/* ** $Id: lvm.c,v 2.268 2016/02/05 19:59:14 roberto Exp $ ** Lua virtual machine ** See Copyright Notice in lua.h */ #define lvm_c #define LUA_CORE #include "lprefix.h" #include <float.h> #include <limits.h> #include <math.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include "lua.h" #include "ldebug.h" #include "ldo.h" #include "lfunc.h" #include "lgc.h" #include "lobject.h" #include "lopcodes.h" #include "lstate.h" #include "lstring.h" #include "ltable.h" #include "ltm.h" #include "lvm.h" /* limit for table tag-method chains (to avoid loops) */ #define MAXTAGLOOP 2000 /* ** 'l_intfitsf' checks whether a given integer can be converted to a ** float without rounding. Used in comparisons. Left undefined if ** all integers fit in a float precisely. */ #if !defined(l_intfitsf) /* number of bits in the mantissa of a float */ #define NBM (l_mathlim(MANT_DIG)) /* ** Check whether some integers may not fit in a float, that is, whether ** (maxinteger >> NBM) > 0 (that implies (1 << NBM) <= maxinteger). ** (The shifts are done in parts to avoid shifting by more than the size ** of an integer. In a worst case, NBM == 113 for long double and ** sizeof(integer) == 32.) */ #if ((((LUA_MAXINTEGER >> (NBM / 4)) >> (NBM / 4)) >> (NBM / 4)) \ >> (NBM - (3 * (NBM / 4)))) > 0 #define l_intfitsf(i) \ (-((lua_Integer)1 << NBM) <= (i) && (i) <= ((lua_Integer)1 << NBM)) #endif #endif /* ** Try to convert a value to a float. The float case is already handled ** by the macro 'tonumber'. */ int luaV_tonumber_ (const TValue *obj, lua_Number *n) { TValue v; if (ttisinteger(obj)) { *n = cast_num(ivalue(obj)); return 1; } else if (cvt2num(obj) && /* string convertible to number? */ luaO_str2num(svalue(obj), &v) == vslen(obj) + 1) { *n = nvalue(&v); /* convert result of 'luaO_str2num' to a float */ return 1; } else return 0; /* conversion failed */ } /* ** try to convert a value to an integer, rounding according to 'mode': ** mode == 0: accepts only integral values ** mode == 1: takes the floor of the number ** mode == 2: takes the ceil of the number */ int luaV_tointeger (const TValue *obj, lua_Integer *p, int mode) { TValue v; again: if (ttisfloat(obj)) { lua_Number n = fltvalue(obj); lua_Number f = l_floor(n); if (n != f) { /* not an integral value? */ if (mode == 0) return 0; /* fails if mode demands integral value */ else if (mode > 1) /* needs ceil? */ f += 1; /* convert floor to ceil (remember: n != f) */ } return lua_numbertointeger(f, p); } else if (ttisinteger(obj)) { *p = ivalue(obj); return 1; } else if (cvt2num(obj) && luaO_str2num(svalue(obj), &v) == vslen(obj) + 1) { obj = &v; goto again; /* convert result from 'luaO_str2num' to an integer */ } return 0; /* conversion failed */ } /* ** Try to convert a 'for' limit to an integer, preserving the ** semantics of the loop. ** (The following explanation assumes a non-negative step; it is valid ** for negative steps mutatis mutandis.) ** If the limit can be converted to an integer, rounding down, that is ** it. ** Otherwise, check whether the limit can be converted to a number. If ** the number is too large, it is OK to set the limit as LUA_MAXINTEGER, ** which means no limit. If the number is too negative, the loop ** should not run, because any initial integer value is larger than the ** limit. So, it sets the limit to LUA_MININTEGER. 'stopnow' corrects ** the extreme case when the initial value is LUA_MININTEGER, in which ** case the LUA_MININTEGER limit would still run the loop once. */ static int forlimit (const TValue *obj, lua_Integer *p, lua_Integer step, int *stopnow) { *stopnow = 0; /* usually, let loops run */ if (!luaV_tointeger(obj, p, (step < 0 ? 2 : 1))) { /* not fit in integer? */ lua_Number n; /* try to convert to float */ if (!tonumber(obj, &n)) /* cannot convert to float? */ return 0; /* not a number */ if (luai_numlt(0, n)) { /* if true, float is larger than max integer */ *p = LUA_MAXINTEGER; if (step < 0) *stopnow = 1; } else { /* float is smaller than min integer */ *p = LUA_MININTEGER; if (step >= 0) *stopnow = 1; } } return 1; } /* ** Finish the table access 'val = t[key]'. ** if 'slot' is NULL, 't' is not a table; otherwise, 'slot' points to ** t[k] entry (which must be nil). */ void luaV_finishget (lua_State *L, const TValue *t, TValue *key, StkId val, const TValue *slot) { int loop; /* counter to avoid infinite loops */ const TValue *tm; /* metamethod */ for (loop = 0; loop < MAXTAGLOOP; loop++) { if (slot == NULL) { /* 't' is not a table? */ lua_assert(!ttistable(t)); tm = luaT_gettmbyobj(L, t, TM_INDEX); if (ttisnil(tm)) luaG_typeerror(L, t, "index"); /* no metamethod */ /* else will try the metamethod */ } else { /* 't' is a table */ lua_assert(ttisnil(slot)); tm = fasttm(L, hvalue(t)->metatable, TM_INDEX); /* table's metamethod */ if (tm == NULL) { /* no metamethod? */ setnilvalue(val); /* result is nil */ return; } /* else will try the metamethod */ } if (ttisfunction(tm)) { /* is metamethod a function? */ luaT_callTM(L, tm, t, key, val, 1); /* call it */ return; } t = tm; /* else try to access 'tm[key]' */ if (luaV_fastget(L,t,key,slot,luaH_get)) { /* fast track? */ setobj2s(L, val, slot); /* done */ return; } /* else repeat (tail call 'luaV_finishget') */ } luaG_runerror(L, "'__index' chain too long; possible loop"); } /* ** Finish a table assignment 't[key] = val'. ** If 'slot' is NULL, 't' is not a table. Otherwise, 'slot' points ** to the entry 't[key]', or to 'luaO_nilobject' if there is no such ** entry. (The value at 'slot' must be nil, otherwise 'luaV_fastset' ** would have done the job.) */ void luaV_finishset (lua_State *L, const TValue *t, TValue *key, StkId val, const TValue *slot) { int loop; /* counter to avoid infinite loops */ for (loop = 0; loop < MAXTAGLOOP; loop++) { const TValue *tm; /* '__newindex' metamethod */ if (slot != NULL) { /* is 't' a table? */ Table *h = hvalue(t); /* save 't' table */ lua_assert(ttisnil(slot)); /* old value must be nil */ tm = fasttm(L, h->metatable, TM_NEWINDEX); /* get metamethod */ if (tm == NULL) { /* no metamethod? */ if (slot == luaO_nilobject) /* no previous entry? */ slot = luaH_newkey(L, h, key); /* create one */ /* no metamethod and (now) there is an entry with given key */ setobj2t(L, cast(TValue *, slot), val); /* set its new value */ invalidateTMcache(h); luaC_barrierback(L, h, val); return; } /* else will try the metamethod */ } else { /* not a table; check metamethod */ if (ttisnil(tm = luaT_gettmbyobj(L, t, TM_NEWINDEX))) luaG_typeerror(L, t, "index"); } /* try the metamethod */ if (ttisfunction(tm)) { luaT_callTM(L, tm, t, key, val, 0); return; } t = tm; /* else repeat assignment over 'tm' */ if (luaV_fastset(L, t, key, slot, luaH_get, val)) return; /* done */ /* else loop */ } luaG_runerror(L, "'__newindex' chain too long; possible loop"); } /* ** Compare two strings 'ls' x 'rs', returning an integer smaller-equal- ** -larger than zero if 'ls' is smaller-equal-larger than 'rs'. ** The code is a little tricky because it allows '\0' in the strings ** and it uses 'strcoll' (to respect locales) for each segments ** of the strings. */ static int l_strcmp (const TString *ls, const TString *rs) { const char *l = getstr(ls); size_t ll = tsslen(ls); const char *r = getstr(rs); size_t lr = tsslen(rs); for (;;) { /* for each segment */ int temp = strcoll(l, r); if (temp != 0) /* not equal? */ return temp; /* done */ else { /* strings are equal up to a '\0' */ size_t len = strlen(l); /* index of first '\0' in both strings */ if (len == lr) /* 'rs' is finished? */ return (len == ll) ? 0 : 1; /* check 'ls' */ else if (len == ll) /* 'ls' is finished? */ return -1; /* 'ls' is smaller than 'rs' ('rs' is not finished) */ /* both strings longer than 'len'; go on comparing after the '\0' */ len++; l += len; ll -= len; r += len; lr -= len; } } } /* ** Check whether integer 'i' is less than float 'f'. If 'i' has an ** exact representation as a float ('l_intfitsf'), compare numbers as ** floats. Otherwise, if 'f' is outside the range for integers, result ** is trivial. Otherwise, compare them as integers. (When 'i' has no ** float representation, either 'f' is "far away" from 'i' or 'f' has ** no precision left for a fractional part; either way, how 'f' is ** truncated is irrelevant.) When 'f' is NaN, comparisons must result ** in false. */ static int LTintfloat (lua_Integer i, lua_Number f) { #if defined(l_intfitsf) if (!l_intfitsf(i)) { if (f >= -cast_num(LUA_MININTEGER)) /* -minint == maxint + 1 */ return 1; /* f >= maxint + 1 > i */ else if (f > cast_num(LUA_MININTEGER)) /* minint < f <= maxint ? */ return (i < cast(lua_Integer, f)); /* compare them as integers */ else /* f <= minint <= i (or 'f' is NaN) --> not(i < f) */ return 0; } #endif return luai_numlt(cast_num(i), f); /* compare them as floats */ } /* ** Check whether integer 'i' is less than or equal to float 'f'. ** See comments on previous function. */ static int LEintfloat (lua_Integer i, lua_Number f) { #if defined(l_intfitsf) if (!l_intfitsf(i)) { if (f >= -cast_num(LUA_MININTEGER)) /* -minint == maxint + 1 */ return 1; /* f >= maxint + 1 > i */ else if (f >= cast_num(LUA_MININTEGER)) /* minint <= f <= maxint ? */ return (i <= cast(lua_Integer, f)); /* compare them as integers */ else /* f < minint <= i (or 'f' is NaN) --> not(i <= f) */ return 0; } #endif return luai_numle(cast_num(i), f); /* compare them as floats */ } /* ** Return 'l < r', for numbers. */ static int LTnum (const TValue *l, const TValue *r) { if (ttisinteger(l)) { lua_Integer li = ivalue(l); if (ttisinteger(r)) return li < ivalue(r); /* both are integers */ else /* 'l' is int and 'r' is float */ return LTintfloat(li, fltvalue(r)); /* l < r ? */ } else { lua_Number lf = fltvalue(l); /* 'l' must be float */ if (ttisfloat(r)) return luai_numlt(lf, fltvalue(r)); /* both are float */ else if (luai_numisnan(lf)) /* 'r' is int and 'l' is float */ return 0; /* NaN < i is always false */ else /* without NaN, (l < r) <--> not(r <= l) */ return !LEintfloat(ivalue(r), lf); /* not (r <= l) ? */ } } /* ** Return 'l <= r', for numbers. */ static int LEnum (const TValue *l, const TValue *r) { if (ttisinteger(l)) { lua_Integer li = ivalue(l); if (ttisinteger(r)) return li <= ivalue(r); /* both are integers */ else /* 'l' is int and 'r' is float */ return LEintfloat(li, fltvalue(r)); /* l <= r ? */ } else { lua_Number lf = fltvalue(l); /* 'l' must be float */ if (ttisfloat(r)) return luai_numle(lf, fltvalue(r)); /* both are float */ else if (luai_numisnan(lf)) /* 'r' is int and 'l' is float */ return 0; /* NaN <= i is always false */ else /* without NaN, (l <= r) <--> not(r < l) */ return !LTintfloat(ivalue(r), lf); /* not (r < l) ? */ } } /* ** Main operation less than; return 'l < r'. */ int luaV_lessthan (lua_State *L, const TValue *l, const TValue *r) { int res; if (ttisnumber(l) && ttisnumber(r)) /* both operands are numbers? */ return LTnum(l, r); else if (ttisstring(l) && ttisstring(r)) /* both are strings? */ return l_strcmp(tsvalue(l), tsvalue(r)) < 0; else if ((res = luaT_callorderTM(L, l, r, TM_LT)) < 0) /* no metamethod? */ luaG_ordererror(L, l, r); /* error */ return res; } /* ** Main operation less than or equal to; return 'l <= r'. If it needs ** a metamethod and there is no '__le', try '__lt', based on ** l <= r iff !(r < l) (assuming a total order). If the metamethod ** yields during this substitution, the continuation has to know ** about it (to negate the result of r<l); bit CIST_LEQ in the call ** status keeps that information. */ int luaV_lessequal (lua_State *L, const TValue *l, const TValue *r) { int res; if (ttisnumber(l) && ttisnumber(r)) /* both operands are numbers? */ return LEnum(l, r); else if (ttisstring(l) && ttisstring(r)) /* both are strings? */ return l_strcmp(tsvalue(l), tsvalue(r)) <= 0; else if ((res = luaT_callorderTM(L, l, r, TM_LE)) >= 0) /* try 'le' */ return res; else { /* try 'lt': */ L->ci->callstatus |= CIST_LEQ; /* mark it is doing 'lt' for 'le' */ res = luaT_callorderTM(L, r, l, TM_LT); L->ci->callstatus ^= CIST_LEQ; /* clear mark */ if (res < 0) luaG_ordererror(L, l, r); return !res; /* result is negated */ } } /* ** Main operation for equality of Lua values; return 't1 == t2'. ** L == NULL means raw equality (no metamethods) */ int luaV_equalobj (lua_State *L, const TValue *t1, const TValue *t2) { const TValue *tm; if (ttype(t1) != ttype(t2)) { /* not the same variant? */ if (ttnov(t1) != ttnov(t2) || ttnov(t1) != LUA_TNUMBER) return 0; /* only numbers can be equal with different variants */ else { /* two numbers with different variants */ lua_Integer i1, i2; /* compare them as integers */ return (tointeger(t1, &i1) && tointeger(t2, &i2) && i1 == i2); } } /* values have same type and same variant */ switch (ttype(t1)) { case LUA_TNIL: return 1; case LUA_TNUMINT: return (ivalue(t1) == ivalue(t2)); case LUA_TNUMFLT: return luai_numeq(fltvalue(t1), fltvalue(t2)); case LUA_TBOOLEAN: return bvalue(t1) == bvalue(t2); /* true must be 1 !! */ case LUA_TLIGHTUSERDATA: return pvalue(t1) == pvalue(t2); case LUA_TLCF: return fvalue(t1) == fvalue(t2); case LUA_TSHRSTR: return eqshrstr(tsvalue(t1), tsvalue(t2)); case LUA_TLNGSTR: return luaS_eqlngstr(tsvalue(t1), tsvalue(t2)); case LUA_TUSERDATA: { if (uvalue(t1) == uvalue(t2)) return 1; else if (L == NULL) return 0; tm = fasttm(L, uvalue(t1)->metatable, TM_EQ); if (tm == NULL) tm = fasttm(L, uvalue(t2)->metatable, TM_EQ); break; /* will try TM */ } case LUA_TTABLE: { if (hvalue(t1) == hvalue(t2)) return 1; else if (L == NULL) return 0; tm = fasttm(L, hvalue(t1)->metatable, TM_EQ); if (tm == NULL) tm = fasttm(L, hvalue(t2)->metatable, TM_EQ); break; /* will try TM */ } default: return gcvalue(t1) == gcvalue(t2); } if (tm == NULL) /* no TM? */ return 0; /* objects are different */ luaT_callTM(L, tm, t1, t2, L->top, 1); /* call TM */ return !l_isfalse(L->top); } /* macro used by 'luaV_concat' to ensure that element at 'o' is a string */ #define tostring(L,o) \ (ttisstring(o) || (cvt2str(o) && (luaO_tostring(L, o), 1))) #define isemptystr(o) (ttisshrstring(o) && tsvalue(o)->shrlen == 0) /* copy strings in stack from top - n up to top - 1 to buffer */ static void copy2buff (StkId top, int n, char *buff) { size_t tl = 0; /* size already copied */ do { size_t l = vslen(top - n); /* length of string being copied */ memcpy(buff + tl, svalue(top - n), l * sizeof(char)); tl += l; } while (--n > 0); } /* ** Main operation for concatenation: concat 'total' values in the stack, ** from 'L->top - total' up to 'L->top - 1'. */ void luaV_concat (lua_State *L, int total) { lua_assert(total >= 2); do { StkId top = L->top; int n = 2; /* number of elements handled in this pass (at least 2) */ if (!(ttisstring(top-2) || cvt2str(top-2)) || !tostring(L, top-1)) luaT_trybinTM(L, top-2, top-1, top-2, TM_CONCAT); else if (isemptystr(top - 1)) /* second operand is empty? */ cast_void(tostring(L, top - 2)); /* result is first operand */ else if (isemptystr(top - 2)) { /* first operand is an empty string? */ setobjs2s(L, top - 2, top - 1); /* result is second op. */ } else { /* at least two non-empty string values; get as many as possible */ size_t tl = vslen(top - 1); TString *ts; /* collect total length and number of strings */ for (n = 1; n < total && tostring(L, top - n - 1); n++) { size_t l = vslen(top - n - 1); if (l >= (MAX_SIZE/sizeof(char)) - tl) luaG_runerror(L, "string length overflow"); tl += l; } if (tl <= LUAI_MAXSHORTLEN) { /* is result a short string? */ char buff[LUAI_MAXSHORTLEN]; copy2buff(top, n, buff); /* copy strings to buffer */ ts = luaS_newlstr(L, buff, tl); } else { /* long string; copy strings directly to final result */ ts = luaS_createlngstrobj(L, tl); copy2buff(top, n, getstr(ts)); } setsvalue2s(L, top - n, ts); /* create result */ } total -= n-1; /* got 'n' strings to create 1 new */ L->top -= n-1; /* popped 'n' strings and pushed one */ } while (total > 1); /* repeat until only 1 result left */ } /* ** Main operation 'ra' = #rb'. */ void luaV_objlen (lua_State *L, StkId ra, const TValue *rb) { const TValue *tm; switch (ttype(rb)) { case LUA_TTABLE: { Table *h = hvalue(rb); tm = fasttm(L, h->metatable, TM_LEN); if (tm) break; /* metamethod? break switch to call it */ setivalue(ra, luaH_getn(h)); /* else primitive len */ return; } case LUA_TSHRSTR: { setivalue(ra, tsvalue(rb)->shrlen); return; } case LUA_TLNGSTR: { setivalue(ra, tsvalue(rb)->u.lnglen); return; } default: { /* try metamethod */ tm = luaT_gettmbyobj(L, rb, TM_LEN); if (ttisnil(tm)) /* no metamethod? */ luaG_typeerror(L, rb, "get length of"); break; } } luaT_callTM(L, tm, rb, rb, ra, 1); } /* ** Integer division; return 'm // n', that is, floor(m/n). ** C division truncates its result (rounds towards zero). ** 'floor(q) == trunc(q)' when 'q >= 0' or when 'q' is integer, ** otherwise 'floor(q) == trunc(q) - 1'. */ lua_Integer luaV_div (lua_State *L, lua_Integer m, lua_Integer n) { if (l_castS2U(n) + 1u <= 1u) { /* special cases: -1 or 0 */ if (n == 0) luaG_runerror(L, "attempt to divide by zero"); return intop(-, 0, m); /* n==-1; avoid overflow with 0x80000...//-1 */ } else { lua_Integer q = m / n; /* perform C division */ if ((m ^ n) < 0 && m % n != 0) /* 'm/n' would be negative non-integer? */ q -= 1; /* correct result for different rounding */ return q; } } /* ** Integer modulus; return 'm % n'. (Assume that C '%' with ** negative operands follows C99 behavior. See previous comment ** about luaV_div.) */ lua_Integer luaV_mod (lua_State *L, lua_Integer m, lua_Integer n) { if (l_castS2U(n) + 1u <= 1u) { /* special cases: -1 or 0 */ if (n == 0) luaG_runerror(L, "attempt to perform 'n%%0'"); return 0; /* m % -1 == 0; avoid overflow with 0x80000...%-1 */ } else { lua_Integer r = m % n; if (r != 0 && (m ^ n) < 0) /* 'm/n' would be non-integer negative? */ r += n; /* correct result for different rounding */ return r; } } /* number of bits in an integer */ #define NBITS cast_int(sizeof(lua_Integer) * CHAR_BIT) /* ** Shift left operation. (Shift right just negates 'y'.) */ lua_Integer luaV_shiftl (lua_Integer x, lua_Integer y) { if (y < 0) { /* shift right? */ if (y <= -NBITS) return 0; else return intop(>>, x, -y); } else { /* shift left */ if (y >= NBITS) return 0; else return intop(<<, x, y); } } /* ** check whether cached closure in prototype 'p' may be reused, that is, ** whether there is a cached closure with the same upvalues needed by ** new closure to be created. */ static LClosure *getcached (Proto *p, UpVal **encup, StkId base) { LClosure *c = p->cache; if (c != NULL) { /* is there a cached closure? */ int nup = p->sizeupvalues; Upvaldesc *uv = p->upvalues; int i; for (i = 0; i < nup; i++) { /* check whether it has right upvalues */ TValue *v = uv[i].instack ? base + uv[i].idx : encup[uv[i].idx]->v; if (c->upvals[i]->v != v) return NULL; /* wrong upvalue; cannot reuse closure */ } } return c; /* return cached closure (or NULL if no cached closure) */ } /* ** create a new Lua closure, push it in the stack, and initialize ** its upvalues. Note that the closure is not cached if prototype is ** already black (which means that 'cache' was already cleared by the ** GC). */ static void pushclosure (lua_State *L, Proto *p, UpVal **encup, StkId base, StkId ra) { int nup = p->sizeupvalues; Upvaldesc *uv = p->upvalues; int i; LClosure *ncl = luaF_newLclosure(L, nup); ncl->p = p; setclLvalue(L, ra, ncl); /* anchor new closure in stack */ for (i = 0; i < nup; i++) { /* fill in its upvalues */ if (uv[i].instack) /* upvalue refers to local variable? */ ncl->upvals[i] = luaF_findupval(L, base + uv[i].idx); else /* get upvalue from enclosing function */ ncl->upvals[i] = encup[uv[i].idx]; ncl->upvals[i]->refcount++; /* new closure is white, so we do not need a barrier here */ } if (!isblack(p)) /* cache will not break GC invariant? */ p->cache = ncl; /* save it on cache for reuse */ } /* ** finish execution of an opcode interrupted by an yield */ void luaV_finishOp (lua_State *L) { CallInfo *ci = L->ci; StkId base = ci->u.l.base; Instruction inst = *(ci->u.l.savedpc - 1); /* interrupted instruction */ OpCode op = GET_OPCODE(inst); switch (op) { /* finish its execution */ case OP_ADD: case OP_SUB: case OP_MUL: case OP_DIV: case OP_IDIV: case OP_BAND: case OP_BOR: case OP_BXOR: case OP_SHL: case OP_SHR: case OP_MOD: case OP_POW: case OP_UNM: case OP_BNOT: case OP_LEN: case OP_GETTABUP: case OP_GETTABLE: case OP_SELF: { setobjs2s(L, base + GETARG_A(inst), --L->top); break; } case OP_LE: case OP_LT: case OP_EQ: { int res = !l_isfalse(L->top - 1); L->top--; if (ci->callstatus & CIST_LEQ) { /* "<=" using "<" instead? */ lua_assert(op == OP_LE); ci->callstatus ^= CIST_LEQ; /* clear mark */ res = !res; /* negate result */ } lua_assert(GET_OPCODE(*ci->u.l.savedpc) == OP_JMP); if (res != GETARG_A(inst)) /* condition failed? */ ci->u.l.savedpc++; /* skip jump instruction */ break; } case OP_CONCAT: { StkId top = L->top - 1; /* top when 'luaT_trybinTM' was called */ int b = GETARG_B(inst); /* first element to concatenate */ int total = cast_int(top - 1 - (base + b)); /* yet to concatenate */ setobj2s(L, top - 2, top); /* put TM result in proper position */ if (total > 1) { /* are there elements to concat? */ L->top = top - 1; /* top is one after last element (at top-2) */ luaV_concat(L, total); /* concat them (may yield again) */ } /* move final result to final position */ setobj2s(L, ci->u.l.base + GETARG_A(inst), L->top - 1); L->top = ci->top; /* restore top */ break; } case OP_TFORCALL: { lua_assert(GET_OPCODE(*ci->u.l.savedpc) == OP_TFORLOOP); L->top = ci->top; /* correct top */ break; } case OP_CALL: { if (GETARG_C(inst) - 1 >= 0) /* nresults >= 0? */ L->top = ci->top; /* adjust results */ break; } case OP_TAILCALL: case OP_SETTABUP: case OP_SETTABLE: break; default: lua_assert(0); } } /* ** {================================================================== ** Function 'luaV_execute': main interpreter loop ** =================================================================== */ /* ** some macros for common tasks in 'luaV_execute' */ #define RA(i) (base+GETARG_A(i)) #define RB(i) check_exp(getBMode(GET_OPCODE(i)) == OpArgR, base+GETARG_B(i)) #define RC(i) check_exp(getCMode(GET_OPCODE(i)) == OpArgR, base+GETARG_C(i)) #define RKB(i) check_exp(getBMode(GET_OPCODE(i)) == OpArgK, \ ISK(GETARG_B(i)) ? k+INDEXK(GETARG_B(i)) : base+GETARG_B(i)) #define RKC(i) check_exp(getCMode(GET_OPCODE(i)) == OpArgK, \ ISK(GETARG_C(i)) ? k+INDEXK(GETARG_C(i)) : base+GETARG_C(i)) /* execute a jump instruction */ #define dojump(ci,i,e) \ { int a = GETARG_A(i); \ if (a != 0) luaF_close(L, ci->u.l.base + a - 1); \ ci->u.l.savedpc += GETARG_sBx(i) + e; } /* for test instructions, execute the jump instruction that follows it */ #define donextjump(ci) { i = *ci->u.l.savedpc; dojump(ci, i, 1); } #define Protect(x) { {x;}; base = ci->u.l.base; } #define checkGC(L,c) \ { luaC_condGC(L, L->top = (c), /* limit of live values */ \ Protect(L->top = ci->top)); /* restore top */ \ luai_threadyield(L); } /* fetch an instruction and prepare its execution */ #define vmfetch() { \ i = *(ci->u.l.savedpc++); \ if (L->hookmask & (LUA_MASKLINE | LUA_MASKCOUNT)) \ Protect(luaG_traceexec(L)); \ ra = RA(i); /* WARNING: any stack reallocation invalidates 'ra' */ \ lua_assert(base == ci->u.l.base); \ lua_assert(base <= L->top && L->top < L->stack + L->stacksize); \ } #define vmdispatch(o) switch(o) #define vmcase(l) case l: #define vmbreak break /* ** copy of 'luaV_gettable', but protecting the call to potential ** metamethod (which can reallocate the stack) */ #define gettableProtected(L,t,k,v) { const TValue *slot; \ if (luaV_fastget(L,t,k,slot,luaH_get)) { setobj2s(L, v, slot); } \ else Protect(luaV_finishget(L,t,k,v,slot)); } /* same for 'luaV_settable' */ #define settableProtected(L,t,k,v) { const TValue *slot; \ if (!luaV_fastset(L,t,k,slot,luaH_get,v)) \ Protect(luaV_finishset(L,t,k,v,slot)); } void luaV_execute (lua_State *L) { CallInfo *ci = L->ci; LClosure *cl; TValue *k; StkId base; ci->callstatus |= CIST_FRESH; /* fresh invocation of 'luaV_execute" */ newframe: /* reentry point when frame changes (call/return) */ lua_assert(ci == L->ci); cl = clLvalue(ci->func); /* local reference to function's closure */ k = cl->p->k; /* local reference to function's constant table */ base = ci->u.l.base; /* local copy of function's base */ /* main loop of interpreter */ for (;;) { Instruction i; StkId ra; vmfetch(); vmdispatch (GET_OPCODE(i)) { vmcase(OP_MOVE) { setobjs2s(L, ra, RB(i)); vmbreak; } vmcase(OP_LOADK) { TValue *rb = k + GETARG_Bx(i); setobj2s(L, ra, rb); vmbreak; } vmcase(OP_LOADKX) { TValue *rb; lua_assert(GET_OPCODE(*ci->u.l.savedpc) == OP_EXTRAARG); rb = k + GETARG_Ax(*ci->u.l.savedpc++); setobj2s(L, ra, rb); vmbreak; } vmcase(OP_LOADBOOL) { setbvalue(ra, GETARG_B(i)); if (GETARG_C(i)) ci->u.l.savedpc++; /* skip next instruction (if C) */ vmbreak; } vmcase(OP_LOADNIL) { int b = GETARG_B(i); do { setnilvalue(ra++); } while (b--); vmbreak; } vmcase(OP_GETUPVAL) { int b = GETARG_B(i); setobj2s(L, ra, cl->upvals[b]->v); vmbreak; } vmcase(OP_GETTABUP) { TValue *upval = cl->upvals[GETARG_B(i)]->v; TValue *rc = RKC(i); gettableProtected(L, upval, rc, ra); vmbreak; } vmcase(OP_GETTABLE) { StkId rb = RB(i); TValue *rc = RKC(i); gettableProtected(L, rb, rc, ra); vmbreak; } vmcase(OP_SETTABUP) { TValue *upval = cl->upvals[GETARG_A(i)]->v; TValue *rb = RKB(i); TValue *rc = RKC(i); settableProtected(L, upval, rb, rc); vmbreak; } vmcase(OP_SETUPVAL) { UpVal *uv = cl->upvals[GETARG_B(i)]; setobj(L, uv->v, ra); luaC_upvalbarrier(L, uv); vmbreak; } vmcase(OP_SETTABLE) { TValue *rb = RKB(i); TValue *rc = RKC(i); settableProtected(L, ra, rb, rc); vmbreak; } vmcase(OP_NEWTABLE) { int b = GETARG_B(i); int c = GETARG_C(i); Table *t = luaH_new(L); sethvalue(L, ra, t); if (b != 0 || c != 0) luaH_resize(L, t, luaO_fb2int(b), luaO_fb2int(c)); checkGC(L, ra + 1); vmbreak; } vmcase(OP_SELF) { const TValue *aux; StkId rb = RB(i); TValue *rc = RKC(i); TString *key = tsvalue(rc); /* key must be a string */ setobjs2s(L, ra + 1, rb); if (luaV_fastget(L, rb, key, aux, luaH_getstr)) { setobj2s(L, ra, aux); } else Protect(luaV_finishget(L, rb, rc, ra, aux)); vmbreak; } vmcase(OP_ADD) { TValue *rb = RKB(i); TValue *rc = RKC(i); lua_Number nb; lua_Number nc; if (ttisinteger(rb) && ttisinteger(rc)) { lua_Integer ib = ivalue(rb); lua_Integer ic = ivalue(rc); setivalue(ra, intop(+, ib, ic)); } else if (tonumber(rb, &nb) && tonumber(rc, &nc)) { setfltvalue(ra, luai_numadd(L, nb, nc)); } else { Protect(luaT_trybinTM(L, rb, rc, ra, TM_ADD)); } vmbreak; } vmcase(OP_SUB) { TValue *rb = RKB(i); TValue *rc = RKC(i); lua_Number nb; lua_Number nc; if (ttisinteger(rb) && ttisinteger(rc)) { lua_Integer ib = ivalue(rb); lua_Integer ic = ivalue(rc); setivalue(ra, intop(-, ib, ic)); } else if (tonumber(rb, &nb) && tonumber(rc, &nc)) { setfltvalue(ra, luai_numsub(L, nb, nc)); } else { Protect(luaT_trybinTM(L, rb, rc, ra, TM_SUB)); } vmbreak; } vmcase(OP_MUL) { TValue *rb = RKB(i); TValue *rc = RKC(i); lua_Number nb; lua_Number nc; if (ttisinteger(rb) && ttisinteger(rc)) { lua_Integer ib = ivalue(rb); lua_Integer ic = ivalue(rc); setivalue(ra, intop(*, ib, ic)); } else if (tonumber(rb, &nb) && tonumber(rc, &nc)) { setfltvalue(ra, luai_nummul(L, nb, nc)); } else { Protect(luaT_trybinTM(L, rb, rc, ra, TM_MUL)); } vmbreak; } vmcase(OP_DIV) { /* float division (always with floats) */ TValue *rb = RKB(i); TValue *rc = RKC(i); lua_Number nb; lua_Number nc; if (tonumber(rb, &nb) && tonumber(rc, &nc)) { setfltvalue(ra, luai_numdiv(L, nb, nc)); } else { Protect(luaT_trybinTM(L, rb, rc, ra, TM_DIV)); } vmbreak; } vmcase(OP_BAND) { TValue *rb = RKB(i); TValue *rc = RKC(i); lua_Integer ib; lua_Integer ic; if (tointeger(rb, &ib) && tointeger(rc, &ic)) { setivalue(ra, intop(&, ib, ic)); } else { Protect(luaT_trybinTM(L, rb, rc, ra, TM_BAND)); } vmbreak; } vmcase(OP_BOR) { TValue *rb = RKB(i); TValue *rc = RKC(i); lua_Integer ib; lua_Integer ic; if (tointeger(rb, &ib) && tointeger(rc, &ic)) { setivalue(ra, intop(|, ib, ic)); } else { Protect(luaT_trybinTM(L, rb, rc, ra, TM_BOR)); } vmbreak; } vmcase(OP_BXOR) { TValue *rb = RKB(i); TValue *rc = RKC(i); lua_Integer ib; lua_Integer ic; if (tointeger(rb, &ib) && tointeger(rc, &ic)) { setivalue(ra, intop(^, ib, ic)); } else { Protect(luaT_trybinTM(L, rb, rc, ra, TM_BXOR)); } vmbreak; } vmcase(OP_SHL) { TValue *rb = RKB(i); TValue *rc = RKC(i); lua_Integer ib; lua_Integer ic; if (tointeger(rb, &ib) && tointeger(rc, &ic)) { setivalue(ra, luaV_shiftl(ib, ic)); } else { Protect(luaT_trybinTM(L, rb, rc, ra, TM_SHL)); } vmbreak; } vmcase(OP_SHR) { TValue *rb = RKB(i); TValue *rc = RKC(i); lua_Integer ib; lua_Integer ic; if (tointeger(rb, &ib) && tointeger(rc, &ic)) { setivalue(ra, luaV_shiftl(ib, -ic)); } else { Protect(luaT_trybinTM(L, rb, rc, ra, TM_SHR)); } vmbreak; } vmcase(OP_MOD) { TValue *rb = RKB(i); TValue *rc = RKC(i); lua_Number nb; lua_Number nc; if (ttisinteger(rb) && ttisinteger(rc)) { lua_Integer ib = ivalue(rb); lua_Integer ic = ivalue(rc); setivalue(ra, luaV_mod(L, ib, ic)); } else if (tonumber(rb, &nb) && tonumber(rc, &nc)) { lua_Number m; luai_nummod(L, nb, nc, m); setfltvalue(ra, m); } else { Protect(luaT_trybinTM(L, rb, rc, ra, TM_MOD)); } vmbreak; } vmcase(OP_IDIV) { /* floor division */ TValue *rb = RKB(i); TValue *rc = RKC(i); lua_Number nb; lua_Number nc; if (ttisinteger(rb) && ttisinteger(rc)) { lua_Integer ib = ivalue(rb); lua_Integer ic = ivalue(rc); setivalue(ra, luaV_div(L, ib, ic)); } else if (tonumber(rb, &nb) && tonumber(rc, &nc)) { setfltvalue(ra, luai_numidiv(L, nb, nc)); } else { Protect(luaT_trybinTM(L, rb, rc, ra, TM_IDIV)); } vmbreak; } vmcase(OP_POW) { TValue *rb = RKB(i); TValue *rc = RKC(i); lua_Number nb; lua_Number nc; if (tonumber(rb, &nb) && tonumber(rc, &nc)) { setfltvalue(ra, luai_numpow(L, nb, nc)); } else { Protect(luaT_trybinTM(L, rb, rc, ra, TM_POW)); } vmbreak; } vmcase(OP_UNM) { TValue *rb = RB(i); lua_Number nb; if (ttisinteger(rb)) { lua_Integer ib = ivalue(rb); setivalue(ra, intop(-, 0, ib)); } else if (tonumber(rb, &nb)) { setfltvalue(ra, luai_numunm(L, nb)); } else { Protect(luaT_trybinTM(L, rb, rb, ra, TM_UNM)); } vmbreak; } vmcase(OP_BNOT) { TValue *rb = RB(i); lua_Integer ib; if (tointeger(rb, &ib)) { setivalue(ra, intop(^, ~l_castS2U(0), ib)); } else { Protect(luaT_trybinTM(L, rb, rb, ra, TM_BNOT)); } vmbreak; } vmcase(OP_NOT) { TValue *rb = RB(i); int res = l_isfalse(rb); /* next assignment may change this value */ setbvalue(ra, res); vmbreak; } vmcase(OP_LEN) { Protect(luaV_objlen(L, ra, RB(i))); vmbreak; } vmcase(OP_CONCAT) { int b = GETARG_B(i); int c = GETARG_C(i); StkId rb; L->top = base + c + 1; /* mark the end of concat operands */ Protect(luaV_concat(L, c - b + 1)); ra = RA(i); /* 'luaV_concat' may invoke TMs and move the stack */ rb = base + b; setobjs2s(L, ra, rb); checkGC(L, (ra >= rb ? ra + 1 : rb)); L->top = ci->top; /* restore top */ vmbreak; } vmcase(OP_JMP) { dojump(ci, i, 0); vmbreak; } vmcase(OP_EQ) { TValue *rb = RKB(i); TValue *rc = RKC(i); Protect( if (luaV_equalobj(L, rb, rc) != GETARG_A(i)) ci->u.l.savedpc++; else donextjump(ci); ) vmbreak; } vmcase(OP_LT) { Protect( if (luaV_lessthan(L, RKB(i), RKC(i)) != GETARG_A(i)) ci->u.l.savedpc++; else donextjump(ci); ) vmbreak; } vmcase(OP_LE) { Protect( if (luaV_lessequal(L, RKB(i), RKC(i)) != GETARG_A(i)) ci->u.l.savedpc++; else donextjump(ci); ) vmbreak; } vmcase(OP_TEST) { if (GETARG_C(i) ? l_isfalse(ra) : !l_isfalse(ra)) ci->u.l.savedpc++; else donextjump(ci); vmbreak; } vmcase(OP_TESTSET) { TValue *rb = RB(i); if (GETARG_C(i) ? l_isfalse(rb) : !l_isfalse(rb)) ci->u.l.savedpc++; else { setobjs2s(L, ra, rb); donextjump(ci); } vmbreak; } vmcase(OP_CALL) { int b = GETARG_B(i); int nresults = GETARG_C(i) - 1; if (b != 0) L->top = ra+b; /* else previous instruction set top */ if (luaD_precall(L, ra, nresults)) { /* C function? */ if (nresults >= 0) L->top = ci->top; /* adjust results */ Protect((void)0); /* update 'base' */ } else { /* Lua function */ ci = L->ci; goto newframe; /* restart luaV_execute over new Lua function */ } vmbreak; } vmcase(OP_TAILCALL) { int b = GETARG_B(i); if (b != 0) L->top = ra+b; /* else previous instruction set top */ lua_assert(GETARG_C(i) - 1 == LUA_MULTRET); if (luaD_precall(L, ra, LUA_MULTRET)) { /* C function? */ Protect((void)0); /* update 'base' */ } else { /* tail call: put called frame (n) in place of caller one (o) */ CallInfo *nci = L->ci; /* called frame */ CallInfo *oci = nci->previous; /* caller frame */ StkId nfunc = nci->func; /* called function */ StkId ofunc = oci->func; /* caller function */ /* last stack slot filled by 'precall' */ StkId lim = nci->u.l.base + getproto(nfunc)->numparams; int aux; /* close all upvalues from previous call */ if (cl->p->sizep > 0) luaF_close(L, oci->u.l.base); /* move new frame into old one */ for (aux = 0; nfunc + aux < lim; aux++) setobjs2s(L, ofunc + aux, nfunc + aux); oci->u.l.base = ofunc + (nci->u.l.base - nfunc); /* correct base */ oci->top = L->top = ofunc + (L->top - nfunc); /* correct top */ oci->u.l.savedpc = nci->u.l.savedpc; oci->callstatus |= CIST_TAIL; /* function was tail called */ ci = L->ci = oci; /* remove new frame */ lua_assert(L->top == oci->u.l.base + getproto(ofunc)->maxstacksize); goto newframe; /* restart luaV_execute over new Lua function */ } vmbreak; } vmcase(OP_RETURN) { int b = GETARG_B(i); if (cl->p->sizep > 0) luaF_close(L, base); b = luaD_poscall(L, ci, ra, (b != 0 ? b - 1 : cast_int(L->top - ra))); if (ci->callstatus & CIST_FRESH) /* local 'ci' still from callee */ return; /* external invocation: return */ else { /* invocation via reentry: continue execution */ ci = L->ci; if (b) L->top = ci->top; lua_assert(isLua(ci)); lua_assert(GET_OPCODE(*((ci)->u.l.savedpc - 1)) == OP_CALL); goto newframe; /* restart luaV_execute over new Lua function */ } } vmcase(OP_FORLOOP) { if (ttisinteger(ra)) { /* integer loop? */ lua_Integer step = ivalue(ra + 2); lua_Integer idx = intop(+, ivalue(ra), step); /* increment index */ lua_Integer limit = ivalue(ra + 1); if ((0 < step) ? (idx <= limit) : (limit <= idx)) { ci->u.l.savedpc += GETARG_sBx(i); /* jump back */ chgivalue(ra, idx); /* update internal index... */ setivalue(ra + 3, idx); /* ...and external index */ } } else { /* floating loop */ lua_Number step = fltvalue(ra + 2); lua_Number idx = luai_numadd(L, fltvalue(ra), step); /* inc. index */ lua_Number limit = fltvalue(ra + 1); if (luai_numlt(0, step) ? luai_numle(idx, limit) : luai_numle(limit, idx)) { ci->u.l.savedpc += GETARG_sBx(i); /* jump back */ chgfltvalue(ra, idx); /* update internal index... */ setfltvalue(ra + 3, idx); /* ...and external index */ } } vmbreak; } vmcase(OP_FORPREP) { TValue *init = ra; TValue *plimit = ra + 1; TValue *pstep = ra + 2; lua_Integer ilimit; int stopnow; if (ttisinteger(init) && ttisinteger(pstep) && forlimit(plimit, &ilimit, ivalue(pstep), &stopnow)) { /* all values are integer */ lua_Integer initv = (stopnow ? 0 : ivalue(init)); setivalue(plimit, ilimit); setivalue(init, intop(-, initv, ivalue(pstep))); } else { /* try making all values floats */ lua_Number ninit; lua_Number nlimit; lua_Number nstep; if (!tonumber(plimit, &nlimit)) luaG_runerror(L, "'for' limit must be a number"); setfltvalue(plimit, nlimit); if (!tonumber(pstep, &nstep)) luaG_runerror(L, "'for' step must be a number"); setfltvalue(pstep, nstep); if (!tonumber(init, &ninit)) luaG_runerror(L, "'for' initial value must be a number"); setfltvalue(init, luai_numsub(L, ninit, nstep)); } ci->u.l.savedpc += GETARG_sBx(i); vmbreak; } vmcase(OP_TFORCALL) { StkId cb = ra + 3; /* call base */ setobjs2s(L, cb+2, ra+2); setobjs2s(L, cb+1, ra+1); setobjs2s(L, cb, ra); L->top = cb + 3; /* func. + 2 args (state and index) */ Protect(luaD_call(L, cb, GETARG_C(i))); L->top = ci->top; i = *(ci->u.l.savedpc++); /* go to next instruction */ ra = RA(i); lua_assert(GET_OPCODE(i) == OP_TFORLOOP); goto l_tforloop; } vmcase(OP_TFORLOOP) { l_tforloop: if (!ttisnil(ra + 1)) { /* continue loop? */ setobjs2s(L, ra, ra + 1); /* save control variable */ ci->u.l.savedpc += GETARG_sBx(i); /* jump back */ } vmbreak; } vmcase(OP_SETLIST) { int n = GETARG_B(i); int c = GETARG_C(i); unsigned int last; Table *h; if (n == 0) n = cast_int(L->top - ra) - 1; if (c == 0) { lua_assert(GET_OPCODE(*ci->u.l.savedpc) == OP_EXTRAARG); c = GETARG_Ax(*ci->u.l.savedpc++); } h = hvalue(ra); last = ((c-1)*LFIELDS_PER_FLUSH) + n; if (last > h->sizearray) /* needs more space? */ luaH_resizearray(L, h, last); /* preallocate it at once */ for (; n > 0; n--) { TValue *val = ra+n; luaH_setint(L, h, last--, val); luaC_barrierback(L, h, val); } L->top = ci->top; /* correct top (in case of previous open call) */ vmbreak; } vmcase(OP_CLOSURE) { Proto *p = cl->p->p[GETARG_Bx(i)]; LClosure *ncl = getcached(p, cl->upvals, base); /* cached closure */ if (ncl == NULL) /* no match? */ pushclosure(L, p, cl->upvals, base, ra); /* create a new one */ else setclLvalue(L, ra, ncl); /* push cashed closure */ checkGC(L, ra + 1); vmbreak; } vmcase(OP_VARARG) { int b = GETARG_B(i) - 1; /* required results */ int j; int n = cast_int(base - ci->func) - cl->p->numparams - 1; if (n < 0) /* less arguments than parameters? */ n = 0; /* no vararg arguments */ if (b < 0) { /* B == 0? */ b = n; /* get all var. arguments */ Protect(luaD_checkstack(L, n)); ra = RA(i); /* previous call may change the stack */ L->top = ra + n; } for (j = 0; j < b && j < n; j++) setobjs2s(L, ra + j, base - n + j); for (; j < b; j++) /* complete required results with nil */ setnilvalue(ra + j); vmbreak; } vmcase(OP_EXTRAARG) { lua_assert(0); vmbreak; } } } } /* }================================================================== */