using an empty LLDB target which can cause slow memory reads from remote devices.

1、使用6或者6P模拟器运行代码就报

Warning: Error creating LLDB target at path '/Users/xxx/Library/Developer/Xcode/DerivedData/xxxx/Build/Products/Debug-iphonesimulator/

xxxx.app'- using an empty LLDB target which can cause slow memory reads from remote devices.

苹果认为iPhone6以及以后的设备都要支持64bit，如果没有特别的原因，最好都包含

arm64在你的

build architecture里面

附:

NOTE ABOUT 64-BIT ARCHITECTURE

An app extension target must include the arm64 architecture in its Architectures build settings or it will be rejected by the App Store. Xcode includes this architecture with its “Standard architectures” setting when you create a new app extension target.

If your containing app target links to an embedded framework, the app must also include the arm64 architecture or it will be rejected by the App Store.

For more information about 64-bit development, see 64-Bit Transition Guide for Cocoa Touch or 64-Bit Transition Guide for Cocoa, depending on your target platform.

Source:https://developer.apple.com/library/prerelease/ios/documentation/General/Conceptual/ExtensibilityPG/ExtensionCreation.html#//apple_ref/doc/uid/TP40014214-CH5-SW1

配置如下：

2. 选择你的工程 -> Build Settings

3. 改变 'Architectures' to 'Standard architectures (armv7, arm64) - $(ARCHS_STANDARD)' 

4. 在iOS 5.1.1可能有一个支撑警告说明,  点击 'Change Deployment Target to 5.1.1'

4. 重复以上步骤，如果设置没有自动改变的话

这是首选的编译设置，苹果要求开发商建立支持

64bit的应用体系

Apple document Link