Cannot build fprime-zephyr reference project

[ReggieMarr]

I was trying to follow along with the zephyr reference project so as to add support for more boards and I ran into this issue:

Alternatively when I adjust the cmakelists.txt like so

restrict_platforms(Zephyr)

add_fprime_subdirectory("${CMAKE_CURRENT_LIST_DIR}/Top/")
set(SOURCE_FILES "${CMAKE_CURRENT_LIST_DIR}/Stub.cpp")
set(MOD_DEPS ${FPRIME_CURRENT_MODULE}/Top)
register_fprime_deployment()

target_sources(app PRIVATE
    "${CMAKE_CURRENT_LIST_DIR}/Main.cpp"
)

target_link_libraries(LedBlinker_Top PUBLIC zephyr_interface)

add_dependencies(LedBlinker zephyr)
target_link_libraries(LedBlinker PUBLIC zephyr_interface)
target_link_libraries(LedBlinker PUBLIC zephyr)
set_target_properties(LedBlinker PROPERTIES
    ENABLE_EXPORTS ON
)

# Use Zephyr's link group mechanism
target_link_libraries(app PUBLIC
    LedBlinker_Top
    LedBlinker
)

set_target_properties(Svc_FatalHandler PROPERTIES EXCLUDE_FROM_ALL TRUE)

and build manually I encounter this error:

FAILED: bin/zephyr/LedBlinker 
: && ccache /home/user/zephyr-sdk-0.17.0/arm-zephyr-eabi/bin/arm-zephyr-eabi-g++  -gdwarf-4 LedBlinker/CMakeFiles/LedBlinker.dir/Stub.cpp.obj LedBlinker/CMakeFiles/LedBlinker.dir/__/fprime/Os/Stub/DefaultFile.cpp.obj LedBlinker/CMakeFiles/LedBlinker.dir/__/fprime-baremetal/fprime-baremetal/Os/Baremetal/DefaultCpu.cpp.obj LedBlinker/CMakeFiles/LedBlinker.dir/__/fprime-baremetal/fprime-baremetal/Os/Baremetal/DefaultMemory.cpp.obj LedBlinker/CMakeFiles/LedBlinker.dir/__/fprime-zephyr/Zephyr/Os/DefaultQueue.cpp.obj LedBlinker/CMakeFiles/LedBlinker.dir/__/fprime-zephyr/Zephyr/Os/DefaultMutex.cpp.obj LedBlinker/CMakeFiles/LedBlinker.dir/__/fprime-zephyr/Zephyr/Os/DefaultTask.cpp.obj LedBlinker/CMakeFiles/LedBlinker.dir/__/fprime-zephyr/Zephyr/Os/DefaultConsole.cpp.obj LedBlinker/CMakeFiles/LedBlinker.dir/__/fprime-zephyr/Zephyr/Os/DefaultRawTime.cpp.obj -o bin/zephyr/LedBlinker  lib/zephyr/libconfig.a  lib/zephyr/libFw_Cfg.a  lib/zephyr/libFw_Types.a  lib/zephyr/libFw_Logger.a  lib/zephyr/libFw_Obj.a  lib/zephyr/libFw_Port.a  lib/zephyr/libFw_Time.a  lib/zephyr/libFw_Comp.a  lib/zephyr/libZephyr_Svc_ZephyrTime.a  lib/zephyr/libFw_Com.a  lib/zephyr/libFw_Tlm.a  lib/zephyr/libFw_Log.a  lib/zephyr/libFw_Cmd.a  lib/zephyr/libFw_Prm.a  lib/zephyr/libFw_Buffer.a  lib/zephyr/libDrv_Ports.a  lib/zephyr/libSvc_Sched.a  lib/zephyr/libComponents_Led.a  lib/zephyr/libSvc_Fatal.a  lib/zephyr/libfprime-baremetal_Svc_FatalHandler.a  lib/zephyr/libZephyr_Drv_ZephyrGpioDriver.a  lib/zephyr/libOs.a  lib/zephyr/libSvc_Cycle.a  lib/zephyr/libZephyr_Drv_ZephyrRateDriver.a  lib/zephyr/libDrv_ByteStreamDriverModel.a  lib/zephyr/libZephyr_Drv_ZephyrUartDriver.a  lib/zephyr/libSvc_Ping.a  lib/zephyr/libFw_CompQueued.a  lib/zephyr/libSvc_ActiveLogger.a  lib/zephyr/libSvc_AssertFatalAdapter.a  lib/zephyr/libSvc_CmdDispatcher.a  lib/zephyr/libUtils_Hash.a  lib/zephyr/libUtils_Types.a  lib/zephyr/libSvc_FramingProtocol.a  lib/zephyr/libSvc_Deframer.a  lib/zephyr/libFw_Ports_SuccessCondition.a  lib/zephyr/libSvc_Framer.a  lib/zephyr/libSvc_PassiveConsoleTextLogger.a  lib/zephyr/libSvc_PassiveRateGroup.a  lib/zephyr/libSvc_RateGroupDriver.a  lib/zephyr/libSvc_StaticMemory.a  lib/zephyr/libSvc_SystemResources.a  lib/zephyr/libSvc_TlmChan.a  lib/zephyr/libLedBlinker_Top.a  lib/zephyr/libOs_File_Stub.a  lib/zephyr/libOs_Cpu_Baremetal.a  lib/zephyr/libOs_Memory_Baremetal.a  lib/zephyr/libOs_Queue_Zephyr.a  lib/zephyr/libOs_Mutex_Zephyr.a  lib/zephyr/libOs_Task_Zephyr.a  lib/zephyr/libOs_Console_Zephyr.a  lib/zephyr/libOs_RawTime_Zephyr.a  zephyr/libzephyr.a  lib/zephyr/libZephyr_Svc_ZephyrTime.a  lib/zephyr/libComponents_Led.a  lib/zephyr/libfprime-baremetal_Svc_FatalHandler.a  lib/zephyr/libZephyr_Drv_ZephyrGpioDriver.a  lib/zephyr/libZephyr_Drv_ZephyrRateDriver.a  lib/zephyr/libDrv_Ports.a  lib/zephyr/libZephyr_Drv_ZephyrUartDriver.a  lib/zephyr/libSvc_ActiveLogger.a  lib/zephyr/libSvc_Fatal.a  lib/zephyr/libSvc_AssertFatalAdapter.a  lib/zephyr/libSvc_CmdDispatcher.a  lib/zephyr/libSvc_Deframer.a  lib/zephyr/libSvc_Framer.a  lib/zephyr/libDrv_ByteStreamDriverModel.a  lib/zephyr/libSvc_FramingProtocol.a  lib/zephyr/libUtils_Types.a  lib/zephyr/libFw_Ports_SuccessCondition.a  lib/zephyr/libSvc_PassiveConsoleTextLogger.a  lib/zephyr/libSvc_PassiveRateGroup.a  lib/zephyr/libSvc_RateGroupDriver.a  lib/zephyr/libSvc_Cycle.a  lib/zephyr/libSvc_StaticMemory.a  lib/zephyr/libSvc_SystemResources.a  lib/zephyr/libSvc_TlmChan.a  lib/zephyr/libSvc_Sched.a  lib/zephyr/libSvc_Ping.a  lib/zephyr/libFw_CompQueued.a  lib/zephyr/libFw_Comp.a  lib/zephyr/libOs.a  lib/zephyr/libOs_File_Common.a  lib/zephyr/libUtils_Hash.a  lib/zephyr/libOs_Cpu_Common.a  lib/zephyr/libOs_Memory_Common.a  lib/zephyr/libOs_Queue_Common.a  lib/zephyr/libOs_Mutex_Common.a  lib/zephyr/libOs_Task_Common.a  lib/zephyr/libOs_Console_Common.a  lib/zephyr/libOs_RawTime_Common.a  lib/zephyr/libFw_Buffer.a  lib/zephyr/libFw_Prm.a  lib/zephyr/libFw_Cmd.a  lib/zephyr/libFw_Log.a  lib/zephyr/libFw_Tlm.a  lib/zephyr/libFw_Com.a  lib/zephyr/libFw_Time.a  lib/zephyr/libFw_Port.a  lib/zephyr/libFw_Obj.a  lib/zephyr/libFw_Logger.a  lib/zephyr/libFw_Types.a  lib/zephyr/libFw_Cfg.a  lib/zephyr/libconfig.a  zephyr/kernel/libkernel.a  lib/zephyr/libOs_Zephyr_Shared.a  -mcpu=cortex-m7  -mthumb  -mabi=aapcs  -mfpu=fpv5-d16  -mfloat-abi=hard  -mfp16-format=ieee  -fuse-ld=bfd  -Wl,--gc-sections  -Wl,--build-id=none  -Wl,--no-relax  -Wl,--sort-common=descending  -Wl,--sort-section=alignment  -Wl,-u,_OffsetAbsSyms  -Wl,-u,_ConfigAbsSyms  -nostdlib  -static  -Wl,-X  -Wl,-N  -Wl,--orphan-handling=warn  -Wl,-no-pie  -L"/home/user/zephyr-sdk-0.17.0/arm-zephyr-eabi/arm-zephyr-eabi"/lib/thumb/v7e-m+dp/hard && cd /fprime-zephyr-reference/build/LedBlinker && /usr/bin/cmake -DCMAKE_INSTALL_COMPONENT=LedBlinker -P /fprime-zephyr-reference/build/cmake_install.cmake
/home/user/zephyr-sdk-0.17.0/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/../../../../arm-zephyr-eabi/bin/ld.bfd: warning: cannot find entry symbol _start; defaulting to 0000000000008000
/home/user/zephyr-sdk-0.17.0/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/../../../../arm-zephyr-eabi/bin/ld.bfd: lib/zephyr/libOs_Task_Common.a(Task.cpp.obj): in function `_GLOBAL__sub_I__ZN2Os13TaskInterface9ArgumentsC2ERKN2Fw10StringBaseEPFvPvES6_jjjj':
/fprime-zephyr-reference/fprime/Os/Task.cpp:54: undefined reference to `Os::Mutex::Mutex()'
/home/user/zephyr-sdk-0.17.0/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/../../../../arm-zephyr-eabi/bin/ld.bfd: lib/zephyr/libOs_Task_Common.a(Task.cpp.obj): in function `__static_initialization_and_destruction_0':
/fprime-zephyr-reference/fprime/Os/Task.cpp:54: undefined reference to `__dso_handle'
/home/user/zephyr-sdk-0.17.0/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/../../../../arm-zephyr-eabi/bin/ld.bfd: /fprime-zephyr-reference/fprime/Os/Task.cpp:54: undefined reference to `Os::Mutex::~Mutex()'
/home/user/zephyr-sdk-0.17.0/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/../../../../arm-zephyr-eabi/bin/ld.bfd: /fprime-zephyr-reference/fprime/Os/Task.cpp:54: undefined reference to `__aeabi_atexit'
/home/user/zephyr-sdk-0.17.0/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/../../../../arm-zephyr-eabi/bin/ld.bfd: bin/zephyr/LedBlinker: hidden symbol `__dso_handle' isn't defined
/home/user/zephyr-sdk-0.17.0/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/../../../../arm-zephyr-eabi/bin/ld.bfd: final link failed: bad value

It seems as though the executable must be the zephyr executable and then use the fprime build as a library.

I looked a bit into the "How-To: Develop an F´ Library" but it doesn't really seem applicable for this case where we want to expose the deployment as a library.

If there's any other suggestions here I'd appreciate it.

[ReggieMarr]

So I managed to get things to build for my zephyr reference project fork, one of the core hurdles was that zephyr and fprime's build systems both really want the final target (in fprime's case deployment) to be an executable.

I got around this by adding my own "generate" function in the deployments CMakeLists.txt which looks like so:

restrict_platforms(Zephyr)

add_fprime_subdirectory("${CMAKE_CURRENT_LIST_DIR}/Top/")
set(SOURCE_FILES "${CMAKE_CURRENT_LIST_DIR}/Stub.cpp")
set(MOD_DEPS ${FPRIME_CURRENT_MODULE}/Top)

# This results in creating a new library target based on this module's sources
register_fprime_module()

include("${FPRIME_FRAMEWORK_PATH}/cmake/target/build.cmake")
function(generate_zephyr_deployment TARGET_TYPE TARGET_NAME SOURCE_FILES DEPENDENCIES)
    get_nearest_build_root(${CMAKE_CURRENT_LIST_DIR})
    set_property(GLOBAL PROPERTY MODULE_DETECTION TRUE)

    # The function this is based off of would call add_executable or add_library here
    # but zephyr handles this for us already

    # Modules properties for posterity
    set_target_properties("${TARGET_NAME}" PROPERTIES
        IS_DEPLOYMENT_LIB TRUE
        FP_TYPE "Deployment"
    )
    set_property(GLOBAL APPEND PROPERTY FPRIME_MODULES ${TARGET_NAME})

    setup_single_target("build" "${TARGET_NAME}" "${SOURCE_FILES}" "${DEPENDENCIES}")
endfunction(generate_zephyr_deployment)

# Links LedBlinker_Top to zephyr interface library
target_link_libraries(LedBlinker PUBLIC zephyr_interface)

target_sources(app PRIVATE
    "${CMAKE_CURRENT_LIST_DIR}/Main.cpp"
)

generate_zephyr_deployment("Deployment" "app" "${SOURCE_FILES}" "${MOD_DEPS}")

# Use Zephyr's link group mechanism
target_link_libraries(app PUBLIC
    LedBlinker
)

set_target_properties(Svc_FatalHandler PROPERTIES EXCLUDE_FROM_ALL TRUE)

and then modifying the "is_target_library" function in fprime/cmake/utilities like so:

function(is_target_library OUTPUT TEST_TARGET)
    set("${OUTPUT}" FALSE PARENT_SCOPE)
    if (TARGET "${TEST_TARGET}")
        # Check if marked as deployment
        get_target_property(IS_DEPLOYMENT "${TEST_TARGET}" IS_DEPLOYMENT_LIB)
        if(IS_DEPLOYMENT)
            set("${OUTPUT}" FALSE PARENT_SCOPE)
            return()
        endif()

        # Original library check
        get_target_property(TARGET_TYPE "${TEST_TARGET}" TYPE)
        ends_with(IS_LIBRARY "${TARGET_TYPE}" "_LIBRARY")
        set("${OUTPUT}" "${IS_LIBRARY}" PARENT_SCOPE)
    endif()
endfunction()

in combination with setting the FPRIME_SUB_BUILD_TARGETS to avoid the install and util targets (which would cause conflicts)

This is all key in ensuring that the setup_executable_implementations gets called to link the os implementations to the zephyr "app" which also is linked to the LedBlinker library. Originally this was the deployment target but I instead called register_fprime_module making it a static library which I could force to have the right flags by linking against the zephyr_interface (something I picked up from stackoverflow)

A more elegant solution would be adding something to the API to support registering deployments as applications. I started at this but figured I could use some input from @LeStarch and/or @ethancheez before getting too far.

Also on a related note @ethancheez I ran into some startup faults mostly related to tuning stack sizes, due to the way the Zephyr/Os/Task.cpp has been setup we're kinda reliant on malloc'ing task stacks at run time and there seems to be a similar approach with the ZephyrRateDriver where instead of leveraging the singleton pattern and defining the timer at compile time we do so at runtime.

I get that where you land on dynamic allocation for runtime flexibility vs static allocation for more determinism/reliability is dependent on your con-ops but for me I think I'm gonna want to either refactor these modules to support static definitions or just provide separate implementations which could be leveraged with choose_fprime_implementation.
However I'd be curious to hear some context on why you went with a more dynamic approach in case I'm about to run into some fprime "gotcha".

[LeStarch]

The project: fprime-zephyr-reference now builds!