add CVf_CVGV_RC flag

after the recent commit 803f274831f937654d48f8cf0468521cbf8f5dff,
the CvGV field is sometimes reference counted. Since it was intended that
the reference counting would happen only for anonymous CVs, the CVf_ANON
flag was co-opted to indicate whether RC was being used. This is not
entirely robust; for example, sub __ANON__ {} is a non-anon sub which
points to the same GV used by anon subs, which while itself doesn't
directly break things, shows that the potential for breakage is there.

So add a separate flag just to indicate the reference count status of the
CvGV field.

1 files changed, 2 insertions, 2 deletions

diff --git a/op.c b/op.c
index e5f9604521..3ae15cb874 100644
--- a/op.c
+++ b/op.c
@@ -5476,9 +5476,9 @@ Perl_cv_undef(pTHX_ CV *cv)
     if (CvISXSUB(cv) && CvXSUB(cv)) {
 	CvXSUB(cv) = NULL;
     }
-    /* delete all flags except WEAKOUTSIDE and ANON, which indicate the
+    /* delete all flags except WEAKOUTSIDE and CVGV_RC, which indicate the
      * ref status of CvOUTSIDE and CvGV */
-    CvFLAGS(cv) &= (CVf_WEAKOUTSIDE|CVf_ANON);
+    CvFLAGS(cv) &= (CVf_WEAKOUTSIDE|CVf_CVGV_RC);
 }
 
 void