[SO-a/73343830/5690248] An example of lazily named class

main.m

//
//  main.m
//  ObjCPlayground
//
//  Created by Aleksandr Medvedev on 04.08.2022.
//

#include <objc/runtime.h>
#include <stdio.h>

@import Foundation;

#pragma mark - Class Layout

struct LazyNameClassLayout {
    struct LazyNameClassLayout *isa;
    struct LazyNameClassLayout *superclass;
    void *cachePtr;
    uintptr_t zero;
    uintptr_t roSection;
};

struct LazyNameClassLayoutRO {
} LazyNameMetaclassRO;

#pragma mark - Meta Class

#pragma mark Magic Stuff from runtime
extern struct objc_cache _objc_empty_cache;
extern struct LazyNameClassLayout OBJC_METACLASS_$_NSObject;
extern struct LazyNameClassLayout OBJC_CLASS_$_NSObject;

struct LazyNameClassLayout LazyNameMetaclass = {
    .isa = &OBJC_METACLASS_$_NSObject,
    .superclass = &OBJC_METACLASS_$_NSObject,
    .cachePtr = &_objc_empty_cache,
    .roSection = (uintptr_t)&LazyNameMetaclassRO,
};

#pragma mark - Concrete Class

struct LazyNameClassLayoutRO LazyNameClassRO = {};

struct LazyNameClassLayout LazyNameClass = {
    .isa = &LazyNameMetaclass,
    .superclass = Nil,
    .cachePtr = &_objc_empty_cache,
    .roSection = (uintptr_t)&LazyNameClassRO,
};

#pragma mark - Namer

static objc_hook_lazyClassNamer OrigNamer;

static const char *ClassNamer(Class cls) {
    if (cls == (__bridge Class)(&LazyNameClass)) {
        return "Lazy Name";
    }
    return OrigNamer(cls);
}

#pragma mark - Main

int main(int argc, const char * argv[]) {
    objc_setHook_lazyClassNamer(ClassNamer, &OrigNamer);
    printf("%s\n", class_getName([(__bridge Class)&LazyNameClass class]));
    return 0;
}