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前言：LLDB是个开源的调试器，与XCode绑定的
LLDB的使用中，Swift与Objective C还是有一些差别的
本文主要侧重LLDB的常用命令
资料（目前状态XCode 7.2 Swift 2.1.1），非XCode 7.2+本文代码可能不能运行
- objc.io(强烈建议有Objective C经验，但是对LLDB不熟悉的深入研究下)
- Apple官方文档
- LLDB的文档
- 一个封装LLDB的库，可以辅助调试
- 2015 WWDC视频
对了，Swift到现在也不过一岁半，所以LLDB对于Swift的支持肯定不如OC那么好。
如何打开LLDB如何使用？
通常的方式就是断点，另外，关于利用XCode图形化调试，在我这篇文章里有详细讲解
本文适合XCode 7.2 ＋
不管是在程序中加断点
还是手动的暂停程序
让代码停在Swift Error 或者Objective C异常
停在Objective C异常
(lldb) br s -E objc
Breakpoint 6: where = libobjc.A.dylib`objc_exception_throw,address = 0x000000010dededbb
停在Swift Error
(lldb) br s -E swift
Breakpoint 7: where = libswiftCore.dylib`swift_willThrow,address = 0x000000010e55ccc0
停在某一种类型的Swift Error
(lldb) br s -E swift -O EnumError
Breakpoint 8: where = libswiftCore.dylib`swift_willThrow,address = 0x000000010e55ccc0
以此作为开端，希望读者能耐心看完，本文很长
准备工作
为了方便，我们先写好这样的一个Model类,定义个ErrorType，并且定义个实例方法抛出异常
enum CustomError:ErrorType{
case LeoError1
case LeoError2
}
class Person:NSObject{
var name:String
var age:UInt32
init(name:String,age:UInt32){
self.name = name
self.age = age
}
//重写description是为了方便调试
override var description:String{
return "name:\(name) age:\(age)"
}
func PersonException() throws{
throw CustomError.LeoError1
}
}
然后在viewDidLoad中初始化一个对象，并打一个断点
let person = Person(name: "Leo",age: 23)
打印命令 p/po
p
(lldb) p person
(SwiftLLDBDemo.Person) $R0 = 0x00007f99b8d30b40 {
ObjectiveC.NSObject = {
isa = SwiftLLDBDemo.Person
}
name = "Leo"
age = 23
}
po
(lldb) po person
name:Leo age:23
p命令会打印出对象的类型，如果是Objective C对象，会打印出isa，以及属性的值
po 命令 对于继承自NSObject得对象，指示会打印出description中的内容
再举个例子
(lldb) po ["123","345"]
▿ 2 elements
- [0] : "123"
- [1] : "345"
(lldb) p ["123","345"]
([String]) $R2 = 2 values {
[0] = "123"
[1] = "345"
}
也可以，调用一段代码
(lldb) p for i in 1...3{ print(i) }
1
2
3
执行代码 e
expression命令可以帮助我们执行代码，
(lldb) e person.name = "Jack"
(lldb) p person
(SwiftLLDBDemo.Person) $R1 = 0x00007f9bf1424c20 {
ObjectiveC.NSObject = {
isa = SwiftLLDBDemo.Person
}
name = "Jack"
age = 23
}
在这我们深入的研究所有命令
(lldb) help
内容太多，不拷贝进来了，自己在XCode里敲敲试试吧。
可以看到，有一部分是alias部分，有linux经验的同学应该知道，alias就是将一个简单的命令设置为复杂命令的别名。我们上面讲到的两个命令p/po就是两个alias命令
p -- ('expression --') Evaluate an expression (ObjC++ or Swift) in
the current program context,using user defined variables and
variables currently in scope.
po -- ('expression -O -- ') Evaluate an expression (ObjC++ or Swift)
in the current program context,using user defined variables and
variables currently in scope.
所以，p命令，本质是expression -- ；po命令，本质是expression -O --
(lldb) expression -- person
(SwiftLLDBDemo.Person) $R0 = 0x00007f96a3f792d0 {
ObjectiveC.NSObject = {
isa = SwiftLLDBDemo.Person
}
name = "Leo"
age = 23
}
(lldb) expression -O -- person
name:Leo age:23
更加复杂的执行
例如，动态的修改view的背景色
e self.view.backgroundColor = UIColor.blueColor
Expression命令很灵活
格式化打印 -f (format)
(lldb) expr -f bin -- person.age
(UInt32) $R2 = 0b00000000000000000000000000010111
(lldb) expr -f oct -- person.age
(UInt32) $R3 = 027
(lldb) expr -f hex -- person.age
(UInt32) $R4 = 0x00000017
格式化打印可以更简单
(lldb) p/x person.age
(UInt32) $R5 = 0x00000017
打印Raw value expr -R -- 变量
(lldb) expr -R -- person
(SwiftLLDBDemo.Person) $R6 = 0x00007f96a3f792d0 { ObjectiveC.NSObject = {}
name = { _core = { _baseAddress = { _rawValue = 0x0000000101041298 "Leo" }
_countAndFlags = { value = 3 }
_owner = None { Some = { instance_type = 0x0000000000000000 }
}
}
}
age = { value = 23 }
}
显示变量类型expr -T -- 变量
(lldb) expr -T -- person
(SwiftLLDBDemo.Person) $R7 = 0x00007f96a3f792d0 {
(NSObject) ObjectiveC.NSObject = {
(Class) isa = SwiftLLDBDemo.Person
}
(String) name = "Leo"
(UInt32) age = 23
}
当然也可以结合多个使用expr -RRT -- person
帮助命令，可以再深入看看其他执行选项，不过不是很常用
help expression
LLDB变量
LLDB的变量和脚本语言类似，以美元符号开头，使用的时候也要带着美元符号，调用的时候和Swift的语法一致
例如
(lldb) e var $a = 10
(lldb) p $a
(Int) $a = 10
(lldb) e var $b = Person(name: "Jack",age: 25)
(lldb) p $b
(SWTest.Person) $b = 0x00007f8909539080 {
ObjectiveC.NSObject = {
isa = SWTest.Person
}
name = "Jack"
age = 25
}
断点
断点采用这个命令breakpoint，缩写br
断点命令的文档较少，这里先列出文档
(lldb) help breakpoint
The following subcommands are supported:
clear -- Clears a breakpoint or set of breakpoints in the executable.
command -- A set of commands for adding,removing and examining bits of
code to be executed when the breakpoint is hit (breakpoint
'commands').
delete -- Delete the specified breakpoint(s). If no breakpoints are specified,delete them all. disable -- disable the specified breakpoint(s) without removing them. If none are specified,disable all breakpoints. enable -- Enable the specified disabled breakpoint(s). If no breakpoints are specified,enable all of them. list -- List some or all breakpoints at configurable levels of detail. modify -- Modify the options on a breakpoint or set of breakpoints in the executable. If no breakpoint is specified,acts on the last created breakpoint. With the exception of -e,-d and -i,passing an empty argument clears the modification. name -- A set of commands to manage name tags for breakpoints set -- Sets a breakpoint or set of breakpoints in the executable.
breakpoint set -E languagebreakpoint s -E swift -O ErrorType
列出断点
(lldb) br li
Current breakpoints:
1: file = '/Users/huangwenchen/Desktop/SWTest/SWTest/ViewController.swift',line = 27,locations = 1,resolved = 1,hit count = 1
1.1: where = SWTest`SWTest.ViewController.viewDidLoad (SWTest.ViewController)() -> () + 75 at ViewController.swift:27,address = 0x000000010ef8556b,resolved,hit count = 1
禁用断点
(lldb) br dis 1
1 breakpoints disabled.
删除断点
(lldb) br del 1
1 breakpoints deleted; 0 breakpoint locations disabled.
(lldb) br li
No breakpoints currently set.
添加断点
(lldb) br set -f ViewController.swift -l 28
Breakpoint 2: where = SWTest`SWTest.ViewController.viewDidLoad (SWTest.ViewController)() -> () + 139 at ViewController.swift:29,address = 0x000000010ef855ab
也可以简写为
(lldb) b ViewController.swift:28
Breakpoint 3: where = SWTest`SWTest.ViewController.viewDidLoad (SWTest.ViewController)() -> () + 139 at ViewController.swift:29,address = 0x000000010ef855ab
(lldb) br li
Current breakpoints:
2: file = 'ViewController.swift',line = 28,hit count = 0
2.1: where = SWTest`SWTest.ViewController.viewDidLoad (SWTest.ViewController)() -> () + 139 at ViewController.swift:29,address = 0x000000010ef855ab,hit count = 0
3: file = 'ViewController.swift',hit count = 0
3.1: where = SWTest`SWTest.ViewController.viewDidLoad (SWTest.ViewController)() -> () + 139 at ViewController.swift:29,hit count = 0
断点Name
断点名称是用来管理一组断点的，通过name可以启用或者禁用一组断点，一个断点可以有多个name，很像tag。
br set -f ViewController.swift -l 28 -N leo
(lldb) br set -f ViewController.swift -l 28 -N leo
Breakpoint 2: 3 locations.
(lldb) br li
Current breakpoints:
1: file = '/Users/huangwenchen/Desktop/SWTest/SWTest/ViewController.swift',line = 34,hit count = 1
1.1: where = SWTest`SWTest.ViewController.viewDidLoad (SWTest.ViewController)() -> () + 75 at ViewController.swift:34,address = 0x00000001070d51fb,hit count = 1
2: file = 'ViewController.swift',locations = 3,resolved = 3,hit count = 0
Names:
leo
2.1: where = SWTest`SWTest.ViewController.__deallocating_deinit + 12 at ViewController.swift,address = 0x00000001070d538c,hit count = 0
2.2: where = SWTest`SWTest.ViewController.init (SWTest.ViewController.Type)(nibName : Swift.Optional<Swift.String>,bundle : Swift.Optional<__ObjC.NSBundle>) -> SWTest.ViewController + 57 at ViewController.swift,address = 0x00000001070d53f9,hit count = 0
2.3: where = SWTest`SWTest.ViewController.init (SWTest.ViewController.Type)(coder : __ObjC.NSCoder) -> Swift.Optional<SWTest.ViewController> + 16 at ViewController.swift,address = 0x00000001070d56d0,hit count = 0
在加上名字以后，我们就可以通过名字来操作断点了
(lldb) br disable -N leo
1 breakpoints disabled.
在某一个函数上加断点
例如，在准备Person的函数中personLoop添加断点
(lldb) br s -F personLoop
Breakpoint 2: 2 locations.
(lldb) br li
Current breakpoints:
1: file = '/Users/huangwenchen/Desktop/SWTest/SWTest/ViewController.swift',line = 40,hit count = 1
1.1: where = SWTest`SWTest.ViewController.viewDidLoad (SWTest.ViewController)() -> () + 75 at ViewController.swift:40,address = 0x000000010f6d51bb,hit count = 1
2: name = 'personLoop',locations = 2,resolved = 2,hit count = 0
2.1: where = SWTest`SWTest.Person.personLoop (SWTest.Person)() -> () + 12 at ViewController.swift:25,address = 0x000000010f6d45cc,hit count = 0
2.2: where = SWTest`@objc SWTest.Person.personLoop (SWTest.Person)() -> () + 4 at ViewController.swift,address = 0x000000010f6d4664,hit count = 0
条件断点
先在这里加一个断点
当某种条件产生的时候触发的断点，例如停在1000次循环的第800次
然后添加条件，停在i == 80
(lldb) br li
Current breakpoints:
1: file = '/Users/huangwenchen/Desktop/SWTest/SWTest/ViewController.swift',address = 0x00000001094d81bb,hit count = 1
2: file = '/Users/huangwenchen/Desktop/SWTest/SWTest/ViewController.swift',hit count = 1
2.1: where = SWTest`SWTest.Person.personLoop (SWTest.Person)() -> () + 111 at ViewController.swift:27,address = 0x00000001094d762f,hit count = 1
(lldb) br modify -c 'i == 80'
(lldb) po i
80
断点行为
当断点触发的时候，执行的LLDB代码
例如，当i==80的时候，输出sum
(lldb) br li
Current breakpoints:
1: file = '/Users/huangwenchen/Desktop/SWTest/SWTest/ViewController.swift',line = 40,hit count = 1
1.1: where = SWTest`SWTest.ViewController.viewDidLoad (SWTest.ViewController)() -> () + 75 at ViewController.swift:40,address = 0x00000001057391bb,hit count = 1
3: file = '/Users/huangwenchen/Desktop/SWTest/SWTest/ViewController.swift',line = 27,hit count = 0
3.1: where = SWTest`SWTest.Person.personLoop (SWTest.Person)() -> () + 111 at ViewController.swift:27,address = 0x000000010573862f,hit count = 0
(lldb) br modify -c 'i == 80' 3
(lldb) br command add 3
Enter your debugger command(s). Type 'DONE' to end.
> po sum
> DONE
po sum
3160
其他断点相关
lldb中输入
(lldb) help br set
篇幅限制，不列出help的结果了
类型查找Type
抛出一个异常，不知道是啥的时候怎么办？
(lldb) type lookup CustomError
enum CustomError : ErrorType {
case LeoError1
case LeoError2
var hashValue: Swift.Int {
get {}
}
var _code: Swift.Int {
get {}
}
}
可以简写
(lldb) ty l CustomError
enum CustomError : ErrorType {
case LeoError1
case LeoError2
var hashValue: Swift.Int {
get {}
}
var _code: Swift.Int {
get {}
}
}
LLDB中的异常处理
执行一个抛出异常的方法
(lldb) e person.personException()
(SWTest.CustomError) $E0 = LeoError1
流程控制
frame info 查看当前所在的位置
(lldb) frame info
frame #0: 0x000000010573862f SWTest`SWTest.Person.personLoop (self=0x00007fbaf1d054d0)() -> () + 111 at ViewController.swift:27
- c 继续运行
- n next 下一行
- s step in
- finish step out
函数提前返回
thread return
通过这个命令，可以很好的隔离函数，通常用在函数的最开始位置，避免ARC引用计数问题
最后
欢饮关注我的CSDN博客，很长一段时间内，我会持续的更新iOS/Swift/Objective C相关的文章
LLDB调试的文章应该还有一篇进阶使用的，近期会更新