xref: /illumos-gate/usr/src/uts/common/fs/zfs/lua/lvm.c (revision dfc115332c94a2f62058ac7f2bce7631fbd20b3d)
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 <sys/zfs_context.h>
9 
10 #define	strcoll(l,r) (strcmp((l),(r)))
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 
luaV_tonumber(const TValue * obj,TValue * n)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 
luaV_tostring(lua_State * L,StkId obj)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 
traceexec(lua_State * L)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 
callTM(lua_State * L,const TValue * f,const TValue * p1,const TValue * p2,TValue * p3,int hasres)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 
luaV_gettable(lua_State * L,const TValue * t,TValue * key,StkId val)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 
luaV_settable(lua_State * L,const TValue * t,TValue * key,StkId val)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 
call_binTM(lua_State * L,const TValue * p1,const TValue * p2,StkId res,TMS event)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 
get_equalTM(lua_State * L,Table * mt1,Table * mt2,TMS event)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 
call_orderTM(lua_State * L,const TValue * p1,const TValue * p2,TMS event)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 
l_strcmp(const TString * ls,const TString * rs)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 
luaV_lessthan(lua_State * L,const TValue * l,const TValue * r)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 
luaV_lessequal(lua_State * L,const TValue * l,const TValue * r)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 */
luaV_equalobj_(lua_State * L,const TValue * t1,const TValue * t2)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 
luaV_concat(lua_State * L,int total)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 
luaV_objlen(lua_State * L,StkId ra,const TValue * rb)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  * luaV_div and luaV_mod patched in from Lua 5.3.2 in order to properly handle
361  * div/mod by zero (instead of crashing, which is the default behavior in
362  * Lua 5.2)
363  */
364 
365 /*
366 ** Integer division; return 'm // n', that is, floor(m/n).
367 ** C division truncates its result (rounds towards zero).
368 ** 'floor(q) == trunc(q)' when 'q >= 0' or when 'q' is integer,
369 ** otherwise 'floor(q) == trunc(q) - 1'.
370 */
luaV_div(lua_State * L,lua_Number m,lua_Number n)371 static lua_Number luaV_div (lua_State *L, lua_Number m, lua_Number n) {
372   if ((lua_Unsigned)(n) + 1u <= 1u) {  /* special cases: -1 or 0 */
373     if (n == 0)
374       luaG_runerror(L, "attempt to divide by zero");
375     return (0 - m);   /* n==-1; avoid overflow with 0x80000...//-1 */
376   }
377   else {
378     lua_Number q = m / n;  /* perform C division */
379     if ((m ^ n) < 0 && m % n != 0)  /* 'm/n' would be negative non-integer? */
380       q -= 1;  /* correct result for different rounding */
381     return q;
382   }
383 }
384 
385 
386 /*
387 ** Integer modulus; return 'm % n'. (Assume that C '%' with
388 ** negative operands follows C99 behavior. See previous comment
389 ** about luaV_div.)
390 */
luaV_mod(lua_State * L,lua_Number m,lua_Number n)391 static lua_Number luaV_mod (lua_State *L, lua_Number m, lua_Number n) {
392   if ((lua_Unsigned)(n) + 1u <= 1u) {  /* special cases: -1 or 0 */
393     if (n == 0)
394       luaG_runerror(L, "attempt to perform 'n%%0'");
395     return 0;   /* m % -1 == 0; avoid overflow with 0x80000...%-1 */
396   }
397   else {
398     lua_Number r = m % n;
399     if (r != 0 && (m ^ n) < 0)  /* 'm/n' would be non-integer negative? */
400       r += n;  /* correct result for different rounding */
401     return r;
402   }
403 }
404 
405 /*
406  * End patch from 5.3.2
407  */
408 
luaV_arith(lua_State * L,StkId ra,const TValue * rb,const TValue * rc,TMS op)409 void luaV_arith (lua_State *L, StkId ra, const TValue *rb,
410                  const TValue *rc, TMS op) {
411   TValue tempb, tempc;
412   const TValue *b, *c;
413   if ((b = luaV_tonumber(rb, &tempb)) != NULL &&
414       (c = luaV_tonumber(rc, &tempc)) != NULL) {
415     /*
416      * Patched: if dividing or modding, use patched functions from 5.3
417      */
418     lua_Number res;
419     int lop = op - TM_ADD + LUA_OPADD;
420     if (lop == LUA_OPDIV) {
421       res = luaV_div(L, nvalue(b), nvalue(c));
422     } else if (lop == LUA_OPMOD) {
423       res = luaV_mod(L, nvalue(b), nvalue(c));
424     } else {
425       res = luaO_arith(op - TM_ADD + LUA_OPADD, nvalue(b), nvalue(c));
426     }
427     setnvalue(ra, res);
428   }
429   else if (!call_binTM(L, rb, rc, ra, op))
430     luaG_aritherror(L, rb, rc);
431 }
432 
433 
434 /*
435 ** check whether cached closure in prototype 'p' may be reused, that is,
436 ** whether there is a cached closure with the same upvalues needed by
437 ** new closure to be created.
438 */
getcached(Proto * p,UpVal ** encup,StkId base)439 static Closure *getcached (Proto *p, UpVal **encup, StkId base) {
440   Closure *c = p->cache;
441   if (c != NULL) {  /* is there a cached closure? */
442     int nup = p->sizeupvalues;
443     Upvaldesc *uv = p->upvalues;
444     int i;
445     for (i = 0; i < nup; i++) {  /* check whether it has right upvalues */
446       TValue *v = uv[i].instack ? base + uv[i].idx : encup[uv[i].idx]->v;
447       if (c->l.upvals[i]->v != v)
448         return NULL;  /* wrong upvalue; cannot reuse closure */
449     }
450   }
451   return c;  /* return cached closure (or NULL if no cached closure) */
452 }
453 
454 
455 /*
456 ** create a new Lua closure, push it in the stack, and initialize
457 ** its upvalues. Note that the call to 'luaC_barrierproto' must come
458 ** before the assignment to 'p->cache', as the function needs the
459 ** original value of that field.
460 */
pushclosure(lua_State * L,Proto * p,UpVal ** encup,StkId base,StkId ra)461 static void pushclosure (lua_State *L, Proto *p, UpVal **encup, StkId base,
462                          StkId ra) {
463   int nup = p->sizeupvalues;
464   Upvaldesc *uv = p->upvalues;
465   int i;
466   Closure *ncl = luaF_newLclosure(L, nup);
467   ncl->l.p = p;
468   setclLvalue(L, ra, ncl);  /* anchor new closure in stack */
469   for (i = 0; i < nup; i++) {  /* fill in its upvalues */
470     if (uv[i].instack)  /* upvalue refers to local variable? */
471       ncl->l.upvals[i] = luaF_findupval(L, base + uv[i].idx);
472     else  /* get upvalue from enclosing function */
473       ncl->l.upvals[i] = encup[uv[i].idx];
474   }
475   luaC_barrierproto(L, p, ncl);
476   p->cache = ncl;  /* save it on cache for reuse */
477 }
478 
479 
480 /*
481 ** finish execution of an opcode interrupted by an yield
482 */
luaV_finishOp(lua_State * L)483 void luaV_finishOp (lua_State *L) {
484   CallInfo *ci = L->ci;
485   StkId base = ci->u.l.base;
486   Instruction inst = *(ci->u.l.savedpc - 1);  /* interrupted instruction */
487   OpCode op = GET_OPCODE(inst);
488   switch (op) {  /* finish its execution */
489     case OP_ADD: case OP_SUB: case OP_MUL: case OP_DIV:
490     case OP_MOD: case OP_POW: case OP_UNM: case OP_LEN:
491     case OP_GETTABUP: case OP_GETTABLE: case OP_SELF: {
492       setobjs2s(L, base + GETARG_A(inst), --L->top);
493       break;
494     }
495     case OP_LE: case OP_LT: case OP_EQ: {
496       int res = !l_isfalse(L->top - 1);
497       L->top--;
498       /* metamethod should not be called when operand is K */
499       lua_assert(!ISK(GETARG_B(inst)));
500       if (op == OP_LE &&  /* "<=" using "<" instead? */
501           ttisnil(luaT_gettmbyobj(L, base + GETARG_B(inst), TM_LE)))
502         res = !res;  /* invert result */
503       lua_assert(GET_OPCODE(*ci->u.l.savedpc) == OP_JMP);
504       if (res != GETARG_A(inst))  /* condition failed? */
505         ci->u.l.savedpc++;  /* skip jump instruction */
506       break;
507     }
508     case OP_CONCAT: {
509       StkId top = L->top - 1;  /* top when 'call_binTM' was called */
510       int b = GETARG_B(inst);      /* first element to concatenate */
511       int total = cast_int(top - 1 - (base + b));  /* yet to concatenate */
512       setobj2s(L, top - 2, top);  /* put TM result in proper position */
513       if (total > 1) {  /* are there elements to concat? */
514         L->top = top - 1;  /* top is one after last element (at top-2) */
515         luaV_concat(L, total);  /* concat them (may yield again) */
516       }
517       /* move final result to final position */
518       setobj2s(L, ci->u.l.base + GETARG_A(inst), L->top - 1);
519       L->top = ci->top;  /* restore top */
520       break;
521     }
522     case OP_TFORCALL: {
523       lua_assert(GET_OPCODE(*ci->u.l.savedpc) == OP_TFORLOOP);
524       L->top = ci->top;  /* correct top */
525       break;
526     }
527     case OP_CALL: {
528       if (GETARG_C(inst) - 1 >= 0)  /* nresults >= 0? */
529         L->top = ci->top;  /* adjust results */
530       break;
531     }
532     case OP_TAILCALL: case OP_SETTABUP: case OP_SETTABLE:
533       break;
534     default: lua_assert(0);
535   }
536 }
537 
538 
539 
540 /*
541 ** some macros for common tasks in `luaV_execute'
542 */
543 
544 #if !defined luai_runtimecheck
545 #define luai_runtimecheck(L, c)		/* void */
546 #endif
547 
548 
549 #define RA(i)	(base+GETARG_A(i))
550 /* to be used after possible stack reallocation */
551 #define RB(i)	check_exp(getBMode(GET_OPCODE(i)) == OpArgR, base+GETARG_B(i))
552 #define RC(i)	check_exp(getCMode(GET_OPCODE(i)) == OpArgR, base+GETARG_C(i))
553 #define RKB(i)	check_exp(getBMode(GET_OPCODE(i)) == OpArgK, \
554 	ISK(GETARG_B(i)) ? k+INDEXK(GETARG_B(i)) : base+GETARG_B(i))
555 #define RKC(i)	check_exp(getCMode(GET_OPCODE(i)) == OpArgK, \
556 	ISK(GETARG_C(i)) ? k+INDEXK(GETARG_C(i)) : base+GETARG_C(i))
557 #define KBx(i)  \
558   (k + (GETARG_Bx(i) != 0 ? GETARG_Bx(i) - 1 : GETARG_Ax(*ci->u.l.savedpc++)))
559 
560 
561 /* execute a jump instruction */
562 #define dojump(ci,i,e) \
563   { int a = GETARG_A(i); \
564     if (a > 0) luaF_close(L, ci->u.l.base + a - 1); \
565     ci->u.l.savedpc += GETARG_sBx(i) + e; }
566 
567 /* for test instructions, execute the jump instruction that follows it */
568 #define donextjump(ci)	{ i = *ci->u.l.savedpc; dojump(ci, i, 1); }
569 
570 
571 #define Protect(x)	{ {x;}; base = ci->u.l.base; }
572 
573 #define checkGC(L,c)  \
574   Protect( luaC_condGC(L,{L->top = (c);  /* limit of live values */ \
575                           luaC_step(L); \
576                           L->top = ci->top;})  /* restore top */ \
577            luai_threadyield(L); )
578 
579 
580 #define arith_op(op,tm) { \
581         TValue *rb = RKB(i); \
582         TValue *rc = RKC(i); \
583         if (ttisnumber(rb) && ttisnumber(rc)) { \
584           lua_Number nb = nvalue(rb), nc = nvalue(rc); \
585           setnvalue(ra, op(L, nb, nc)); \
586         } \
587         else { Protect(luaV_arith(L, ra, rb, rc, tm)); } }
588 
589 
590 #define vmdispatch(o)	switch(o)
591 #define vmcase(l,b)	case l: {b}  break;
592 #define vmcasenb(l,b)	case l: {b}		/* nb = no break */
593 
luaV_execute(lua_State * L)594 void luaV_execute (lua_State *L) {
595   CallInfo *ci = L->ci;
596   LClosure *cl;
597   TValue *k;
598   StkId base;
599  newframe:  /* reentry point when frame changes (call/return) */
600   lua_assert(ci == L->ci);
601   cl = clLvalue(ci->func);
602   k = cl->p->k;
603   base = ci->u.l.base;
604   /* main loop of interpreter */
605   for (;;) {
606     Instruction i = *(ci->u.l.savedpc++);
607     StkId ra;
608     if ((L->hookmask & (LUA_MASKLINE | LUA_MASKCOUNT)) &&
609         (--L->hookcount == 0 || L->hookmask & LUA_MASKLINE)) {
610       Protect(traceexec(L));
611     }
612     /* WARNING: several calls may realloc the stack and invalidate `ra' */
613     ra = RA(i);
614     lua_assert(base == ci->u.l.base);
615     lua_assert(base <= L->top && L->top < L->stack + L->stacksize);
616     vmdispatch (GET_OPCODE(i)) {
617       vmcase(OP_MOVE,
618         setobjs2s(L, ra, RB(i));
619       )
620       vmcase(OP_LOADK,
621         TValue *rb = k + GETARG_Bx(i);
622         setobj2s(L, ra, rb);
623       )
624       vmcase(OP_LOADKX,
625         TValue *rb;
626         lua_assert(GET_OPCODE(*ci->u.l.savedpc) == OP_EXTRAARG);
627         rb = k + GETARG_Ax(*ci->u.l.savedpc++);
628         setobj2s(L, ra, rb);
629       )
630       vmcase(OP_LOADBOOL,
631         setbvalue(ra, GETARG_B(i));
632         if (GETARG_C(i)) ci->u.l.savedpc++;  /* skip next instruction (if C) */
633       )
634       vmcase(OP_LOADNIL,
635         int b = GETARG_B(i);
636         do {
637           setnilvalue(ra++);
638         } while (b--);
639       )
640       vmcase(OP_GETUPVAL,
641         int b = GETARG_B(i);
642         setobj2s(L, ra, cl->upvals[b]->v);
643       )
644       vmcase(OP_GETTABUP,
645         int b = GETARG_B(i);
646         Protect(luaV_gettable(L, cl->upvals[b]->v, RKC(i), ra));
647       )
648       vmcase(OP_GETTABLE,
649         Protect(luaV_gettable(L, RB(i), RKC(i), ra));
650       )
651       vmcase(OP_SETTABUP,
652         int a = GETARG_A(i);
653         Protect(luaV_settable(L, cl->upvals[a]->v, RKB(i), RKC(i)));
654       )
655       vmcase(OP_SETUPVAL,
656         UpVal *uv = cl->upvals[GETARG_B(i)];
657         setobj(L, uv->v, ra);
658         luaC_barrier(L, uv, ra);
659       )
660       vmcase(OP_SETTABLE,
661         Protect(luaV_settable(L, ra, RKB(i), RKC(i)));
662       )
663       vmcase(OP_NEWTABLE,
664         int b = GETARG_B(i);
665         int c = GETARG_C(i);
666         Table *t = luaH_new(L);
667         sethvalue(L, ra, t);
668         if (b != 0 || c != 0)
669           luaH_resize(L, t, luaO_fb2int(b), luaO_fb2int(c));
670         checkGC(L, ra + 1);
671       )
672       vmcase(OP_SELF,
673         StkId rb = RB(i);
674         setobjs2s(L, ra+1, rb);
675         Protect(luaV_gettable(L, rb, RKC(i), ra));
676       )
677       vmcase(OP_ADD,
678         arith_op(luai_numadd, TM_ADD);
679       )
680       vmcase(OP_SUB,
681         arith_op(luai_numsub, TM_SUB);
682       )
683       vmcase(OP_MUL,
684         arith_op(luai_nummul, TM_MUL);
685       )
686       /*
687        * Patched: use luaV_* instead of luai_* to handle div/mod by 0
688        */
689       vmcase(OP_DIV,
690         arith_op(luaV_div, TM_DIV);
691       )
692       vmcase(OP_MOD,
693         arith_op(luaV_mod, TM_MOD);
694       )
695       vmcase(OP_POW,
696         arith_op(luai_numpow, TM_POW);
697       )
698       vmcase(OP_UNM,
699         TValue *rb = RB(i);
700         if (ttisnumber(rb)) {
701           lua_Number nb = nvalue(rb);
702           setnvalue(ra, luai_numunm(L, nb));
703         }
704         else {
705           Protect(luaV_arith(L, ra, rb, rb, TM_UNM));
706         }
707       )
708       vmcase(OP_NOT,
709         TValue *rb = RB(i);
710         int res = l_isfalse(rb);  /* next assignment may change this value */
711         setbvalue(ra, res);
712       )
713       vmcase(OP_LEN,
714         Protect(luaV_objlen(L, ra, RB(i)));
715       )
716       vmcase(OP_CONCAT,
717         int b = GETARG_B(i);
718         int c = GETARG_C(i);
719         StkId rb;
720         L->top = base + c + 1;  /* mark the end of concat operands */
721         Protect(luaV_concat(L, c - b + 1));
722         ra = RA(i);  /* 'luav_concat' may invoke TMs and move the stack */
723         rb = b + base;
724         setobjs2s(L, ra, rb);
725         checkGC(L, (ra >= rb ? ra + 1 : rb));
726         L->top = ci->top;  /* restore top */
727       )
728       vmcase(OP_JMP,
729         dojump(ci, i, 0);
730       )
731       vmcase(OP_EQ,
732         TValue *rb = RKB(i);
733         TValue *rc = RKC(i);
734         Protect(
735           if (cast_int(equalobj(L, rb, rc)) != GETARG_A(i))
736             ci->u.l.savedpc++;
737           else
738             donextjump(ci);
739         )
740       )
741       vmcase(OP_LT,
742         Protect(
743           if (luaV_lessthan(L, RKB(i), RKC(i)) != GETARG_A(i))
744             ci->u.l.savedpc++;
745           else
746             donextjump(ci);
747         )
748       )
749       vmcase(OP_LE,
750         Protect(
751           if (luaV_lessequal(L, RKB(i), RKC(i)) != GETARG_A(i))
752             ci->u.l.savedpc++;
753           else
754             donextjump(ci);
755         )
756       )
757       vmcase(OP_TEST,
758         if (GETARG_C(i) ? l_isfalse(ra) : !l_isfalse(ra))
759             ci->u.l.savedpc++;
760           else
761           donextjump(ci);
762       )
763       vmcase(OP_TESTSET,
764         TValue *rb = RB(i);
765         if (GETARG_C(i) ? l_isfalse(rb) : !l_isfalse(rb))
766           ci->u.l.savedpc++;
767         else {
768           setobjs2s(L, ra, rb);
769           donextjump(ci);
770         }
771       )
772       vmcase(OP_CALL,
773         int b = GETARG_B(i);
774         int nresults = GETARG_C(i) - 1;
775         if (b != 0) L->top = ra+b;  /* else previous instruction set top */
776         if (luaD_precall(L, ra, nresults)) {  /* C function? */
777           if (nresults >= 0) L->top = ci->top;  /* adjust results */
778           base = ci->u.l.base;
779         }
780         else {  /* Lua function */
781           ci = L->ci;
782           ci->callstatus |= CIST_REENTRY;
783           goto newframe;  /* restart luaV_execute over new Lua function */
784         }
785       )
786       vmcase(OP_TAILCALL,
787         int b = GETARG_B(i);
788         if (b != 0) L->top = ra+b;  /* else previous instruction set top */
789         lua_assert(GETARG_C(i) - 1 == LUA_MULTRET);
790         if (luaD_precall(L, ra, LUA_MULTRET))  /* C function? */
791           base = ci->u.l.base;
792         else {
793           /* tail call: put called frame (n) in place of caller one (o) */
794           CallInfo *nci = L->ci;  /* called frame */
795           CallInfo *oci = nci->previous;  /* caller frame */
796           StkId nfunc = nci->func;  /* called function */
797           StkId ofunc = oci->func;  /* caller function */
798           /* last stack slot filled by 'precall' */
799           StkId lim = nci->u.l.base + getproto(nfunc)->numparams;
800           int aux;
801           /* close all upvalues from previous call */
802           if (cl->p->sizep > 0) luaF_close(L, oci->u.l.base);
803           /* move new frame into old one */
804           for (aux = 0; nfunc + aux < lim; aux++)
805             setobjs2s(L, ofunc + aux, nfunc + aux);
806           oci->u.l.base = ofunc + (nci->u.l.base - nfunc);  /* correct base */
807           oci->top = L->top = ofunc + (L->top - nfunc);  /* correct top */
808           oci->u.l.savedpc = nci->u.l.savedpc;
809           oci->callstatus |= CIST_TAIL;  /* function was tail called */
810           ci = L->ci = oci;  /* remove new frame */
811           lua_assert(L->top == oci->u.l.base + getproto(ofunc)->maxstacksize);
812           goto newframe;  /* restart luaV_execute over new Lua function */
813         }
814       )
815       vmcasenb(OP_RETURN,
816         int b = GETARG_B(i);
817         if (b != 0) L->top = ra+b-1;
818         if (cl->p->sizep > 0) luaF_close(L, base);
819         b = luaD_poscall(L, ra);
820         if (!(ci->callstatus & CIST_REENTRY))  /* 'ci' still the called one */
821           return;  /* external invocation: return */
822         else {  /* invocation via reentry: continue execution */
823           ci = L->ci;
824           if (b) L->top = ci->top;
825           lua_assert(isLua(ci));
826           lua_assert(GET_OPCODE(*((ci)->u.l.savedpc - 1)) == OP_CALL);
827           goto newframe;  /* restart luaV_execute over new Lua function */
828         }
829       )
830       vmcase(OP_FORLOOP,
831         lua_Number step = nvalue(ra+2);
832         lua_Number idx = luai_numadd(L, nvalue(ra), step); /* increment index */
833         lua_Number limit = nvalue(ra+1);
834         if (luai_numlt(L, 0, step) ? luai_numle(L, idx, limit)
835                                    : luai_numle(L, limit, idx)) {
836           ci->u.l.savedpc += GETARG_sBx(i);  /* jump back */
837           setnvalue(ra, idx);  /* update internal index... */
838           setnvalue(ra+3, idx);  /* ...and external index */
839         }
840       )
841       vmcase(OP_FORPREP,
842         const TValue *init = ra;
843         const TValue *plimit = ra+1;
844         const TValue *pstep = ra+2;
845         if (!tonumber(init, ra))
846           luaG_runerror(L, LUA_QL("for") " initial value must be a number");
847         else if (!tonumber(plimit, ra+1))
848           luaG_runerror(L, LUA_QL("for") " limit must be a number");
849         else if (!tonumber(pstep, ra+2))
850           luaG_runerror(L, LUA_QL("for") " step must be a number");
851         setnvalue(ra, luai_numsub(L, nvalue(ra), nvalue(pstep)));
852         ci->u.l.savedpc += GETARG_sBx(i);
853       )
854       vmcasenb(OP_TFORCALL,
855         StkId cb = ra + 3;  /* call base */
856         setobjs2s(L, cb+2, ra+2);
857         setobjs2s(L, cb+1, ra+1);
858         setobjs2s(L, cb, ra);
859         L->top = cb + 3;  /* func. + 2 args (state and index) */
860         Protect(luaD_call(L, cb, GETARG_C(i), 1));
861         L->top = ci->top;
862         i = *(ci->u.l.savedpc++);  /* go to next instruction */
863         ra = RA(i);
864         lua_assert(GET_OPCODE(i) == OP_TFORLOOP);
865         goto l_tforloop;
866       )
867       vmcase(OP_TFORLOOP,
868         l_tforloop:
869         if (!ttisnil(ra + 1)) {  /* continue loop? */
870           setobjs2s(L, ra, ra + 1);  /* save control variable */
871            ci->u.l.savedpc += GETARG_sBx(i);  /* jump back */
872         }
873       )
874       vmcase(OP_SETLIST,
875         int n = GETARG_B(i);
876         int c = GETARG_C(i);
877         int last;
878         Table *h;
879         if (n == 0) n = cast_int(L->top - ra) - 1;
880         if (c == 0) {
881           lua_assert(GET_OPCODE(*ci->u.l.savedpc) == OP_EXTRAARG);
882           c = GETARG_Ax(*ci->u.l.savedpc++);
883         }
884         luai_runtimecheck(L, ttistable(ra));
885         h = hvalue(ra);
886         last = ((c-1)*LFIELDS_PER_FLUSH) + n;
887         if (last > h->sizearray)  /* needs more space? */
888           luaH_resizearray(L, h, last);  /* pre-allocate it at once */
889         for (; n > 0; n--) {
890           TValue *val = ra+n;
891           luaH_setint(L, h, last--, val);
892           luaC_barrierback(L, obj2gco(h), val);
893         }
894         L->top = ci->top;  /* correct top (in case of previous open call) */
895       )
896       vmcase(OP_CLOSURE,
897         Proto *p = cl->p->p[GETARG_Bx(i)];
898         Closure *ncl = getcached(p, cl->upvals, base);  /* cached closure */
899         if (ncl == NULL)  /* no match? */
900           pushclosure(L, p, cl->upvals, base, ra);  /* create a new one */
901         else
902           setclLvalue(L, ra, ncl);  /* push cashed closure */
903         checkGC(L, ra + 1);
904       )
905       vmcase(OP_VARARG,
906         int b = GETARG_B(i) - 1;
907         int j;
908         int n = cast_int(base - ci->func) - cl->p->numparams - 1;
909         if (b < 0) {  /* B == 0? */
910           b = n;  /* get all var. arguments */
911           Protect(luaD_checkstack(L, n));
912           ra = RA(i);  /* previous call may change the stack */
913           L->top = ra + n;
914         }
915         for (j = 0; j < b; j++) {
916           if (j < n) {
917             setobjs2s(L, ra + j, base - n + j);
918           }
919           else {
920             setnilvalue(ra + j);
921           }
922         }
923       )
924       vmcase(OP_EXTRAARG,
925         lua_assert(0);
926       )
927     }
928   }
929 }
930 
931