Move SVt_BIND to be the lowest type after SVt_NULL. This will force all

code attempting to upgrade a BIND to anything into sv_upgrade(), which
for now will croak, but in future can DTRT, for whatever TRT is decided
to be. Make SvOK() check the flags of the referenant for a BIND, as I
envisage that the only flag bit that will get set on a BIND is SVf_UTF8
even if the referant has a defined value.

p4raw-id: //depot/perl@29642

4 files changed, 17 insertions, 13 deletions

diff --git a/dump.c b/dump.c
index 0ad48d1e99..7f221814a9 100644
--- a/dump.c
+++ b/dump.c
@@ -29,10 +29,10 @@
 
 static const char* const svtypenames[SVt_LAST] = {
     "NULL",
+    "BIND",
     "IV",
     "NV",
     "RV",
-    "BIND",
     "PV",
     "PVIV",
     "PVNV",
@@ -49,10 +49,10 @@ static const char* const svtypenames[SVt_LAST] = {
 
 static const char* const svshorttypenames[SVt_LAST] = {
     "UNDEF",
+    "BIND",
     "IV",
     "NV",
     "RV",
-    "BIND",
     "PV",
     "PVIV",
     "PVNV",
diff --git a/ext/B/B.xs b/ext/B/B.xs
index 84b29055c6..a782d68963 100644
--- a/ext/B/B.xs
+++ b/ext/B/B.xs
@@ -21,12 +21,12 @@ typedef FILE * InputStream;
 
 static const char* const svclassnames[] = {
     "B::NULL",
-    "B::IV",
-    "B::NV",
-    "B::RV",
 #if PERL_VERSION >= 9
     "B::BIND",
 #endif
+    "B::IV",
+    "B::NV",
+    "B::RV",
     "B::PV",
     "B::PVIV",
     "B::PVNV",
diff --git a/sv.c b/sv.c
index 65060fa12f..6303c4c36e 100644
--- a/sv.c
+++ b/sv.c
@@ -887,6 +887,11 @@ static const struct body_details bodies_by_type[] = {
     { sizeof(HE), 0, 0, SVt_NULL,
       FALSE, NONV, NOARENA, FIT_ARENA(0, sizeof(HE)) },
 
+    /* The bind placeholder pretends to be an RV for now.
+       Also it's marked as "can't upgrade" top stop anyone using it before it's
+       implemented.  */
+    { 0, 0, 0, SVt_BIND, TRUE, NONV, NOARENA, 0 },
+
     /* IVs are in the head, so the allocation size is 0.
        However, the slot is overloaded for PTEs.  */
     { sizeof(struct ptr_tbl_ent), /* This is used for PTEs.  */
@@ -904,9 +909,6 @@ static const struct body_details bodies_by_type[] = {
     /* RVs are in the head now.  */
     { 0, 0, 0, SVt_RV, FALSE, NONV, NOARENA, 0 },
 
-    /* The bind placeholder pretends to be an RV for now.  */
-    { 0, 0, 0, SVt_BIND, FALSE, NONV, NOARENA, 0 },
-
     /* 8 bytes on most ILP32 with IEEE doubles */
     { sizeof(xpv_allocated),
       copy_length(XPV, xpv_len)
diff --git a/sv.h b/sv.h
index f7a7ba0935..0bafb9914d 100644
--- a/sv.h
+++ b/sv.h
@@ -45,10 +45,10 @@ Type flag for code refs.  See C<svtype>.
 
 typedef enum {
 	SVt_NULL,	/* 0 */
-	SVt_IV,		/* 1 */
-	SVt_NV,		/* 2 */
-	SVt_RV,		/* 3 */
-	SVt_BIND,	/* 4 */
+	SVt_BIND,	/* 1 */
+	SVt_IV,		/* 2 */
+	SVt_NV,		/* 3 */
+	SVt_RV,		/* 4 */
 	SVt_PV,		/* 5 */
 	SVt_PVIV,	/* 6 */
 	SVt_PVNV,	/* 7 */
@@ -942,7 +942,9 @@ Set the actual length of the string which is in the SV.  See C<SvIV_set>.
 #define assert_not_glob(sv)	
 #endif
 
-#define SvOK(sv)		(SvFLAGS(sv) & SVf_OK)
+#define SvOK(sv)		((SvTYPE(sv) == SVt_BIND)		\
+				 ? (SvFLAGS(SvRV(sv)) & SVf_OK)		\
+				 : (SvFLAGS(sv) & SVf_OK))
 #define SvOK_off(sv)		(assert_not_ROK(sv) assert_not_glob(sv)	\
 				 SvFLAGS(sv) &=	~(SVf_OK|		\
 						  SVf_IVisUV|SVf_UTF8),	\