Swift Compiler: `warning: using sysroot for 'iPhoneOS' but targeting 'MacOSX'`

CraigEmteq · January 13, 2023, 1:21pm

When building a Swift codebase targeting CMAKE_SYSTEM_NAME: "iOS" the platform doesn’t appear to be propagated onto the swiftc call?

For what I gather the -target should be passed to swiftc. I checked the source and it appears as though this was incomplete or am I going mad?

github.com

Kitware/CMake/blob/c759f4605c8e1641895275ea03886b6c4d207eb7/Modules/CMakeSwiftInformation.cmake#L41


      
            set(CMAKE_SHARED_LIBRARY_RUNTIME_Swift_FLAG "-Xlinker -rpath -Xlinker ")
            if(CMAKE_SYSTEM_NAME STREQUAL Darwin)
              set(CMAKE_EXECUTABLE_RUNTIME_Swift_FLAG_SEP "")
              set(CMAKE_SHARED_LIBRARY_RUNTIME_Swift_FLAG_SEP "")
            else()
              set(CMAKE_EXECUTABLE_RUNTIME_Swift_FLAG_SEP ":")
              set(CMAKE_SHARED_LIBRARY_RUNTIME_Swift_FLAG_SEP ":")
            endif()
          endif()
          
          
set(CMAKE_Swift_COMPILE_OPTIONS_TARGET "-target ")
          set(CMAKE_Swift_COMPILE_OPTIONS_EXTERNAL_TOOLCHAIN "-tools-directory ")
          # NOTE(compnerd) the `-sdk` support is not yet ready in the compiler; when that
          # is fully working, we should be able to enable this.
          # set(CMAKE_Swift_COMPILE_OPTIONS_SYSROOT "-sdk ")
          # NOTE(compnerd) do not setup `-frontend` as we use the compiler as the driver
          # during the link phase and use that to drive the compilation
          set(CMAKE_Swift_COMPILER_ARG1 "")
          set(CMAKE_Swift_DEFINE_FLAG -D)
          set(CMAKE_Swift_FRAMEWORK_SEARCH_FLAG "-F ")
          set(CMAKE_Swift_LIBRARY_PATH_FLAG "-L ")

As a workaround I have used this after the first call to project()

# Swift on iOS needs explicit specify target platform but not sure this is correct but appears to work
if (IOS)
    set(CMAKE_Swift_FLAGS_INIT 
        "-target ${CMAKE_OSX_ARCHITECTURES}-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}"
    )
endif()