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fast track for 'settable'

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This commit is contained in:
Roberto Ierusalimschy
2015-08-03 16:50:49 -03:00
parent 20b9e59441
commit 3b795541c4
3 changed files with 67 additions and 39 deletions
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33
lvm.c
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@@ -1,5 +1,5 @@
/*
** $Id: lvm.c,v 2.247 2015/07/04 16:31:03 roberto Exp roberto $
** $Id: lvm.c,v 2.248 2015/07/20 18:24:50 roberto Exp roberto $
** Lua virtual machine
** See Copyright Notice in lua.h
*/
@@ -184,40 +184,43 @@ void luaV_finishget (lua_State *L, const TValue *t, TValue *key, StkId val,
** Main function for table assignment (invoking metamethods if needed).
** Compute 't[key] = val'
*/
void luaV_settable (lua_State *L, const TValue *t, TValue *key, StkId val) {
void luaV_finishset (lua_State *L, const TValue *t, TValue *key,
StkId val, const TValue *oldval) {
int loop; /* counter to avoid infinite loops */
for (loop = 0; loop < MAXTAGLOOP; loop++) {
const TValue *tm;
if (ttistable(t)) { /* 't' is a table? */
Table *h = hvalue(t);
TValue *oldval = cast(TValue *, luaH_get(h, key));
/* if previous value is not nil, there must be a previous entry
in the table; a metamethod has no relevance */
if (!ttisnil(oldval) ||
/* previous value is nil; must check the metamethod */
((tm = fasttm(L, h->metatable, TM_NEWINDEX)) == NULL &&
if (oldval != NULL) {
lua_assert(ttistable(t) && ttisnil(oldval));
/* must check the metamethod */
if ((tm = fasttm(L, hvalue(t)->metatable, TM_NEWINDEX)) == NULL &&
/* no metamethod; is there a previous entry in the table? */
(oldval != luaO_nilobject ||
/* no previous entry; must create one. (The next test is
always true; we only need the assignment.) */
(oldval = luaH_newkey(L, h, key), 1)))) {
(oldval = luaH_newkey(L, hvalue(t), key), 1))) {
/* no metamethod and (now) there is an entry with given key */
setobj2t(L, oldval, val); /* assign new value to that entry */
invalidateTMcache(h);
luaC_barrierback(L, h, val);
setobj2t(L, cast(TValue *, oldval), val);
invalidateTMcache(hvalue(t));
luaC_barrierback(L, hvalue(t), val);
return;
}
/* else will try the metamethod */
}
else /* not a table; check 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, oldval, luaH_get, val)) {
setobj2t(L, cast(TValue *, oldval), val);
return;
}
/* else loop */
}
luaG_runerror(L, "settable chain too long; possible loop");
}