FreeBSD/Linux Kernel Cross Reference
sys/contrib/openzfs/module/lua/lvm.c

     /*
     ** $Id: lvm.c,v 2.155.1.1 2013/04/12 18:48:47 roberto Exp $
     ** Lua virtual machine
     ** See Copyright Notice in lua.h
     */
     
     
     #define lvm_c
     #define LUA_CORE
    
    #include <sys/lua/lua.h>
    
    #include "ldebug.h"
    #include "ldo.h"
    #include "lfunc.h"
    #include "lgc.h"
    #include "lobject.h"
    #include "lopcodes.h"
    #include "lstate.h"
    #include "lstring.h"
    #include "ltable.h"
    #include "ltm.h"
    #include "lvm.h"
    
    #ifdef _KERNEL
    #define strcoll(l,r) (strcmp((l),(r)))
    #endif
    
    /* limit for table tag-method chains (to avoid loops) */
    #define MAXTAGLOOP      100
    
    
    const TValue *luaV_tonumber (const TValue *obj, TValue *n) {
      lua_Number num;
      if (ttisnumber(obj)) return obj;
      if (ttisstring(obj) && luaO_str2d(svalue(obj), tsvalue(obj)->len, &num)) {
        setnvalue(n, num);
        return n;
      }
      else
        return NULL;
    }
    
    
    int luaV_tostring (lua_State *L, StkId obj) {
      if (!ttisnumber(obj))
        return 0;
      else {
        char s[LUAI_MAXNUMBER2STR];
        lua_Number n = nvalue(obj);
        int l = lua_number2str(s, n);
        setsvalue2s(L, obj, luaS_newlstr(L, s, l));
        return 1;
      }
    }
    
    
    static void traceexec (lua_State *L) {
      CallInfo *ci = L->ci;
      lu_byte mask = L->hookmask;
      int counthook = ((mask & LUA_MASKCOUNT) && L->hookcount == 0);
      if (counthook)
        resethookcount(L);  /* reset count */
      if (ci->callstatus & CIST_HOOKYIELD) {  /* called hook last time? */
        ci->callstatus &= ~CIST_HOOKYIELD;  /* erase mark */
        return;  /* do not call hook again (VM yielded, so it did not move) */
      }
      if (counthook)
        luaD_hook(L, LUA_HOOKCOUNT, -1);  /* call count hook */
      if (mask & LUA_MASKLINE) {
        Proto *p = ci_func(ci)->p;
        int npc = pcRel(ci->u.l.savedpc, p);
        int newline = getfuncline(p, npc);
        if (npc == 0 ||  /* call linehook when enter a new function, */
            ci->u.l.savedpc <= L->oldpc ||  /* when jump back (loop), or when */
            newline != getfuncline(p, pcRel(L->oldpc, p)))  /* enter a new line */
          luaD_hook(L, LUA_HOOKLINE, newline);  /* call line hook */
      }
      L->oldpc = ci->u.l.savedpc;
      if (L->status == LUA_YIELD) {  /* did hook yield? */
        if (counthook)
          L->hookcount = 1;  /* undo decrement to zero */
        ci->u.l.savedpc--;  /* undo increment (resume will increment it again) */
        ci->callstatus |= CIST_HOOKYIELD;  /* mark that it yielded */
        ci->func = L->top - 1;  /* protect stack below results */
        luaD_throw(L, LUA_YIELD);
      }
    }
    
    
    static void callTM (lua_State *L, const TValue *f, const TValue *p1,
                        const TValue *p2, TValue *p3, int hasres) {
      if (L == NULL) return;
    
      ptrdiff_t result = savestack(L, p3);
      setobj2s(L, L->top++, f);  /* push function */
      setobj2s(L, L->top++, p1);  /* 1st argument */
      setobj2s(L, L->top++, p2);  /* 2nd argument */
      if (!hasres)  /* no result? 'p3' is third argument */
       setobj2s(L, L->top++, p3);  /* 3rd argument */
     /* metamethod may yield only when called from Lua code */
     luaD_call(L, L->top - (4 - hasres), hasres, isLua(L->ci));
     if (hasres) {  /* if has result, move it to its place */
       p3 = restorestack(L, result);
       setobjs2s(L, p3, --L->top);
     }
   }
   
   
   void luaV_gettable (lua_State *L, const TValue *t, TValue *key, StkId val) {
     int loop;
     for (loop = 0; loop < MAXTAGLOOP; loop++) {
       const TValue *tm;
       if (ttistable(t)) {  /* `t' is a table? */
         Table *h = hvalue(t);
         const TValue *res = luaH_get(h, key); /* do a primitive get */
         if (!ttisnil(res) ||  /* result is not nil? */
             (tm = fasttm(L, h->metatable, TM_INDEX)) == NULL) { /* or no TM? */
           setobj2s(L, val, res);
           return;
         }
         /* else will try the tag method */
       }
       else if (ttisnil(tm = luaT_gettmbyobj(L, t, TM_INDEX)))
         luaG_typeerror(L, t, "index");
       if (ttisfunction(tm)) {
         callTM(L, tm, t, key, val, 1);
         return;
       }
       t = tm;  /* else repeat with 'tm' */
     }
     luaG_runerror(L, "loop in gettable");
   }
   
   
   void luaV_settable (lua_State *L, const TValue *t, TValue *key, StkId val) {
     int loop;
     for (loop = 0; loop < MAXTAGLOOP; loop++) {
       const TValue *tm;
       if (ttistable(t)) {  /* `t' is a table? */
         Table *h = hvalue(t);
         TValue *oldval = cast(TValue *, luaH_get(h, key));
         /* if previous value is not nil, there must be a previous entry
            in the table; moreover, a metamethod has no relevance */
         if (!ttisnil(oldval) ||
            /* previous value is nil; must check the metamethod */
            ((tm = fasttm(L, h->metatable, TM_NEWINDEX)) == NULL &&
            /* no metamethod; is there a previous entry in the table? */
            (oldval != luaO_nilobject ||
            /* no previous entry; must create one. (The next test is
               always true; we only need the assignment.) */
            (oldval = luaH_newkey(L, h, key), 1)))) {
           /* no metamethod and (now) there is an entry with given key */
           setobj2t(L, oldval, val);  /* assign new value to that entry */
           invalidateTMcache(h);
           luaC_barrierback(L, obj2gco(h), val);
           return;
         }
         /* else will try the metamethod */
       }
       else  /* not a table; check metamethod */
         if (ttisnil(tm = luaT_gettmbyobj(L, t, TM_NEWINDEX)))
           luaG_typeerror(L, t, "index");
       /* there is a metamethod */
       if (ttisfunction(tm)) {
         callTM(L, tm, t, key, val, 0);
         return;
       }
       t = tm;  /* else repeat with 'tm' */
     }
     luaG_runerror(L, "loop in settable");
   }
   
   
   static int call_binTM (lua_State *L, const TValue *p1, const TValue *p2,
                          StkId res, TMS event) {
     const TValue *tm = luaT_gettmbyobj(L, p1, event);  /* try first operand */
     if (ttisnil(tm))
       tm = luaT_gettmbyobj(L, p2, event);  /* try second operand */
     if (ttisnil(tm)) return 0;
     callTM(L, tm, p1, p2, res, 1);
     return 1;
   }
   
   
   static const TValue *get_equalTM (lua_State *L, Table *mt1, Table *mt2,
                                     TMS event) {
     const TValue *tm1 = fasttm(L, mt1, event);
     const TValue *tm2;
     if (tm1 == NULL) return NULL;  /* no metamethod */
     if (mt1 == mt2) return tm1;  /* same metatables => same metamethods */
     tm2 = fasttm(L, mt2, event);
     if (tm2 == NULL) return NULL;  /* no metamethod */
     if (luaV_rawequalobj(tm1, tm2))  /* same metamethods? */
       return tm1;
     return NULL;
   }
   
   
   static int call_orderTM (lua_State *L, const TValue *p1, const TValue *p2,
                            TMS event) {
     if (!call_binTM(L, p1, p2, L->top, event))
       return -1;  /* no metamethod */
     else
       return !l_isfalse(L->top);
   }
   
   
   static int l_strcmp (const TString *ls, const TString *rs) {
     const char *l = getstr(ls);
     size_t ll = ls->tsv.len;
     const char *r = getstr(rs);
     size_t lr = rs->tsv.len;
     for (;;) {
       int temp = strcoll(l, r);
       if (temp != 0) return temp;
       else {  /* strings are equal up to a `\0' */
         size_t len = strlen(l);  /* index of first `\0' in both strings */
         if (len == lr)  /* r is finished? */
           return (len == ll) ? 0 : 1;
         else if (len == ll)  /* l is finished? */
           return -1;  /* l is smaller than r (because r is not finished) */
         /* both strings longer than `len'; go on comparing (after the `\0') */
         len++;
         l += len; ll -= len; r += len; lr -= len;
       }
     }
   }
   
   
   int luaV_lessthan (lua_State *L, const TValue *l, const TValue *r) {
     int res;
     if (ttisnumber(l) && ttisnumber(r))
       return luai_numlt(L, nvalue(l), nvalue(r));
     else if (ttisstring(l) && ttisstring(r))
       return l_strcmp(rawtsvalue(l), rawtsvalue(r)) < 0;
     else if ((res = call_orderTM(L, l, r, TM_LT)) < 0)
       luaG_ordererror(L, l, r);
     return res;
   }
   
   
   int luaV_lessequal (lua_State *L, const TValue *l, const TValue *r) {
     int res;
     if (ttisnumber(l) && ttisnumber(r))
       return luai_numle(L, nvalue(l), nvalue(r));
     else if (ttisstring(l) && ttisstring(r))
       return l_strcmp(rawtsvalue(l), rawtsvalue(r)) <= 0;
     else if ((res = call_orderTM(L, l, r, TM_LE)) >= 0)  /* first try `le' */
       return res;
     else if ((res = call_orderTM(L, r, l, TM_LT)) < 0)  /* else try `lt' */
       luaG_ordererror(L, l, r);
     return !res;
   }
   
   
   /*
   ** equality of Lua values. L == NULL means raw equality (no metamethods)
   */
   int luaV_equalobj_ (lua_State *L, const TValue *t1, const TValue *t2) {
     const TValue *tm;
     lua_assert(ttisequal(t1, t2));
     switch (ttype(t1)) {
       case LUA_TNIL: return 1;
       case LUA_TNUMBER: return luai_numeq(nvalue(t1), nvalue(t2));
       case LUA_TBOOLEAN: return bvalue(t1) == bvalue(t2);  /* true must be 1 !! */
       case LUA_TLIGHTUSERDATA: return pvalue(t1) == pvalue(t2);
       case LUA_TLCF: return fvalue(t1) == fvalue(t2);
       case LUA_TSHRSTR: return eqshrstr(rawtsvalue(t1), rawtsvalue(t2));
       case LUA_TLNGSTR: return luaS_eqlngstr(rawtsvalue(t1), rawtsvalue(t2));
       case LUA_TUSERDATA: {
         if (uvalue(t1) == uvalue(t2)) return 1;
         else if (L == NULL) return 0;
         tm = get_equalTM(L, uvalue(t1)->metatable, uvalue(t2)->metatable, TM_EQ);
         break;  /* will try TM */
       }
       case LUA_TTABLE: {
         if (hvalue(t1) == hvalue(t2)) return 1;
         else if (L == NULL) return 0;
         tm = get_equalTM(L, hvalue(t1)->metatable, hvalue(t2)->metatable, TM_EQ);
         break;  /* will try TM */
       }
       default:
         lua_assert(iscollectable(t1));
         return gcvalue(t1) == gcvalue(t2);
     }
     if (tm == NULL || L == NULL) return 0;  /* no TM? */
     callTM(L, tm, t1, t2, L->top, 1);  /* call TM */
     return !l_isfalse(L->top);
   }
   
   
   void luaV_concat (lua_State *L, int total) {
     lua_assert(total >= 2);
     do {
       StkId top = L->top;
       int n = 2;  /* number of elements handled in this pass (at least 2) */
       if (!(ttisstring(top-2) || ttisnumber(top-2)) || !tostring(L, top-1)) {
         if (!call_binTM(L, top-2, top-1, top-2, TM_CONCAT))
           luaG_concaterror(L, top-2, top-1);
       }
       else if (tsvalue(top-1)->len == 0)  /* second operand is empty? */
         (void)tostring(L, top - 2);  /* result is first operand */
       else if (ttisstring(top-2) && tsvalue(top-2)->len == 0) {
         setobjs2s(L, top - 2, top - 1);  /* result is second op. */
       }
       else {
         /* at least two non-empty string values; get as many as possible */
         size_t tl = tsvalue(top-1)->len;
         char *buffer;
         int i;
         /* collect total length */
         for (i = 1; i < total && tostring(L, top-i-1); i++) {
           size_t l = tsvalue(top-i-1)->len;
           if (l >= (MAX_SIZET/sizeof(char)) - tl)
             luaG_runerror(L, "string length overflow");
           tl += l;
         }
         buffer = luaZ_openspace(L, &G(L)->buff, tl);
         tl = 0;
         n = i;
         do {  /* concat all strings */
           size_t l = tsvalue(top-i)->len;
           memcpy(buffer+tl, svalue(top-i), l * sizeof(char));
           tl += l;
         } while (--i > 0);
         setsvalue2s(L, top-n, luaS_newlstr(L, buffer, tl));
       }
       total -= n-1;  /* got 'n' strings to create 1 new */
       L->top -= n-1;  /* popped 'n' strings and pushed one */
     } while (total > 1);  /* repeat until only 1 result left */
   }
   
   
   void luaV_objlen (lua_State *L, StkId ra, const TValue *rb) {
     const TValue *tm;
     switch (ttypenv(rb)) {
       case LUA_TTABLE: {
         Table *h = hvalue(rb);
         tm = fasttm(L, h->metatable, TM_LEN);
         if (tm) break;  /* metamethod? break switch to call it */
         setnvalue(ra, cast_num(luaH_getn(h)));  /* else primitive len */
         return;
       }
       case LUA_TSTRING: {
         setnvalue(ra, cast_num(tsvalue(rb)->len));
         return;
       }
       default: {  /* try metamethod */
         tm = luaT_gettmbyobj(L, rb, TM_LEN);
         if (ttisnil(tm))  /* no metamethod? */
           luaG_typeerror(L, rb, "get length of");
         break;
       }
     }
     callTM(L, tm, rb, rb, ra, 1);
   }
   
   /*
    * luaV_div and luaV_mod patched in from Lua 5.3.2 in order to properly handle
    * div/mod by zero (instead of crashing, which is the default behavior in
    * Lua 5.2)
    */
   
   /*
   ** Integer division; return 'm // n', that is, floor(m/n).
   ** C division truncates its result (rounds towards zero).
   ** 'floor(q) == trunc(q)' when 'q >= 0' or when 'q' is integer,
   ** otherwise 'floor(q) == trunc(q) - 1'.
   */
   static lua_Number luaV_div (lua_State *L, lua_Number m, lua_Number n) {
     if ((lua_Unsigned)(n) + 1u <= 1u) {  /* special cases: -1 or 0 */
       if (n == 0)
         luaG_runerror(L, "attempt to divide by zero");
       return (0 - m);   /* n==-1; avoid overflow with 0x80000...//-1 */
     }
     else {
       lua_Number q = m / n;  /* perform C division */
       if ((m ^ n) < 0 && m % n != 0)  /* 'm/n' would be negative non-integer? */
         q -= 1;  /* correct result for different rounding */
       return q;
     }
   }
   
   
   /*
   ** Integer modulus; return 'm % n'. (Assume that C '%' with
   ** negative operands follows C99 behavior. See previous comment
   ** about luaV_div.)
   */
   static lua_Number luaV_mod (lua_State *L, lua_Number m, lua_Number n) {
     if ((lua_Unsigned)(n) + 1u <= 1u) {  /* special cases: -1 or 0 */
       if (n == 0)
         luaG_runerror(L, "attempt to perform 'n%%0'");
       return 0;   /* m % -1 == 0; avoid overflow with 0x80000...%-1 */
     }
     else {
       lua_Number r = m % n;
       if (r != 0 && (m ^ n) < 0)  /* 'm/n' would be non-integer negative? */
         r += n;  /* correct result for different rounding */
       return r;
     }
   }
   
   /*
    * End patch from 5.3.2
    */
   
   void luaV_arith (lua_State *L, StkId ra, const TValue *rb,
                    const TValue *rc, TMS op) {
     TValue tempb, tempc;
     const TValue *b, *c;
     if ((b = luaV_tonumber(rb, &tempb)) != NULL &&
         (c = luaV_tonumber(rc, &tempc)) != NULL) {
       /*
        * Patched: if dividing or modding, use patched functions from 5.3
        */
       lua_Number res;
       int lop = op - TM_ADD + LUA_OPADD;
       if (lop == LUA_OPDIV) {
         res = luaV_div(L, nvalue(b), nvalue(c));
       } else if (lop == LUA_OPMOD) {
         res = luaV_mod(L, nvalue(b), nvalue(c));
       } else {
         res = luaO_arith(op - TM_ADD + LUA_OPADD, nvalue(b), nvalue(c));
       }
       setnvalue(ra, res);
     }
     else if (!call_binTM(L, rb, rc, ra, op))
       luaG_aritherror(L, rb, rc);
   }
   
   
   /*
   ** check whether cached closure in prototype 'p' may be reused, that is,
   ** whether there is a cached closure with the same upvalues needed by
   ** new closure to be created.
   */
   static Closure *getcached (Proto *p, UpVal **encup, StkId base) {
     Closure *c = p->cache;
     if (c != NULL) {  /* is there a cached closure? */
       int nup = p->sizeupvalues;
       Upvaldesc *uv = p->upvalues;
       int i;
       for (i = 0; i < nup; i++) {  /* check whether it has right upvalues */
         TValue *v = uv[i].instack ? base + uv[i].idx : encup[uv[i].idx]->v;
         if (c->l.upvals[i]->v != v)
           return NULL;  /* wrong upvalue; cannot reuse closure */
       }
     }
     return c;  /* return cached closure (or NULL if no cached closure) */
   }
   
   
   /*
   ** create a new Lua closure, push it in the stack, and initialize
   ** its upvalues. Note that the call to 'luaC_barrierproto' must come
   ** before the assignment to 'p->cache', as the function needs the
   ** original value of that field.
   */
   static void pushclosure (lua_State *L, Proto *p, UpVal **encup, StkId base,
                            StkId ra) {
     int nup = p->sizeupvalues;
     Upvaldesc *uv = p->upvalues;
     int i;
     Closure *ncl = luaF_newLclosure(L, nup);
     ncl->l.p = p;
     setclLvalue(L, ra, ncl);  /* anchor new closure in stack */
     for (i = 0; i < nup; i++) {  /* fill in its upvalues */
       if (uv[i].instack)  /* upvalue refers to local variable? */
         ncl->l.upvals[i] = luaF_findupval(L, base + uv[i].idx);
       else  /* get upvalue from enclosing function */
         ncl->l.upvals[i] = encup[uv[i].idx];
     }
     luaC_barrierproto(L, p, ncl);
     p->cache = ncl;  /* save it on cache for reuse */
   }
   
   
   /*
   ** finish execution of an opcode interrupted by an yield
   */
   void luaV_finishOp (lua_State *L) {
     CallInfo *ci = L->ci;
     StkId base = ci->u.l.base;
     Instruction inst = *(ci->u.l.savedpc - 1);  /* interrupted instruction */
     OpCode op = GET_OPCODE(inst);
     switch (op) {  /* finish its execution */
       case OP_ADD: case OP_SUB: case OP_MUL: case OP_DIV:
       case OP_MOD: case OP_POW: case OP_UNM: case OP_LEN:
       case OP_GETTABUP: case OP_GETTABLE: case OP_SELF: {
         setobjs2s(L, base + GETARG_A(inst), --L->top);
         break;
       }
       case OP_LE: case OP_LT: case OP_EQ: {
         int res = !l_isfalse(L->top - 1);
         L->top--;
         /* metamethod should not be called when operand is K */
         lua_assert(!ISK(GETARG_B(inst)));
         if (op == OP_LE &&  /* "<=" using "<" instead? */
             ttisnil(luaT_gettmbyobj(L, base + GETARG_B(inst), TM_LE)))
           res = !res;  /* invert result */
         lua_assert(GET_OPCODE(*ci->u.l.savedpc) == OP_JMP);
         if (res != GETARG_A(inst))  /* condition failed? */
           ci->u.l.savedpc++;  /* skip jump instruction */
         break;
       }
       case OP_CONCAT: {
         StkId top = L->top - 1;  /* top when 'call_binTM' was called */
         int b = GETARG_B(inst);      /* first element to concatenate */
         int total = cast_int(top - 1 - (base + b));  /* yet to concatenate */
         setobj2s(L, top - 2, top);  /* put TM result in proper position */
         if (total > 1) {  /* are there elements to concat? */
           L->top = top - 1;  /* top is one after last element (at top-2) */
           luaV_concat(L, total);  /* concat them (may yield again) */
         }
         /* move final result to final position */
         setobj2s(L, ci->u.l.base + GETARG_A(inst), L->top - 1);
         L->top = ci->top;  /* restore top */
         break;
       }
       case OP_TFORCALL: {
         lua_assert(GET_OPCODE(*ci->u.l.savedpc) == OP_TFORLOOP);
         L->top = ci->top;  /* correct top */
         break;
       }
       case OP_CALL: {
         if (GETARG_C(inst) - 1 >= 0)  /* nresults >= 0? */
           L->top = ci->top;  /* adjust results */
         break;
       }
       case OP_TAILCALL: case OP_SETTABUP: case OP_SETTABLE:
         break;
       default: lua_assert(0);
     }
   }
   
   
   
   /*
   ** some macros for common tasks in `luaV_execute'
   */
   
   #if !defined luai_runtimecheck
   #define luai_runtimecheck(L, c)         /* void */
   #endif
   
   
   #define RA(i)   (base+GETARG_A(i))
   /* to be used after possible stack reallocation */
   #define RB(i)   check_exp(getBMode(GET_OPCODE(i)) == OpArgR, base+GETARG_B(i))
   #define RC(i)   check_exp(getCMode(GET_OPCODE(i)) == OpArgR, base+GETARG_C(i))
   #define RKB(i)  check_exp(getBMode(GET_OPCODE(i)) == OpArgK, \
           ISK(GETARG_B(i)) ? k+INDEXK(GETARG_B(i)) : base+GETARG_B(i))
   #define RKC(i)  check_exp(getCMode(GET_OPCODE(i)) == OpArgK, \
           ISK(GETARG_C(i)) ? k+INDEXK(GETARG_C(i)) : base+GETARG_C(i))
   #define KBx(i)  \
     (k + (GETARG_Bx(i) != 0 ? GETARG_Bx(i) - 1 : GETARG_Ax(*ci->u.l.savedpc++)))
   
   
   /* execute a jump instruction */
   #define dojump(ci,i,e) \
     { int a = GETARG_A(i); \
       if (a > 0) luaF_close(L, ci->u.l.base + a - 1); \
       ci->u.l.savedpc += GETARG_sBx(i) + e; }
   
   /* for test instructions, execute the jump instruction that follows it */
   #define donextjump(ci)  { i = *ci->u.l.savedpc; dojump(ci, i, 1); }
   
   
   #define Protect(x)      { {x;} base = ci->u.l.base; }
   
   #define checkGC(L,c)  \
     Protect( luaC_condGC(L,{L->top = (c);  /* limit of live values */ \
                             luaC_step(L); \
                             L->top = ci->top;})  /* restore top */ \
              luai_threadyield(L); )
   
   
   #define arith_op(op,tm) { \
           TValue *rb = RKB(i); \
           TValue *rc = RKC(i); \
           if (ttisnumber(rb) && ttisnumber(rc)) { \
             lua_Number nb = nvalue(rb), nc = nvalue(rc); \
             setnvalue(ra, op(L, nb, nc)); \
           } \
           else { Protect(luaV_arith(L, ra, rb, rc, tm)); } }
   
   
   #define vmdispatch(o)   switch(o)
   #define vmcase(l,b)     case l: {b}  break;
   #define vmcasenb(l,b)   case l: {b}             /* nb = no break */
   
   void luaV_execute (lua_State *L) {
     CallInfo *ci = L->ci;
     LClosure *cl;
     TValue *k;
     StkId base;
    newframe:  /* reentry point when frame changes (call/return) */
     lua_assert(ci == L->ci);
     cl = clLvalue(ci->func);
     k = cl->p->k;
     base = ci->u.l.base;
     /* main loop of interpreter */
     for (;;) {
       Instruction i = *(ci->u.l.savedpc++);
       StkId ra;
       if ((L->hookmask & (LUA_MASKLINE | LUA_MASKCOUNT)) &&
           (--L->hookcount == 0 || L->hookmask & LUA_MASKLINE)) {
         Protect(traceexec(L));
       }
       /* WARNING: several calls may realloc the stack and invalidate `ra' */
       ra = RA(i);
       lua_assert(base == ci->u.l.base);
       lua_assert(base <= L->top && L->top < L->stack + L->stacksize);
       vmdispatch (GET_OPCODE(i)) {
         vmcase(OP_MOVE,
           setobjs2s(L, ra, RB(i));
         )
         vmcase(OP_LOADK,
           TValue *rb = k + GETARG_Bx(i);
           setobj2s(L, ra, rb);
         )
         vmcase(OP_LOADKX,
           TValue *rb;
           lua_assert(GET_OPCODE(*ci->u.l.savedpc) == OP_EXTRAARG);
           rb = k + GETARG_Ax(*ci->u.l.savedpc++);
           setobj2s(L, ra, rb);
         )
         vmcase(OP_LOADBOOL,
           setbvalue(ra, GETARG_B(i));
           if (GETARG_C(i)) ci->u.l.savedpc++;  /* skip next instruction (if C) */
         )
         vmcase(OP_LOADNIL,
           int b = GETARG_B(i);
           do {
             setnilvalue(ra++);
           } while (b--);
         )
         vmcase(OP_GETUPVAL,
           int b = GETARG_B(i);
           setobj2s(L, ra, cl->upvals[b]->v);
         )
         vmcase(OP_GETTABUP,
           int b = GETARG_B(i);
           Protect(luaV_gettable(L, cl->upvals[b]->v, RKC(i), ra));
         )
         vmcase(OP_GETTABLE,
           Protect(luaV_gettable(L, RB(i), RKC(i), ra));
         )
         vmcase(OP_SETTABUP,
           int a = GETARG_A(i);
           Protect(luaV_settable(L, cl->upvals[a]->v, RKB(i), RKC(i)));
         )
         vmcase(OP_SETUPVAL,
           UpVal *uv = cl->upvals[GETARG_B(i)];
           setobj(L, uv->v, ra);
           luaC_barrier(L, uv, ra);
         )
         vmcase(OP_SETTABLE,
           Protect(luaV_settable(L, ra, RKB(i), RKC(i)));
         )
         vmcase(OP_NEWTABLE,
           int b = GETARG_B(i);
           int c = GETARG_C(i);
           Table *t = luaH_new(L);
           sethvalue(L, ra, t);
           if (b != 0 || c != 0)
             luaH_resize(L, t, luaO_fb2int(b), luaO_fb2int(c));
           checkGC(L, ra + 1);
         )
         vmcase(OP_SELF,
           StkId rb = RB(i);
           setobjs2s(L, ra+1, rb);
           Protect(luaV_gettable(L, rb, RKC(i), ra));
         )
         vmcase(OP_ADD,
           arith_op(luai_numadd, TM_ADD);
         )
         vmcase(OP_SUB,
           arith_op(luai_numsub, TM_SUB);
         )
         vmcase(OP_MUL,
           arith_op(luai_nummul, TM_MUL);
         )
         /*
          * Patched: use luaV_* instead of luai_* to handle div/mod by 0
          */
         vmcase(OP_DIV,
           arith_op(luaV_div, TM_DIV);
         )
         vmcase(OP_MOD,
           arith_op(luaV_mod, TM_MOD);
         )
         vmcase(OP_POW,
           arith_op(luai_numpow, TM_POW);
         )
         vmcase(OP_UNM,
           TValue *rb = RB(i);
           if (ttisnumber(rb)) {
             lua_Number nb = nvalue(rb);
             setnvalue(ra, luai_numunm(L, nb));
           }
           else {
             Protect(luaV_arith(L, ra, rb, rb, TM_UNM));
           }
         )
         vmcase(OP_NOT,
           TValue *rb = RB(i);
           int res = l_isfalse(rb);  /* next assignment may change this value */
           setbvalue(ra, res);
         )
         vmcase(OP_LEN,
           Protect(luaV_objlen(L, ra, RB(i)));
         )
         vmcase(OP_CONCAT,
           int b = GETARG_B(i);
           int c = GETARG_C(i);
           StkId rb;
           L->top = base + c + 1;  /* mark the end of concat operands */
           Protect(luaV_concat(L, c - b + 1));
           ra = RA(i);  /* 'luav_concat' may invoke TMs and move the stack */
           rb = b + base;
           setobjs2s(L, ra, rb);
           checkGC(L, (ra >= rb ? ra + 1 : rb));
           L->top = ci->top;  /* restore top */
         )
         vmcase(OP_JMP,
           dojump(ci, i, 0);
         )
         vmcase(OP_EQ,
           TValue *rb = RKB(i);
           TValue *rc = RKC(i);
           Protect(
             if (cast_int(equalobj(L, rb, rc)) != GETARG_A(i))
               ci->u.l.savedpc++;
             else
               donextjump(ci);
           )
         )
         vmcase(OP_LT,
           Protect(
             if (luaV_lessthan(L, RKB(i), RKC(i)) != GETARG_A(i))
               ci->u.l.savedpc++;
             else
               donextjump(ci);
           )
         )
         vmcase(OP_LE,
           Protect(
             if (luaV_lessequal(L, RKB(i), RKC(i)) != GETARG_A(i))
               ci->u.l.savedpc++;
             else
               donextjump(ci);
           )
         )
         vmcase(OP_TEST,
           if (GETARG_C(i) ? l_isfalse(ra) : !l_isfalse(ra))
               ci->u.l.savedpc++;
             else
             donextjump(ci);
         )
         vmcase(OP_TESTSET,
           TValue *rb = RB(i);
           if (GETARG_C(i) ? l_isfalse(rb) : !l_isfalse(rb))
             ci->u.l.savedpc++;
           else {
             setobjs2s(L, ra, rb);
             donextjump(ci);
           }
         )
         vmcase(OP_CALL,
           int b = GETARG_B(i);
           int nresults = GETARG_C(i) - 1;
           if (b != 0) L->top = ra+b;  /* else previous instruction set top */
           if (luaD_precall(L, ra, nresults)) {  /* C function? */
             if (nresults >= 0) L->top = ci->top;  /* adjust results */
             base = ci->u.l.base;
           }
           else {  /* Lua function */
             ci = L->ci;
             ci->callstatus |= CIST_REENTRY;
             goto newframe;  /* restart luaV_execute over new Lua function */
           }
         )
         vmcase(OP_TAILCALL,
           int b = GETARG_B(i);
           if (b != 0) L->top = ra+b;  /* else previous instruction set top */
           lua_assert(GETARG_C(i) - 1 == LUA_MULTRET);
           if (luaD_precall(L, ra, LUA_MULTRET))  /* C function? */
             base = ci->u.l.base;
           else {
             /* tail call: put called frame (n) in place of caller one (o) */
             CallInfo *nci = L->ci;  /* called frame */
             CallInfo *oci = nci->previous;  /* caller frame */
             StkId nfunc = nci->func;  /* called function */
             StkId ofunc = oci->func;  /* caller function */
             /* last stack slot filled by 'precall' */
             StkId lim = nci->u.l.base + getproto(nfunc)->numparams;
             int aux;
             /* close all upvalues from previous call */
             if (cl->p->sizep > 0) luaF_close(L, oci->u.l.base);
             /* move new frame into old one */
             for (aux = 0; nfunc + aux < lim; aux++)
               setobjs2s(L, ofunc + aux, nfunc + aux);
             oci->u.l.base = ofunc + (nci->u.l.base - nfunc);  /* correct base */
             oci->top = L->top = ofunc + (L->top - nfunc);  /* correct top */
             oci->u.l.savedpc = nci->u.l.savedpc;
             oci->callstatus |= CIST_TAIL;  /* function was tail called */
             ci = L->ci = oci;  /* remove new frame */
             lua_assert(L->top == oci->u.l.base + getproto(ofunc)->maxstacksize);
             goto newframe;  /* restart luaV_execute over new Lua function */
           }
         )
         vmcasenb(OP_RETURN,
           int b = GETARG_B(i);
           if (b != 0) L->top = ra+b-1;
           if (cl->p->sizep > 0) luaF_close(L, base);
           b = luaD_poscall(L, ra);
           if (!(ci->callstatus & CIST_REENTRY))  /* 'ci' still the called one */
             return;  /* external invocation: return */
           else {  /* invocation via reentry: continue execution */
             ci = L->ci;
             if (b) L->top = ci->top;
             lua_assert(isLua(ci));
             lua_assert(GET_OPCODE(*((ci)->u.l.savedpc - 1)) == OP_CALL);
             goto newframe;  /* restart luaV_execute over new Lua function */
           }
         )
         vmcase(OP_FORLOOP,
           lua_Number step = nvalue(ra+2);
           lua_Number idx = luai_numadd(L, nvalue(ra), step); /* increment index */
           lua_Number limit = nvalue(ra+1);
           if (luai_numlt(L, 0, step) ? luai_numle(L, idx, limit)
                                      : luai_numle(L, limit, idx)) {
             ci->u.l.savedpc += GETARG_sBx(i);  /* jump back */
             setnvalue(ra, idx);  /* update internal index... */
             setnvalue(ra+3, idx);  /* ...and external index */
           }
         )
         vmcase(OP_FORPREP,
           const TValue *init = ra;
           const TValue *plimit = ra+1;
           const TValue *pstep = ra+2;
           if (!tonumber(init, ra))
             luaG_runerror(L, LUA_QL("for") " initial value must be a number");
           else if (!tonumber(plimit, ra+1))
             luaG_runerror(L, LUA_QL("for") " limit must be a number");
           else if (!tonumber(pstep, ra+2))
             luaG_runerror(L, LUA_QL("for") " step must be a number");
           setnvalue(ra, luai_numsub(L, nvalue(ra), nvalue(pstep)));
           ci->u.l.savedpc += GETARG_sBx(i);
         )
         vmcasenb(OP_TFORCALL,
           StkId cb = ra + 3;  /* call base */
           setobjs2s(L, cb+2, ra+2);
           setobjs2s(L, cb+1, ra+1);
           setobjs2s(L, cb, ra);
           L->top = cb + 3;  /* func. + 2 args (state and index) */
           Protect(luaD_call(L, cb, GETARG_C(i), 1));
           L->top = ci->top;
           i = *(ci->u.l.savedpc++);  /* go to next instruction */
           ra = RA(i);
           lua_assert(GET_OPCODE(i) == OP_TFORLOOP);
           goto l_tforloop;
         )
         vmcase(OP_TFORLOOP,
           l_tforloop:
           if (!ttisnil(ra + 1)) {  /* continue loop? */
             setobjs2s(L, ra, ra + 1);  /* save control variable */
              ci->u.l.savedpc += GETARG_sBx(i);  /* jump back */
           }
         )
         vmcase(OP_SETLIST,
           int n = GETARG_B(i);
           int c = GETARG_C(i);
           int last;
           Table *h;
           if (n == 0) n = cast_int(L->top - ra) - 1;
           if (c == 0) {
             lua_assert(GET_OPCODE(*ci->u.l.savedpc) == OP_EXTRAARG);
             c = GETARG_Ax(*ci->u.l.savedpc++);
           }
           luai_runtimecheck(L, ttistable(ra));
           h = hvalue(ra);
           last = ((c-1)*LFIELDS_PER_FLUSH) + n;
           if (last > h->sizearray)  /* needs more space? */
             luaH_resizearray(L, h, last);  /* pre-allocate it at once */
           for (; n > 0; n--) {
             TValue *val = ra+n;
             luaH_setint(L, h, last--, val);
             luaC_barrierback(L, obj2gco(h), val);
           }
           L->top = ci->top;  /* correct top (in case of previous open call) */
         )
         vmcase(OP_CLOSURE,
           Proto *p = cl->p->p[GETARG_Bx(i)];
           Closure *ncl = getcached(p, cl->upvals, base);  /* cached closure */
           if (ncl == NULL)  /* no match? */
             pushclosure(L, p, cl->upvals, base, ra);  /* create a new one */
           else
             setclLvalue(L, ra, ncl);  /* push cashed closure */
           checkGC(L, ra + 1);
         )
         vmcase(OP_VARARG,
           int b = GETARG_B(i) - 1;
           int j;
           int n = cast_int(base - ci->func) - cl->p->numparams - 1;
           if (b < 0) {  /* B == 0? */
             b = n;  /* get all var. arguments */
             Protect(luaD_checkstack(L, n));
             ra = RA(i);  /* previous call may change the stack */
             L->top = ra + n;
           }
           for (j = 0; j < b; j++) {
             if (j < n) {
               setobjs2s(L, ra + j, base - n + j);
             }
             else {
               setnilvalue(ra + j);
             }
           }
         )
         vmcase(OP_EXTRAARG,
           lua_assert(0);
         )
       }
     }
   }

Cache object: da33a2fb6598c7eac09d0da01cd3f8b0