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lua/lvm.c

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/*
** $Id: lvm.c,v 1.187 2001/06/20 17:22:46 roberto Exp roberto $
** Lua virtual machine
** See Copyright Notice in lua.h
*/
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define LUA_PRIVATE
#include "lua.h"
#include "lapi.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"
static void luaV_checkGC (lua_State *L, StkId top) {
if (G(L)->nblocks >= G(L)->GCthreshold) {
StkId temp = L->top;
L->top = top;
luaC_collectgarbage(L);
L->top = temp; /* restore old top position */
}
}
const TObject *luaV_tonumber (const TObject *obj, TObject *n) {
if (ttype(obj) == LUA_TNUMBER) return obj;
if (ttype(obj) == LUA_TSTRING && luaO_str2d(svalue(obj), &nvalue(n))) {
setttype(n, LUA_TNUMBER);
return n;
}
else
return NULL;
}
int luaV_tostring (lua_State *L, TObject *obj) {
if (ttype(obj) != LUA_TNUMBER)
return 1;
else {
l_char s[32]; /* 16 digits, sign, point and \0 (+ some extra...) */
lua_number2str(s, nvalue(obj)); /* convert `s' to number */
setsvalue(obj, luaS_new(L, s));
return 0;
}
}
static void traceexec (lua_State *L, lua_Hook linehook) {
CallInfo *ci = L->ci;
int *lineinfo = ci_func(ci)->f.l->lineinfo;
int pc = (*ci->pc - ci_func(ci)->f.l->code) - 1;
int newline;
if (pc == 0) { /* may be first time? */
ci->line = 1;
ci->refi = 0;
ci->lastpc = pc+1; /* make sure it will call linehook */
}
newline = luaG_getline(lineinfo, pc, ci->line, &ci->refi);
/* calls linehook when enters a new line or jumps back (loop) */
if (newline != ci->line || pc <= ci->lastpc) {
ci->line = newline;
luaD_lineHook(L, newline, linehook);
}
ci->lastpc = pc;
}
static Closure *luaV_closure (lua_State *L, int nelems) {
Closure *c = luaF_newclosure(L, nelems);
L->top -= nelems;
while (nelems--)
setobj(&c->upvalue[nelems], L->top+nelems);
setclvalue(L->top, c);
incr_top;
return c;
}
void luaV_Cclosure (lua_State *L, lua_CFunction c, int nelems) {
Closure *cl = luaV_closure(L, nelems);
cl->f.c = c;
cl->isC = 1;
}
void luaV_Lclosure (lua_State *L, Proto *l, int nelems) {
Closure *cl = luaV_closure(L, nelems);
cl->f.l = l;
cl->isC = 0;
}
/* maximum stack used by a call to a tag method (func + args) */
#define MAXSTACK_TM 4
static StkId callTM (lua_State *L, Closure *f, const l_char *fmt, ...) {
va_list argp;
StkId base = L->top;
lua_assert(strlen(fmt)+1 <= MAXSTACK_TM);
luaD_checkstack(L, MAXSTACK_TM);
va_start(argp, fmt);
setclvalue(L->top, f); /* push function */
L->top++;
while (*fmt) {
if (*fmt++ == l_c('o')) {
setobj(L->top, va_arg(argp, TObject *));
}
else {
lua_assert(*(fmt-1) == l_c('s'));
setsvalue(L->top, va_arg(argp, TString *));
}
L->top++;
}
luaD_call(L, base);
va_end(argp);
return base;
}
#define setTM(L, base) (L->top = (base))
static void setTMresult (lua_State *L, TObject *result, StkId base) {
if (L->top == base) { /* are there valid results? */
setnilvalue(result); /* function had no results */
}
else {
setobj(result, base); /* get first result */
}
L->top = base; /* restore top */
}
/*
** Function to index a table.
** Receives the table at `t' and the key at the `key'.
** leaves the result at `res'.
*/
void luaV_gettable (lua_State *L, StkId t, TObject *key, StkId res) {
Closure *tm;
if (ttype(t) == LUA_TTABLE) { /* `t' is a table? */
int tg = hvalue(t)->htag;
if (tg == LUA_TTABLE || /* with default tag? */
(tm = luaT_gettm(G(L), tg, TM_GETTABLE)) == NULL) { /* or no TM? */
const TObject *h = luaH_get(hvalue(t), key); /* do a primitive get */
/* result is no nil or there is no `index' tag method? */
if (ttype(h) != LUA_TNIL || /* no nil? */
((tm=luaT_gettm(G(L), tg, TM_INDEX)) == NULL)) { /* or no index TM? */
setobj(res, h); /* default get */
return;
}
}
/* else will call the tag method */
} else { /* not a table; try a `gettable' tag method */
tm = luaT_gettmbyObj(G(L), t, TM_GETTABLE);
if (tm == NULL) /* no tag method? */
luaG_typeerror(L, t, l_s("index"));
}
setTMresult(L, res, callTM(L, tm, l_s("oo"), t, key));
}
/*
** Receives table at `t', key at `key' and value at `val'.
*/
void luaV_settable (lua_State *L, StkId t, TObject *key, StkId val) {
Closure *tm;
if (ttype(t) == LUA_TTABLE) { /* `t' is a table? */
int tg = hvalue(t)->htag;
if (hvalue(t)->htag == LUA_TTABLE || /* with default tag? */
(tm = luaT_gettm(G(L), tg, TM_SETTABLE)) == NULL) { /* or no TM? */
setobj(luaH_set(L, hvalue(t), key), val); /* do a primitive set */
return;
}
/* else will call the tag method */
} else { /* not a table; try a `settable' tag method */
tm = luaT_gettmbyObj(G(L), t, TM_SETTABLE);
if (tm == NULL) /* no tag method? */
luaG_typeerror(L, t, l_s("index"));
}
setTM(L, callTM(L, tm, l_s("ooo"), t, key, val));
}
void luaV_getglobal (lua_State *L, TString *name, StkId res) {
const TObject *value = luaH_getstr(L->gt, name);
Closure *tm;
if (!HAS_TM_GETGLOBAL(L, ttype(value)) || /* is there a tag method? */
(tm = luaT_gettmbyObj(G(L), value, TM_GETGLOBAL)) == NULL) {
setobj(res, value); /* default behavior */
}
else
setTMresult(L, res, callTM(L, tm, l_s("so"), name, value));
}
void luaV_setglobal (lua_State *L, TString *name, StkId val) {
TObject *oldvalue = luaH_setstr(L, L->gt, name);
Closure *tm;
if (!HAS_TM_SETGLOBAL(L, ttype(oldvalue)) || /* no tag methods? */
(tm = luaT_gettmbyObj(G(L), oldvalue, TM_SETGLOBAL)) == NULL) {
setobj(oldvalue, val); /* raw set */
}
else
setTM(L, callTM(L, tm, l_s("soo"), name, oldvalue, val));
}
static int call_binTM (lua_State *L, const TObject *p1, const TObject *p2,
TObject *res, TMS event) {
Closure *tm = luaT_gettmbyObj(G(L), p1, event); /* try first operand */
if (tm == NULL) {
tm = luaT_gettmbyObj(G(L), p2, event); /* try second operand */
if (tm == NULL) {
tm = luaT_gettm(G(L), 0, event); /* try a `global' method */
if (tm == NULL)
return 0; /* no tag method */
}
}
setTMresult(L, res, callTM(L, tm, l_s("oo"), p1, p2));
return 1;
}
static void call_arith (lua_State *L, StkId p1, TObject *p2,
StkId res, TMS event) {
if (!call_binTM(L, p1, p2, res, event))
luaG_aritherror(L, p1, p2);
}
static int luaV_strlessthan (const TString *ls, const TString *rs) {
const l_char *l = getstr(ls);
size_t ll = ls->tsv.len;
const l_char *r = getstr(rs);
size_t lr = rs->tsv.len;
for (;;) {
int temp = strcoll(l, r);
if (temp != 0) return (temp < 0);
else { /* strings are equal up to a `\0' */
size_t len = strlen(l); /* index of first `\0' in both strings */
if (len == lr) /* r is finished? */
return 0; /* l is equal or greater than r */
else if (len == ll) /* l is finished? */
return 1; /* l is smaller than r (because r is not finished) */
/* both strings longer than `len'; go on comparing (after the `\0') */
len++;
l += len; ll -= len; r += len; lr -= len;
}
}
}
int luaV_lessthan (lua_State *L, const TObject *l, const TObject *r) {
if (ttype(l) == LUA_TNUMBER && ttype(r) == LUA_TNUMBER)
return (nvalue(l) < nvalue(r));
else if (ttype(l) == LUA_TSTRING && ttype(r) == LUA_TSTRING)
return luaV_strlessthan(tsvalue(l), tsvalue(r));
else { /* try TM */
if (!call_binTM(L, l, r, L->top, TM_LT))
luaG_ordererror(L, l, r);
return (ttype(L->top) != LUA_TNIL);
}
}
void luaV_strconc (lua_State *L, int total, StkId top) {
luaV_checkGC(L, top);
do {
int n = 2; /* number of elements handled in this pass (at least 2) */
if (tostring(L, top-2) || tostring(L, top-1)) {
if (!call_binTM(L, top-2, top-1, top-2, TM_CONCAT))
luaG_concaterror(L, top-2, top-1);
} else if (tsvalue(top-1)->tsv.len > 0) { /* if len=0, do nothing */
/* at least two string values; get as many as possible */
lu_mem tl = (lu_mem)tsvalue(top-1)->tsv.len +
(lu_mem)tsvalue(top-2)->tsv.len;
l_char *buffer;
int i;
while (n < total && !tostring(L, top-n-1)) { /* collect total length */
tl += tsvalue(top-n-1)->tsv.len;
n++;
}
if (tl > MAX_SIZET) luaD_error(L, l_s("string size overflow"));
buffer = luaO_openspace(L, tl, l_char);
tl = 0;
for (i=n; i>0; i--) { /* concat all strings */
size_t l = tsvalue(top-i)->tsv.len;
memcpy(buffer+tl, svalue(top-i), l);
tl += l;
}
setsvalue(top-n, luaS_newlstr(L, buffer, tl));
}
total -= n-1; /* got `n' strings to create 1 new */
top -= n-1;
} while (total > 1); /* repeat until only 1 result left */
}
static void luaV_pack (lua_State *L, StkId firstelem) {
int i;
Hash *htab = luaH_new(L, 0);
TObject *n;
for (i=0; firstelem+i<L->top; i++)
setobj(luaH_setnum(L, htab, i+1), firstelem+i);
/* store counter in field `n' */
n = luaH_setstr(L, htab, luaS_newliteral(L, l_s("n")));
setnvalue(n, i);
L->top = firstelem; /* remove elements from the stack */
sethvalue(L->top, htab);
incr_top;
}
static void adjust_varargs (lua_State *L, StkId base, int nfixargs) {
int nvararg = (L->top-base) - nfixargs;
StkId firstvar = base + nfixargs; /* position of first vararg */
if (nvararg < 0) {
luaD_checkstack(L, -nvararg);
luaD_adjusttop(L, firstvar);
}
luaV_pack(L, firstvar);
}
/*
** some macros for common tasks in `luaV_execute'
*/
#define runtime_check(L, c) { if (!(c)) return L->top; }
#define RA(i) (base+GETARG_A(i))
#define RB(i) (base+GETARG_B(i))
#define RC(i) (base+GETARG_C(i))
#define RKC(i) ((GETARG_C(i) < MAXSTACK) ? \
base+GETARG_C(i) : \
tf->k+GETARG_C(i)-MAXSTACK)
#define KBc(i) (tf->k+GETARG_Bc(i))
#define Arith(op, optm) { \
const TObject *b = RB(i); const TObject *c = RKC(i); \
TObject tempb, tempc; \
if ((ttype(b) == LUA_TNUMBER || (b = luaV_tonumber(b, &tempb)) != NULL) && \
(ttype(c) == LUA_TNUMBER || (c = luaV_tonumber(c, &tempc)) != NULL)) { \
setnvalue(ra, nvalue(b) op nvalue(c)); \
} else \
call_arith(L, RB(i), RKC(i), ra, optm); \
}
#define dojump(pc, i) ((pc) += GETARG_sBc(i))
/*
** Executes the given Lua function. Parameters are between [base,top).
** Returns n such that the the results are between [n,top).
*/
StkId luaV_execute (lua_State *L, const Closure *cl, StkId base) {
const Proto *const tf = cl->f.l;
const Instruction *pc;
lua_Hook linehook;
if (tf->is_vararg) /* varargs? */
adjust_varargs(L, base, tf->numparams);
if (base > L->stack_last - tf->maxstacksize)
luaD_stackerror(L);
luaD_adjusttop(L, base + tf->maxstacksize);
pc = tf->code;
L->ci->pc = &pc;
linehook = L->linehook;
/* main loop of interpreter */
for (;;) {
const Instruction i = *pc++;
const StkId ra = RA(i);
if (linehook)
traceexec(L, linehook);
switch (GET_OPCODE(i)) {
case OP_MOVE: {
setobj(ra, RB(i));
break;
}
case OP_LOADK: {
setobj(ra, KBc(i));
break;
}
case OP_LOADINT: {
setnvalue(ra, (lua_Number)GETARG_sBc(i));
break;
}
case OP_LOADUPVAL: {
setobj(ra, cl->upvalue+GETARG_Bc(i));
break;
}
case OP_LOADNIL: {
TObject *rb = RB(i);
do {
setnilvalue(rb--);
} while (rb >= ra);
break;
}
case OP_GETGLOBAL: {
lua_assert(ttype(KBc(i)) == LUA_TSTRING);
luaV_getglobal(L, tsvalue(KBc(i)), ra);
break;
}
case OP_GETTABLE: {
luaV_gettable(L, RB(i), RKC(i), ra);
break;
}
case OP_SETGLOBAL: {
lua_assert(ttype(KBc(i)) == LUA_TSTRING);
luaV_setglobal(L, tsvalue(KBc(i)), ra);
break;
}
case OP_SETTABLE: {
luaV_settable(L, RB(i), RKC(i), ra);
break;
}
case OP_NEWTABLE: {
sethvalue(ra, luaH_new(L, GETARG_Bc(i)));
luaV_checkGC(L, ra+1);
break;
}
case OP_SELF: {
StkId rb = RB(i);
setobj(ra+1, rb);
luaV_gettable(L, rb, RKC(i), ra);
break;
}
case OP_ADD: {
Arith( + , TM_ADD);
break;
}
case OP_SUB: {
Arith( - , TM_SUB);
break;
}
case OP_MUL: {
Arith( * , TM_MUL);
break;
}
case OP_DIV: {
Arith( / , TM_DIV);
break;
}
case OP_POW: {
call_arith(L, RB(i), RKC(i), ra, TM_POW);
break;
}
case OP_UNM: {
const TObject *rb = RB(i);
if (ttype(rb) == LUA_TNUMBER || (rb=luaV_tonumber(rb, ra)) != NULL) {
setnvalue(ra, -nvalue(rb));
}
else {
TObject temp;
setnilvalue(&temp);
call_arith(L, RB(i), &temp, ra, TM_UNM);
}
break;
}
case OP_NOT: {
if (ttype(RB(i)) == LUA_TNIL) {
setnvalue(ra, 1);
} else {
setnilvalue(ra);
}
break;
}
case OP_CONCAT: {
StkId top = RC(i)+1;
StkId rb = RB(i);
luaV_strconc(L, top-rb, top);
setobj(ra, rb);
break;
}
case OP_CJMP:
case OP_JMP: {
dojump(pc, i);
break;
}
case OP_TESTEQ: {
lua_assert(GET_OPCODE(*pc) == OP_CJMP);
if (luaO_equalObj(ra, RKC(i))) dojump(pc, *pc);
pc++;
break;
}
case OP_TESTNE: {
lua_assert(GET_OPCODE(*pc) == OP_CJMP);
if (!luaO_equalObj(ra, RKC(i))) dojump(pc, *pc);
pc++;
break;
}
case OP_TESTLT: {
lua_assert(GET_OPCODE(*pc) == OP_CJMP);
if (luaV_lessthan(L, ra, RKC(i))) dojump(pc, *pc);
pc++;
break;
}
case OP_TESTLE: { /* b <= c === !(c<b) */
lua_assert(GET_OPCODE(*pc) == OP_CJMP);
if (!luaV_lessthan(L, RKC(i), ra)) dojump(pc, *pc);
pc++;
break;
}
case OP_TESTGT: { /* b > c === (c<b) */
lua_assert(GET_OPCODE(*pc) == OP_CJMP);
if (luaV_lessthan(L, RKC(i), ra)) dojump(pc, *pc);
pc++;
break;
}
case OP_TESTGE: { /* b >= c === !(b<c) */
lua_assert(GET_OPCODE(*pc) == OP_CJMP);
if (!luaV_lessthan(L, ra, RKC(i))) dojump(pc, *pc);
pc++;
break;
}
case OP_TESTT: {
StkId rb = RB(i);
lua_assert(GET_OPCODE(*pc) == OP_CJMP);
if (ttype(rb) != LUA_TNIL) {
setobj(ra, rb);
dojump(pc, *pc);
}
pc++;
break;
}
case OP_TESTF: {
lua_assert(GET_OPCODE(*pc) == OP_CJMP);
if (ttype(RB(i)) == LUA_TNIL) {
setnilvalue(ra);
dojump(pc, *pc);
}
pc++;
break;
}
case OP_NILJMP: {
setnilvalue(ra);
pc++;
break;
}
case OP_CALL: {
int c;
int b = GETARG_B(i);
if (b != NO_REG)
L->top = ra+b+1;
luaD_call(L, ra);
c = GETARG_C(i);
if (c != NO_REG) {
while (L->top < ra+c) setnilvalue(L->top++);
L->top = base + tf->maxstacksize;
}
break;
}
case OP_RETURN: {
int b = GETARG_B(i);
if (b != NO_REG)
L->top = ra+b;
return ra;
}
case OP_FORPREP: {
if (luaV_tonumber(ra, ra) == NULL)
luaD_error(L, l_s("`for' initial value must be a number"));
if (luaV_tonumber(ra+1, ra+1) == NULL)
luaD_error(L, l_s("`for' limit must be a number"));
if (luaV_tonumber(ra+2, ra+2) == NULL)
luaD_error(L, l_s("`for' step must be a number"));
nvalue(ra) -= nvalue(ra+2);/* decrement index (to be incremented) */
pc += -GETARG_sBc(i); /* `jump' to loop end (delta is negated here) */
/* store in `ra+1' total number of repetitions */
nvalue(ra+1) = ((nvalue(ra+1)-nvalue(ra))/nvalue(ra+2));
/* go through */
}
case OP_FORLOOP: {
runtime_check(L, ttype(ra+1) == LUA_TNUMBER &&
ttype(ra+2) == LUA_TNUMBER);
if (ttype(ra) != LUA_TNUMBER)
luaD_error(L, l_s("`for' index must be a number"));
if (--nvalue(ra+1) >= 0) {
nvalue(ra) += nvalue(ra+2); /* increment index */
dojump(pc, i); /* repeat loop */
}
break;
}
case OP_TFORPREP: {
if (ttype(ra) != LUA_TTABLE)
luaD_error(L, l_s("`for' table must be a table"));
setnvalue(ra+1, -1); /* initial index */
setnilvalue(ra+2);
setnilvalue(ra+3);
pc += -GETARG_sBc(i); /* `jump' to loop end (delta is negated here) */
/* go through */
}
case OP_TFORLOOP: {
Hash *t;
int n;
runtime_check(L, ttype(ra) == LUA_TTABLE &&
ttype(ra+1) == LUA_TNUMBER);
t = hvalue(ra);
n = (int)nvalue(ra+1);
n = luaH_nexti(t, n);
if (n != -1) { /* repeat loop? */
Node *node = node(t, n);
setnvalue(ra+1, n); /* index */
setobj(ra+2, key(node));
setobj(ra+3, val(node));
dojump(pc, i); /* repeat loop */
}
break;
}
case OP_SETLIST:
case OP_SETLISTO: {
int bc;
int n;
Hash *h;
runtime_check(L, ttype(ra) == LUA_TTABLE);
h = hvalue(ra);
bc = GETARG_Bc(i);
if (GET_OPCODE(i) == OP_SETLIST)
n = (bc&(LFIELDS_PER_FLUSH-1)) + 1;
else
n = L->top - ra - 1;
bc &= ~(LFIELDS_PER_FLUSH-1); /* bc = bc - bc%FPF */
for (; n > 0; n--)
setobj(luaH_setnum(L, h, bc+n), ra+n);
break;
}
case OP_CLOSURE: {
Proto *p = tf->kproto[GETARG_Bc(i)];
int nup = p->nupvalues;
luaV_checkGC(L, ra+nup);
L->top = ra+nup;
luaV_Lclosure(L, p, nup);
L->top = base + tf->maxstacksize;
break;
}
}
}
}
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