lldb根据block地址一句话获取block签名

Arm64版:

po [NSMethodSignature signatureWithObjCTypes:*((char**)(*((char**)(0x16fd96a40/*换成你的block实例地址*/ + 24))+ 32))]
# 或者
po [[NSMethodSignature signatureWithObjCTypes:*((char**)(*((char**)(blockAddress + 24))+ 32))] debugDescription]

Arm32版:

(iPhone5s以前的机型)

将上述 +24 , +32 改为 +16 , +16. 

依据

block结构体源码

struct Block_literal_1 {
    void *isa; // initialized to &_NSConcreteStackBlock or &_NSConcreteGlobalBlock
    int flags;
    int reserved;
    void (*invoke)(void *, ...);　　　　//
    struct Block_descriptor_1 {
        unsigned long int reserved;　　// NULL
        unsigned long int size;       // sizeof(struct Block_literal_1)
        // optional helper functions
        void (*copy_helper)(void *dst, void *src);     // IFF (1<<25)
        void (*dispose_helper)(void *src);             // IFF (1<<25)
        // required ABI.2010.3.16
        const char *signature;                         // IFF (1<<30)
    } *descriptor;
    // imported variables
};

 一般block都会有签名, 当然科学的方法是根据结构体中的flags来判断是否有签名

enum {
    BLOCK_HAS_COPY_DISPOSE =  (1 << 25),
    BLOCK_HAS_CTOR =          (1 << 26), // helpers have C++ code
    BLOCK_IS_GLOBAL =         (1 << 28),
    BLOCK_HAS_STRET =         (1 << 29), // IFF BLOCK_HAS_SIGNATURE
    BLOCK_HAS_SIGNATURE =     (1 << 30),
};

如果 ((flags & (1 << 30)) == (1 << 30)) 的话证明该block是带签名的.