Assert that BmRARE, BmUSEFUL and BmPREVIOUS are only called on SVtPVBM

p4raw-id: //depot/perl@29487

diff --git a/sv.h b/sv.h
index 57911d3..4d3e488 100644 (file)
--- a/sv.h
+++ b/sv.h
@@ -1300,9 +1300,27 @@ the scalar's value cannot change unless written to.
                     }                                                  \
                 } STMT_END
 
-#define BmRARE(sv)     ((XPVBM*)  SvANY(sv))->xbm_rare
-#define BmUSEFUL(sv)   ((XPVBM*)  SvANY(sv))->xbm_useful
-#define BmPREVIOUS(sv) ((XPVBM*)  SvANY(sv))->xbm_previous
+#if defined (DEBUGGING) && defined(__GNUC__) && !defined(PERL_GCC_BRACE_GROUPS_FORBIDDEN)
+#  define BmRARE(sv)                                                   \
+       (*({ SV *const _svi = (SV *) (sv);                              \
+           assert(SvTYPE(_svi) == SVt_PVBM);                           \
+           &(((XPVBM*) SvANY(_svi))->xbm_rare);                        \
+        }))
+#  define BmUSEFUL(sv)                                                 \
+       (*({ SV *const _svi = (SV *) (sv);                              \
+           assert(SvTYPE(_svi) == SVt_PVBM);                           \
+           &(((XPVBM*) SvANY(_svi))->xbm_useful);                      \
+        }))
+#  define BmPREVIOUS(sv)                                               \
+       (*({ SV *const _svi = (SV *) (sv);                              \
+           assert(SvTYPE(_svi) == SVt_PVBM);                           \
+           &(((XPVBM*) SvANY(_svi))->xbm_previous);                    \
+        }))
+#else
+#  define BmRARE(sv)   ((XPVBM*)  SvANY(sv))->xbm_rare
+#  define BmUSEFUL(sv) ((XPVBM*)  SvANY(sv))->xbm_useful
+#  define BmPREVIOUS(sv)       ((XPVBM*)  SvANY(sv))->xbm_previous
+#endif
 
 #define FmLINES(sv)    ((XPVFM*)  SvANY(sv))->xfm_lines