[Question] 为什么SetPointer需要把指针拆成高4位和低4位

[BlurryLight]

    //替代 Object->SetAlignedPointerInInternalField(Index, Ptr);
    FORCEINLINE static void SetPointer(v8::Isolate* Isolate, v8::Local<v8::Object> Object, const void* Ptr, int Index)
    {
        // Object->SetInternalField(Index, v8::External::New(Isolate, Ptr));
        // Object->SetAlignedPointerInInternalField(Index, Ptr);
        UPTRINT High;
        UPTRINT Low;
        SplitAddressToHighPartOfTwo(Ptr, High, Low);
        Object->SetAlignedPointerInInternalField(Index * 2, reinterpret_cast<void*>(High));
        Object->SetAlignedPointerInInternalField(Index * 2 + 1, reinterpret_cast<void*>(Low));
    }

比如参考下v8pp是直接把指针注册进去

https://github.com/pmed/v8pp/blob/fa7f72afba0674322d0448fb55a28fd16caa1958/v8pp/class.ipp#L207

	if (class_function_template()->GetFunction(context).ToLocal(&func)
		&& func->NewInstance(context).ToLocal(&obj))
	{
		obj->SetAlignedPointerInInternalField(0, Traits::pointer_id(object));
		obj->SetAlignedPointerInInternalField(1, this);

[chexiongsheng]

AlignedPointer要求字节对齐，低一位还是两位必须为0。
class/struct是可以设置0字节对齐的，它的field的地址可能不字节对齐。
不知道为啥v8pp发布那么久连这点都没遇到过？而且我拆了性能还远比它高：https://zhuanlan.zhihu.com/p/649362608