机缘
以前有一阵觉得chisel真的挺好用的,后来翻看了历年的WWDC关于lldb的video 还是发现一些tips
Tip
lldb 统一格式
<noun> <verb> [options] [argument [argument ...]]
lldb 命令行都遵循上述格式,例如:
target create /bin/ls
breakpoint set —-name malloc
process attach --pid 1234
breakpoint set --file hello.c --line 100
breakpoint modify —condition “self = $myModel"
lldb简写
help
-> h
expression -O --
-> po
expression --
-> p
thread until 11
-> th u 11
breakpoint modify —condition "self = $myModel"
-> br m -c “self == $myModel"
lldb command alias
lldb 启动都会加载 ~/.lldbinit
,故而我们可以通过修改它来实现自己的增强
例如command alias
,常见的例子,譬如耳熟能详的Reveal
能通过下列命令启动
command alias reveal_load_sim expr (void*)dlopen("/Applications/Reveal.app/Contents/SharedSupport/iOS-Libraries/libReveal.dylib", 0x2);
我自己扩展了这个别名pwv
:
command alias pwv expr (void)NSLog((NSString*)[[[UIApplication sharedApplication] keyWindow] recursiveDescription])
该命令可以打印keyWindow上的view的层级结构。
command regex
同样放在~/.lldbinit
,跟alias类似,不过可以带参数,使用正则。
command regex pv 's/(.+)/expr (void)NSLog((NSString*)[(UIView*)%1 recursiveDescription])/'
command regex postNoti 's/(.+)/expr (void)[[NSNotificationCenter defaultCenter] postNotificationName:%1 object:nil]/'
命令pv %1
用来打印%1
上的所有view的层级结构。
命令postNoti %1
用来post 一个notication如:
(lldb) postNoti @"MyNotification"
根据日常开发的需要,alias
和regex
都可以用来当做打开/关闭某些扩展功能,如第三方的调试工具:
打开/关闭FLEX
command alias flex expr [[FLEXManager sharedManager] toggleExplorer]
regex
我用得也比较简单,基本跟alias差不多。相信还会有更geek的用法。
command script
chisel就是用下列命令初始化的:
command script import /path/to/fblldb.py
simple example
myCommands.py
def caflushCommand(debugger, command, result, internal_dict):
debugger.HandleCommand("e (void)[CATransaction flush]")
command script import ~/myCommands.py
lldb关于python的接口我看得也不细,具体参见wwdc和lldb。chisel的github上也有讲。
流程控制
下列命令其意不言自明,日常其实不一定能用到,但thread return
在debug时还是相当有用的,调试时发现某些bug,当重现步骤又太麻烦,不想修改代码后重新编译,可以在某些critical method中进行fake return。
process continue
continue
c
thread step-over
next
n
thread step-in
step
s
thread step-out
finish
thread return
thread return
thread return NO
thread return @"hi"
Examining Data
fr
ame v
ariable
(lldb) fr v self
(MyProject.ViewController) self = 0x00007fd63c221fa0 {
UIKit.UIViewController = {
UIResponder = {
NSObject = {
isa = YourProject.ViewController
}
_hasAlternateNextResponder = false
_hasInputAssistantItem = false
}
_overrideTransitioningDelegate = nil
以下省略
其他拾遗
寄存器相关
(lldb) register read
General Purpose Registers:
rax = 0x0000000010004005
rbx = 0x00000000ffffffff
rcx = 0x00007fff5559b718
rdx = 0x0000000000000000
rdi = 0x00007fff5559b880
rsi = 0x0000000007000806
rbp = 0x00007fff5559b760
rsp = 0x00007fff5559b718
r8 = 0x0000000000001403
r9 = 0x00000000ffffffff
r10 = 0x0000000000000c00
r11 = 0x0000000000000206
r12 = 0x0000000000000c00
r13 = 0x0000000000000000
r14 = 0x00007fff5559b880
r15 = 0x0000000000001403
rip = 0x000000010e151386 libsystem_kernel.dylib`mach_msg_trap + 10
rflags = 0x0000000000000206
cs = 0x000000000000002b
fs = 0x0000000000000000
gs = 0x0000000000000000
platform shell
在lldb中执行shell命令,如
(lldb)platform shell ls
objective-c set exception 断点
(lldb) br s -E objc
查看类型
(lldb) type lookup ErrorType
protocol ErrorType {
var _domain: Swift.String { get }
var _code: Swift.Int { get }
}
extension ErrorType {
var _domain: Swift.String {
get {}
}
}
其他
wwdc上有说修好了lldb的一些known issue,比如
(lldb) p NSLog(@“%d”, i)
error: 'NSLog' has unknown return type;
cast the call to its declared return type
error: 1 errors parsing expression
(lldb) p [NSApplication sharedApplication].undoManager error: property ‘undoManager’ not found on object of type ‘id’
error: 1 errors parsing expression
这些问题都修好了。
总结
其他的以后再补充。
有些东西其实对于大多数开发者用处不大,大家随便看看。
原作写于segmentfault 链接