 
+    /* Mark recursive calls, they have dummy f_line */
+    if (!sym->function->len)
+      what->flags |= FIF_RECURSIVE;
+
     FID_SAME_BODY()
-      if (!(f1->sym->flags & SYM_FLAG_SAME))
-	return 0;
+    if (!(f1->sym->flags & SYM_FLAG_SAME) && !(f1_->flags & FIF_RECURSIVE))
+      return 0;
 
     FID_ITERATE_BODY()
+    if (!(what->flags & FIF_RECURSIVE))
       BUFFER_PUSH(fit->lines) = whati->sym->function;
 
     FID_INTERPRET_BODY()