导致EXC_BAD_ACCESS（SIGSEGV）的奇怪错误

Question

Hey Guys, I know there are about 100.000 thread about EXC_BAD_ACCESS (SIGSEGV) Errors. But no one helped me out. I'm not able to solve my problem myself.

A few hours ago, I duplicated the target of my Xcode Project (a iPhone game) to make a free version. But since this Point I get very strange errors. Sometimes the app works as if nothing happened. But most of the time, I get errors like this:

Running pass 'X86 DAG->DAG Instruction Selection' on function '@gleLLVMVecPrimMultiRender13'

And the stack looks like this:

    Thread 0 Crashed:  Dispatch queue: com.apple.main-thread
0   libobjc.A.dylib                 0x015c6c6f prepareForMethodLookup + 31
1   libobjc.A.dylib                 0x015c06ad lookUpMethod + 86
2   libobjc.A.dylib                 0x015c081a _class_lookupMethodAndLoadCache + 40
3   libobjc.A.dylib                 0x015ceaa3 objc_msgSend + 87
4   Birdy Free                      0x0001b46d -[SMApplicationManager dealloc] + 58 (SMApplicationManager.m:226)
5   Foundation                      0x00489257 -[NSURLConnection(NSURLConnectionReallyInternal) releaseDelegate] + 57
6   Foundation                      0x004891f9 _NSURLConnectionReleaseClient + 68
7   CFNetwork                       0x01a45742 ClientContextHolder<CFURLConnectionClient_V4>::forget() + 48
8   CFNetwork                       0x01a3beee URLConnectionClient::processEvents() + 278
9   CFNetwork                       0x01a3bcb7 MultiplexerSource::perform() + 251
10  CoreFoundation                  0x0144e01f __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 15
11  CoreFoundation                  0x013ac28b __CFRunLoopDoSources0 + 571
12  CoreFoundation                  0x013ab786 __CFRunLoopRun + 470
13  CoreFoundation                  0x013ab240 CFRunLoopRunSpecific + 208
14  CoreFoundation                  0x013ab161 CFRunLoopRunInMode + 97
15  GraphicsServices                0x02a13268 GSEventRunModal + 217
16  GraphicsServices                0x02a1332d GSEventRun + 115
17  UIKit                           0x0086d42e UIApplicationMain + 1160
18  Birdy Free                      0x000024a0 main + 82 (main.m:13)
19  Birdy Free                      0x00002445 start + 53

But the method called is not always the same. In this case it was [SMApplicationManager dealloc] and a few minutes ago it was [CCNode draw]. I can't get the source of this error. I think it has something to do with the second target. Do any of you guys know anything more?

Sandro Meier

Answer 1

It's weird i got this error, and i went through countless solutions. Turned out, i had duplicated a line of code by accident. Just make sure when you duplicated, there is not code interfering with each other.

Answer 2

Finally after a few more hours of frustrating experiments I found the solution. The whole thing hadn't to anything with the second target. The Problem was the NSURLConnectionDelegate. In this class I implemented a Property named appID. And in one of the methods of the class, I set the variable without the setter. So I placed an autoreleased object at the position of a property. This one get released and the pointer to the variable gets invalid. As soon as the Delegate was released, a Method was sent to this yet released object.

But I can't explain why there appears this strange error Method. I haven't seen anything like that before. Can someone tell my why the error is called Running pass 'X86 DAG->DAG Instruction Selection' on function '@gleLLVMVecPrimMultiRender13' ?

Sandro Meier `