Hacking native ARM64 binaries to run on the iOS Simulator

migrate.sh

#!/usr/bin/env bash
set -ex

# https://bogo.wtf/arm64-to-sim.html

ios_plat=ios
simulator_plat=simulator

make() {
    for name in $@; do
        extension=${name##*.}
        if [ "$extension" = "a" ]; then
            make_static_lib_xcframework $name
        elif [ "$extension" = "framework" ];  then
            make_xcframework $name
        fi
    done
}

clear_dirs() {
    rm -rf $ios_plat $simulator_plat
}

make_xcframework() {
    cwd=$(pwd)
    framework=$1
    framework_name="${framework%%.*}"

    rm -rf $framework_name.xcframework

    make_ios_framework $framework_name $ios_plat
    ios_framework_dir=$ios_plat/$framework_name.framework
    make_simulator_framework $framework_name $simulator_plat
    simulator_framework_dir=$simulator_plat/$framework_name.framework

    clear_dirs

    cd $cwd
    xcodebuild -create-xcframework -output ./$framework_name.xcframework -framework ./$simulator_framework_dir -framework ./$ios_framework_dir

    clear_dirs
}

make_static_lib_xcframework() {
    cwd=$(pwd)
    lib=$1
    lib_name="${lib%%.*}"

    rm -rf $lib_name.xcframework

    make_ios_lib $lib_name $ios_plat
    ios_framework_dir=$ios_plat/$lib_name/$lib_name.a
    make_simulator_lib $lib_name $simulator_plat
    simulator_framework_dir=$simulator_plat/$lib_name/$lib_name.a

    clear_dirs

    cd $cwd
    xcodebuild -create-xcframework -output ./$lib_name.xcframework -library ./$simulator_framework_dir -library ./$ios_framework_dir

    clear_dirs
}

make_ios_lib() {
    framework_name=$1
    plat=$2
    framework_dir=$plat/$framework_name
    mkdir -p $framework_dir
    cp -a $framework_name.a $framework_dir/
    remove_simulator_archs $framework_dir/$framework_name.a
}

make_simulator_lib() {
    framework_name=$1
    plat=$2
    framework_dir=$plat/$framework_name
    mkdir -p $framework_dir
    cp -a $framework_name.a $framework_dir/
    merge_simulator_archs $framework_dir/$framework_name.a
}

make_ios_framework() {
    framework_name=$1
    plat=$2
    framework_dir=$plat/$framework_name.framework
    mkdir -p $framework_dir
    cp -a $framework_name.framework/ $framework_dir/
    remove_simulator_archs $framework_dir/$framework_name
}

make_simulator_framework() {
    framework_name=$1
    plat=$2
    framework_dir=$plat/$framework_name.framework
    mkdir -p $framework_dir
    cp -a $framework_name.framework/ $framework_dir/
    merge_simulator_archs $framework_dir/$framework_name
}

remove_simulator_archs() {
    binary=$1
    for arch in x86_64 i386; do
        lipo -remove $arch $binary -o $binary || true
    done
}


extract_simulator_archs() {
    binary=$1
    for arch in arm64 x86_64; do
        lipo -thin $arch $binary -output $binary.$arch
    done
}

merge_simulator_archs() {
    binary_path=$1
    framework_dir="$(dirname $binary_path)"
    framework_name="$(basename $binary_path)"
    extract_simulator_archs $framework_dir/$framework_name
    mkdir -p $framework_dir/arm64
    cd $framework_dir/arm64
    ar -x ../$framework_name.arm64
    rm -f __.SYMDEF '__.SYMDEF SORTED'    
    for file in *.o; do
        # https://github.com/bogo/arm64-to-sim
        ~/Developer/arm64-to-sim/.build/release/arm64-to-sim "$file"
    done

    cd ..
    ar crv $framework_name.arm64-simulator arm64/*
    lipo -create -output ${framework_name} $framework_name.x86_64 $framework_name.arm64-simulator
    rm -rf arm64
}


make $@⏎