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, 6 insertions, 4 deletions

diff --git a/cv.h b/cv.h
index fe96aa3e3a..d762a062cf 100644
--- a/cv.h
+++ b/cv.h
@@ -70,14 +70,12 @@ Returns the stash of the CV.
 #define CVf_WEAKOUTSIDE	0x0010  /* CvOUTSIDE isn't ref counted */
 #define CVf_CLONE	0x0020	/* anon CV uses external lexicals */
 #define CVf_CLONED	0x0040	/* a clone of one of those */
-#define CVf_ANON	0x0080	/* implies: CV is not pointed to by a GV,
-				            CvGV is refcounted, and
-					    points to an __ANON__ GV;
-				   at compile time only, also implies sub {} */
+#define CVf_ANON	0x0080	/* CV is not pointed to by a GV */
 #define CVf_UNIQUE	0x0100	/* sub is only called once (eg PL_main_cv,
 				 * require, eval). */
 #define CVf_NODEBUG	0x0200	/* no DB::sub indirection for this CV
 				   (esp. useful for special XSUBs) */
+#define CVf_CVGV_RC	0x0400	/* CvGV is reference counted */
 
 /* This symbol for optimised communication between toke.c and op.c: */
 #define CVf_BUILTIN_ATTRS	(CVf_METHOD|CVf_LVALUE)
@@ -131,6 +129,10 @@ Returns the stash of the CV.
 #define CvISXSUB_on(cv)		(CvFLAGS(cv) |= CVf_ISXSUB)
 #define CvISXSUB_off(cv)	(CvFLAGS(cv) &= ~CVf_ISXSUB)
 
+#define CvCVGV_RC(cv)		(CvFLAGS(cv) & CVf_CVGV_RC)
+#define CvCVGV_RC_on(cv)	(CvFLAGS(cv) |= CVf_CVGV_RC)
+#define CvCVGV_RC_off(cv)	(CvFLAGS(cv) &= ~CVf_CVGV_RC)
+
 /* Flags for newXS_flags  */
 #define XS_DYNAMIC_FILENAME	0x01	/* The filename isn't static  */