1
+ (id)alloc {
2
    return _objc_rootAlloc(self);
3
}
4

5
id _objc_rootAlloc(Class cls)
6
{
7
    return callAlloc(cls, false/*checkNil*/, true/*allocWithZone*/);
8
}
9

10
static ALWAYS_INLINE id
11
callAlloc(Class cls, bool checkNil, bool allocWithZone=false)
12
{
13
    if (slowpath(checkNil && !cls)) return nil;
14

15
#if __OBJC2__
16
    if (fastpath(!cls->ISA()->hasCustomAWZ())) {
17
        if (fastpath(cls->canAllocFast())) {
18
            // No ctors, raw isa, etc. Go straight to the metal.
19
            bool dtor = cls->hasCxxDtor();
20
            id obj = (id)calloc(1, cls->bits.fastInstanceSize());
21
            if (slowpath(!obj)) return callBadAllocHandler(cls);
22
            obj->initInstanceIsa(cls, dtor);
23
            return obj;
24
        }
25
        else {
26
            // Has ctor or raw isa or something. Use the slower path.
27
            id obj = class_createInstance(cls, 0);
28
            if (slowpath(!obj)) return callBadAllocHandler(cls);
29
            return obj;
30
        }
31
    }
32
#endif
33

34
    // No shortcuts available.
35
    if (allocWithZone) return [cls allocWithZone:nil];
36
    return [cls alloc];
37
}

1
- (id)init {
2
    return _objc_rootInit(self);
3
}
4

5
id _objc_rootInit(id obj)
6
{
7
    // In practice, it will be hard to rely on this function.
8
    // Many classes do not properly chain -init calls.
9
    return obj;
10
}

1
+ (id)new {
2
    return [callAlloc(self, false/*checkNil*/) init];
3
}