Fixed "conceptual" bug in 'luaK_setreturns'

This function was computing invalid instruction addresses when the
expression was not a multi-return instruction. (Virtually all machines
don't raise errors when computing an invalid address, as long as the
address is not accessed, but this computation is undefined behavior in
ISO C.)
This commit is contained in:
Roberto Ierusalimschy 2020-03-02 13:24:06 -03:00
parent 92594f0939
commit e460752323
2 changed files with 5 additions and 5 deletions

View File

@ -703,19 +703,18 @@ static void const2exp (TValue *v, expdesc *e) {
/*
** Fix an expression to return the number of results 'nresults'.
** Either 'e' is a multi-ret expression (function call or vararg)
** or 'nresults' is LUA_MULTRET (as any expression can satisfy that).
** 'e' must be a multi-ret expression (function call or vararg).
*/
void luaK_setreturns (FuncState *fs, expdesc *e, int nresults) {
Instruction *pc = &getinstruction(fs, e);
if (e->k == VCALL) /* expression is an open function call? */
SETARG_C(*pc, nresults + 1);
else if (e->k == VVARARG) {
else {
lua_assert(e->k == VVARARG);
SETARG_C(*pc, nresults + 1);
SETARG_A(*pc, fs->freereg);
luaK_reserveregs(fs, 1);
}
else lua_assert(nresults == LUA_MULTRET);
}

View File

@ -1014,7 +1014,8 @@ static void funcargs (LexState *ls, expdesc *f, int line) {
args.k = VVOID;
else {
explist(ls, &args);
luaK_setmultret(fs, &args);
if (hasmultret(args.k))
luaK_setmultret(fs, &args);
}
check_match(ls, ')', '(', line);
break;