diff -urN lua-5.1.4-orig/src/lobject.h lua-5.1.4/src/lobject.h
--- lua-5.1.4-orig/src/lobject.h	2008-08-06 22:29:48 +0900
+++ lua-5.1.4/src/lobject.h	2010-06-14 04:38:48 +0900
@@ -201,7 +201,9 @@
   struct {
     CommonHeader;
     lu_byte reserved;
+#ifndef LUA_OMIT_STRING_HASH
     unsigned int hash;
+#endif
     size_t len;
   } tsv;
 } TString;
diff -urN lua-5.1.4-orig/src/lstring.c lua-5.1.4/src/lstring.c
--- lua-5.1.4-orig/src/lstring.c	2007-12-27 22:02:25 +0900
+++ lua-5.1.4/src/lstring.c	2010-06-14 04:45:53 +0900
@@ -19,6 +19,19 @@
 
 
 
+static unsigned int hashstr (const char *str, size_t l) {
+  unsigned int h = cast(unsigned int, l);  /* seed */
+  size_t step = (l>>5)+1;  /* if string is too long, don't hash all its chars */
+  size_t l1;
+  for (l1=l; l1>=step; l1-=step)  /* compute hash */
+    h = h ^ ((h<<5)+(h>>2)+cast(unsigned char, str[l1-1]));
+  return h;
+}
+
+unsigned int luaS_hashstr (const TString *ts) {
+  return hashstr(getstr(ts), ts->tsv.len);
+}
+
 void luaS_resize (lua_State *L, int newsize) {
   GCObject **newhash;
   stringtable *tb;
@@ -33,7 +46,12 @@
     GCObject *p = tb->hash[i];
     while (p) {  /* for each node in the list */
       GCObject *next = p->gch.next;  /* save next */
+#ifndef LUA_OMIT_STRING_HASH
       unsigned int h = gco2ts(p)->hash;
+#else  /* have to recompute it */
+      TString *ts = rawgco2ts(p);
+      unsigned int h = hashstr(getstr(ts), ts->tsv.len);
+#endif
       int h1 = lmod(h, newsize);  /* new position */
       lua_assert(cast_int(h%newsize) == lmod(h, newsize));
       p->gch.next = newhash[h1];  /* chain it */
@@ -55,7 +73,9 @@
     luaM_toobig(L);
   ts = cast(TString *, luaM_malloc(L, (l+1)*sizeof(char)+sizeof(TString)));
   ts->tsv.len = l;
+#ifndef LUA_OMIT_STRING_HASH
   ts->tsv.hash = h;
+#endif
   ts->tsv.marked = luaC_white(G(L));
   ts->tsv.tt = LUA_TSTRING;
   ts->tsv.reserved = 0;
@@ -74,11 +94,7 @@
 
 TString *luaS_newlstr (lua_State *L, const char *str, size_t l) {
   GCObject *o;
-  unsigned int h = cast(unsigned int, l);  /* seed */
-  size_t step = (l>>5)+1;  /* if string is too long, don't hash all its chars */
-  size_t l1;
-  for (l1=l; l1>=step; l1-=step)  /* compute hash */
-    h = h ^ ((h<<5)+(h>>2)+cast(unsigned char, str[l1-1]));
+  unsigned int h = hashstr(str, l);
   for (o = G(L)->strt.hash[lmod(h, G(L)->strt.size)];
        o != NULL;
        o = o->gch.next) {
diff -urN lua-5.1.4-orig/src/lstring.h lua-5.1.4/src/lstring.h
--- lua-5.1.4-orig/src/lstring.h	2007-12-27 22:02:25 +0900
+++ lua-5.1.4/src/lstring.h	2010-06-14 04:46:21 +0900
@@ -23,6 +23,7 @@
 
 #define luaS_fix(s)	l_setbit((s)->tsv.marked, FIXEDBIT)
 
+LUAI_FUNC unsigned int luaS_hashstr (const TString *ts);
 LUAI_FUNC void luaS_resize (lua_State *L, int newsize);
 LUAI_FUNC Udata *luaS_newudata (lua_State *L, size_t s, Table *e);
 LUAI_FUNC TString *luaS_newlstr (lua_State *L, const char *str, size_t l);
diff -urN lua-5.1.4-orig/src/ltable.c lua-5.1.4/src/ltable.c
--- lua-5.1.4-orig/src/ltable.c	2007-12-29 00:32:23 +0900
+++ lua-5.1.4/src/ltable.c	2010-06-14 04:46:47 +0900
@@ -49,7 +49,13 @@
 
 #define hashpow2(t,n)      (gnode(t, lmod((n), sizenode(t))))
   
+#ifndef LUA_OMIT_STRING_HASH
 #define hashstr(t,str)  hashpow2(t, (str)->tsv.hash)
+#else  /* have to recompute it */
+#include "lstring.h"
+#define hashstr(t,str)  hashpow2(t, luaS_hashstr((str)))
+#endif
+
 #define hashboolean(t,p)        hashpow2(t, p)
 
 
diff -urN lua-5.1.4-orig/src/luaconf.h lua-5.1.4/src/luaconf.h
--- lua-5.1.4-orig/src/luaconf.h	2008-02-12 01:25:08 +0900
+++ lua-5.1.4/src/luaconf.h	2010-06-14 04:38:48 +0900
@@ -758,6 +758,21 @@
 */
 
 
+/*
+@@ LUA_OMIT_STRING_HASH controls whether string hashes are stored
+** along with string objects or not.  If defined, the hashes will
+** be omitted from the string object structures, saving 4 bytes of
+** memory per string, but the hashes of all strings stored in a
+** string table must then be recomputed each time the table is
+** expanded or traversed.  CHANGE it (define it) if saving the
+** 4 bytes per string is more important than the execution time
+** cost of rehashing.
+**
+** NOTE that this will not have any effect on memory usage if the
+** alignment of LUAI_USER_ALIGNMENT_T is greater than 4.
+*/
+/* #define LUA_OMIT_STRING_HASH */
+
 
 #endif