学习郭总的深入了解block 记录

2021-01-01 00:00:00

lxkt

下断点到 反汇编的 block bl 跳转 地址上

(lldb) br s -a "0x00000001000060b4+0x00000000000c4000"

Breakpoint 1: where = block_hook`-[ViewController btn:] + 192 at ViewController.m:29, address = 0x00000001000ca0b4

Process 44042 stopped

* thread #1, queue = 'com.apple.main-thread', stop reason = breakpoint 1.1

    frame #0: 0x00000001000ca0b4 block_hook`-[ViewController btn:](self=0x000000013feb23a0, _cmd="btn:", sender=0x000000013feb96a0) at ViewController.m:29

   26

   27 ViewController1 *vc = [ViewController1 new];

   28

-> 29 [vc back:^(BOOL isHid, NSDictionary *dict, int age ) {

   30 self.age.text = [NSString stringWithFormat:@"%d",age];

   31 self.dict.text = dict[@"name"];

   32 self.isHid.text = [NSString stringWithFormat:@"%@",isHid?@"YES":@"NO"];

Target 0: (block_hook) stopped.

查看是否定位到断点上

(lldb) po $x0

(lldb) p (char *)$x1

(char *) $1 = 0x000000018c6d237d "back:"

(lldb) po $x1

6650930045

(lldb) po $x2

<__NSStackBlock__: 0x16fd39f58>

(lldb) memory read --size 8 --format x 0x16fd39f58

0x16fd39f58: 0x00000001a1014218 0x00000000c2000000

0x16fd39f68: 0x00000001000ca0fc 0x00000001000cc098

0x16fd39f78: 0x000000013feb23a0 0x000000013fd4f930

0x16fd39f88: 0x000000013feb96a0 0x00000001000cab8a

(lldb) disassemble --start-address 0x00000001000ca0fc

block_hook`__22-[ViewController btn:]_block_invoke:

    0x1000ca0fc <+0>:  sub    sp, sp, #0x90            ; =0x90 

    0x1000ca100 <+4>:  stp    x29, x30, [sp, #0x80]

    0x1000ca104 <+8>:  add    x29, sp, #0x80            ; =0x80 

    0x1000ca108 <+12>: sub    x8, x29, #0x18            ; =0x18 

    0x1000ca10c <+16>: mov    x9, #0x0

    0x1000ca110 <+20>: stur  x0, [x29, #-0x8]

    0x1000ca114 <+24>: mov    x10, x0

    0x1000ca118 <+28>: sturb  w1, [x29, #-0x9]

(lldb) br s -a 0x00000001000ca0fc

Breakpoint 2: where = block_hook`__22-[ViewController btn:]_block_invoke at ViewController.m:29, address = 0x00000001000ca0fc

(lldb) memory read --size 4 --format x 0x16fd39f58

0x16fd39f58: 0xa1014218 0x00000001 0xc2000000 0x00000000

0x16fd39f68: 0x000ca0fc 0x00000001 0x000cc098 0x00000001

查看是否有函数签名

(lldb) expression -- ((0xc2000000 & (1 << 30)) != 0)

(bool) $4 = true

(lldb) expression -- ((0xc2000000 & (1 << 25)) != 0)

(bool) $5 = true

(lldb) memory read --size 8 --format x 0x00000001000cc098

0x1000cc098: 0x0000000000000000 0x0000000000000028

0x1000cc0a8: 0x00000001000ca33c 0x00000001000ca388

0x1000cc0b8: 0x00000001000cb5ef 0x0000000000000100

0x1000cc0c8: 0x00000001a1016ae8 0x00000000000007c8

(lldb) p (char *)0x00000001000cb5ef

(char *) $6 = 0x00000001000cb5ef "v24@?0B8@"NSDictionary"12i20"

(lldb) po [NSMethodSignature signatureWithObjCTypes:"v24@?0B8@\"NSDictionary\"12i20"]

    number of arguments = 4

    frame size = 224

    is special struct return? NO

    return value: -------- -------- -------- --------

        type encoding (v) 'v'

        flags {}

        modifiers {}

        frame {offset = 0, offset adjust = 0, size = 0, size adjust = 0}

        memory {offset = 0, size = 0}

    argument 0: -------- -------- -------- --------

        type encoding (@) '@?'

        flags {isObject, isBlock}

        modifiers {}

        frame {offset = 0, offset adjust = 0, size = 8, size adjust = 0}

        memory {offset = 0, size = 8}

    argument 1: -------- -------- -------- --------

        type encoding (B) 'B'

        flags {}

        modifiers {}

        frame {offset = 8, offset adjust = 0, size = 8, size adjust = -7}

        memory {offset = 0, size = 1}

    argument 2: -------- -------- -------- --------

        type encoding (@) '@"NSDictionary"'

        flags {isObject}

        modifiers {}

        frame {offset = 16, offset adjust = 0, size = 8, size adjust = 0}

        memory {offset = 0, size = 8}

            class 'NSDictionary'

    argument 3: -------- -------- -------- --------

        type encoding (i) 'i'

        flags {isSigned}

        modifiers {}

        frame {offset = 24, offset adjust = 0, size = 8, size adjust = -4}

        memory {offset = 0, size = 4}

(lldb) 

还原后方法的 block 参数

- (void)back:(void(^)(bool,NSDictionary,int))arg1;