cleaner and more correct code for 'luaD_shrinkstack' (the old

test "inuse <= LUAI_MAXSTACK" for stack overflow is not correct,
as the real maximum usable size is "LUAI_MAXSTACK - EXTRA_STACK")
This commit is contained in:
Roberto Ierusalimschy
2016-09-08 13:36:26 -03:00
parent dbb6f11e8e
commit 7fe1a4cff3

13
ldo.c
View File

@@ -221,14 +221,17 @@ static int stackinuse (lua_State *L) {
void luaD_shrinkstack (lua_State *L) { void luaD_shrinkstack (lua_State *L) {
int inuse = stackinuse(L); int inuse = stackinuse(L);
int goodsize = inuse + (inuse / 8) + 2*EXTRA_STACK; int goodsize = inuse + (inuse / 8) + 2*EXTRA_STACK;
if (goodsize > LUAI_MAXSTACK) goodsize = LUAI_MAXSTACK; if (goodsize > LUAI_MAXSTACK)
if (L->stacksize > LUAI_MAXSTACK) /* was handling stack overflow? */ goodsize = LUAI_MAXSTACK; /* respect stack limit */
if (L->stacksize > LUAI_MAXSTACK) /* had been handling stack overflow? */
luaE_freeCI(L); /* free all CIs (list grew because of an error) */ luaE_freeCI(L); /* free all CIs (list grew because of an error) */
else else
luaE_shrinkCI(L); /* shrink list */ luaE_shrinkCI(L); /* shrink list */
if (inuse <= LUAI_MAXSTACK && /* not handling stack overflow? */ /* if thread is currently not handling a stack overflow and its
goodsize < L->stacksize) /* trying to shrink? */ good size is smaller than current size, shrink its stack */
luaD_reallocstack(L, goodsize); /* shrink it */ if (inuse <= (LUAI_MAXSTACK - EXTRA_STACK) &&
goodsize < L->stacksize)
luaD_reallocstack(L, goodsize);
else else
condmovestack(L,,); /* don't change stack (change only for debugging) */ condmovestack(L,,); /* don't change stack (change only for debugging) */
} }