iOS高级调试

Question

当在“编辑模式->诊断”中启用“守护malloc”时，我在下面找到了问题的解决方案。第三方代码不恰当地使用内存。

我在我的iOS应用程序上随机崩溃了几次(使用ARC，参见下面)。我觉得这是由于过度释放的物体造成的。

我试图在NSZombie中启用xCode，但在崩溃前控制台中没有收到警告。僵尸仪器也有同样的问题--没有检测到错误。“所有异常”上的断点在objc_msgSend或类似的东西上停止。

我无法在这里粘贴任何代码或执行逐行调试，因为我不了解崩溃的位置。

那么，有谁知道在iOS上查找错误来源的其他高级技术吗？回溯的样本：

#0  0x3c2e1cda in realizeClass(class_t*) ()
#1  0x3c2e1d46 in realizeClass(class_t*) ()
#2  0x3c2e1d46 in realizeClass(class_t*) ()
#3  0x3c2dc094 in prepareForMethodLookup ()
#4  0x3c2dbf9a in lookUpMethod ()
#5  0x3c2dbf66 in _class_lookupMethodAndLoadCache3 ()
#6  0x3c2db61a in objc_msgSend_uncached ()
#7  0x3627784c in -[UIButtonContent dealloc] ()
#8  0x34388310 in CFRelease ()
#9  0x34463434 in __CFBasicHashDrain ()
#10 0x343883d0 in CFRelease ()
#11 0x3627dee6 in -[UIButton dealloc] ()
#12 0x3627e0b4 in -[UIView dealloc] ()
#13 0x34388310 in CFRelease ()
#14 0x3439295c in -[__NSArrayM dealloc] ()
#15 0x3c2dd488 in (anonymous namespace)::AutoreleasePoolPage::pop(void*) ()
#16 0x3438a440 in _CFAutoreleasePoolPop ()
#17 0x34cbb782 in -[NSAutoreleasePool drain] ()
#18 0x341ce2ca in -[NSManagedObjectContext(_NSInternalChangeProcessing) _processRecentChanges:] ()
#19 0x341cd10e in _performRunLoopAction ()
#20 0x3441c6cc in __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ ()
#21 0x3441a9c0 in __CFRunLoopDoObservers ()
#22 0x3441ad16 in __CFRunLoopRun ()
#23 0x3438debc in CFRunLoopRunSpecific ()
#24 0x3438dd48 in CFRunLoopRunInMode ()
#25 0x37f402ea in GSEventRunModal ()
#26 0x362a3300 in UIApplicationMain ()
#27 0x000a879c in main at main.m:16

#0  0x3c2db5be in objc_msgSend ()
#1  0x34388aaa in CFDictionaryGetValue ()
#2  0x362656cc in -[UIButton(UIButtonContentLookup) _contentForState:] ()
#3  0x36274f38 in -[UIButton(UIButtonContentLookup) _backgroundForState:usesBackgroundForNormalState:] ()
#4  0x36274e54 in -[UIButton contentRectForBounds:] ()
#5  0x362954c4 in -[UIButton layoutSubviews] ()
#6  0x36252802 in -[UIView(CALayerDelegate) layoutSublayersOfLayer:] ()
#7  0x35ffcd8a in -[CALayer layoutSublayers] ()
#8  0x35ffc928 in CA::Layer::layout_if_needed(CA::Transaction*) ()
#9  0x35ffd85c in CA::Layer::layout_and_display_if_needed(CA::Transaction*) ()
#10 0x35ffd242 in CA::Context::commit_transaction(CA::Transaction*) ()
#11 0x35ffd050 in CA::Transaction::commit() ()
#12 0x35ffceb0 in CA::Transaction::observer_callback(__CFRunLoopObserver*, unsigned long, void*) ()
#13 0x3441c6cc in __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ ()
#14 0x3441a9c0 in __CFRunLoopDoObservers ()
#15 0x3441ad16 in __CFRunLoopRun ()
#16 0x3438debc in CFRunLoopRunSpecific ()
#17 0x3438dd48 in CFRunLoopRunInMode ()
#18 0x37f402ea in GSEventRunModal ()
#19 0x362a3300 in UIApplicationMain ()
#20 0x0007479c in main at main.m:16

#0  0x33750f78 in objc_msgSend ()
#1  0x35a7b2e6 in CFRelease ()
#2  0x35af7b36 in __CFDictionaryStandardReleaseValue ()
#3  0x35b4b3bc in __CFBasicHashDrain ()
#4  0x35a7b39a in CFRelease ()
#5  0x332a0c88 in -[UIButton dealloc] ()
#6  0x33752174 in _objc_rootRelease ()
#7  0x35a7b2e6 in CFRelease ()
#8  0x35a9106a in -[__NSArrayM dealloc] ()
#9  0x33752174 in _objc_rootRelease ()
#10 0x33753e56 in objc_release ()
#11 0x33752eac in (anonymous namespace)::AutoreleasePoolPage::pop(void*) ()
#12 0x33752dc8 in _objc_autoreleasePoolPop ()
#13 0x35a82cfe in _CFAutoreleasePoolPop ()
#14 0x34f5898c in __NSFireDelayedPerform ()
#15 0x35b06a32 in __CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION__ ()
#16 0x35b06698 in __CFRunLoopDoTimer ()
#17 0x35b0526e in __CFRunLoopRun ()
#18 0x35a884a4 in CFRunLoopRunSpecific ()
#19 0x35a8836c in CFRunLoopRunInMode ()
#20 0x33823438 in GSEventRunModal ()
#21 0x33260cd4 in UIApplicationMain ()
#22 0x001185b8 in main at main.m:16
#23 0x000f7d78 in start ()

Answer 1

这不是一个可捕捉的例外；没有抛出。这是一次严重的撞击。最有可能是由于内存损坏，进一步证实是因为NSZombie没有帮助。

虽然这通常是对Debugging over-released objects, problem with NSZombie的欺骗，但是对于这些崩溃，有一些特定的上下文可能会有所帮助。

在这两种情况下，UIButtonContent的操作都崩溃了。UIButtonContent是UIKit的内部实现细节，最终引用到各种图像、标题等.按钮所使用的。

如果图像数据被过早释放(或损坏)，则可能导致此类崩溃。我建议仔细研究一下你是如何管理图像数据的。