CODEWITHSUNDEEP
iosmemory-managementios-simulatorinstrumentsnszombie
Dru Freeman
Dru Freeman

Reputation: 1826

NSZombie on iOS not in the simulator

I have a bug where I'm crashing in the Autorelease function. Classic: Access object after over-release.

The problem is that the iOS program is using EAAccessory and happening somewhere as a result of data being received from the device.

As a result, the problem needs to be diagnosed off the Simulator. Due to the memory requirements of NSZombie, NSZombie is disabled for iOS outside the simulator.

Any tips/ideas how to track down an over-release bug that would be easy with NSZombie in the iOS world outside the simulator?

I've already contemplated trying to stub the behaviour of the EAAcessory for the simulator; but due to time constraints that more of a "Next rev-refactor/enhancement" due to the amount of work needed.

Right now I just need to find the bad access bug.

Upvotes: 1

Views: 407

Answers (1)

Jano
Jano

Reputation: 63707

Since I don't have experience with EAAccessory I don't know if this is viable, but here is a suggestion. From retain/release debugging (rentzsch.tumblr.com):

#if 1
- (id)retain {
    NSUInteger oldRetainCount = [super retainCount];
    id result = [super retain];
    NSUInteger newRetainCount = [super retainCount];
    printf("%s<%p> ++retainCount: %lu => %lu\n", [[self className] UTF8String], self, oldRetainCount, newRetainCount);
    printf("%s\n", [[[NSThread callStackSymbols] description] UTF8String]);
    return result;
}

- (void)release {
    NSUInteger oldRetainCount = [super retainCount];
    BOOL gonnaDealloc = oldRetainCount == 1;
    if (gonnaDealloc) {
        printf("%s<%p> --retainCount: 1 => 0 (gonna dealloc)\n", [[self className] UTF8String], self);
        printf("%s\n", [[[NSThread callStackSymbols] description] UTF8String]);
    }
    [super release];
    if (!gonnaDealloc) {
        NSUInteger newRetainCount = [super retainCount];
        printf("%s<%p> --retainCount: %lu => %lu\n", [[self className] UTF8String], self, oldRetainCount, newRetainCount);
        printf("%s\n", [[[NSThread callStackSymbols] description] UTF8String]);
    }
}
#endif

You can add a filter by class to run the debug code only for specific classes you suspect.

Upvotes: 1

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