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lua/lvm.c
Roberto Ierusalimschy 063d4e4543 Lua 5.3.5 ported to git 
This is the first commit for the branch Lua 5.3. All source files
were copied from the official distribution of 5.3.5 in the Lua site.
The test files are the same of 5.3.4. The manual came from the
previous RCS repository, revision 1.167.1.2.
2018-12-17 14:46:37 -02:00

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/*
** $Id: lvm.c,v 2.268.1.1 2017/04/19 17:39:34 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;
}
}
}
}
/* }================================================================== */
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