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Checks for read-only globals

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This commit is contained in:
Roberto Ierusalimschy
2025-05-06 15:54:05 -03:00
parent be81209063
commit 4365a45d68
4 changed files with 33 additions and 9 deletions
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24
lparser.c
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@@ -200,7 +200,7 @@ static int new_varkind (LexState *ls, TString *name, lu_byte kind) {
luaY_checklimit(fs, dyd->actvar.n + 1 - fs->firstlocal,
MAXVARS, "local variables");
luaM_growvector(L, dyd->actvar.arr, dyd->actvar.n + 1,
dyd->actvar.size, Vardesc, SHRT_MAX, "local variables");
dyd->actvar.size, Vardesc, SHRT_MAX, "variable declarationss");
var = &dyd->actvar.arr[dyd->actvar.n++];
var->vd.kind = kind; /* default */
var->vd.name = name;
@@ -276,7 +276,7 @@ static LocVar *localdebuginfo (FuncState *fs, int vidx) {
static void init_var (FuncState *fs, expdesc *e, int vidx) {
e->f = e->t = NO_JUMP;
e->k = VLOCAL;
e->u.var.vidx = cast(unsigned short, vidx);
e->u.var.vidx = cast(short, vidx);
e->u.var.ridx = getlocalvardesc(fs, vidx)->vd.ridx;
}
@@ -304,8 +304,16 @@ static void check_readonly (LexState *ls, expdesc *e) {
varname = up->name;
break;
}
case VINDEXUP: case VINDEXSTR: case VINDEXED: {
int vidx = e->u.ind.vidx;
/* is it a read-only declared global? */
if (vidx != -1 && ls->dyd->actvar.arr[vidx].vd.kind == GDKCONST)
varname = ls->dyd->actvar.arr[vidx].vd.name;
break;
}
default:
return; /* other cases cannot be read-only */
lua_assert(e->k == VINDEXI); /* this one doesn't need any check */
return; /* integer index cannot be read-only */
}
if (varname)
luaK_semerror(ls, "attempt to assign to const variable '%s'",
@@ -391,7 +399,7 @@ static int newupvalue (FuncState *fs, TString *name, expdesc *v) {
/*
** Look for an active local variable with the name 'n' in the
** Look for an active variable with the name 'n' in the
** function 'fs'. If found, initialize 'var' with it and return
** its expression kind; otherwise return -1.
*/
@@ -403,7 +411,7 @@ static int searchvar (FuncState *fs, TString *n, expdesc *var) {
if (vd->vd.kind == RDKCTC) /* compile-time constant? */
init_exp(var, VCONST, fs->firstlocal + i);
else if (vd->vd.kind == GDKREG || vd->vd.kind == GDKCONST)
init_exp(var, VGLOBAL, i);
init_exp(var, VGLOBAL, fs->firstlocal + i);
else /* local variable */
init_var(fs, var, i);
return cast_int(var->k);
@@ -475,8 +483,11 @@ static void singlevar (LexState *ls, expdesc *var) {
singlevaraux(fs, varname, var, 1);
if (var->k == VGLOBAL) { /* global name? */
expdesc key;
int info = var->u.info;
lua_assert(info == -1 ||
eqstr(ls->dyd->actvar.arr[info].vd.name, varname));
/* global by default in the scope of a global declaration? */
if (var->u.info == -1 && fs->bl->globdec)
if (info == -1 && fs->bl->globdec)
luaK_semerror(ls, "variable '%s' not declared", getstr(varname));
singlevaraux(fs, ls->envn, var, 1); /* get environment variable */
if (var->k == VGLOBAL)
@@ -485,6 +496,7 @@ static void singlevar (LexState *ls, expdesc *var) {
luaK_exp2anyregup(fs, var); /* but could be a constant */
codestring(&key, varname); /* key is variable name */
luaK_indexed(fs, var, &key); /* env[varname] */
var->u.ind.vidx = cast(short, info); /* mark it as a declared global */
}
}