Creating a Universal iOS Framework in Xcode 7

Several months ago, I posted a script for creating a universal iOS framework (i.e. one that will run in both the simulator as well as on an actual device) in Xcode 6. The following is an updated version for use in Xcode 7 (this version supports bitcode):

FRAMEWORK=<framework name>

BUILD=build
FRAMEWORK_PATH=$FRAMEWORK.framework

rm -Rf $BUILD
rm -f $FRAMEWORK_PATH.tar.gz

xcodebuild archive -project $FRAMEWORK.xcodeproj -scheme $FRAMEWORK -sdk iphoneos SYMROOT=$BUILD
xcodebuild build -project $FRAMEWORK.xcodeproj -target $FRAMEWORK -sdk iphonesimulator SYMROOT=$BUILD

cp -RL $BUILD/Release-iphoneos $BUILD/Release-universal

lipo -create $BUILD/Release-iphoneos/$FRAMEWORK_PATH/$FRAMEWORK $BUILD/Release-iphonesimulator/$FRAMEWORK_PATH/$FRAMEWORK -output $BUILD/Release-universal/$FRAMEWORK_PATH/$FRAMEWORK

tar -czv -C $BUILD/Release-universal -f $FRAMEWORK.framework.tar.gz $FRAMEWORK_PATH

As with the previous version, when located in the same directory as the .xcodeproj file, this script will invoke xcodebuild twice on a framework project and join the resulting binaries together into a single universal binary. It will then package the framework up in a gzipped tarball and place it in the same directory. The same script is used to generate the release artifacts for MarkupKit and HTTP-RPC.

I didn't realize this when I posted the first version, but apps that contain “fat” binaries like this don't pass app store validation. Before submitting an app containing a universal framework, the binaries need to be trimmed so that they include only iOS-native code. The following script (adapted from this article) can be used to do this:

FRAMEWORK=$1
echo "Trimming $FRAMEWORK..."

FRAMEWORK_EXECUTABLE_PATH="${BUILT_PRODUCTS_DIR}/${FRAMEWORKS_FOLDER_PATH}/$FRAMEWORK.framework/$FRAMEWORK"

EXTRACTED_ARCHS=()

for ARCH in $ARCHS
do
    echo "Extracting $ARCH..."
    lipo -extract "$ARCH" "$FRAMEWORK_EXECUTABLE_PATH" -o "$FRAMEWORK_EXECUTABLE_PATH-$ARCH"
    EXTRACTED_ARCHS+=("$FRAMEWORK_EXECUTABLE_PATH-$ARCH")
done

echo "Merging binaries..."
lipo -o "$FRAMEWORK_EXECUTABLE_PATH-merged" -create "${EXTRACTED_ARCHS[@]}"
rm "${EXTRACTED_ARCHS[@]}"

rm "$FRAMEWORK_EXECUTABLE_PATH"
mv "$FRAMEWORK_EXECUTABLE_PATH-merged" "$FRAMEWORK_EXECUTABLE_PATH"

echo "Done."

To use this script:

  1. Place the script in your project root directory and name it trim.sh or something similar
  2. Create a new “Run Script” build phase after the “Embed Frameworks” phase
  3. Rename the new build phase to “Trim Framework Executables” or similar (optional)
  4. Invoke the script for each framework you want to trim (e.g. ${SRCROOT}/trim.sh)

For more ways to simplify iOS app development, please see my projects on GitHub:

  • MarkupKit – Declarative UI for iOS and tvOS
  • HTTP-RPC – Lightweight multi-platform REST

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