How do i make fat framework with bitcode option?

13
votes

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

4
iosxcodebitcode
Shouldn't that be grep LLVM and not grep -LLVM? – l00phole
Same problem here. *.a contains bitcode before lipo, but not after. – Nestor
Did you check whether binary for iphoneos (i.e. for device before being integrated by lipo) has bit code ? If it doesn't have, it isn't lipo who removes bitcode section. – Takamitsu Mizutori

4 Answers

9
votes

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

8
votes

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

1
votes

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.

0
votes

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.