Xcode 8.3 Linker Warnings

Question

Trying to Archive app prior to submitting to Apple. Warning limit exceeded - showing first 200 warnings only. Sample warnings:

ld: warning: Linker asked to preserve internal global: 'sharedInstance.sharedInstance'
ld: warning: Linker asked to preserve internal global: '__block_descriptor_tmp'
ld: warning: Linker asked to preserve internal global: '__block_descriptor_tmp'
ld: warning: Linker asked to preserve internal global: '__block_descriptor_tmp'
ld: warning: Linker asked to preserve internal global: '__block_descriptor_tmp'
ld: warning: Linker asked to preserve internal global: '__block_literal_global'
ld: warning: Linker asked to preserve internal global: '__block_descriptor_tmp'
ld: warning: Linker asked to preserve internal global: '__block_descriptor_tmp'
ld: warning: Linker asked to preserve internal global: '__block_descriptor_tmp'

Using Xcode 8.3.3. Swift 3. Relevant Firebase pod entries:

Using Firebase (4.0.2)
Using FirebaseAnalytics (4.0.1)
Using FirebaseAuth (4.0.0)
Using FirebaseCore (4.0.2)
Using FirebaseDatabase (4.0.0)
Using FirebaseInstanceID (2.0.0)
Using FirebaseMessaging (2.0.0)
Using FirebaseStorage (2.0.0)

I had this problem a while back and Firebase 3.16 seemed to have fixed it but now the warnings are back. Warnings come only on Archive. Anybody else reliving this situation?

Answer 1

After importing the AdMob SDK, when I archived my project ( workspace), I had the following warning:

ld: warning: Linker asked to preserve internal global: '__block_descriptor_tmp'

I've found a way to get rid of it:

Target \ Build Settings \ Build Options \ Enable bitcode = NO

Hope this helps!