lua/lvm.c
changeset 0 d7ee4e2ed49d
equal deleted inserted replaced
-1:000000000000 0:d7ee4e2ed49d
       
     1 /*
       
     2 ** $Id: lvm.c,v 2.155.1.1 2013/04/12 18:48:47 roberto Exp $
       
     3 ** Lua virtual machine
       
     4 ** See Copyright Notice in lua.h
       
     5 */
       
     6 
       
     7 
       
     8 #include <stdio.h>
       
     9 #include <stdlib.h>
       
    10 #include <string.h>
       
    11 
       
    12 #define lvm_c
       
    13 #define LUA_CORE
       
    14 
       
    15 #include "lua.h"
       
    16 
       
    17 #include "ldebug.h"
       
    18 #include "ldo.h"
       
    19 #include "lfunc.h"
       
    20 #include "lgc.h"
       
    21 #include "lobject.h"
       
    22 #include "lopcodes.h"
       
    23 #include "lstate.h"
       
    24 #include "lstring.h"
       
    25 #include "ltable.h"
       
    26 #include "ltm.h"
       
    27 #include "lvm.h"
       
    28 
       
    29 
       
    30 
       
    31 /* limit for table tag-method chains (to avoid loops) */
       
    32 #define MAXTAGLOOP	100
       
    33 
       
    34 
       
    35 const TValue *luaV_tonumber (const TValue *obj, TValue *n) {
       
    36   lua_Number num;
       
    37   if (ttisnumber(obj)) return obj;
       
    38   if (ttisstring(obj) && luaO_str2d(svalue(obj), tsvalue(obj)->len, &num)) {
       
    39     setnvalue(n, num);
       
    40     return n;
       
    41   }
       
    42   else
       
    43     return NULL;
       
    44 }
       
    45 
       
    46 
       
    47 int luaV_tostring (lua_State *L, StkId obj) {
       
    48   if (!ttisnumber(obj))
       
    49     return 0;
       
    50   else {
       
    51     char s[LUAI_MAXNUMBER2STR];
       
    52     lua_Number n = nvalue(obj);
       
    53     int l = lua_number2str(s, n);
       
    54     setsvalue2s(L, obj, luaS_newlstr(L, s, l));
       
    55     return 1;
       
    56   }
       
    57 }
       
    58 
       
    59 
       
    60 static void traceexec (lua_State *L) {
       
    61   CallInfo *ci = L->ci;
       
    62   lu_byte mask = L->hookmask;
       
    63   int counthook = ((mask & LUA_MASKCOUNT) && L->hookcount == 0);
       
    64   if (counthook)
       
    65     resethookcount(L);  /* reset count */
       
    66   if (ci->callstatus & CIST_HOOKYIELD) {  /* called hook last time? */
       
    67     ci->callstatus &= ~CIST_HOOKYIELD;  /* erase mark */
       
    68     return;  /* do not call hook again (VM yielded, so it did not move) */
       
    69   }
       
    70   if (counthook)
       
    71     luaD_hook(L, LUA_HOOKCOUNT, -1);  /* call count hook */
       
    72   if (mask & LUA_MASKLINE) {
       
    73     Proto *p = ci_func(ci)->p;
       
    74     int npc = pcRel(ci->u.l.savedpc, p);
       
    75     int newline = getfuncline(p, npc);
       
    76     if (npc == 0 ||  /* call linehook when enter a new function, */
       
    77         ci->u.l.savedpc <= L->oldpc ||  /* when jump back (loop), or when */
       
    78         newline != getfuncline(p, pcRel(L->oldpc, p)))  /* enter a new line */
       
    79       luaD_hook(L, LUA_HOOKLINE, newline);  /* call line hook */
       
    80   }
       
    81   L->oldpc = ci->u.l.savedpc;
       
    82   if (L->status == LUA_YIELD) {  /* did hook yield? */
       
    83     if (counthook)
       
    84       L->hookcount = 1;  /* undo decrement to zero */
       
    85     ci->u.l.savedpc--;  /* undo increment (resume will increment it again) */
       
    86     ci->callstatus |= CIST_HOOKYIELD;  /* mark that it yielded */
       
    87     ci->func = L->top - 1;  /* protect stack below results */
       
    88     luaD_throw(L, LUA_YIELD);
       
    89   }
       
    90 }
       
    91 
       
    92 
       
    93 static void callTM (lua_State *L, const TValue *f, const TValue *p1,
       
    94                     const TValue *p2, TValue *p3, int hasres) {
       
    95   ptrdiff_t result = savestack(L, p3);
       
    96   setobj2s(L, L->top++, f);  /* push function */
       
    97   setobj2s(L, L->top++, p1);  /* 1st argument */
       
    98   setobj2s(L, L->top++, p2);  /* 2nd argument */
       
    99   if (!hasres)  /* no result? 'p3' is third argument */
       
   100     setobj2s(L, L->top++, p3);  /* 3rd argument */
       
   101   /* metamethod may yield only when called from Lua code */
       
   102   luaD_call(L, L->top - (4 - hasres), hasres, isLua(L->ci));
       
   103   if (hasres) {  /* if has result, move it to its place */
       
   104     p3 = restorestack(L, result);
       
   105     setobjs2s(L, p3, --L->top);
       
   106   }
       
   107 }
       
   108 
       
   109 
       
   110 void luaV_gettable (lua_State *L, const TValue *t, TValue *key, StkId val) {
       
   111   int loop;
       
   112   for (loop = 0; loop < MAXTAGLOOP; loop++) {
       
   113     const TValue *tm;
       
   114     if (ttistable(t)) {  /* `t' is a table? */
       
   115       Table *h = hvalue(t);
       
   116       const TValue *res = luaH_get(h, key); /* do a primitive get */
       
   117       if (!ttisnil(res) ||  /* result is not nil? */
       
   118           (tm = fasttm(L, h->metatable, TM_INDEX)) == NULL) { /* or no TM? */
       
   119         setobj2s(L, val, res);
       
   120         return;
       
   121       }
       
   122       /* else will try the tag method */
       
   123     }
       
   124     else if (ttisnil(tm = luaT_gettmbyobj(L, t, TM_INDEX)))
       
   125       luaG_typeerror(L, t, "index");
       
   126     if (ttisfunction(tm)) {
       
   127       callTM(L, tm, t, key, val, 1);
       
   128       return;
       
   129     }
       
   130     t = tm;  /* else repeat with 'tm' */
       
   131   }
       
   132   luaG_runerror(L, "loop in gettable");
       
   133 }
       
   134 
       
   135 
       
   136 void luaV_settable (lua_State *L, const TValue *t, TValue *key, StkId val) {
       
   137   int loop;
       
   138   for (loop = 0; loop < MAXTAGLOOP; loop++) {
       
   139     const TValue *tm;
       
   140     if (ttistable(t)) {  /* `t' is a table? */
       
   141       Table *h = hvalue(t);
       
   142       TValue *oldval = cast(TValue *, luaH_get(h, key));
       
   143       /* if previous value is not nil, there must be a previous entry
       
   144          in the table; moreover, a metamethod has no relevance */
       
   145       if (!ttisnil(oldval) ||
       
   146          /* previous value is nil; must check the metamethod */
       
   147          ((tm = fasttm(L, h->metatable, TM_NEWINDEX)) == NULL &&
       
   148          /* no metamethod; is there a previous entry in the table? */
       
   149          (oldval != luaO_nilobject ||
       
   150          /* no previous entry; must create one. (The next test is
       
   151             always true; we only need the assignment.) */
       
   152          (oldval = luaH_newkey(L, h, key), 1)))) {
       
   153         /* no metamethod and (now) there is an entry with given key */
       
   154         setobj2t(L, oldval, val);  /* assign new value to that entry */
       
   155         invalidateTMcache(h);
       
   156         luaC_barrierback(L, obj2gco(h), val);
       
   157         return;
       
   158       }
       
   159       /* else will try the metamethod */
       
   160     }
       
   161     else  /* not a table; check metamethod */
       
   162       if (ttisnil(tm = luaT_gettmbyobj(L, t, TM_NEWINDEX)))
       
   163         luaG_typeerror(L, t, "index");
       
   164     /* there is a metamethod */
       
   165     if (ttisfunction(tm)) {
       
   166       callTM(L, tm, t, key, val, 0);
       
   167       return;
       
   168     }
       
   169     t = tm;  /* else repeat with 'tm' */
       
   170   }
       
   171   luaG_runerror(L, "loop in settable");
       
   172 }
       
   173 
       
   174 
       
   175 static int call_binTM (lua_State *L, const TValue *p1, const TValue *p2,
       
   176                        StkId res, TMS event) {
       
   177   const TValue *tm = luaT_gettmbyobj(L, p1, event);  /* try first operand */
       
   178   if (ttisnil(tm))
       
   179     tm = luaT_gettmbyobj(L, p2, event);  /* try second operand */
       
   180   if (ttisnil(tm)) return 0;
       
   181   callTM(L, tm, p1, p2, res, 1);
       
   182   return 1;
       
   183 }
       
   184 
       
   185 
       
   186 static const TValue *get_equalTM (lua_State *L, Table *mt1, Table *mt2,
       
   187                                   TMS event) {
       
   188   const TValue *tm1 = fasttm(L, mt1, event);
       
   189   const TValue *tm2;
       
   190   if (tm1 == NULL) return NULL;  /* no metamethod */
       
   191   if (mt1 == mt2) return tm1;  /* same metatables => same metamethods */
       
   192   tm2 = fasttm(L, mt2, event);
       
   193   if (tm2 == NULL) return NULL;  /* no metamethod */
       
   194   if (luaV_rawequalobj(tm1, tm2))  /* same metamethods? */
       
   195     return tm1;
       
   196   return NULL;
       
   197 }
       
   198 
       
   199 
       
   200 static int call_orderTM (lua_State *L, const TValue *p1, const TValue *p2,
       
   201                          TMS event) {
       
   202   if (!call_binTM(L, p1, p2, L->top, event))
       
   203     return -1;  /* no metamethod */
       
   204   else
       
   205     return !l_isfalse(L->top);
       
   206 }
       
   207 
       
   208 
       
   209 static int l_strcmp (const TString *ls, const TString *rs) {
       
   210   const char *l = getstr(ls);
       
   211   size_t ll = ls->tsv.len;
       
   212   const char *r = getstr(rs);
       
   213   size_t lr = rs->tsv.len;
       
   214   for (;;) {
       
   215     int temp = strcoll(l, r);
       
   216     if (temp != 0) return temp;
       
   217     else {  /* strings are equal up to a `\0' */
       
   218       size_t len = strlen(l);  /* index of first `\0' in both strings */
       
   219       if (len == lr)  /* r is finished? */
       
   220         return (len == ll) ? 0 : 1;
       
   221       else if (len == ll)  /* l is finished? */
       
   222         return -1;  /* l is smaller than r (because r is not finished) */
       
   223       /* both strings longer than `len'; go on comparing (after the `\0') */
       
   224       len++;
       
   225       l += len; ll -= len; r += len; lr -= len;
       
   226     }
       
   227   }
       
   228 }
       
   229 
       
   230 
       
   231 int luaV_lessthan (lua_State *L, const TValue *l, const TValue *r) {
       
   232   int res;
       
   233   if (ttisnumber(l) && ttisnumber(r))
       
   234     return luai_numlt(L, nvalue(l), nvalue(r));
       
   235   else if (ttisstring(l) && ttisstring(r))
       
   236     return l_strcmp(rawtsvalue(l), rawtsvalue(r)) < 0;
       
   237   else if ((res = call_orderTM(L, l, r, TM_LT)) < 0)
       
   238     luaG_ordererror(L, l, r);
       
   239   return res;
       
   240 }
       
   241 
       
   242 
       
   243 int luaV_lessequal (lua_State *L, const TValue *l, const TValue *r) {
       
   244   int res;
       
   245   if (ttisnumber(l) && ttisnumber(r))
       
   246     return luai_numle(L, nvalue(l), nvalue(r));
       
   247   else if (ttisstring(l) && ttisstring(r))
       
   248     return l_strcmp(rawtsvalue(l), rawtsvalue(r)) <= 0;
       
   249   else if ((res = call_orderTM(L, l, r, TM_LE)) >= 0)  /* first try `le' */
       
   250     return res;
       
   251   else if ((res = call_orderTM(L, r, l, TM_LT)) < 0)  /* else try `lt' */
       
   252     luaG_ordererror(L, l, r);
       
   253   return !res;
       
   254 }
       
   255 
       
   256 
       
   257 /*
       
   258 ** equality of Lua values. L == NULL means raw equality (no metamethods)
       
   259 */
       
   260 int luaV_equalobj_ (lua_State *L, const TValue *t1, const TValue *t2) {
       
   261   const TValue *tm;
       
   262   lua_assert(ttisequal(t1, t2));
       
   263   switch (ttype(t1)) {
       
   264     case LUA_TNIL: return 1;
       
   265     case LUA_TNUMBER: return luai_numeq(nvalue(t1), nvalue(t2));
       
   266     case LUA_TBOOLEAN: return bvalue(t1) == bvalue(t2);  /* true must be 1 !! */
       
   267     case LUA_TLIGHTUSERDATA: return pvalue(t1) == pvalue(t2);
       
   268     case LUA_TLCF: return fvalue(t1) == fvalue(t2);
       
   269     case LUA_TSHRSTR: return eqshrstr(rawtsvalue(t1), rawtsvalue(t2));
       
   270     case LUA_TLNGSTR: return luaS_eqlngstr(rawtsvalue(t1), rawtsvalue(t2));
       
   271     case LUA_TUSERDATA: {
       
   272       if (uvalue(t1) == uvalue(t2)) return 1;
       
   273       else if (L == NULL) return 0;
       
   274       tm = get_equalTM(L, uvalue(t1)->metatable, uvalue(t2)->metatable, TM_EQ);
       
   275       break;  /* will try TM */
       
   276     }
       
   277     case LUA_TTABLE: {
       
   278       if (hvalue(t1) == hvalue(t2)) return 1;
       
   279       else if (L == NULL) return 0;
       
   280       tm = get_equalTM(L, hvalue(t1)->metatable, hvalue(t2)->metatable, TM_EQ);
       
   281       break;  /* will try TM */
       
   282     }
       
   283     default:
       
   284       lua_assert(iscollectable(t1));
       
   285       return gcvalue(t1) == gcvalue(t2);
       
   286   }
       
   287   if (tm == NULL) return 0;  /* no TM? */
       
   288   callTM(L, tm, t1, t2, L->top, 1);  /* call TM */
       
   289   return !l_isfalse(L->top);
       
   290 }
       
   291 
       
   292 
       
   293 void luaV_concat (lua_State *L, int total) {
       
   294   lua_assert(total >= 2);
       
   295   do {
       
   296     StkId top = L->top;
       
   297     int n = 2;  /* number of elements handled in this pass (at least 2) */
       
   298     if (!(ttisstring(top-2) || ttisnumber(top-2)) || !tostring(L, top-1)) {
       
   299       if (!call_binTM(L, top-2, top-1, top-2, TM_CONCAT))
       
   300         luaG_concaterror(L, top-2, top-1);
       
   301     }
       
   302     else if (tsvalue(top-1)->len == 0)  /* second operand is empty? */
       
   303       (void)tostring(L, top - 2);  /* result is first operand */
       
   304     else if (ttisstring(top-2) && tsvalue(top-2)->len == 0) {
       
   305       setobjs2s(L, top - 2, top - 1);  /* result is second op. */
       
   306     }
       
   307     else {
       
   308       /* at least two non-empty string values; get as many as possible */
       
   309       size_t tl = tsvalue(top-1)->len;
       
   310       char *buffer;
       
   311       int i;
       
   312       /* collect total length */
       
   313       for (i = 1; i < total && tostring(L, top-i-1); i++) {
       
   314         size_t l = tsvalue(top-i-1)->len;
       
   315         if (l >= (MAX_SIZET/sizeof(char)) - tl)
       
   316           luaG_runerror(L, "string length overflow");
       
   317         tl += l;
       
   318       }
       
   319       buffer = luaZ_openspace(L, &G(L)->buff, tl);
       
   320       tl = 0;
       
   321       n = i;
       
   322       do {  /* concat all strings */
       
   323         size_t l = tsvalue(top-i)->len;
       
   324         memcpy(buffer+tl, svalue(top-i), l * sizeof(char));
       
   325         tl += l;
       
   326       } while (--i > 0);
       
   327       setsvalue2s(L, top-n, luaS_newlstr(L, buffer, tl));
       
   328     }
       
   329     total -= n-1;  /* got 'n' strings to create 1 new */
       
   330     L->top -= n-1;  /* popped 'n' strings and pushed one */
       
   331   } while (total > 1);  /* repeat until only 1 result left */
       
   332 }
       
   333 
       
   334 
       
   335 void luaV_objlen (lua_State *L, StkId ra, const TValue *rb) {
       
   336   const TValue *tm;
       
   337   switch (ttypenv(rb)) {
       
   338     case LUA_TTABLE: {
       
   339       Table *h = hvalue(rb);
       
   340       tm = fasttm(L, h->metatable, TM_LEN);
       
   341       if (tm) break;  /* metamethod? break switch to call it */
       
   342       setnvalue(ra, cast_num(luaH_getn(h)));  /* else primitive len */
       
   343       return;
       
   344     }
       
   345     case LUA_TSTRING: {
       
   346       setnvalue(ra, cast_num(tsvalue(rb)->len));
       
   347       return;
       
   348     }
       
   349     default: {  /* try metamethod */
       
   350       tm = luaT_gettmbyobj(L, rb, TM_LEN);
       
   351       if (ttisnil(tm))  /* no metamethod? */
       
   352         luaG_typeerror(L, rb, "get length of");
       
   353       break;
       
   354     }
       
   355   }
       
   356   callTM(L, tm, rb, rb, ra, 1);
       
   357 }
       
   358 
       
   359 
       
   360 void luaV_arith (lua_State *L, StkId ra, const TValue *rb,
       
   361                  const TValue *rc, TMS op) {
       
   362   TValue tempb, tempc;
       
   363   const TValue *b, *c;
       
   364   if ((b = luaV_tonumber(rb, &tempb)) != NULL &&
       
   365       (c = luaV_tonumber(rc, &tempc)) != NULL) {
       
   366     lua_Number res = luaO_arith(op - TM_ADD + LUA_OPADD, nvalue(b), nvalue(c));
       
   367     setnvalue(ra, res);
       
   368   }
       
   369   else if (!call_binTM(L, rb, rc, ra, op))
       
   370     luaG_aritherror(L, rb, rc);
       
   371 }
       
   372 
       
   373 
       
   374 /*
       
   375 ** check whether cached closure in prototype 'p' may be reused, that is,
       
   376 ** whether there is a cached closure with the same upvalues needed by
       
   377 ** new closure to be created.
       
   378 */
       
   379 static Closure *getcached (Proto *p, UpVal **encup, StkId base) {
       
   380   Closure *c = p->cache;
       
   381   if (c != NULL) {  /* is there a cached closure? */
       
   382     int nup = p->sizeupvalues;
       
   383     Upvaldesc *uv = p->upvalues;
       
   384     int i;
       
   385     for (i = 0; i < nup; i++) {  /* check whether it has right upvalues */
       
   386       TValue *v = uv[i].instack ? base + uv[i].idx : encup[uv[i].idx]->v;
       
   387       if (c->l.upvals[i]->v != v)
       
   388         return NULL;  /* wrong upvalue; cannot reuse closure */
       
   389     }
       
   390   }
       
   391   return c;  /* return cached closure (or NULL if no cached closure) */
       
   392 }
       
   393 
       
   394 
       
   395 /*
       
   396 ** create a new Lua closure, push it in the stack, and initialize
       
   397 ** its upvalues. Note that the call to 'luaC_barrierproto' must come
       
   398 ** before the assignment to 'p->cache', as the function needs the
       
   399 ** original value of that field.
       
   400 */
       
   401 static void pushclosure (lua_State *L, Proto *p, UpVal **encup, StkId base,
       
   402                          StkId ra) {
       
   403   int nup = p->sizeupvalues;
       
   404   Upvaldesc *uv = p->upvalues;
       
   405   int i;
       
   406   Closure *ncl = luaF_newLclosure(L, nup);
       
   407   ncl->l.p = p;
       
   408   setclLvalue(L, ra, ncl);  /* anchor new closure in stack */
       
   409   for (i = 0; i < nup; i++) {  /* fill in its upvalues */
       
   410     if (uv[i].instack)  /* upvalue refers to local variable? */
       
   411       ncl->l.upvals[i] = luaF_findupval(L, base + uv[i].idx);
       
   412     else  /* get upvalue from enclosing function */
       
   413       ncl->l.upvals[i] = encup[uv[i].idx];
       
   414   }
       
   415   luaC_barrierproto(L, p, ncl);
       
   416   p->cache = ncl;  /* save it on cache for reuse */
       
   417 }
       
   418 
       
   419 
       
   420 /*
       
   421 ** finish execution of an opcode interrupted by an yield
       
   422 */
       
   423 void luaV_finishOp (lua_State *L) {
       
   424   CallInfo *ci = L->ci;
       
   425   StkId base = ci->u.l.base;
       
   426   Instruction inst = *(ci->u.l.savedpc - 1);  /* interrupted instruction */
       
   427   OpCode op = GET_OPCODE(inst);
       
   428   switch (op) {  /* finish its execution */
       
   429     case OP_ADD: case OP_SUB: case OP_MUL: case OP_DIV:
       
   430     case OP_MOD: case OP_POW: case OP_UNM: case OP_LEN:
       
   431     case OP_GETTABUP: case OP_GETTABLE: case OP_SELF: {
       
   432       setobjs2s(L, base + GETARG_A(inst), --L->top);
       
   433       break;
       
   434     }
       
   435     case OP_LE: case OP_LT: case OP_EQ: {
       
   436       int res = !l_isfalse(L->top - 1);
       
   437       L->top--;
       
   438       /* metamethod should not be called when operand is K */
       
   439       lua_assert(!ISK(GETARG_B(inst)));
       
   440       if (op == OP_LE &&  /* "<=" using "<" instead? */
       
   441           ttisnil(luaT_gettmbyobj(L, base + GETARG_B(inst), TM_LE)))
       
   442         res = !res;  /* invert result */
       
   443       lua_assert(GET_OPCODE(*ci->u.l.savedpc) == OP_JMP);
       
   444       if (res != GETARG_A(inst))  /* condition failed? */
       
   445         ci->u.l.savedpc++;  /* skip jump instruction */
       
   446       break;
       
   447     }
       
   448     case OP_CONCAT: {
       
   449       StkId top = L->top - 1;  /* top when 'call_binTM' was called */
       
   450       int b = GETARG_B(inst);      /* first element to concatenate */
       
   451       int total = cast_int(top - 1 - (base + b));  /* yet to concatenate */
       
   452       setobj2s(L, top - 2, top);  /* put TM result in proper position */
       
   453       if (total > 1) {  /* are there elements to concat? */
       
   454         L->top = top - 1;  /* top is one after last element (at top-2) */
       
   455         luaV_concat(L, total);  /* concat them (may yield again) */
       
   456       }
       
   457       /* move final result to final position */
       
   458       setobj2s(L, ci->u.l.base + GETARG_A(inst), L->top - 1);
       
   459       L->top = ci->top;  /* restore top */
       
   460       break;
       
   461     }
       
   462     case OP_TFORCALL: {
       
   463       lua_assert(GET_OPCODE(*ci->u.l.savedpc) == OP_TFORLOOP);
       
   464       L->top = ci->top;  /* correct top */
       
   465       break;
       
   466     }
       
   467     case OP_CALL: {
       
   468       if (GETARG_C(inst) - 1 >= 0)  /* nresults >= 0? */
       
   469         L->top = ci->top;  /* adjust results */
       
   470       break;
       
   471     }
       
   472     case OP_TAILCALL: case OP_SETTABUP: case OP_SETTABLE:
       
   473       break;
       
   474     default: lua_assert(0);
       
   475   }
       
   476 }
       
   477 
       
   478 
       
   479 
       
   480 /*
       
   481 ** some macros for common tasks in `luaV_execute'
       
   482 */
       
   483 
       
   484 #if !defined luai_runtimecheck
       
   485 #define luai_runtimecheck(L, c)		/* void */
       
   486 #endif
       
   487 
       
   488 
       
   489 #define RA(i)	(base+GETARG_A(i))
       
   490 /* to be used after possible stack reallocation */
       
   491 #define RB(i)	check_exp(getBMode(GET_OPCODE(i)) == OpArgR, base+GETARG_B(i))
       
   492 #define RC(i)	check_exp(getCMode(GET_OPCODE(i)) == OpArgR, base+GETARG_C(i))
       
   493 #define RKB(i)	check_exp(getBMode(GET_OPCODE(i)) == OpArgK, \
       
   494 	ISK(GETARG_B(i)) ? k+INDEXK(GETARG_B(i)) : base+GETARG_B(i))
       
   495 #define RKC(i)	check_exp(getCMode(GET_OPCODE(i)) == OpArgK, \
       
   496 	ISK(GETARG_C(i)) ? k+INDEXK(GETARG_C(i)) : base+GETARG_C(i))
       
   497 #define KBx(i)  \
       
   498   (k + (GETARG_Bx(i) != 0 ? GETARG_Bx(i) - 1 : GETARG_Ax(*ci->u.l.savedpc++)))
       
   499 
       
   500 
       
   501 /* execute a jump instruction */
       
   502 #define dojump(ci,i,e) \
       
   503   { int a = GETARG_A(i); \
       
   504     if (a > 0) luaF_close(L, ci->u.l.base + a - 1); \
       
   505     ci->u.l.savedpc += GETARG_sBx(i) + e; }
       
   506 
       
   507 /* for test instructions, execute the jump instruction that follows it */
       
   508 #define donextjump(ci)	{ i = *ci->u.l.savedpc; dojump(ci, i, 1); }
       
   509 
       
   510 
       
   511 #define Protect(x)	{ {x;}; base = ci->u.l.base; }
       
   512 
       
   513 #define checkGC(L,c)  \
       
   514   Protect( luaC_condGC(L,{L->top = (c);  /* limit of live values */ \
       
   515                           luaC_step(L); \
       
   516                           L->top = ci->top;})  /* restore top */ \
       
   517            luai_threadyield(L); )
       
   518 
       
   519 
       
   520 #define arith_op(op,tm) { \
       
   521         TValue *rb = RKB(i); \
       
   522         TValue *rc = RKC(i); \
       
   523         if (ttisnumber(rb) && ttisnumber(rc)) { \
       
   524           lua_Number nb = nvalue(rb), nc = nvalue(rc); \
       
   525           setnvalue(ra, op(L, nb, nc)); \
       
   526         } \
       
   527         else { Protect(luaV_arith(L, ra, rb, rc, tm)); } }
       
   528 
       
   529 
       
   530 #define vmdispatch(o)	switch(o)
       
   531 #define vmcase(l,b)	case l: {b}  break;
       
   532 #define vmcasenb(l,b)	case l: {b}		/* nb = no break */
       
   533 
       
   534 void luaV_execute (lua_State *L) {
       
   535   CallInfo *ci = L->ci;
       
   536   LClosure *cl;
       
   537   TValue *k;
       
   538   StkId base;
       
   539  newframe:  /* reentry point when frame changes (call/return) */
       
   540   lua_assert(ci == L->ci);
       
   541   cl = clLvalue(ci->func);
       
   542   k = cl->p->k;
       
   543   base = ci->u.l.base;
       
   544   /* main loop of interpreter */
       
   545   for (;;) {
       
   546     Instruction i = *(ci->u.l.savedpc++);
       
   547     StkId ra;
       
   548     if ((L->hookmask & (LUA_MASKLINE | LUA_MASKCOUNT)) &&
       
   549         (--L->hookcount == 0 || L->hookmask & LUA_MASKLINE)) {
       
   550       Protect(traceexec(L));
       
   551     }
       
   552     /* WARNING: several calls may realloc the stack and invalidate `ra' */
       
   553     ra = RA(i);
       
   554     lua_assert(base == ci->u.l.base);
       
   555     lua_assert(base <= L->top && L->top < L->stack + L->stacksize);
       
   556     vmdispatch (GET_OPCODE(i)) {
       
   557       vmcase(OP_MOVE,
       
   558         setobjs2s(L, ra, RB(i));
       
   559       )
       
   560       vmcase(OP_LOADK,
       
   561         TValue *rb = k + GETARG_Bx(i);
       
   562         setobj2s(L, ra, rb);
       
   563       )
       
   564       vmcase(OP_LOADKX,
       
   565         TValue *rb;
       
   566         lua_assert(GET_OPCODE(*ci->u.l.savedpc) == OP_EXTRAARG);
       
   567         rb = k + GETARG_Ax(*ci->u.l.savedpc++);
       
   568         setobj2s(L, ra, rb);
       
   569       )
       
   570       vmcase(OP_LOADBOOL,
       
   571         setbvalue(ra, GETARG_B(i));
       
   572         if (GETARG_C(i)) ci->u.l.savedpc++;  /* skip next instruction (if C) */
       
   573       )
       
   574       vmcase(OP_LOADNIL,
       
   575         int b = GETARG_B(i);
       
   576         do {
       
   577           setnilvalue(ra++);
       
   578         } while (b--);
       
   579       )
       
   580       vmcase(OP_GETUPVAL,
       
   581         int b = GETARG_B(i);
       
   582         setobj2s(L, ra, cl->upvals[b]->v);
       
   583       )
       
   584       vmcase(OP_GETTABUP,
       
   585         int b = GETARG_B(i);
       
   586         Protect(luaV_gettable(L, cl->upvals[b]->v, RKC(i), ra));
       
   587       )
       
   588       vmcase(OP_GETTABLE,
       
   589         Protect(luaV_gettable(L, RB(i), RKC(i), ra));
       
   590       )
       
   591       vmcase(OP_SETTABUP,
       
   592         int a = GETARG_A(i);
       
   593         Protect(luaV_settable(L, cl->upvals[a]->v, RKB(i), RKC(i)));
       
   594       )
       
   595       vmcase(OP_SETUPVAL,
       
   596         UpVal *uv = cl->upvals[GETARG_B(i)];
       
   597         setobj(L, uv->v, ra);
       
   598         luaC_barrier(L, uv, ra);
       
   599       )
       
   600       vmcase(OP_SETTABLE,
       
   601         Protect(luaV_settable(L, ra, RKB(i), RKC(i)));
       
   602       )
       
   603       vmcase(OP_NEWTABLE,
       
   604         int b = GETARG_B(i);
       
   605         int c = GETARG_C(i);
       
   606         Table *t = luaH_new(L);
       
   607         sethvalue(L, ra, t);
       
   608         if (b != 0 || c != 0)
       
   609           luaH_resize(L, t, luaO_fb2int(b), luaO_fb2int(c));
       
   610         checkGC(L, ra + 1);
       
   611       )
       
   612       vmcase(OP_SELF,
       
   613         StkId rb = RB(i);
       
   614         setobjs2s(L, ra+1, rb);
       
   615         Protect(luaV_gettable(L, rb, RKC(i), ra));
       
   616       )
       
   617       vmcase(OP_ADD,
       
   618         arith_op(luai_numadd, TM_ADD);
       
   619       )
       
   620       vmcase(OP_SUB,
       
   621         arith_op(luai_numsub, TM_SUB);
       
   622       )
       
   623       vmcase(OP_MUL,
       
   624         arith_op(luai_nummul, TM_MUL);
       
   625       )
       
   626       vmcase(OP_DIV,
       
   627         arith_op(luai_numdiv, TM_DIV);
       
   628       )
       
   629       vmcase(OP_MOD,
       
   630         arith_op(luai_nummod, TM_MOD);
       
   631       )
       
   632       vmcase(OP_POW,
       
   633         arith_op(luai_numpow, TM_POW);
       
   634       )
       
   635       vmcase(OP_UNM,
       
   636         TValue *rb = RB(i);
       
   637         if (ttisnumber(rb)) {
       
   638           lua_Number nb = nvalue(rb);
       
   639           setnvalue(ra, luai_numunm(L, nb));
       
   640         }
       
   641         else {
       
   642           Protect(luaV_arith(L, ra, rb, rb, TM_UNM));
       
   643         }
       
   644       )
       
   645       vmcase(OP_NOT,
       
   646         TValue *rb = RB(i);
       
   647         int res = l_isfalse(rb);  /* next assignment may change this value */
       
   648         setbvalue(ra, res);
       
   649       )
       
   650       vmcase(OP_LEN,
       
   651         Protect(luaV_objlen(L, ra, RB(i)));
       
   652       )
       
   653       vmcase(OP_CONCAT,
       
   654         int b = GETARG_B(i);
       
   655         int c = GETARG_C(i);
       
   656         StkId rb;
       
   657         L->top = base + c + 1;  /* mark the end of concat operands */
       
   658         Protect(luaV_concat(L, c - b + 1));
       
   659         ra = RA(i);  /* 'luav_concat' may invoke TMs and move the stack */
       
   660         rb = b + base;
       
   661         setobjs2s(L, ra, rb);
       
   662         checkGC(L, (ra >= rb ? ra + 1 : rb));
       
   663         L->top = ci->top;  /* restore top */
       
   664       )
       
   665       vmcase(OP_JMP,
       
   666         dojump(ci, i, 0);
       
   667       )
       
   668       vmcase(OP_EQ,
       
   669         TValue *rb = RKB(i);
       
   670         TValue *rc = RKC(i);
       
   671         Protect(
       
   672           if (cast_int(equalobj(L, rb, rc)) != GETARG_A(i))
       
   673             ci->u.l.savedpc++;
       
   674           else
       
   675             donextjump(ci);
       
   676         )
       
   677       )
       
   678       vmcase(OP_LT,
       
   679         Protect(
       
   680           if (luaV_lessthan(L, RKB(i), RKC(i)) != GETARG_A(i))
       
   681             ci->u.l.savedpc++;
       
   682           else
       
   683             donextjump(ci);
       
   684         )
       
   685       )
       
   686       vmcase(OP_LE,
       
   687         Protect(
       
   688           if (luaV_lessequal(L, RKB(i), RKC(i)) != GETARG_A(i))
       
   689             ci->u.l.savedpc++;
       
   690           else
       
   691             donextjump(ci);
       
   692         )
       
   693       )
       
   694       vmcase(OP_TEST,
       
   695         if (GETARG_C(i) ? l_isfalse(ra) : !l_isfalse(ra))
       
   696             ci->u.l.savedpc++;
       
   697           else
       
   698           donextjump(ci);
       
   699       )
       
   700       vmcase(OP_TESTSET,
       
   701         TValue *rb = RB(i);
       
   702         if (GETARG_C(i) ? l_isfalse(rb) : !l_isfalse(rb))
       
   703           ci->u.l.savedpc++;
       
   704         else {
       
   705           setobjs2s(L, ra, rb);
       
   706           donextjump(ci);
       
   707         }
       
   708       )
       
   709       vmcase(OP_CALL,
       
   710         int b = GETARG_B(i);
       
   711         int nresults = GETARG_C(i) - 1;
       
   712         if (b != 0) L->top = ra+b;  /* else previous instruction set top */
       
   713         if (luaD_precall(L, ra, nresults)) {  /* C function? */
       
   714           if (nresults >= 0) L->top = ci->top;  /* adjust results */
       
   715           base = ci->u.l.base;
       
   716         }
       
   717         else {  /* Lua function */
       
   718           ci = L->ci;
       
   719           ci->callstatus |= CIST_REENTRY;
       
   720           goto newframe;  /* restart luaV_execute over new Lua function */
       
   721         }
       
   722       )
       
   723       vmcase(OP_TAILCALL,
       
   724         int b = GETARG_B(i);
       
   725         if (b != 0) L->top = ra+b;  /* else previous instruction set top */
       
   726         lua_assert(GETARG_C(i) - 1 == LUA_MULTRET);
       
   727         if (luaD_precall(L, ra, LUA_MULTRET))  /* C function? */
       
   728           base = ci->u.l.base;
       
   729         else {
       
   730           /* tail call: put called frame (n) in place of caller one (o) */
       
   731           CallInfo *nci = L->ci;  /* called frame */
       
   732           CallInfo *oci = nci->previous;  /* caller frame */
       
   733           StkId nfunc = nci->func;  /* called function */
       
   734           StkId ofunc = oci->func;  /* caller function */
       
   735           /* last stack slot filled by 'precall' */
       
   736           StkId lim = nci->u.l.base + getproto(nfunc)->numparams;
       
   737           int aux;
       
   738           /* close all upvalues from previous call */
       
   739           if (cl->p->sizep > 0) luaF_close(L, oci->u.l.base);
       
   740           /* move new frame into old one */
       
   741           for (aux = 0; nfunc + aux < lim; aux++)
       
   742             setobjs2s(L, ofunc + aux, nfunc + aux);
       
   743           oci->u.l.base = ofunc + (nci->u.l.base - nfunc);  /* correct base */
       
   744           oci->top = L->top = ofunc + (L->top - nfunc);  /* correct top */
       
   745           oci->u.l.savedpc = nci->u.l.savedpc;
       
   746           oci->callstatus |= CIST_TAIL;  /* function was tail called */
       
   747           ci = L->ci = oci;  /* remove new frame */
       
   748           lua_assert(L->top == oci->u.l.base + getproto(ofunc)->maxstacksize);
       
   749           goto newframe;  /* restart luaV_execute over new Lua function */
       
   750         }
       
   751       )
       
   752       vmcasenb(OP_RETURN,
       
   753         int b = GETARG_B(i);
       
   754         if (b != 0) L->top = ra+b-1;
       
   755         if (cl->p->sizep > 0) luaF_close(L, base);
       
   756         b = luaD_poscall(L, ra);
       
   757         if (!(ci->callstatus & CIST_REENTRY))  /* 'ci' still the called one */
       
   758           return;  /* external invocation: return */
       
   759         else {  /* invocation via reentry: continue execution */
       
   760           ci = L->ci;
       
   761           if (b) L->top = ci->top;
       
   762           lua_assert(isLua(ci));
       
   763           lua_assert(GET_OPCODE(*((ci)->u.l.savedpc - 1)) == OP_CALL);
       
   764           goto newframe;  /* restart luaV_execute over new Lua function */
       
   765         }
       
   766       )
       
   767       vmcase(OP_FORLOOP,
       
   768         lua_Number step = nvalue(ra+2);
       
   769         lua_Number idx = luai_numadd(L, nvalue(ra), step); /* increment index */
       
   770         lua_Number limit = nvalue(ra+1);
       
   771         if (luai_numlt(L, 0, step) ? luai_numle(L, idx, limit)
       
   772                                    : luai_numle(L, limit, idx)) {
       
   773           ci->u.l.savedpc += GETARG_sBx(i);  /* jump back */
       
   774           setnvalue(ra, idx);  /* update internal index... */
       
   775           setnvalue(ra+3, idx);  /* ...and external index */
       
   776         }
       
   777       )
       
   778       vmcase(OP_FORPREP,
       
   779         const TValue *init = ra;
       
   780         const TValue *plimit = ra+1;
       
   781         const TValue *pstep = ra+2;
       
   782         if (!tonumber(init, ra))
       
   783           luaG_runerror(L, LUA_QL("for") " initial value must be a number");
       
   784         else if (!tonumber(plimit, ra+1))
       
   785           luaG_runerror(L, LUA_QL("for") " limit must be a number");
       
   786         else if (!tonumber(pstep, ra+2))
       
   787           luaG_runerror(L, LUA_QL("for") " step must be a number");
       
   788         setnvalue(ra, luai_numsub(L, nvalue(ra), nvalue(pstep)));
       
   789         ci->u.l.savedpc += GETARG_sBx(i);
       
   790       )
       
   791       vmcasenb(OP_TFORCALL,
       
   792         StkId cb = ra + 3;  /* call base */
       
   793         setobjs2s(L, cb+2, ra+2);
       
   794         setobjs2s(L, cb+1, ra+1);
       
   795         setobjs2s(L, cb, ra);
       
   796         L->top = cb + 3;  /* func. + 2 args (state and index) */
       
   797         Protect(luaD_call(L, cb, GETARG_C(i), 1));
       
   798         L->top = ci->top;
       
   799         i = *(ci->u.l.savedpc++);  /* go to next instruction */
       
   800         ra = RA(i);
       
   801         lua_assert(GET_OPCODE(i) == OP_TFORLOOP);
       
   802         goto l_tforloop;
       
   803       )
       
   804       vmcase(OP_TFORLOOP,
       
   805         l_tforloop:
       
   806         if (!ttisnil(ra + 1)) {  /* continue loop? */
       
   807           setobjs2s(L, ra, ra + 1);  /* save control variable */
       
   808            ci->u.l.savedpc += GETARG_sBx(i);  /* jump back */
       
   809         }
       
   810       )
       
   811       vmcase(OP_SETLIST,
       
   812         int n = GETARG_B(i);
       
   813         int c = GETARG_C(i);
       
   814         int last;
       
   815         Table *h;
       
   816         if (n == 0) n = cast_int(L->top - ra) - 1;
       
   817         if (c == 0) {
       
   818           lua_assert(GET_OPCODE(*ci->u.l.savedpc) == OP_EXTRAARG);
       
   819           c = GETARG_Ax(*ci->u.l.savedpc++);
       
   820         }
       
   821         luai_runtimecheck(L, ttistable(ra));
       
   822         h = hvalue(ra);
       
   823         last = ((c-1)*LFIELDS_PER_FLUSH) + n;
       
   824         if (last > h->sizearray)  /* needs more space? */
       
   825           luaH_resizearray(L, h, last);  /* pre-allocate it at once */
       
   826         for (; n > 0; n--) {
       
   827           TValue *val = ra+n;
       
   828           luaH_setint(L, h, last--, val);
       
   829           luaC_barrierback(L, obj2gco(h), val);
       
   830         }
       
   831         L->top = ci->top;  /* correct top (in case of previous open call) */
       
   832       )
       
   833       vmcase(OP_CLOSURE,
       
   834         Proto *p = cl->p->p[GETARG_Bx(i)];
       
   835         Closure *ncl = getcached(p, cl->upvals, base);  /* cached closure */
       
   836         if (ncl == NULL)  /* no match? */
       
   837           pushclosure(L, p, cl->upvals, base, ra);  /* create a new one */
       
   838         else
       
   839           setclLvalue(L, ra, ncl);  /* push cashed closure */
       
   840         checkGC(L, ra + 1);
       
   841       )
       
   842       vmcase(OP_VARARG,
       
   843         int b = GETARG_B(i) - 1;
       
   844         int j;
       
   845         int n = cast_int(base - ci->func) - cl->p->numparams - 1;
       
   846         if (b < 0) {  /* B == 0? */
       
   847           b = n;  /* get all var. arguments */
       
   848           Protect(luaD_checkstack(L, n));
       
   849           ra = RA(i);  /* previous call may change the stack */
       
   850           L->top = ra + n;
       
   851         }
       
   852         for (j = 0; j < b; j++) {
       
   853           if (j < n) {
       
   854             setobjs2s(L, ra + j, base - n + j);
       
   855           }
       
   856           else {
       
   857             setnilvalue(ra + j);
       
   858           }
       
   859         }
       
   860       )
       
   861       vmcase(OP_EXTRAARG,
       
   862         lua_assert(0);
       
   863       )
       
   864     }
       
   865   }
       
   866 }
       
   867