How do i make fat framework with bitcode option? - ios

Question

Environment: XCode 7.0.1
Module: Objective-C
Bundle Type: Framework
Hi, I am trying to create a framework to support armv7, armv7s, arm64, i386 and x86_64. I am using aggregate to make the fat library. Inside the aggregate script, i am running two xcodebuild commands 1. for armv7, armv7s and arm64 and 2. for i386 and x86_64 architectures. Also, I have set Enable Bitcode=YES and Other C Flags=-fembed-bitcode under target build settings. As a precautionary mesasure, i am adding ENABLE_BITCODE=YES and OTHER_CFLAGS="-fembed-bitcode" options to the xcodebuild command
My xcode build commands are as follows -
#Build The framework Target for iPhoneOS
xcodebuild -project "${PROJECT_FILE_PATH}" -target "${AN_TARGET}"
ONLY_ACTIVE_ARCH=NO -configuration "${CONFIGURATION}" -sdk iphoneos
BUILD_DIR="${BUILD_DIR}" OBJROOT="${OBJROOT}" BUILD_ROOT="${BUILD_ROOT}"
CONFIGURATION_BUILD_DIR="${IPHONE_DEVICE_BUILD_DIR}" SYMROOT="${SYMROOT}"
ARCHS="armv7 armv7s arm64" ENABLE_BITCODE=YES OTHER_CFLAGS="-fembed-bitcode" $ACTION
#Build The framework Target for iPhoneSimulator
xcodebuild -project "${PROJECT_FILE_PATH}" -target "${AN_TARGET}"
ONLY_ACTIVE_ARCH=NO -configuration "${CONFIGURATION}" -sdk iphonesimulator
BUILD_DIR="${BUILD_DIR}" OBJROOT="${OBJROOT}" BUILD_ROOT="${BUILD_ROOT}"
CONFIGURATION_BUILD_DIR="${IPHONE_SIMULATOR_BUILD_DIR}" SYMROOT="${SYMROOT}"
ARCHS="i386 x86_64" ENABLE_BITCODE=YES OTHER_CFLAGS="-fembed-bitcode" $ACTION
after running the above two commands, i am combining these two builds to make a fat framework binary using the below command
# create a fat Framework
lipo -create
"${IPHONE_DEVICE_BUILD_DIR}/${PROJECT_NAME}.framework/${PROJECT_NAME}"
"${IPHONE_SIMULATOR_BUILD_DIR}/${PROJECT_NAME}.framework/${PROJECT_NAME}" -
output "${FRAMEWORK_FOLDER}/${AN_END_USER_FRAMEWORK_NAME}"
The issue iam facing is after the lipo is created, i am unable to use it in the bitcode enabled application. After running the otool -l framework_binary | grep -LLVM, i do not see the bitcode enabled flags or __LLVM.
Lipo removes bitcode from the fat binary. Is there a way i can retain bitcode while running the lipo command?
Correction: Based on the reply from Nestor, i ran the otool command as otool -l -arch armv7 framework_binary | grep LLVM and much to my surprise, i could see the segname __LLVM clang. However when i integrate the same fat framework binary into my project, it builds fine on simulator however throws the following error while running on device - ld: 'MyBinary' does not contain bitcode. You must rebuild it with bitcode enabled (Xcode setting ENABLE_BITCODE), obtain an updated library from the vendor, or disable bitcode for this target. for architecture armv7

Answer 1

Happily it's just a problem with otool's reporting, not lipo; you have to add the -arch parameter:
otool -arch arm64 -l myLipoOutput.a
Source: http://www.openradar.me/radar?id=6301306440384512

Answer 2

This is something weird, there are not many documentation for do this, at the end I use this command:
xcodebuild -project ${PROJECT_NAME}.xcodeproj -target ${FRAMEWORK_NAME} ONLY_ACTIVE_ARCH=NO BITCODE_GENERATION_MODE=bitcode FRAMEWORK_SEARCH_PATHS="${FRAMEWORK_SEARCH_PARTH} ${SRCROOT}/**" -sdk ${SIMULATOR_SDK} -configuration ${CONFIGURATION} clean build CONFIGURATION_BUILD_DIR=${BUILD_DIR}/${CONFIGURATION}-${SIMULATOR_SDK} 2>&1
xcodebuild -project ${PROJECT_NAME}.xcodeproj -target ${FRAMEWORK_NAME} -sdk ${DEVICE_SDK} ONLY_ACTIVE_ARCH=NO BITCODE_GENERATION_MODE=bitcode FRAMEWORK_SEARCH_PATHS="${FRAMEWORK_SEARCH_PARTH} ${SRCROOT}/**" -configuration ${CONFIGURATION} clean build CONFIGURATION_BUILD_DIR=${BUILD_DIR}/${CONFIGURATION}-${DEVICE_SDK} 2>&1
Add the BITCODE_GENERATION_MODE=bitcode flag to the xcodebuild command

Answer 3

Try to use archive for the arm slices instead of build
xcodebuild -scheme "${SCHEME}" -workspace "${WORKSPACE}" -configuration "${CONFIGURATION}" -sdk iphoneos ARCHS="arm64 armv7 armv7s" CONFIGURATION_BUILD_DIR="${CONFIGURATION_BUILD_DIR}/arm" CODE_SIGN_IDENTITY="" CODE_SIGNING_REQUIRED=NO ONLY_ACTIVE_ARCH=NO archive
After that run lipo to merge the simulator and the arm ones.
And after that run otool -arch arm64 -l myLipoOutput.a and it should work.

Answer 4

It looks like a bug in Xcode 7.0.1 . I've had the same issue and downgrading Xcode to version 7 fixed it.
Update:
Actually it may be a bug in Xcode 7 that was fixed in 7.0.1 - this SO answer solved the issue for me.