Fix taking address out of bounds of stack'd array, introduced in r3983.

Clang's UBSan reports this as undefined behavior. I think that the reason
is as follows: C99 6.5.3.2#1 (Constraints) says:

 The operand of the unary & operator shall be either a function designator, the
 result of a [] or unary * operator, or an lvalue that designates an object that
 is not a bit-field and is not declared with the register storage-class specifier.

But in case of an expression like "&array[-1]", the operand ("array[-1]") does
not designate a valid object.

Moral: check first -- assure that an expression is valid for a particular
operation before carrying it out. Keep in mind that otherwise, the compiler
is absolutely free to optimize out the *check*.

git-svn-id: https://svn.eduke32.com/eduke32@4014 1a8010ca-5511-0410-912e-c29ae57300e0
This commit is contained in:
helixhorned 2013-08-12 15:18:18 +00:00
parent 2aa55e5900
commit 4b44063853

View file

@ -4270,11 +4270,13 @@ static void G_OROR_DupeSprites(void)
// dupe the sprites touching the portal to the other sector
// viewing from bottom
int32_t k;
spritetype *sp = &sprite[ror_sprite];
spritetype *sp;
if ((unsigned) ror_sprite >= MAXSPRITES || drawing_ror != 1)
return;
sp = &sprite[ror_sprite];
for (k = headspritesect[sp->sectnum]; k != -1; k = nextspritesect[k])
{
if (sprite[k].picnum != SECTOREFFECTOR && (sprite[k].z >= sp->z))