ad-hoc testing crashes with EXEC_BAD_ACCESS build with llvm 2.0 compiler

Question

I migrated an on-going project from Xcode 3 to Xcode 4. The ad-hoc build by LLVM 2.0 compiler crashes on iPod Touch 2G (iOS 4.2.1), but works well on iPad (iOS 4.3). This never happened prior migrating to Xcode 4.

When I tested with debug configuration on device, no crash happened. When I tested with ad-hoc configuration (duplicated from release), it'll crash. When I switch compiler version in the ad-hoc configuration from "LLVM 2.0" to "LLVM GCC4.2" or "GCC 4.2", no crash.

Therefore, I'm using "LLVM GCC 4.2" for ad-hoc and release configuration as an workaround. But I want to know what's the possible causes of crash.

I didn't post the crash report because it say nothing but crash on thread 0, no stack flow.

Answer 1

Please try Xcode 4.0.2, which contains a targeted bug fix for LLVM Compiler 2.0 that corrects a problem that has symptoms like this.

Thanks!

-Chris

Answer 2

I think this has to do with the remote debugger failing to connect to your application on the phone for whatever reason. Does your Xcode 3 project have an Entitlements.plist with get-task-allow set? Are you stripping debugging symbols? Compiler optimizations? Take a look in the Organizer window at the Console log for your device and I bet you'll see errors about com.apple.debugserver if you're sure you don't have other code problems.

I was having a similar situation, and maybe it's still not completely resolved. In my "Release" scheme, using an Ad-Hoc build configuration, I told Xcode to not attach to GDB when running, but I noticed it still tried to attach the remote debugger, which is why I think it would crash right away. After it crashes, I would stop the currently running process within Xcode and then manually launch the installed app from the phone, which worked correctly.

It's very likely that it's not directly your apps fault, but rather a perfect storm of your project, build settings, and the remote debugger. Try playing around with run settings and maybe you can get a radr out of it.

Answer 3

Upgrading to xCode 4.0.2 that's all you need! Here is a useful link explaining the issue: https://devforums.apple.com/thread/92279?start=50&tstart=0 (Apple account is needed)