我已经在应用程序上工作了一段时间，一切正常但偶尔会随机崩溃，我不知道为什么/哪里报告只指向main.m.有什么想法吗？
Exception Type: EXC_CRASH (SIGABRT)
Exception Codes: 0x0000000000000000, 0x0000000000000000
Triggered by Thread: 0
Last Exception Backtrace:
0 CoreFoundation 0x2333b0d2 __exceptionPreprocess + 122
1 libobjc.A.dylib 0x31a7ac72 objc_exception_throw + 34
2 CoreFoundation 0x2333ab58 __NSFastEnumerationMutationHandler + 124
3 UIKit 0x26994a7a -[UIView(Hierarchy) subviews] + 298
4 UIKit 0x26fcd94e -[UIView(AdditionalLayoutSupport) _internalUpdateConstraintsIfNeededAccumulatingViewsNeedingSecondPassAndViewsNeedingBaselineUpdate:] + 78
5 Foundation 0x23ff3414 -[NSISEngine withBehaviors:performModifications:] + 252
6 UIKit 0x26fcdbce -[UIView(AdditionalLayoutSupport) _updateConstraintsIfNeededAccumulatingViewsNeedingSecondPassAndViewsNeedingBaselineUpdate:] + 118
7 UIKit 0x26a894cc __60-[UIView(AdditionalLayoutSupport) updateConstraintsIfNeeded]_block_invoke + 80
8 Foundation 0x23ff3414 -[NSISEngine withBehaviors:performModifications:] + 252
9 UIKit 0x26a892a4 -[UIView(AdditionalLayoutSupport) updateConstraintsIfNeeded] + 200
10 UIKit 0x26fcde64 -[UIView(AdditionalLayoutSupport) _updateConstraintsAtEngineLevelIfNeeded] + 168
11 UIKit 0x26c3daea -[UIView(Hierarchy) _updateConstraintsAsNecessaryAndApplyLayoutFromEngine] + 114
12 UIKit 0x269999c6 -[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 542
13 QuartzCore 0x263af3e0 -[CALayer layoutSublayers] + 124
14 QuartzCore 0x263aac30 CA::Layer::layout_if_needed(CA::Transaction*) + 356
15 QuartzCore 0x263aaab8 CA::Layer::layout_and_display_if_needed(CA::Transaction*) + 12
16 QuartzCore 0x263aa45a CA::Context::commit_transaction(CA::Transaction*) + 218
17 QuartzCore 0x263aa24a CA::Transaction::commit() + 430
18 QuartzCore 0x263a3f58 CA::Transaction::observer_callback(__CFRunLoopObserver*, unsigned long, void*) + 52
19 CoreFoundation 0x23301048 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 16
20 CoreFoundation 0x232fe72c __CFRunLoopDoObservers + 272
21 CoreFoundation 0x232feb2e __CFRunLoopRun + 910
22 CoreFoundation 0x2324a6cc CFRunLoopRunSpecific + 472
23 CoreFoundation 0x2324a4de CFRunLoopRunInMode + 102
24 GraphicsServices 0x2abe61a4 GSEventRunModal + 132
25 UIKit 0x269fc440 UIApplicationMain + 1436
26 **My App** 0x0015a91c main (main.m:14)
27 libdyld.dylib 0x32048aaa tlv_initializer + 2