Xcode崩溃调试

1.EXEC_BAD_ACCESS

有时候在程序出错的时候不能能准确定位到崩溃那一行代码,而是直接跑到main循环或者Appdelegate里面， 或者会给你

EXEC_BAD_ACCESS的提示。如下图，在断点的导航面板建立了exception断点全局断点，这样只要遇到错误，debug程序就会自动定位到栈底的信息，也就是你最先出错的代码的那一行

2.Symbolic Breakpoint

如上图，第四个，增加函数断点，输入要断的函数名 funcxxx，这样一来，在程序中所有的 funcxxx 方法被调用时都会触发断点。

3.instruments性能分析工具

https://blog.csdn.net/ggghub/article/details/50325637

4.lldb的常用命令

https://juejin.im/post/5c8702db5188257ded10db58

1.help

 

2.print

 

3.expression

 

4.breakpoint

 

---

5.malloc: pointer being freed was not allocated set a breakpoint in malloc_error_break to debug

崩溃时候的日志

appname(3781,0x1084fabc0) malloc: *** error for object 0x14984b210: pointer being freed was not allocated
appname(3781,0x1084fabc0) malloc: *** set a breakpoint in malloc_error_break to debug

输入lldb调试器命令 bt 看栈信息 （thread info  、   thread backtrace）

或者

直接选中复制看栈信息这个比较详细（直接bt不会显示出下文中加粗的部分）

 

#0  0x000000022947a0dc in __pthread_kill ()
#1  0x00000002294f79b0 in pthread_kill$VARIANT$armv81 ()
#2  0x00000002293d3ea8 in abort ()
#3  0x00000002294cd780 in malloc_vreport ()
#4  0x00000002294cd938 in malloc_report ()
#5  0x00000002294c05e8 in free ()
#6  0x00000001057adaa8 in b2Free(void*) at /Users/mobile/Downloads/CliNet6/CliNet/base/b2Settings.cpp:33
#7  0x00000001057ac214 in b2BlockAllocator::~b2BlockAllocator() at /Users/mobile/Downloads/CliNet6/CliNet/base/b2BlockAllocator.cpp:88
#8  0x00000001057ac240 in b2BlockAllocator::~b2BlockAllocator() at /Users/mobile/Downloads/CliNet6/CliNet/base/b2BlockAllocator.cpp:82
#9  0x000000010519b00c in delete_internal [inlined] at /Users/builduser/buildslave/unity/build/Runtime/Allocator/MemoryMacros.h:187
#10 0x000000010519b008 in ::DestroyWorld() at /Users/builduser/buildslave/unity/build/Modules/Physics2D/Public/PhysicsScene2D.cpp:176
#11 0x0000000105176048 in ::RecreateWorld() at /Users/builduser/buildslave/unity/build/Modules/Physics2D/PhysicsManager2D.cpp:500
#12 0x0000000105066c24 in Invoke [inlined] at /Users/builduser/buildslave/unity/build/Runtime/Core/Callbacks/CallbackArray.h:70
#13 0x0000000105066c04 in ::Invoke() at /Users/builduser/buildslave/unity/build/Runtime/Core/Callbacks/CallbackArray.h:331
#14 0x0000000105056518 in ::UnloadGameScene() at /Users/builduser/buildslave/unity/build/Runtime/Misc/SceneUnloading.cpp:63
#15 0x000000010506f014 in ::PlayerLoadSceneFromThread() at /Users/builduser/buildslave/unity/build/Runtime/PreloadManager/LoadSceneOperation.cpp:628
#16 0x000000010506f15c in ::CompleteLoadFirstScene() at /Users/builduser/buildslave/unity/build/Runtime/PreloadManager/LoadSceneOperation.cpp:674
#17 0x000000010506ee24 in ::IntegrateMainThread() at /Users/builduser/buildslave/unity/build/Runtime/PreloadManager/LoadSceneOperation.cpp:351
#18 0x000000010506fcc4 in ::UpdatePreloadingSingleStep() at /Users/builduser/buildslave/unity/build/Runtime/PreloadManager/PreloadManager.cpp:431
#19 0x0000000105070374 in ::UpdatePreloading() at /Users/builduser/buildslave/unity/build/Runtime/PreloadManager/PreloadManager.cpp:568
#20 0x000000010532a24c in ::UnityPlayerLoopImpl() at /Users/builduser/buildslave/unity/build/PlatformDependent/iPhonePlayer/LibEntryPoint.mm:281
#21 0x0000000104b00b28 in ::UnityRepaint() at /Users/mobile/Documents/workspace/Dios/MClient/Build/unity2018withlib/101/Classes/UnityAppController+Rendering.mm:277
#22 0x0000000104b00a04 in ::-[UnityAppController(Rendering) repaintDisplayLink]() at /Users/mobile/Documents/workspace/Dios/MClient/Build/unity2018withlib/101/Classes/UnityAppController+Rendering.mm:71
#23 0x00000001083d49fc in -[DYDisplayLinkInterposer forwardDisplayLinkCallback:] ()
#24 0x000000022dc64f90 in CA::Display::DisplayLink::dispatch_items(unsigned long long, unsigned long long, unsigned long long) ()
#25 0x000000022dd2eb10 in display_timer_callback(__CFMachPort*, void*, long, void*) ()
#26 0x0000000229848a8c in __CFMachPortPerform ()
#27 0x000000022986f690 in __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ ()
#28 0x000000022986eddc in __CFRunLoopDoSource1 ()
#29 0x0000000229869c00 in __CFRunLoopRun ()
#30 0x00000002298690b0 in CFRunLoopRunSpecific ()
#31 0x000000022ba6979c in GSEventRunModal ()
#32 0x00000002560d5978 in UIApplicationMain ()
#33 0x0000000104af7f50 in main at /Users/mobile/Documents/workspace/Dios/MClient/Build/unity2018withlib/101/Classes/main.mm:41
#34 0x000000022932e8e0 in start ()
 

错误原因：本来是执行unity中的源码，但是后来执行到了网络库中的一个free函数了，原因是unity中和网络库CliNet中一个类重名了b2BlockAllocator类【xcode编译过去了有warning（我没看）】。本来应该走unity内置的析构的时候，却走到了网络库中，没初始化过，所以就崩了。 

由于ios平台的.a是静态编译的，两个类重名，加载的时候，第一个加载完，第二个再加载就把这段内存覆盖了，就是自定义的这个类覆盖了unity内置的类。而其他平台比如android，同一个网络库没事是因为android是dll动态链接库，内存应该是分配在自己的dll里面，不和运行程序在一起，重名好像也能调用到自己。

似乎编译器就是靠类名分配内存之类的。