17_常用LLDB指令

作者: 伶俐ll | 来源:发表于2020-08-19 12:53 被阅读0次

lldb指令的格式：

<command> [<subcommand> [<subcommand>...]] <action> [-options [option�value]] [argument [argument...]]

<command>：命令
[<subcommand> [<subcommand>...]]：子命令
<action>：命令操作
[-options [option�value]] ：命令选项
[argument [argument...]]：命令参数
[]：表示命令是可选的，可以有也可以没有
例如：给test函数设置断点

(lldb) breakpoint set -n test

breakpoint：命令
set：子命令
-n：命令选项
test：命令参数

常用指令

一、help

查看指令的用法，比如help breakpoin、help breakpoint set

二、Enter

敲Enter，会自动执行上次的指令

三、执行表达式

expression

执行一个表达式，并将表达式返回的结果输出,expression的完整语法是这样的：expression <cmd-options> -- <expr>

<cmd-options>:命令选项
--:命令结束符，表示所有的命令选项已经设置完毕，如果没有命令选项，--可以省略
<expr>:需要执行的表达式

假如我们在运行过程中，想把view的颜色改成红色看看效果，我们不必写下代码，重新run，只需断点调试，用expression改变颜色，再刷新一下界面，就能看到效果

(lldb) expression self.view.layer.backgroundColor = UIColor.redColor.CGColor
(CGColorRef) $0 = 0x0000600000b63540
(lldb) expression (void)[CATransaction flush]

打印对象地址

(lldb) expression self.view
(UIView *) $1 = 0x00007f7f18c085a0

打印对象

(lldb) expression -O -- self.view
<UIView: 0x7f7f18c085a0; frame = (0 0; 375 667); autoresize = W+H; layer = <CALayer: 0x600002f266e0>>

p & print & call

expression的别名，p是print的缩写

(lldb) p self.view.layer.backgroundColor = UIColor.greenColor.CGColor
(CGColorRef) $1 = 0x0000600000b64fc0
(lldb) p (void)[CATransaction flush]
(lldb) call self.view
(UIView *) $2 = 0x00007f7f18c085a0
(lldb) p self.view
(UIView *) $3 = 0x00007f7f18c085a0
(lldb) expression self.view
(UIView *) $4 = 0x00007f7f18c085a0
(lldb) call self.view
(UIView *) $5 = 0x00007f7f18c085a0
(lldb) print self.view
(UIView *) $6 = 0x00007f7f18c085a0

po

expression -O --的别名

(lldb) expression -O -- self.view
<UIView: 0x7f7f18c085a0; frame = (0 0; 375 667); autoresize = W+H; layer = <CALayer: 0x600002f266e0>>

(lldb) po self.view
<UIView: 0x7f7f18c085a0; frame = (0 0; 375 667); autoresize = W+H; layer = <CALayer: 0x600002f266e0>>

四、打印信息

thread backtrace

打印线程堆栈信息

(lldb) thread backtrace
* thread #1, queue = 'com.apple.main-thread', stop reason = breakpoint 3.1
  * frame #0: 0x00000001020b3e6d daf`-[ViewController touchesBegan:withEvent:](self=0x00007f7f18f07170, _cmd="touchesBegan:withEvent:", touches=1 element, event=0x0000600001a60d80) at ViewController.m:34:5
    frame #1: 0x00007fff48cb94e2 UIKitCore`forwardTouchMethod + 323
    frame #2: 0x00007fff48cb938e UIKitCore`-[UIResponder touchesBegan:withEvent:] + 49
    frame #3: 0x00007fff48cc82ab UIKitCore`-[UIWindow _sendTouchesForEvent:] + 622
    frame #4: 0x00007fff48cca311 UIKitCore`-[UIWindow sendEvent:] + 4501
    frame #5: 0x00007fff48ca4755 UIKitCore`-[UIApplication sendEvent:] + 356
    frame #6: 0x00007fff48d2f552 UIKitCore`__dispatchPreprocessedEventFromEventQueue + 7628
    frame #7: 0x00007fff48d32716 UIKitCore`__handleEventQueueInternal + 6584
    frame #8: 0x00007fff48d28fb9 UIKitCore`__handleHIDEventFetcherDrain + 88
    frame #9: 0x00007fff23da0d31 CoreFoundation`__CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
    frame #10: 0x00007fff23da0c5c CoreFoundation`__CFRunLoopDoSource0 + 76
    frame #11: 0x00007fff23da0434 CoreFoundation`__CFRunLoopDoSources0 + 180
    frame #12: 0x00007fff23d9b02e CoreFoundation`__CFRunLoopRun + 974
    frame #13: 0x00007fff23d9a944 CoreFoundation`CFRunLoopRunSpecific + 404
    frame #14: 0x00007fff38ba6c1a GraphicsServices`GSEventRunModal + 139
    frame #15: 0x00007fff48c8b9ec UIKitCore`UIApplicationMain + 1605
    frame #16: 0x00000001020b41a2 daf`main(argc=1, argv=0x00007ffeedb4acd0) at main.m:18:12
    frame #17: 0x00007fff51a231fd libdyld.dylib`start + 1

bt

bt是thread backtrace的别名

thread return []

让函数直接返回某个值，不会执行断点后面的代码，thread return可以接受一个表达式，调用命令之后直接从当前的frame返回表达式的值。

frame variable []

打印当前栈帧的变量，也就是当前函数的局部变量

//打印所有变量
(lldb) frame variable
(ViewController *) self = 0x00007f8ac2c088e0
(SEL) _cmd = "touchesBegan:withEvent:"
(__NSSetM *) touches = 0x0000600000429f00 1 element
(UITouchesEvent *) event = 0x0000600003144b40

//打印指定变量
(lldb) frame variable self
(ViewController *) self = 0x00007f8ac2c088e0

五、流程控制

thread continue、continue、c

表示程序继续运行

Snip20200813_16.png

thread step-over、next、n

源码级别单步运行，把子函数当做整体一步执行

Snip20200813_17.png

thread step-in、step、s

源码级别单步运行，遇到子函数会进入子函数

Snip20200813_18.png

thread step-out、finish

直接执行完当前函数的所有代码，返回到上一个函数

Snip20200813_19.png

threadstep-inst-over、nexti、ni

ni和n类似：n源码级别、ni汇编指令级别

threadstep-inst、stepi、si

si和s类似：s源码级别、si汇编指令级别

五、代码断点

breakpoint set -n 函数名

(lldb) breakpoint set -n test
Breakpoint 3: 4 locations.

(lldb) breakpoint set -n touchesBegan:withEvent:
Breakpoint 2: 90 locations.

(lldb)  breakpoint set -n "-[ViewController touchesBegan:withEvent:]"
Breakpoint 3: where = daf`-[ViewController touchesBegan:withEvent:] + 70 at ViewController.m:30:6, address = 0x0000000106d1ff06

breakpoint set -a 函数地址
breakpointset-r 正则表达式
模糊搜索

(lldb) breakpoint set -n test

breakpoint set -s 动态库 -n 函数名
breakpoint list
列出所有的断点（每个断点都有自己的编号）
breakpoint disable 断点编号
禁用断点
breakpoint enable 断点编号
启用断点
breakpoint delete 断点编号
删除断点
breakpoint command add 断点编号
给断点预先设置需要执行的命令，到触发断点时，就会按顺序执行

(lldb) breakpoint set -n "-[ViewController touchesBegan:withEvent:]"
Breakpoint 2: where = daf`-[ViewController touchesBegan:withEvent:] + 70 at ViewController.m:30:6, address = 0x000000010a6dcf06
(lldb) breakpoint command add 2
Enter your debugger command(s).  Type 'DONE' to end.
> po self
> p self
> p self.view.layer.backgroundColor = [UIColor redColor].CGColor
> DONE
(lldb) c
Process 25531 resuming
 po self
<ViewController: 0x7f87ea40a680>


 p self
(ViewController *) $1 = 0x00007f87ea40a680

 p self.view.layer.backgroundColor = [UIColor redColor].CGColor
(CGColorRef) $2 = 0x00006000007b1f20

breakpoint command list 断点编号
查看某个断点设置的命令

(lldb) breakpoint command list 2
Breakpoint 2:
    Breakpoint commands:
      po self
      p self
      p self.view.layer.backgroundColor = [UIColor redColor].CGColor

breakpoint command delete 断点编号
删除某个断点设置的命令

(lldb) breakpoint command delete 2
(lldb) breakpoint command list 2
Breakpoint 2 does not have an associated command.

六、内存断点

在内存数据发生改变的时候触发

watchpoint set variable 变量
设置断点

(lldb) watchpoint set variable self->_age
Watchpoint created: Watchpoint 1: addr = 0x7fdf1bc07150 size = 4 state = enabled type = w
    watchpoint spec = 'self->_age'
    new value: 0

watchpoint set expression 地址

(lldb) p &(self->_age)
(int *) $0 = 0x00007f8011f06ff0
(lldb) watchpoint set expression 0x00007f8011f06ff0
Watchpoint created: Watchpoint 1: addr = 0x7f8011f06ff0 size = 8 state = enabled type = w
    new value: 0
(lldb)

watchpoint list
查看断点
watchpoint disable 断点编号
禁用断点
watchpoint enable 断点编号
启用断点
watchpoint delete 断点编号
删除断点
watchpoint command add 断点编号
给断点预先设置需要执行的命令，到触发断点时，就会按顺序执行
watchpoint command list 断点编号
查看某个断点设置的命令
watchpoint command delete 断点编号
删除某个断点设置的命令

七、模块查找

image list
列出所加载的模块信息

(lldb) image list
[  0] 4EE15C85-378E-38DE-8790-6047181E3944 0x0000000100c8b000 /Users/zhanglingli/Library/Developer/Xcode/DerivedData/daf-eqaqhhwbbadyvibyktibzhhnytym/Build/Products/Debug-iphonesimulator/daf.app/daf 
[  1] E4698FBD-806A-3396-B279-E685BA37430B 0x0000000105b24000 /usr/lib/dyld 
[  2] 548289A2-DC22-3BAA-A2F6-01EADE8D86D7 0x0000000100c99000 /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/usr/lib/dyld_sim

image lookup -t 类型
查找某个类型的信息

(lldb) image lookup -t ViewController
Best match found in /Users/zhanglingli/Library/Developer/Xcode/DerivedData/daf-eqaqhhwbbadyvibyktibzhhnytym/Build/Products/Debug-iphonesimulator/daf.app/daf:
id = {0x10000002b}, name = "ViewController", byte-size = 16, decl = ViewController.h:11, compiler_type = "@interface ViewController : UIViewController{
    int _age;
}
@property(nonatomic, assign, readwrite, getter = age, setter = setAge:) int age;
@end"

(lldb) image lookup -t NSInteger
Best match found in /Users/zhanglingli/Library/Developer/Xcode/DerivedData/daf-eqaqhhwbbadyvibyktibzhhnytym/Build/Products/Debug-iphonesimulator/daf.app/daf:
id = {0x7fffffff000002e8}, name = "NSInteger", byte-size = 8, decl = NSObjCRuntime.h:12, compiler_type = "typedef NSInteger"
     typedef 'NSInteger': id = {0x7fffffff000005b5}, name = "long int", qualified = "long", byte-size = 8, compiler_type = "long"

image lookup -a 地址
根据内存地址查找在模块中的位置
例如，当我们发生一个crash

2020-08-14 10:09:09.007340+0800 daf[29312:2133141] *** Terminating app due to uncaught exception 'NSRangeException', reason: '*** -[__NSArrayI objectAtIndexedSubscript:]: index 4 beyond bounds [0 .. 2]'
*** First throw call stack:
(
    0   CoreFoundation                      0x00007fff23e3cf0e __exceptionPreprocess + 350
    1   libobjc.A.dylib                     0x00007fff50ba89b2 objc_exception_throw + 48
    2   CoreFoundation                      0x00007fff23ecfa51 _CFThrowFormattedException + 194
    3   CoreFoundation                      0x00007fff23eae9bd -[__NSArrayI objectAtIndexedSubscript:] + 93
    4   daf                                 0x000000010c4b8e16 -[ViewController touchesBegan:withEvent:] + 182
    5   UIKitCore                           0x00007fff48cb94e2 forwardTouchMethod + 323
    6   UIKitCore                           0x00007fff48cb938e -[UIResponder touchesBegan:withEvent:] + 49

我们可以看出，是由于数组越界导致的crash，并且是在ViewController的touchesBegan:withEvent:方法中调用的，那么具体在哪一行呢，我们就可以通过image lookup -a指令查看

(lldb) image lookup -a 0x000000010c4b8e16
      Address: daf[0x0000000100000e16] (daf.__TEXT.__text + 246)
      Summary: daf`-[ViewController touchesBegan:withEvent:] + 182 at ViewController.m:26:5

由此可知，crash发生在ViewController.m的第26行

image lookup -n 符号或者函数名
查找某个符号或者函数的位置

(lldb) image lookup -n touchesBegan:withEvent:
1 match found in /Users/zhanglingli/Library/Developer/Xcode/DerivedData/daf-eqaqhhwbbadyvibyktibzhhnytym/Build/Products/Debug-iphonesimulator/daf.app/daf:
        Address: daf[0x0000000100000d60] (daf.__TEXT.__text + 64)
        Summary: daf`-[ViewController touchesBegan:withEvent:] at ViewController.m:23
79 matches found in /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/UIKitCore.framework/UIKitCore:
        Address: UIKitCore[0x000000000002590c] (UIKitCore.__TEXT.__text + 142380)
        Summary: UIKitCore`-[UIInterfaceActionGroupView touchesBegan:withEvent:]        Address: UIKitCore[0x000000000002c297] (UIKitCore.__TEXT.__text + 169399)

image list -o -f
打印模块的偏移地址、全路径