1/* BEGIN CSTYLED */
2/*
3** $Id: lvm.c,v 2.155.1.1 2013/04/12 18:48:47 roberto Exp $
4** Lua virtual machine
5** See Copyright Notice in lua.h
6*/
7
8
9#define lvm_c
10#define LUA_CORE
11
12#include <sys/lua/lua.h>
13
14#include "ldebug.h"
15#include "ldo.h"
16#include "lfunc.h"
17#include "lgc.h"
18#include "lobject.h"
19#include "lopcodes.h"
20#include "lstate.h"
21#include "lstring.h"
22#include "ltable.h"
23#include "ltm.h"
24#include "lvm.h"
25
26#ifdef _KERNEL
27#define	strcoll(l,r) (strcmp((l),(r)))
28#endif
29
30/* limit for table tag-method chains (to avoid loops) */
31#define MAXTAGLOOP	100
32
33
34const TValue *luaV_tonumber (const TValue *obj, TValue *n) {
35  lua_Number num;
36  if (ttisnumber(obj)) return obj;
37  if (ttisstring(obj) && luaO_str2d(svalue(obj), tsvalue(obj)->len, &num)) {
38    setnvalue(n, num);
39    return n;
40  }
41  else
42    return NULL;
43}
44
45
46int luaV_tostring (lua_State *L, StkId obj) {
47  if (!ttisnumber(obj))
48    return 0;
49  else {
50    char s[LUAI_MAXNUMBER2STR];
51    lua_Number n = nvalue(obj);
52    int l = lua_number2str(s, n);
53    setsvalue2s(L, obj, luaS_newlstr(L, s, l));
54    return 1;
55  }
56}
57
58
59static void traceexec (lua_State *L) {
60  CallInfo *ci = L->ci;
61  lu_byte mask = L->hookmask;
62  int counthook = ((mask & LUA_MASKCOUNT) && L->hookcount == 0);
63  if (counthook)
64    resethookcount(L);  /* reset count */
65  if (ci->callstatus & CIST_HOOKYIELD) {  /* called hook last time? */
66    ci->callstatus &= ~CIST_HOOKYIELD;  /* erase mark */
67    return;  /* do not call hook again (VM yielded, so it did not move) */
68  }
69  if (counthook)
70    luaD_hook(L, LUA_HOOKCOUNT, -1);  /* call count hook */
71  if (mask & LUA_MASKLINE) {
72    Proto *p = ci_func(ci)->p;
73    int npc = pcRel(ci->u.l.savedpc, p);
74    int newline = getfuncline(p, npc);
75    if (npc == 0 ||  /* call linehook when enter a new function, */
76        ci->u.l.savedpc <= L->oldpc ||  /* when jump back (loop), or when */
77        newline != getfuncline(p, pcRel(L->oldpc, p)))  /* enter a new line */
78      luaD_hook(L, LUA_HOOKLINE, newline);  /* call line hook */
79  }
80  L->oldpc = ci->u.l.savedpc;
81  if (L->status == LUA_YIELD) {  /* did hook yield? */
82    if (counthook)
83      L->hookcount = 1;  /* undo decrement to zero */
84    ci->u.l.savedpc--;  /* undo increment (resume will increment it again) */
85    ci->callstatus |= CIST_HOOKYIELD;  /* mark that it yielded */
86    ci->func = L->top - 1;  /* protect stack below results */
87    luaD_throw(L, LUA_YIELD);
88  }
89}
90
91
92static void callTM (lua_State *L, const TValue *f, const TValue *p1,
93                    const TValue *p2, TValue *p3, int hasres) {
94  if (L == NULL) return;
95
96  ptrdiff_t result = savestack(L, p3);
97  setobj2s(L, L->top++, f);  /* push function */
98  setobj2s(L, L->top++, p1);  /* 1st argument */
99  setobj2s(L, L->top++, p2);  /* 2nd argument */
100  if (!hasres)  /* no result? 'p3' is third argument */
101    setobj2s(L, L->top++, p3);  /* 3rd argument */
102  /* metamethod may yield only when called from Lua code */
103  luaD_call(L, L->top - (4 - hasres), hasres, isLua(L->ci));
104  if (hasres) {  /* if has result, move it to its place */
105    p3 = restorestack(L, result);
106    setobjs2s(L, p3, --L->top);
107  }
108}
109
110
111void luaV_gettable (lua_State *L, const TValue *t, TValue *key, StkId val) {
112  int loop;
113  for (loop = 0; loop < MAXTAGLOOP; loop++) {
114    const TValue *tm;
115    if (ttistable(t)) {  /* `t' is a table? */
116      Table *h = hvalue(t);
117      const TValue *res = luaH_get(h, key); /* do a primitive get */
118      if (!ttisnil(res) ||  /* result is not nil? */
119          (tm = fasttm(L, h->metatable, TM_INDEX)) == NULL) { /* or no TM? */
120        setobj2s(L, val, res);
121        return;
122      }
123      /* else will try the tag method */
124    }
125    else if (ttisnil(tm = luaT_gettmbyobj(L, t, TM_INDEX)))
126      luaG_typeerror(L, t, "index");
127    if (ttisfunction(tm)) {
128      callTM(L, tm, t, key, val, 1);
129      return;
130    }
131    t = tm;  /* else repeat with 'tm' */
132  }
133  luaG_runerror(L, "loop in gettable");
134}
135
136
137void luaV_settable (lua_State *L, const TValue *t, TValue *key, StkId val) {
138  int loop;
139  for (loop = 0; loop < MAXTAGLOOP; loop++) {
140    const TValue *tm;
141    if (ttistable(t)) {  /* `t' is a table? */
142      Table *h = hvalue(t);
143      TValue *oldval = cast(TValue *, luaH_get(h, key));
144      /* if previous value is not nil, there must be a previous entry
145         in the table; moreover, a metamethod has no relevance */
146      if (!ttisnil(oldval) ||
147         /* previous value is nil; must check the metamethod */
148         ((tm = fasttm(L, h->metatable, TM_NEWINDEX)) == NULL &&
149         /* no metamethod; is there a previous entry in the table? */
150         (oldval != luaO_nilobject ||
151         /* no previous entry; must create one. (The next test is
152            always true; we only need the assignment.) */
153         (oldval = luaH_newkey(L, h, key), 1)))) {
154        /* no metamethod and (now) there is an entry with given key */
155        setobj2t(L, oldval, val);  /* assign new value to that entry */
156        invalidateTMcache(h);
157        luaC_barrierback(L, obj2gco(h), val);
158        return;
159      }
160      /* else will try the metamethod */
161    }
162    else  /* not a table; check metamethod */
163      if (ttisnil(tm = luaT_gettmbyobj(L, t, TM_NEWINDEX)))
164        luaG_typeerror(L, t, "index");
165    /* there is a metamethod */
166    if (ttisfunction(tm)) {
167      callTM(L, tm, t, key, val, 0);
168      return;
169    }
170    t = tm;  /* else repeat with 'tm' */
171  }
172  luaG_runerror(L, "loop in settable");
173}
174
175
176static int call_binTM (lua_State *L, const TValue *p1, const TValue *p2,
177                       StkId res, TMS event) {
178  const TValue *tm = luaT_gettmbyobj(L, p1, event);  /* try first operand */
179  if (ttisnil(tm))
180    tm = luaT_gettmbyobj(L, p2, event);  /* try second operand */
181  if (ttisnil(tm)) return 0;
182  callTM(L, tm, p1, p2, res, 1);
183  return 1;
184}
185
186
187static const TValue *get_equalTM (lua_State *L, Table *mt1, Table *mt2,
188                                  TMS event) {
189  const TValue *tm1 = fasttm(L, mt1, event);
190  const TValue *tm2;
191  if (tm1 == NULL) return NULL;  /* no metamethod */
192  if (mt1 == mt2) return tm1;  /* same metatables => same metamethods */
193  tm2 = fasttm(L, mt2, event);
194  if (tm2 == NULL) return NULL;  /* no metamethod */
195  if (luaV_rawequalobj(tm1, tm2))  /* same metamethods? */
196    return tm1;
197  return NULL;
198}
199
200
201static int call_orderTM (lua_State *L, const TValue *p1, const TValue *p2,
202                         TMS event) {
203  if (!call_binTM(L, p1, p2, L->top, event))
204    return -1;  /* no metamethod */
205  else
206    return !l_isfalse(L->top);
207}
208
209
210static int l_strcmp (const TString *ls, const TString *rs) {
211  const char *l = getstr(ls);
212  size_t ll = ls->tsv.len;
213  const char *r = getstr(rs);
214  size_t lr = rs->tsv.len;
215  for (;;) {
216    int temp = strcoll(l, r);
217    if (temp != 0) return temp;
218    else {  /* strings are equal up to a `\0' */
219      size_t len = strlen(l);  /* index of first `\0' in both strings */
220      if (len == lr)  /* r is finished? */
221        return (len == ll) ? 0 : 1;
222      else if (len == ll)  /* l is finished? */
223        return -1;  /* l is smaller than r (because r is not finished) */
224      /* both strings longer than `len'; go on comparing (after the `\0') */
225      len++;
226      l += len; ll -= len; r += len; lr -= len;
227    }
228  }
229}
230
231
232int luaV_lessthan (lua_State *L, const TValue *l, const TValue *r) {
233  int res;
234  if (ttisnumber(l) && ttisnumber(r))
235    return luai_numlt(L, nvalue(l), nvalue(r));
236  else if (ttisstring(l) && ttisstring(r))
237    return l_strcmp(rawtsvalue(l), rawtsvalue(r)) < 0;
238  else if ((res = call_orderTM(L, l, r, TM_LT)) < 0)
239    luaG_ordererror(L, l, r);
240  return res;
241}
242
243
244int luaV_lessequal (lua_State *L, const TValue *l, const TValue *r) {
245  int res;
246  if (ttisnumber(l) && ttisnumber(r))
247    return luai_numle(L, nvalue(l), nvalue(r));
248  else if (ttisstring(l) && ttisstring(r))
249    return l_strcmp(rawtsvalue(l), rawtsvalue(r)) <= 0;
250  else if ((res = call_orderTM(L, l, r, TM_LE)) >= 0)  /* first try `le' */
251    return res;
252  else if ((res = call_orderTM(L, r, l, TM_LT)) < 0)  /* else try `lt' */
253    luaG_ordererror(L, l, r);
254  return !res;
255}
256
257
258/*
259** equality of Lua values. L == NULL means raw equality (no metamethods)
260*/
261int luaV_equalobj_ (lua_State *L, const TValue *t1, const TValue *t2) {
262  const TValue *tm;
263  lua_assert(ttisequal(t1, t2));
264  switch (ttype(t1)) {
265    case LUA_TNIL: return 1;
266    case LUA_TNUMBER: return luai_numeq(nvalue(t1), nvalue(t2));
267    case LUA_TBOOLEAN: return bvalue(t1) == bvalue(t2);  /* true must be 1 !! */
268    case LUA_TLIGHTUSERDATA: return pvalue(t1) == pvalue(t2);
269    case LUA_TLCF: return fvalue(t1) == fvalue(t2);
270    case LUA_TSHRSTR: return eqshrstr(rawtsvalue(t1), rawtsvalue(t2));
271    case LUA_TLNGSTR: return luaS_eqlngstr(rawtsvalue(t1), rawtsvalue(t2));
272    case LUA_TUSERDATA: {
273      if (uvalue(t1) == uvalue(t2)) return 1;
274      else if (L == NULL) return 0;
275      tm = get_equalTM(L, uvalue(t1)->metatable, uvalue(t2)->metatable, TM_EQ);
276      break;  /* will try TM */
277    }
278    case LUA_TTABLE: {
279      if (hvalue(t1) == hvalue(t2)) return 1;
280      else if (L == NULL) return 0;
281      tm = get_equalTM(L, hvalue(t1)->metatable, hvalue(t2)->metatable, TM_EQ);
282      break;  /* will try TM */
283    }
284    default:
285      lua_assert(iscollectable(t1));
286      return gcvalue(t1) == gcvalue(t2);
287  }
288  if (tm == NULL || L == NULL) return 0;  /* no TM? */
289  callTM(L, tm, t1, t2, L->top, 1);  /* call TM */
290  return !l_isfalse(L->top);
291}
292
293
294void luaV_concat (lua_State *L, int total) {
295  lua_assert(total >= 2);
296  do {
297    StkId top = L->top;
298    int n = 2;  /* number of elements handled in this pass (at least 2) */
299    if (!(ttisstring(top-2) || ttisnumber(top-2)) || !tostring(L, top-1)) {
300      if (!call_binTM(L, top-2, top-1, top-2, TM_CONCAT))
301        luaG_concaterror(L, top-2, top-1);
302    }
303    else if (tsvalue(top-1)->len == 0)  /* second operand is empty? */
304      (void)tostring(L, top - 2);  /* result is first operand */
305    else if (ttisstring(top-2) && tsvalue(top-2)->len == 0) {
306      setobjs2s(L, top - 2, top - 1);  /* result is second op. */
307    }
308    else {
309      /* at least two non-empty string values; get as many as possible */
310      size_t tl = tsvalue(top-1)->len;
311      char *buffer;
312      int i;
313      /* collect total length */
314      for (i = 1; i < total && tostring(L, top-i-1); i++) {
315        size_t l = tsvalue(top-i-1)->len;
316        if (l >= (MAX_SIZET/sizeof(char)) - tl)
317          luaG_runerror(L, "string length overflow");
318        tl += l;
319      }
320      buffer = luaZ_openspace(L, &G(L)->buff, tl);
321      tl = 0;
322      n = i;
323      do {  /* concat all strings */
324        size_t l = tsvalue(top-i)->len;
325        memcpy(buffer+tl, svalue(top-i), l * sizeof(char));
326        tl += l;
327      } while (--i > 0);
328      setsvalue2s(L, top-n, luaS_newlstr(L, buffer, tl));
329    }
330    total -= n-1;  /* got 'n' strings to create 1 new */
331    L->top -= n-1;  /* popped 'n' strings and pushed one */
332  } while (total > 1);  /* repeat until only 1 result left */
333}
334
335
336void luaV_objlen (lua_State *L, StkId ra, const TValue *rb) {
337  const TValue *tm;
338  switch (ttypenv(rb)) {
339    case LUA_TTABLE: {
340      Table *h = hvalue(rb);
341      tm = fasttm(L, h->metatable, TM_LEN);
342      if (tm) break;  /* metamethod? break switch to call it */
343      setnvalue(ra, cast_num(luaH_getn(h)));  /* else primitive len */
344      return;
345    }
346    case LUA_TSTRING: {
347      setnvalue(ra, cast_num(tsvalue(rb)->len));
348      return;
349    }
350    default: {  /* try metamethod */
351      tm = luaT_gettmbyobj(L, rb, TM_LEN);
352      if (ttisnil(tm))  /* no metamethod? */
353        luaG_typeerror(L, rb, "get length of");
354      break;
355    }
356  }
357  callTM(L, tm, rb, rb, ra, 1);
358}
359
360/*
361 * luaV_div and luaV_mod patched in from Lua 5.3.2 in order to properly handle
362 * div/mod by zero (instead of crashing, which is the default behavior in
363 * Lua 5.2)
364 */
365
366/*
367** Integer division; return 'm // n', that is, floor(m/n).
368** C division truncates its result (rounds towards zero).
369** 'floor(q) == trunc(q)' when 'q >= 0' or when 'q' is integer,
370** otherwise 'floor(q) == trunc(q) - 1'.
371*/
372static lua_Number luaV_div (lua_State *L, lua_Number m, lua_Number n) {
373  if ((lua_Unsigned)(n) + 1u <= 1u) {  /* special cases: -1 or 0 */
374    if (n == 0)
375      luaG_runerror(L, "attempt to divide by zero");
376    return (0 - m);   /* n==-1; avoid overflow with 0x80000...//-1 */
377  }
378  else {
379    lua_Number q = m / n;  /* perform C division */
380    if ((m ^ n) < 0 && m % n != 0)  /* 'm/n' would be negative non-integer? */
381      q -= 1;  /* correct result for different rounding */
382    return q;
383  }
384}
385
386
387/*
388** Integer modulus; return 'm % n'. (Assume that C '%' with
389** negative operands follows C99 behavior. See previous comment
390** about luaV_div.)
391*/
392static lua_Number luaV_mod (lua_State *L, lua_Number m, lua_Number n) {
393  if ((lua_Unsigned)(n) + 1u <= 1u) {  /* special cases: -1 or 0 */
394    if (n == 0)
395      luaG_runerror(L, "attempt to perform 'n%%0'");
396    return 0;   /* m % -1 == 0; avoid overflow with 0x80000...%-1 */
397  }
398  else {
399    lua_Number r = m % n;
400    if (r != 0 && (m ^ n) < 0)  /* 'm/n' would be non-integer negative? */
401      r += n;  /* correct result for different rounding */
402    return r;
403  }
404}
405
406/*
407 * End patch from 5.3.2
408 */
409
410void luaV_arith (lua_State *L, StkId ra, const TValue *rb,
411                 const TValue *rc, TMS op) {
412  TValue tempb, tempc;
413  const TValue *b, *c;
414  if ((b = luaV_tonumber(rb, &tempb)) != NULL &&
415      (c = luaV_tonumber(rc, &tempc)) != NULL) {
416    /*
417     * Patched: if dividing or modding, use patched functions from 5.3
418     */
419    lua_Number res;
420    int lop = op - TM_ADD + LUA_OPADD;
421    if (lop == LUA_OPDIV) {
422      res = luaV_div(L, nvalue(b), nvalue(c));
423    } else if (lop == LUA_OPMOD) {
424      res = luaV_mod(L, nvalue(b), nvalue(c));
425    } else {
426      res = luaO_arith(op - TM_ADD + LUA_OPADD, nvalue(b), nvalue(c));
427    }
428    setnvalue(ra, res);
429  }
430  else if (!call_binTM(L, rb, rc, ra, op))
431    luaG_aritherror(L, rb, rc);
432}
433
434
435/*
436** check whether cached closure in prototype 'p' may be reused, that is,
437** whether there is a cached closure with the same upvalues needed by
438** new closure to be created.
439*/
440static Closure *getcached (Proto *p, UpVal **encup, StkId base) {
441  Closure *c = p->cache;
442  if (c != NULL) {  /* is there a cached closure? */
443    int nup = p->sizeupvalues;
444    Upvaldesc *uv = p->upvalues;
445    int i;
446    for (i = 0; i < nup; i++) {  /* check whether it has right upvalues */
447      TValue *v = uv[i].instack ? base + uv[i].idx : encup[uv[i].idx]->v;
448      if (c->l.upvals[i]->v != v)
449        return NULL;  /* wrong upvalue; cannot reuse closure */
450    }
451  }
452  return c;  /* return cached closure (or NULL if no cached closure) */
453}
454
455
456/*
457** create a new Lua closure, push it in the stack, and initialize
458** its upvalues. Note that the call to 'luaC_barrierproto' must come
459** before the assignment to 'p->cache', as the function needs the
460** original value of that field.
461*/
462static void pushclosure (lua_State *L, Proto *p, UpVal **encup, StkId base,
463                         StkId ra) {
464  int nup = p->sizeupvalues;
465  Upvaldesc *uv = p->upvalues;
466  int i;
467  Closure *ncl = luaF_newLclosure(L, nup);
468  ncl->l.p = p;
469  setclLvalue(L, ra, ncl);  /* anchor new closure in stack */
470  for (i = 0; i < nup; i++) {  /* fill in its upvalues */
471    if (uv[i].instack)  /* upvalue refers to local variable? */
472      ncl->l.upvals[i] = luaF_findupval(L, base + uv[i].idx);
473    else  /* get upvalue from enclosing function */
474      ncl->l.upvals[i] = encup[uv[i].idx];
475  }
476  luaC_barrierproto(L, p, ncl);
477  p->cache = ncl;  /* save it on cache for reuse */
478}
479
480
481/*
482** finish execution of an opcode interrupted by an yield
483*/
484void luaV_finishOp (lua_State *L) {
485  CallInfo *ci = L->ci;
486  StkId base = ci->u.l.base;
487  Instruction inst = *(ci->u.l.savedpc - 1);  /* interrupted instruction */
488  OpCode op = GET_OPCODE(inst);
489  switch (op) {  /* finish its execution */
490    case OP_ADD: case OP_SUB: case OP_MUL: case OP_DIV:
491    case OP_MOD: case OP_POW: case OP_UNM: case OP_LEN:
492    case OP_GETTABUP: case OP_GETTABLE: case OP_SELF: {
493      setobjs2s(L, base + GETARG_A(inst), --L->top);
494      break;
495    }
496    case OP_LE: case OP_LT: case OP_EQ: {
497      int res = !l_isfalse(L->top - 1);
498      L->top--;
499      /* metamethod should not be called when operand is K */
500      lua_assert(!ISK(GETARG_B(inst)));
501      if (op == OP_LE &&  /* "<=" using "<" instead? */
502          ttisnil(luaT_gettmbyobj(L, base + GETARG_B(inst), TM_LE)))
503        res = !res;  /* invert result */
504      lua_assert(GET_OPCODE(*ci->u.l.savedpc) == OP_JMP);
505      if (res != GETARG_A(inst))  /* condition failed? */
506        ci->u.l.savedpc++;  /* skip jump instruction */
507      break;
508    }
509    case OP_CONCAT: {
510      StkId top = L->top - 1;  /* top when 'call_binTM' was called */
511      int b = GETARG_B(inst);      /* first element to concatenate */
512      int total = cast_int(top - 1 - (base + b));  /* yet to concatenate */
513      setobj2s(L, top - 2, top);  /* put TM result in proper position */
514      if (total > 1) {  /* are there elements to concat? */
515        L->top = top - 1;  /* top is one after last element (at top-2) */
516        luaV_concat(L, total);  /* concat them (may yield again) */
517      }
518      /* move final result to final position */
519      setobj2s(L, ci->u.l.base + GETARG_A(inst), L->top - 1);
520      L->top = ci->top;  /* restore top */
521      break;
522    }
523    case OP_TFORCALL: {
524      lua_assert(GET_OPCODE(*ci->u.l.savedpc) == OP_TFORLOOP);
525      L->top = ci->top;  /* correct top */
526      break;
527    }
528    case OP_CALL: {
529      if (GETARG_C(inst) - 1 >= 0)  /* nresults >= 0? */
530        L->top = ci->top;  /* adjust results */
531      break;
532    }
533    case OP_TAILCALL: case OP_SETTABUP: case OP_SETTABLE:
534      break;
535    default: lua_assert(0);
536  }
537}
538
539
540
541/*
542** some macros for common tasks in `luaV_execute'
543*/
544
545#if !defined luai_runtimecheck
546#define luai_runtimecheck(L, c)		/* void */
547#endif
548
549
550#define RA(i)	(base+GETARG_A(i))
551/* to be used after possible stack reallocation */
552#define RB(i)	check_exp(getBMode(GET_OPCODE(i)) == OpArgR, base+GETARG_B(i))
553#define RC(i)	check_exp(getCMode(GET_OPCODE(i)) == OpArgR, base+GETARG_C(i))
554#define RKB(i)	check_exp(getBMode(GET_OPCODE(i)) == OpArgK, \
555	ISK(GETARG_B(i)) ? k+INDEXK(GETARG_B(i)) : base+GETARG_B(i))
556#define RKC(i)	check_exp(getCMode(GET_OPCODE(i)) == OpArgK, \
557	ISK(GETARG_C(i)) ? k+INDEXK(GETARG_C(i)) : base+GETARG_C(i))
558#define KBx(i)  \
559  (k + (GETARG_Bx(i) != 0 ? GETARG_Bx(i) - 1 : GETARG_Ax(*ci->u.l.savedpc++)))
560
561
562/* execute a jump instruction */
563#define dojump(ci,i,e) \
564  { int a = GETARG_A(i); \
565    if (a > 0) luaF_close(L, ci->u.l.base + a - 1); \
566    ci->u.l.savedpc += GETARG_sBx(i) + e; }
567
568/* for test instructions, execute the jump instruction that follows it */
569#define donextjump(ci)	{ i = *ci->u.l.savedpc; dojump(ci, i, 1); }
570
571
572#define Protect(x)	{ {x;}; base = ci->u.l.base; }
573
574#define checkGC(L,c)  \
575  Protect( luaC_condGC(L,{L->top = (c);  /* limit of live values */ \
576                          luaC_step(L); \
577                          L->top = ci->top;})  /* restore top */ \
578           luai_threadyield(L); )
579
580
581#define arith_op(op,tm) { \
582        TValue *rb = RKB(i); \
583        TValue *rc = RKC(i); \
584        if (ttisnumber(rb) && ttisnumber(rc)) { \
585          lua_Number nb = nvalue(rb), nc = nvalue(rc); \
586          setnvalue(ra, op(L, nb, nc)); \
587        } \
588        else { Protect(luaV_arith(L, ra, rb, rc, tm)); } }
589
590
591#define vmdispatch(o)	switch(o)
592#define vmcase(l,b)	case l: {b}  break;
593#define vmcasenb(l,b)	case l: {b}		/* nb = no break */
594
595void luaV_execute (lua_State *L) {
596  CallInfo *ci = L->ci;
597  LClosure *cl;
598  TValue *k;
599  StkId base;
600 newframe:  /* reentry point when frame changes (call/return) */
601  lua_assert(ci == L->ci);
602  cl = clLvalue(ci->func);
603  k = cl->p->k;
604  base = ci->u.l.base;
605  /* main loop of interpreter */
606  for (;;) {
607    Instruction i = *(ci->u.l.savedpc++);
608    StkId ra;
609    if ((L->hookmask & (LUA_MASKLINE | LUA_MASKCOUNT)) &&
610        (--L->hookcount == 0 || L->hookmask & LUA_MASKLINE)) {
611      Protect(traceexec(L));
612    }
613    /* WARNING: several calls may realloc the stack and invalidate `ra' */
614    ra = RA(i);
615    lua_assert(base == ci->u.l.base);
616    lua_assert(base <= L->top && L->top < L->stack + L->stacksize);
617    vmdispatch (GET_OPCODE(i)) {
618      vmcase(OP_MOVE,
619        setobjs2s(L, ra, RB(i));
620      )
621      vmcase(OP_LOADK,
622        TValue *rb = k + GETARG_Bx(i);
623        setobj2s(L, ra, rb);
624      )
625      vmcase(OP_LOADKX,
626        TValue *rb;
627        lua_assert(GET_OPCODE(*ci->u.l.savedpc) == OP_EXTRAARG);
628        rb = k + GETARG_Ax(*ci->u.l.savedpc++);
629        setobj2s(L, ra, rb);
630      )
631      vmcase(OP_LOADBOOL,
632        setbvalue(ra, GETARG_B(i));
633        if (GETARG_C(i)) ci->u.l.savedpc++;  /* skip next instruction (if C) */
634      )
635      vmcase(OP_LOADNIL,
636        int b = GETARG_B(i);
637        do {
638          setnilvalue(ra++);
639        } while (b--);
640      )
641      vmcase(OP_GETUPVAL,
642        int b = GETARG_B(i);
643        setobj2s(L, ra, cl->upvals[b]->v);
644      )
645      vmcase(OP_GETTABUP,
646        int b = GETARG_B(i);
647        Protect(luaV_gettable(L, cl->upvals[b]->v, RKC(i), ra));
648      )
649      vmcase(OP_GETTABLE,
650        Protect(luaV_gettable(L, RB(i), RKC(i), ra));
651      )
652      vmcase(OP_SETTABUP,
653        int a = GETARG_A(i);
654        Protect(luaV_settable(L, cl->upvals[a]->v, RKB(i), RKC(i)));
655      )
656      vmcase(OP_SETUPVAL,
657        UpVal *uv = cl->upvals[GETARG_B(i)];
658        setobj(L, uv->v, ra);
659        luaC_barrier(L, uv, ra);
660      )
661      vmcase(OP_SETTABLE,
662        Protect(luaV_settable(L, ra, RKB(i), RKC(i)));
663      )
664      vmcase(OP_NEWTABLE,
665        int b = GETARG_B(i);
666        int c = GETARG_C(i);
667        Table *t = luaH_new(L);
668        sethvalue(L, ra, t);
669        if (b != 0 || c != 0)
670          luaH_resize(L, t, luaO_fb2int(b), luaO_fb2int(c));
671        checkGC(L, ra + 1);
672      )
673      vmcase(OP_SELF,
674        StkId rb = RB(i);
675        setobjs2s(L, ra+1, rb);
676        Protect(luaV_gettable(L, rb, RKC(i), ra));
677      )
678      vmcase(OP_ADD,
679        arith_op(luai_numadd, TM_ADD);
680      )
681      vmcase(OP_SUB,
682        arith_op(luai_numsub, TM_SUB);
683      )
684      vmcase(OP_MUL,
685        arith_op(luai_nummul, TM_MUL);
686      )
687      /*
688       * Patched: use luaV_* instead of luai_* to handle div/mod by 0
689       */
690      vmcase(OP_DIV,
691        arith_op(luaV_div, TM_DIV);
692      )
693      vmcase(OP_MOD,
694        arith_op(luaV_mod, TM_MOD);
695      )
696      vmcase(OP_POW,
697        arith_op(luai_numpow, TM_POW);
698      )
699      vmcase(OP_UNM,
700        TValue *rb = RB(i);
701        if (ttisnumber(rb)) {
702          lua_Number nb = nvalue(rb);
703          setnvalue(ra, luai_numunm(L, nb));
704        }
705        else {
706          Protect(luaV_arith(L, ra, rb, rb, TM_UNM));
707        }
708      )
709      vmcase(OP_NOT,
710        TValue *rb = RB(i);
711        int res = l_isfalse(rb);  /* next assignment may change this value */
712        setbvalue(ra, res);
713      )
714      vmcase(OP_LEN,
715        Protect(luaV_objlen(L, ra, RB(i)));
716      )
717      vmcase(OP_CONCAT,
718        int b = GETARG_B(i);
719        int c = GETARG_C(i);
720        StkId rb;
721        L->top = base + c + 1;  /* mark the end of concat operands */
722        Protect(luaV_concat(L, c - b + 1));
723        ra = RA(i);  /* 'luav_concat' may invoke TMs and move the stack */
724        rb = b + base;
725        setobjs2s(L, ra, rb);
726        checkGC(L, (ra >= rb ? ra + 1 : rb));
727        L->top = ci->top;  /* restore top */
728      )
729      vmcase(OP_JMP,
730        dojump(ci, i, 0);
731      )
732      vmcase(OP_EQ,
733        TValue *rb = RKB(i);
734        TValue *rc = RKC(i);
735        Protect(
736          if (cast_int(equalobj(L, rb, rc)) != GETARG_A(i))
737            ci->u.l.savedpc++;
738          else
739            donextjump(ci);
740        )
741      )
742      vmcase(OP_LT,
743        Protect(
744          if (luaV_lessthan(L, RKB(i), RKC(i)) != GETARG_A(i))
745            ci->u.l.savedpc++;
746          else
747            donextjump(ci);
748        )
749      )
750      vmcase(OP_LE,
751        Protect(
752          if (luaV_lessequal(L, RKB(i), RKC(i)) != GETARG_A(i))
753            ci->u.l.savedpc++;
754          else
755            donextjump(ci);
756        )
757      )
758      vmcase(OP_TEST,
759        if (GETARG_C(i) ? l_isfalse(ra) : !l_isfalse(ra))
760            ci->u.l.savedpc++;
761          else
762          donextjump(ci);
763      )
764      vmcase(OP_TESTSET,
765        TValue *rb = RB(i);
766        if (GETARG_C(i) ? l_isfalse(rb) : !l_isfalse(rb))
767          ci->u.l.savedpc++;
768        else {
769          setobjs2s(L, ra, rb);
770          donextjump(ci);
771        }
772      )
773      vmcase(OP_CALL,
774        int b = GETARG_B(i);
775        int nresults = GETARG_C(i) - 1;
776        if (b != 0) L->top = ra+b;  /* else previous instruction set top */
777        if (luaD_precall(L, ra, nresults)) {  /* C function? */
778          if (nresults >= 0) L->top = ci->top;  /* adjust results */
779          base = ci->u.l.base;
780        }
781        else {  /* Lua function */
782          ci = L->ci;
783          ci->callstatus |= CIST_REENTRY;
784          goto newframe;  /* restart luaV_execute over new Lua function */
785        }
786      )
787      vmcase(OP_TAILCALL,
788        int b = GETARG_B(i);
789        if (b != 0) L->top = ra+b;  /* else previous instruction set top */
790        lua_assert(GETARG_C(i) - 1 == LUA_MULTRET);
791        if (luaD_precall(L, ra, LUA_MULTRET))  /* C function? */
792          base = ci->u.l.base;
793        else {
794          /* tail call: put called frame (n) in place of caller one (o) */
795          CallInfo *nci = L->ci;  /* called frame */
796          CallInfo *oci = nci->previous;  /* caller frame */
797          StkId nfunc = nci->func;  /* called function */
798          StkId ofunc = oci->func;  /* caller function */
799          /* last stack slot filled by 'precall' */
800          StkId lim = nci->u.l.base + getproto(nfunc)->numparams;
801          int aux;
802          /* close all upvalues from previous call */
803          if (cl->p->sizep > 0) luaF_close(L, oci->u.l.base);
804          /* move new frame into old one */
805          for (aux = 0; nfunc + aux < lim; aux++)
806            setobjs2s(L, ofunc + aux, nfunc + aux);
807          oci->u.l.base = ofunc + (nci->u.l.base - nfunc);  /* correct base */
808          oci->top = L->top = ofunc + (L->top - nfunc);  /* correct top */
809          oci->u.l.savedpc = nci->u.l.savedpc;
810          oci->callstatus |= CIST_TAIL;  /* function was tail called */
811          ci = L->ci = oci;  /* remove new frame */
812          lua_assert(L->top == oci->u.l.base + getproto(ofunc)->maxstacksize);
813          goto newframe;  /* restart luaV_execute over new Lua function */
814        }
815      )
816      vmcasenb(OP_RETURN,
817        int b = GETARG_B(i);
818        if (b != 0) L->top = ra+b-1;
819        if (cl->p->sizep > 0) luaF_close(L, base);
820        b = luaD_poscall(L, ra);
821        if (!(ci->callstatus & CIST_REENTRY))  /* 'ci' still the called one */
822          return;  /* external invocation: return */
823        else {  /* invocation via reentry: continue execution */
824          ci = L->ci;
825          if (b) L->top = ci->top;
826          lua_assert(isLua(ci));
827          lua_assert(GET_OPCODE(*((ci)->u.l.savedpc - 1)) == OP_CALL);
828          goto newframe;  /* restart luaV_execute over new Lua function */
829        }
830      )
831      vmcase(OP_FORLOOP,
832        lua_Number step = nvalue(ra+2);
833        lua_Number idx = luai_numadd(L, nvalue(ra), step); /* increment index */
834        lua_Number limit = nvalue(ra+1);
835        if (luai_numlt(L, 0, step) ? luai_numle(L, idx, limit)
836                                   : luai_numle(L, limit, idx)) {
837          ci->u.l.savedpc += GETARG_sBx(i);  /* jump back */
838          setnvalue(ra, idx);  /* update internal index... */
839          setnvalue(ra+3, idx);  /* ...and external index */
840        }
841      )
842      vmcase(OP_FORPREP,
843        const TValue *init = ra;
844        const TValue *plimit = ra+1;
845        const TValue *pstep = ra+2;
846        if (!tonumber(init, ra))
847          luaG_runerror(L, LUA_QL("for") " initial value must be a number");
848        else if (!tonumber(plimit, ra+1))
849          luaG_runerror(L, LUA_QL("for") " limit must be a number");
850        else if (!tonumber(pstep, ra+2))
851          luaG_runerror(L, LUA_QL("for") " step must be a number");
852        setnvalue(ra, luai_numsub(L, nvalue(ra), nvalue(pstep)));
853        ci->u.l.savedpc += GETARG_sBx(i);
854      )
855      vmcasenb(OP_TFORCALL,
856        StkId cb = ra + 3;  /* call base */
857        setobjs2s(L, cb+2, ra+2);
858        setobjs2s(L, cb+1, ra+1);
859        setobjs2s(L, cb, ra);
860        L->top = cb + 3;  /* func. + 2 args (state and index) */
861        Protect(luaD_call(L, cb, GETARG_C(i), 1));
862        L->top = ci->top;
863        i = *(ci->u.l.savedpc++);  /* go to next instruction */
864        ra = RA(i);
865        lua_assert(GET_OPCODE(i) == OP_TFORLOOP);
866        goto l_tforloop;
867      )
868      vmcase(OP_TFORLOOP,
869        l_tforloop:
870        if (!ttisnil(ra + 1)) {  /* continue loop? */
871          setobjs2s(L, ra, ra + 1);  /* save control variable */
872           ci->u.l.savedpc += GETARG_sBx(i);  /* jump back */
873        }
874      )
875      vmcase(OP_SETLIST,
876        int n = GETARG_B(i);
877        int c = GETARG_C(i);
878        int last;
879        Table *h;
880        if (n == 0) n = cast_int(L->top - ra) - 1;
881        if (c == 0) {
882          lua_assert(GET_OPCODE(*ci->u.l.savedpc) == OP_EXTRAARG);
883          c = GETARG_Ax(*ci->u.l.savedpc++);
884        }
885        luai_runtimecheck(L, ttistable(ra));
886        h = hvalue(ra);
887        last = ((c-1)*LFIELDS_PER_FLUSH) + n;
888        if (last > h->sizearray)  /* needs more space? */
889          luaH_resizearray(L, h, last);  /* pre-allocate it at once */
890        for (; n > 0; n--) {
891          TValue *val = ra+n;
892          luaH_setint(L, h, last--, val);
893          luaC_barrierback(L, obj2gco(h), val);
894        }
895        L->top = ci->top;  /* correct top (in case of previous open call) */
896      )
897      vmcase(OP_CLOSURE,
898        Proto *p = cl->p->p[GETARG_Bx(i)];
899        Closure *ncl = getcached(p, cl->upvals, base);  /* cached closure */
900        if (ncl == NULL)  /* no match? */
901          pushclosure(L, p, cl->upvals, base, ra);  /* create a new one */
902        else
903          setclLvalue(L, ra, ncl);  /* push cashed closure */
904        checkGC(L, ra + 1);
905      )
906      vmcase(OP_VARARG,
907        int b = GETARG_B(i) - 1;
908        int j;
909        int n = cast_int(base - ci->func) - cl->p->numparams - 1;
910        if (b < 0) {  /* B == 0? */
911          b = n;  /* get all var. arguments */
912          Protect(luaD_checkstack(L, n));
913          ra = RA(i);  /* previous call may change the stack */
914          L->top = ra + n;
915        }
916        for (j = 0; j < b; j++) {
917          if (j < n) {
918            setobjs2s(L, ra + j, base - n + j);
919          }
920          else {
921            setnilvalue(ra + j);
922          }
923        }
924      )
925      vmcase(OP_EXTRAARG,
926        lua_assert(0);
927      )
928    }
929  }
930}
931
932/* END CSTYLED */
933