diff --git a/src/lib_base.c b/src/lib_base.c
index 999e4c8f..3d5eb222 100644
--- a/src/lib_base.c
+++ b/src/lib_base.c
@@ -222,16 +222,10 @@ LJLIB_CF(rawlen)		LJLIB_REC(.)
 
 LJLIB_CF(unpack)
 {
-#if LJ_DS_UNPACK_PATCH
-#define TAB_LEN lj_tab_arraylen
-#else
-#define TAB_LEN lj_tab_len
-#endif
-
   GCtab *t = lj_lib_checktab(L, 1);
   int32_t n, i = lj_lib_optint(L, 2, 1);
   int32_t e = (L->base+3-1 < L->top && !tvisnil(L->base+3-1)) ?
-	      lj_lib_checkint(L, 3) : (int32_t)TAB_LEN(t);
+	      lj_lib_checkint(L, 3) : (int32_t)lj_tab_len(t);
   uint32_t nu;
   if (i > e) return 0;
   nu = (uint32_t)e - (uint32_t)i;
diff --git a/src/lj_arch.h b/src/lj_arch.h
index c4398121..5b709f1d 100644
--- a/src/lj_arch.h
+++ b/src/lj_arch.h
@@ -751,8 +751,8 @@ extern void *LJ_WIN_LOADLIBA(const char *path);
 #define LJ_DS_BIG_UPVAL_PATCH LJ_DS
 #endif
 
-#ifndef LJ_DS_UNPACK_PATCH
-#define LJ_DS_UNPACK_PATCH LJ_DS
+#ifndef LJ_DS_PARSER_TABLE_PATCH
+#define LJ_DS_PARSER_TABLE_PATCH LJ_DS
 #endif
 
 #ifndef LJ_NO_SYSTEM
diff --git a/src/lj_parse.c b/src/lj_parse.c
index 8e0e9113..675fd228 100644
--- a/src/lj_parse.c
+++ b/src/lj_parse.c
@@ -1807,8 +1807,14 @@ static void expr_table(LexState *ls, ExpDesc *e)
     else if (narr > 0x7ff) narr = 0x7ff;
     setbc_d(ip, narr|(hsize2hbits(nhash)<<11));
   } else {
+#if LJ_DS_PARSER_TABLE_PATCH
+    if ((needarr && t->asize != narr) ||  hsize2hmask(nhash) != t->hmask) {
+      lj_tab_resize(fs->L, t, narr, hsize2hbits(nhash));
+    }
+#else
     if (needarr && t->asize < narr)
       lj_tab_reasize(fs->L, t, narr-1);
+#endif
     if (fixt) {  /* Fix value for dummy keys in template table. */
       Node *node = noderef(t->node);
       uint32_t i, hmask = t->hmask;
diff --git a/src/lj_tab.c b/src/lj_tab.c
index 1019a745..568c0288 100644
--- a/src/lj_tab.c
+++ b/src/lj_tab.c
@@ -691,14 +691,3 @@ MSize LJ_FASTCALL lj_tab_len_hint(GCtab *t, size_t hint)
 }
 #endif
 
-#if LJ_DS_UNPACK_PATCH
-MSize LJ_FASTCALL lj_tab_arraylen(GCtab *t)
-{
-  MSize j = (MSize)t->asize;
-  while (j > 1 && tvisnil(arrayslot(t, j - 1))) {
-    j--;
-  }
-  if (j) --j;
-  return j;
-}
-#endif
diff --git a/src/lj_tab.h b/src/lj_tab.h
index 95624ac4..611959f5 100644
--- a/src/lj_tab.h
+++ b/src/lj_tab.h
@@ -43,7 +43,7 @@ static LJ_AINLINE Node *hashmask(const GCtab *t, uint32_t hash)
 
 #define hashlohi(t, lo, hi)	hashmask((t), hashrot((lo), (hi)))
 #define hashnum(t, o)		hashlohi((t), (o)->u32.lo, ((o)->u32.hi << 1))
-#if LJ_GC64
+#if LJ_GC64 
 #define hashgcref(t, r) \
   hashlohi((t), (uint32_t)gcrefu(r), (uint32_t)(gcrefu(r) >> 32))
 #else
@@ -51,6 +51,7 @@ static LJ_AINLINE Node *hashmask(const GCtab *t, uint32_t hash)
 #endif
 
 #define hsize2hbits(s)	((s) ? ((s)==1 ? 1 : 1+lj_fls((uint32_t)((s)-1))) : 0)
+#define hsize2hmask(s)  ((s) ? (1u <<hsize2hbits(nhash)) - 1 : 0)
 
 LJ_FUNCA GCtab *lj_tab_new(lua_State *L, uint32_t asize, uint32_t hbits);
 LJ_FUNC GCtab *lj_tab_new_ah(lua_State *L, int32_t a, int32_t h);
@@ -93,8 +94,4 @@ LJ_FUNCA MSize LJ_FASTCALL lj_tab_len(GCtab *t);
 LJ_FUNC MSize LJ_FASTCALL lj_tab_len_hint(GCtab *t, size_t hint);
 #endif
 
-#if LJ_DS_UNPACK_PATCH
-LJ_FUNCA MSize LJ_FASTCALL lj_tab_arraylen(GCtab *t);
-#endif
-
 #endif
diff --git a/src/msvcbuild.bat b/src/msvcbuild.bat
index 42d06d47..87957ee3 100644
--- a/src/msvcbuild.bat
+++ b/src/msvcbuild.bat
@@ -14,8 +14,8 @@
 
 @setlocal
 @rem Add more debug flags here, e.g. DEBUGCFLAGS=/DLUA_USE_APICHECK
-@set DEBUGCFLAGS= /DLUA_USE_APICHECK /DLUA_USE_ASSERT
-@set LJCOMPILE=cl /nologo /c /O2 /W3 /D_CRT_SECURE_NO_DEPRECATE /D_CRT_STDIO_INLINE=__declspec(dllexport)__inline
+@set DEBUGCFLAGS= /DLUA_USE_APICHECK /DLUA_USE_ASSERT /DLUAJIT_USE_SYSMALLOC /fsanitize=address
+@set LJCOMPILE=cl /nologo /c /O2 /W3 /D_CRT_SECURE_NO_DEPRECATE /D_CRT_STDIO_INLINE=__declspec(dllexport)__inline /DLUAJIT_NUMMODE
 @set LJLINK=link /nologo
 @set LJMT=mt /nologo
 @set LJLIB=lib /nologo /nodefaultlib