理论文章
crash分析攻略：https://mp.weixin.qq.com/s/hVj-j61Br3dox37SN79fDQ
常见崩溃原因分析
分享一些常见的崩溃原因
总览
可以通过Exception Information和Backtrace迅速判断出大致崩溃原因。
有些常见的崩溃都有额外的诊断信息，这些信息能够帮助我们进一步排查出问题。
Swift Runtime Error
Swift通过内存安全技术来提前捕获代码问题。Swift Runtime Error会有比较鲜明的特征
Exception Type: EXC_BREAKPOINT (SIGTRAP)
...
Termination Signal: Trace/BPT trap: 5
Termination Reason: Namespace SIGNAL, Code 0x5
在英特尔处理器上，崩溃信如下
Exception Type: EXC_BAD_INSTRUCTION (SIGILL)
...
Exception Note: EXC_CORPSE_NOTIFY
Termination Signal: Illegal instruction: 4
Termination Reason: Namespace SIGNAL, Code 0x4
在堆栈区域也有相关信息
Thread 0 Crashed:
0 MyCoolApp 0x0000000100a71a88 @objc ViewController.viewDidLoad() (in MyCoolApp) (ViewController.swift:18)
如何定位解决swift runtime error
Language Exception（OC崩溃）
Apple的系统框架在发生runtime错误的时候会抛出Language Exception，比如数组越界等。会有如下特征：
Exception Type: EXC_CRASH (SIGABRT)
Exception Codes: 0x0000000000000000, 0x0000000000000000
Exception Note: EXC_CORPSE_NOTIFY
同时此类崩溃还有Last Exception Backtrace
Last Exception Backtrace:
0 CoreFoundation 0x19aae2a48 __exceptionPreprocess + 220
1 libobjc.A.dylib 0x19a809fa4 objc_exception_throw + 55
如何定位解决Language Exception
watch dog强杀
被watchdog强杀一般崩溃类型是SIGKILL，同时Termination Reason里面的Code固定为0x8badf00d。
Exception Type: EXC_CRASH (SIGKILL)
Exception Codes: 0x0000000000000000, 0x0000000000000000
Exception Note: EXC_CORPSE_NOTIFY
Termination Reason: Namespace SPRINGBOARD, Code 0x8badf00d
如果watchdog强杀是因为app长时间没有响应，则可能会有额外信息。
Termination Description: SPRINGBOARD,
scene-create watchdog transgression: application:667
exhausted real (wall clock) time allowance of 19.97 seconds
| ProcessVisibility: Foreground
| ProcessState: Running
| WatchdogEvent: scene-create
| WatchdogVisibility: Foreground
| WatchdogCPUStatistics: (
| "Elapsed total CPU time (seconds): 15.290 (user 15.290, system 0.000), 28% CPU",
| "Elapsed application CPU time (seconds): 0.367, 1% CPU"
| )
如何定位解决watchdog强杀
访问僵尸对象导致的崩溃
访问僵尸对象的，意思是说给已经dealloc的对象发送消息。给已经析构的对象发送消息会发生 objc_msgSend, objc_retain, or objc_release类似这种崩溃。
Thread 0 Crashed:
0 libobjc.A.dylib 0x00000001a186d190 objc_msgSend + 16
1 Foundation 0x00000001a1f31238 __NSThreadPerformPerform + 232
2 CoreFoundation 0x00000001a1ac67e0 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 24
另外一种情况也可能代表是访问了僵尸对象，这时候会有Last Exception Backtrace信息
Last Exception Backtrace:
0 CoreFoundation 0x1bf596a48 __exceptionPreprocess + 220
1 libobjc.A.dylib 0x1bf2bdfa4 objc_exception_throw + 55
2 CoreFoundation 0x1bf49a5a8 -[NSObject+ 193960 (NSObject) doesNotRecognizeSelector:] + 139
如何定位解决访问僵尸对象问题
Memory Access野指针问题
野指针异常类型一般是EXC_BAD_ACCESS，同时还就会有VM Region Info信息。
Exception Type: EXC_BAD_ACCESS (SIGSEGV)
Exception Subtype: KERN_INVALID_ADDRESS at 0x0000000000000000
VM Region Info: 0 is not in any region. Bytes before following region: 4307009536
REGION TYPE START - END [ VSIZE] PRT/MAX SHRMOD REGION DETAIL
UNUSED SPACE AT START
--->
__TEXT 0000000100b7c000-0000000100b84000 [ 32K] r-x/r-x SM=COW ...pp/MyGreatApp
如何定位解决野指针问题
Framework丢失
如果app运行时发现缺少framework，会抛出 EXC_CRASH (SIGABRT)异常错误码，而且你也会收到Termination Description中断描述。
Exception Type: EXC_CRASH (SIGABRT)
Exception Codes: 0x0000000000000000, 0x0000000000000000
Exception Note: EXC_CORPSE_NOTIFY
Termination Description: DYLD, dependent dylib '@rpath/MyFramework.framework/MyFramework'
not found for '/MyCoolApp.app/MyCoolApp', tried but didn't find:
'/usr/lib/swift/MyFramework.framework/MyFramework'
'/MyCoolApp.app/Frameworks/MyFramework.framework/MyFramework'
'@rpath/MyFramework.framework/MyFramework'
'/System/Library/Frameworks/MyFramework.framework/MyFramework'