How to check if a framework is BITCODE supported for Xcode7

Question

From Xcode 7 it became one of the common problem that third party frameworks should support Bitcode. We can also disable the BITCODE by setting ENABLE_BITCODE to NO in Build

Answer 1

The accepted answer suggests you shall do grep __LLVM but I'd rather do this

otool -l libName.o | grep __bitcode

as there are different __LLVM segments and not all of these indicate the presence of Bitcode. Here's an example:

Section
  sectname __bitcode
   segname __LLVM
      addr 0x00000000000007d0
      size 0x0000000000000f10
    offset 3360
     align 2^4 (16)
    reloff 0
    nreloc 0
     flags 0x00000000
 reserved1 0
 reserved2 0
Section
  sectname __cmdline
   segname __LLVM
      addr 0x00000000000016e0
      size 0x0000000000000069
    offset 7216
     align 2^4 (16)
    reloff 0
    nreloc 0
     flags 0x00000000
 reserved1 0
 reserved2 0

The presence of the __cmdline Section does not indicate that Bitcode is present, yet it would also be found when just searching for __LLVM.

Answer 2

Set the flag in the Targets:

Bitcode enabled

otool -arch arm64 -l myFramework | grep __LLVM
  segname __LLVM
   segname __LLVM

I ( wrongly ) expected to read the same output against a local iOS app build. That was not the case. The same command produced nothing, despite have ENABLE_BITCODE YES. Only when you selected Archive did the bitcode process start.

This answer helped me:

What's the difference between `-fembed-bitcode` and BITCODE_GENERATION_MODE?

Answer 3

From this Apple Developers Forum discussion, user dshirley and bwilson suggest using command line tools otool and grep to check if bitcode sections exist.

$ otool -l libName.o | grep __LLVM

or

$ otool -l MyFramework.framework/Versions/A/MyFramework | grep __LLVM

Running the above command, if the library contains bitcode you will see segname __LLVM output.

Answer 4

I have observed that __bitcode section is only present for static Libs and not for dynamic libs. So, one solution is the below command.

otool -l libDeviceManager.a | grep __LLVM 

Also, sometimes with fat binaries otool may not give __LLVM segments even though they are present. You can use the following command for those cases

otool -arch armv7 -l libDeviceManager.framework/libDeviceManager | grep __LLVM

Answer 5

you can try these commands:

otool -arch armv7 -l libDeviceManager.a | grep bit code

and

otool -arch arm64 -l libDeviceManager.a | grep bitcode