美文网首页
LLDB指令

LLDB指令

作者: fanglaoda | 来源:发表于2018-11-22 21:58 被阅读0次

    平时开发的过程中使用Xcode都是图形化操作习惯了,要是脱离了xcode你还能调试代码吗,恩,Xcode已经把我们惯坏了,不管怎样,作为一个开发对于了解图形操作背后的东西应该要了解。

    申明:本文的[]都表示命令简写

    一、增加方法断点

    • breakpoint set --name[-n] "方法名称"
    • breakpoint set --address[-a] 方法的内存地址
    15428751580151.jpg

    上面4个都是等价的,通过breakpoint list查看已经添加的断点

    • 模糊设置断点 breakpoint set -r 方法名称,r 是正则的意思

      (lldb) breakpoint set -r foo
      Breakpoint 2: 136 locations.
      

      发现有136个地方包含了foo字符串的方法,通过breakpoint list查看可以知道在哪里有这个方法,输出太多这边就截取一部分。

      (lldb) breakpoint list
      Current breakpoints:
      1: file = '/Users/fangshufeng/Desktop/thirdPart/image/Image/Image/ViewController.m', line = 24, exact_match = 0, locations = 1, resolved = 1, hit count = 2
      
        1.1: where = Image`-[ViewController touchesBegan:withEvent:] + 77 at ViewController.m:24, address = 0x000000010a4f768d, resolved, hit count = 2 
      
      2: regex = 'foo', locations = 136, resolved = 136, hit count = 2
        2.1: where = Image`-[ViewController foo] + 23 at ViewController.m:30, address = 0x000000010a4f76f7, resolved, hit count = 2 
        2.2: where = libbsm.0.dylib`au_print_xml_footer, address = 0x000000010ce5d665, resolved, hit count = 0 
        2.3: where = libsystem_kernel.dylib`proc_reset_footprint_interval, address = 0x000000010d5254ed, resolved, hit count = 0 
        
       [...]
        
      
    • 开关断点

      • breakpoint disable 断点编号(让某个断点不可用但是不是删除)
      • breakpoint enable 断点编号(让断点由不可用到可用)
      • breakpoint delete 断点编号 (删除断点不可恢复,需重新添加,不加编号则让你选择是否全部删除)
    15428758913025.jpg

    二、线程断点

    源码调试

    这个平时用的最多了,看下图

    • thread continue [continue] [c ] : 程序继续
    • thread step-over [next] [n] : 单步运⾏,把子函数当做整体⼀一步执行
    • thread step-in [step] [s] : 单步运⾏,遇到子函数会进入⼦函数
    • thread step-out [finish] : 直接执行完函数,返回函数调用处

    太常用不贴代码了

    15428763316698.jpg
    • thread backtrace [bt]:查看调用栈回溯
    15428766389548.jpg

    如图有时想查看代码的调用堆栈,但是xcode无法查看全,左边的地方只能看到部分,当然你可以点击这个地方,去查看。

    15428767683217.jpg

    也可以通过命令thread backtrace或者bt

    15428770034517.jpg

    frame为栈帧的意思,想了解函数栈帧的点击此处

    • frame variable :查看函数栈帧内的局部变量的值
    (lldb) frame variable
    (ViewController *) self = 0x00007fe390a04960
    (SEL) _cmd = "touchesBegan:withEvent:"
    (__NSSetM *) touches = 0x0000600003d30640 1 element
    (UITouchesEvent *) event = 0x0000600000f66250
    (int) a = 10
    
    

    我们知道oc的方法内置了self_cmd参数,所以上面有self_cmd

    汇编代码调试

    开启汇编模式

    15428781223072.jpg

    和源码的区别是

    • ni : 单步运⾏,把子函数当做整体⼀一步执行
    • si: 单步运⾏,遇到子函数会进入⼦函数

    三、内存断点

    有时候想看某个内存发生改变的时候触发断点

    • watchpoint set variable 变量
    • watchpoint set variable 地址

    我们给vc增加一个属性bar

    - (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
        NSLog(@"fff");
        [self foo];
      
    }
    
    
    - (void)foo {
        NSLog(@"--foo--");
        NSLog(@"--foo2--");
        NSLog(@"--foo3--");
        
        for ( int i = 0; i < 3; i++) {
            self.bar += 10;
        }
    }
    
    

    通过该命令,每当内存地址内容被修改都会断到

    15428798696567.jpg

    还可以配合watchpoint command使用

    • watchpoint command add 断点编号:当内存断点触发的时候执行一些操作

    每次改变都会输出值。


    15428800472134.jpg
     watchpoint command add 1 // 1 表示 watchpoint 断点编号
    Enter your debugger command(s).  Type 'DONE' to end.
    > p self.bar;
    > DONE // DONE 表示命令输入结束
    
    

    相关指令如下,见名知意了不需要作介绍了

    • watchpoint list
    • watchpoint disable 断点编号
    • watchpoint enable 断点编号
    • watchpoint delete 断点编号
    • watchpoint command list 断点编号
    • watchpoint command delete 断点编号

    四、不常用但很实用的指令

    场景1:

    15428794369809.jpg

    要想代码执行到31行的断点的时候直接返回,不想执行后面的代码,就可以通过thread return指令,当代码执行到31行断点时,thread return可以实现。

    场景2:有时崩溃了直接到main函数了,无法知道崩溃的地方

    都知道下面的代码会崩溃

    15428804652206.jpg

    此时崩溃在下面的main函数处

    15428805038949.jpg

    终端输出信息

    15428805244685.jpg

    并不知道函数崩溃在哪一行可以使用image lookup指令

    (lldb) image lookup -a 0x00000001022365db
          Address: Image[0x00000001000015db] (Image.__TEXT.__text + 203)
          Summary: Image`-[ViewController touchesBegan:withEvent:] + 139 at ViewController.m:30
          
    

    发现崩溃在ViewControllertouchesBegan:withEvent:在30行处。

    image lookup周边

    • image lookup -t 类:查看类的属性
    (lldb) image lookup -t UIView
    Best match found in /Users/fangshufeng/Library/Developer/Xcode/DerivedData/Image-cncplmezlusnyackyzpyppykazhf/Build/Products/Debug-iphonesimulator/Image.app/Image:
    id = {0x00001063}, name = "UIView", byte-size = 8, decl = UIView.h:143, compiler_type = "@interface UIView : UIResponder
    @property ( readonly,getter = layerClass,setter = <null selector>,nonatomic,class ) Class layerClass;
    @property ( getter = isUserInteractionEnabled,setter = setUserInteractionEnabled:,assign,readwrite,nonatomic ) BOOL userInteractionEnabled;
    @property ( getter = tag,setter = setTag:,assign,readwrite,nonatomic ) NSInteger tag;
    @property ( readonly,getter = layer,setter = <null selector>,nonatomic ) CALayer * layer;
    @property ( readonly,getter = canBecomeFocused,setter = <null selector>,nonatomic ) BOOL canBecomeFocused;
    @property ( readonly,getter = isFocused,setter = <null selector>,nonatomic ) BOOL focused;
    @property ( getter = semanticContentAttribute,setter = setSemanticContentAttribute:,assign,readwrite,nonatomic ) UISemanticContentAttribute semanticContentAttribute;
    @property ( readonly,getter = effectiveUserInterfaceLayoutDirection,setter = <null selector>,nonatomic ) UIUserInterfaceLayoutDirection effectiveUserInterfaceLayoutDirection;
    @end"
    
    • image lookup -n 方法名称:查看方法的位置
    (lldb) image lookup -n foo
    1 match found in /Users/fangshufeng/Library/Developer/Xcode/DerivedData/Image-cncplmezlusnyackyzpyppykazhf/Build/Products/Debug-iphonesimulator/Image.app/Image:
            Address: Image[0x0000000100001660] (Image.__TEXT.__text + 224)
            Summary: Image`-[ViewController foo] at ViewController.m:33
            
    
    • image lookup -o -f :可以查看内存的偏移量,这个再逆向中很常用

    还有一些常见的指令比如ppoexpression就不说了。

    相关文章

      网友评论

          本文标题:LLDB指令

          本文链接:https://www.haomeiwen.com/subject/xdfnfqtx.html