add CvGV_set() macro and make CvGV() rvalue only

Now that CvGV can sometimes be reference counted, stop people from directly
assigning to it (by using CvGV as an lvalue), and instead force them to use
CvGV_set()

6 files changed, 13 insertions, 12 deletions

diff --git a/cv.h b/cv.h
index d762a062cf..7979a05c80 100644
--- a/cv.h
+++ b/cv.h
@@ -41,7 +41,8 @@ Returns the stash of the CV.
 #define CvROOT(sv)	((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_root_u.xcv_root
 #define CvXSUB(sv)	((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_root_u.xcv_xsub
 #define CvXSUBANY(sv)	((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_start_u.xcv_xsubany
-#define CvGV(sv)	((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_gv
+#define CvGV(sv)	(0+((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_gv)
+#define CvGV_set(cv,gv)	Perl_cvgv_set(aTHX_ cv, gv)
 #define CvFILE(sv)	((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_file
 #ifdef USE_ITHREADS
 #  define CvFILE_set_from_cop(sv, cop)	(CvFILE(sv) = savepv(CopFILE(cop)))
diff --git a/gv.c b/gv.c
index 917cfb7ee9..a5c33d93f1 100644
--- a/gv.c
+++ b/gv.c
@@ -215,7 +215,7 @@ Perl_cvgv_set(pTHX_ CV* cv, GV* gv)
 	}
     }
 
-    CvGV(cv) = gv;
+    SvANY(cv)->xcv_gv = gv;
     assert(!CvCVGV_RC(cv));
 
     if (!gv)
@@ -303,7 +303,7 @@ Perl_gv_init(pTHX_ GV *gv, HV *stash, const char *name, STRLEN len, int multi)
 	LEAVE;
 
         mro_method_changed_in(GvSTASH(gv)); /* sub Foo::bar($) { (shift) } sub ASDF::baz($); *ASDF::baz = \&Foo::bar */
-	cvgv_set(cv, gv);
+	CvGV_set(cv, gv);
 	CvFILE_set_from_cop(cv, PL_curcop);
 	CvSTASH(cv) = PL_curstash;
 	if (PL_curstash)
diff --git a/op.c b/op.c
index 3ae15cb874..276e10093e 100644
--- a/op.c
+++ b/op.c
@@ -5459,7 +5459,7 @@ Perl_cv_undef(pTHX_ CV *cv)
 	LEAVE;
     }
     SvPOK_off(MUTABLE_SV(cv));		/* forget prototype */
-    cvgv_set(cv, NULL);
+    CvGV_set(cv, NULL);
 
     pad_undef(cv);
 
@@ -5872,7 +5872,7 @@ Perl_newATTRSUB(pTHX_ I32 floor, OP *o, OP *proto, OP *attrs, OP *block)
 	}
     }
     if (!CvGV(cv)) {
-	cvgv_set(cv, gv);
+	CvGV_set(cv, gv);
 	CvFILE_set_from_cop(cv, PL_curcop);
 	CvSTASH(cv) = PL_curstash;
 	if (PL_curstash)
@@ -6236,7 +6236,7 @@ Perl_newXS(pTHX_ const char *name, XSUBADDR_t subaddr, const char *filename)
     }
     if (!name)
 	CvANON_on(cv);
-    cvgv_set(cv, gv);
+    CvGV_set(cv, gv);
     (void)gv_fetchfile(filename);
     CvFILE(cv) = (char *)filename; /* NOTE: not copied, as it is expected to be
 				   an external constant string */
@@ -6285,7 +6285,7 @@ Perl_newFORM(pTHX_ I32 floor, OP *o, OP *block)
     }
     cv = PL_compcv;
     GvFORM(gv) = cv;
-    cvgv_set(cv, gv);
+    CvGV_set(cv, gv);
     CvFILE_set_from_cop(cv, PL_curcop);
 
 
diff --git a/pad.c b/pad.c
index 3582544475..0b3c948ef2 100644
--- a/pad.c
+++ b/pad.c
@@ -1571,7 +1571,7 @@ Perl_cv_clone(pTHX_ CV *proto)
 #else
     CvFILE(cv)		= CvFILE(proto);
 #endif
-    cvgv_set(cv,CvGV(proto));
+    CvGV_set(cv,CvGV(proto));
     CvSTASH(cv)		= CvSTASH(proto);
     if (CvSTASH(cv))
 	Perl_sv_add_backref(aTHX_ MUTABLE_SV(CvSTASH(cv)), MUTABLE_SV(cv));
diff --git a/pp.c b/pp.c
index a78c1cca74..129c94811f 100644
--- a/pp.c
+++ b/pp.c
@@ -838,7 +838,7 @@ PP(pp_undef)
 	    /* let user-undef'd sub keep its identity */
 	    GV* const gv = CvGV((const CV *)sv);
 	    cv_undef(MUTABLE_CV(sv));
-	    cvgv_set(MUTABLE_CV(sv), gv);
+	    CvGV_set(MUTABLE_CV(sv), gv);
 	}
 	break;
     case SVt_PVGV:
diff --git a/sv.c b/sv.c
index 1e756f2420..10e41a9c99 100644
--- a/sv.c
+++ b/sv.c
@@ -5675,7 +5675,7 @@ S_anonymise_cv_maybe(pTHX_ GV *gv, CV* cv)
 
     /* will the CV shortly be freed by gp_free() ? */
     if (GvCV(gv) == cv && GvGP(gv)->gp_refcnt < 2 && SvREFCNT(cv) < 2) {
-	CvGV(cv) = NULL;
+	SvANY(cv)->xcv_gv = NULL;
 	return;
     }
 
@@ -5688,7 +5688,7 @@ S_anonymise_cv_maybe(pTHX_ GV *gv, CV* cv)
 
     CvANON_on(cv);
     CvCVGV_RC_on(cv);
-    CvGV(cv) = MUTABLE_GV(SvREFCNT_inc(anongv));
+    SvANY(cv)->xcv_gv = MUTABLE_GV(SvREFCNT_inc(anongv));
 }
 
 
@@ -11438,7 +11438,7 @@ S_sv_dup_common(pTHX_ const SV *const sstr, CLONE_PARAMS *const param)
 		}
 		/* don't dup if copying back - CvGV isn't refcounted, so the
 		 * duped GV may never be freed. A bit of a hack! DAPM */
-		CvGV(dstr) =
+		SvANY(MUTABLE_CV(dstr))->xcv_gv =
 		    CvCVGV_RC(dstr)
 		    ? gv_dup_inc(CvGV(sstr), param)
 		    : (param->flags & CLONEf_JOIN_IN)