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Treat metatables of special userdata objects as immutable.

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This commit is contained in:
Mike Pall 2011-02-05 14:09:50 +01:00
parent c29ed4dbbf
commit 223d85aa06
1 changed files with 26 additions and 12 deletions
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38
src/lj_record.c
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@ -661,7 +661,32 @@ int lj_record_mm_lookup(jit_State *J, RecordIndex *ix, MMS mm)
mt = tabref(tabV(&ix->tabv)->metatable);
mix.tab = emitir(IRT(IR_FLOAD, IRT_TAB), ix->tab, IRFL_TAB_META);
} else if (tref_isudata(ix->tab)) {
int udtype = udataV(&ix->tabv)->udtype;
mt = tabref(udataV(&ix->tabv)->metatable);
/* The metatables of special userdata objects are treated as immutable. */
if (udtype != UDTYPE_USERDATA) {
cTValue *mo;
if (LJ_HASFFI && udtype == UDTYPE_FFI_CLIB) {
/* Specialize to the C library namespace object. */
emitir(IRTG(IR_EQ, IRT_P32), ix->tab, lj_ir_kptr(J, udataV(&ix->tabv)));
} else {
/* Specialize to the type of userdata. */
TRef tr = emitir(IRT(IR_FLOAD, IRT_U8), ix->tab, IRFL_UDATA_UDTYPE);
emitir(IRTGI(IR_EQ), tr, lj_ir_kint(J, udtype));
}
immutable_mt:
mo = lj_tab_getstr(mt, mmname_str(J2G(J), mm));
if (!mo || tvisnil(mo))
return 0; /* No metamethod. */
/* Treat metamethod or index table as immutable, too. */
if (!(tvisfunc(mo) || tvistab(mo)))
lj_trace_err(J, LJ_TRERR_BADTYPE);
copyTV(J->L, &ix->mobjv, mo);
ix->mobj = lj_ir_kgc(J, gcV(mo), tvisfunc(mo) ? IRT_FUNC : IRT_TAB);
ix->mtv = mt;
ix->mt = TREF_NIL; /* Dummy value for comparison semantics. */
return 1; /* Got metamethod or index table. */
}
mix.tab = emitir(IRT(IR_FLOAD, IRT_TAB), ix->tab, IRFL_UDATA_META);
} else {
/* Specialize to base metatable. Must flush mcode in lua_setmetatable(). */
@ -670,19 +695,8 @@ int lj_record_mm_lookup(jit_State *J, RecordIndex *ix, MMS mm)
ix->mt = TREF_NIL;
return 0; /* No metamethod. */
}
#if LJ_HASFFI
/* The cdata metatable is treated as immutable. */
if (tref_iscdata(ix->tab)) {
cTValue *mo = lj_tab_getstr(mt, mmname_str(J2G(J), mm));
if (!mo || tvisnil(mo))
return 0; /* No metamethod. */
setfuncV(J->L, &ix->mobjv, funcV(mo));
ix->mobj = lj_ir_kfunc(J, funcV(mo)); /* Immutable metamethod. */
ix->mtv = mt;
ix->mt = TREF_NIL; /* Dummy value for comparison semantics. */
return 1; /* Got cdata metamethod. */
}
#endif
if (LJ_HASFFI && tref_iscdata(ix->tab)) goto immutable_mt;
ix->mt = mix.tab = lj_ir_ktab(J, mt);
goto nocheck;
}