[CMake] Embedded build using ExternalProject

[Hendrik Sattler]

Am 26. Juni 2019 15:53:16 MESZ schrieb Torsten Robitzki <Torsten at Robitzki.de>:
>Hello,
>
>I have a project, where binaries are build for an embedded platform and
>for a PC platform. To build software update packages for the embedded
>platforms (files that can be used to make in the field firmware
>updates), tools that have to run during the build have to be build from
>source first. For example firmware.tfp have to be build by running
>create_package with firmware.bin. firmware.bin have to build with
>settings for the embedded platform and create_package have to be build
>with setting of the build host.
>
>I’ve asked this question already a year or so ago and got the response,
>that using super builds will help me. Now I try to convert the project
>to a super build structure. Fortunately, there was very little content
>inside my main CMakeLists.txt, mainly `add_subdirectory( source )`.
>Mainly, I want to build different sets of artifacts from the same
>source tree, but with different
>
>Now I’m stuck with a number of issues. First, I want to build all
>firmware binaries for the NRF52 embedded platform:
>
>    ExternalProject_Add(firmware_binaries
>        SOURCE_DIR  ${CMAKE_CURRENT_LIST_DIR}/source
>        INSTALL_DIR ${installDir}
>        CMAKE_ARGS
>            -DCMAKE_INSTALL_PREFIX:PATH=<INSTALL_DIR>
>            -DBOOTLOADER_AES_KEY=${BOOTLOADER_AES_KEY}
>            -DBOOTLOADER_VERSION=${BOOTLOADER_VERSION}
>            -DBUILD_DEBUG=1
>            -DBUILD_NRF52=1
>BUILD_COMMAND ${CMAKE_COMMAND} --build ${CMAKE_CURRENT_BINARY_DIR}
>--target firmware_binaries
>    )

The build command is using the wrong directory.

>I don’t want to build any EOL test firmware, test-tools etc. just the
>stuff that will be shipped, thus the explicit target. I can build the
>firmware_binaries, from the source directly, without problems. But when
>I try to build with the top-level cmake file, that contains the
>ExternalProject_Add(), I get the usual configure output and then:
>
>-- Configuring done
>-- Generating done
>-- Build files have been written to:
>/Users/todi/blueswd_firmware/build/firmware_binaries-prefix/src/firmware_binaries-build
>[ 75%] Performing build step for 'firmware_binaries'
>[ 12%] Performing build step for 'firmware_binaries'
>[ 12%] Performing build step for 'firmware_binaries'
>[ 12%] Performing build step for ‚firmware_binaries‘
>…
>
>This line repeats until make reports:
>
>make[776]: /usr/local/Cellar/cmake/3.14.3/bin/cmake: Resource
>temporarily unavailable
>make[776]: *** wait: No child processes.  Stop.
>make[776]: *** Waiting for unfinished jobs....
>make[776]: *** wait: No child processes.  Stop.
>
>Any idea, what might be wrong here? Some kind of recursion?
>
>An other issue: I want to forward targets to the super build, so that I
>can build them there. For example I have ~30 unit test programs and
>when I’m working in a certain area, I usually want to build exactly one
>of this programs. Is it possible to export them as targets of the super
>build?
>
>A third issue that I have is, that changes to the CMakeLists.txt files
>in the Project are not reflected by the super build. If I make a change
>to one of the CMake files under ${CMAKE_CURRENT_LIST_DIR}/source, I
>usually have to delete the whole build folder and start from scratch
>with the build. Is there an other way to force the super build to
>recognize the changes? (Note: ${CMAKE_CURRENT_LIST_DIR}/source is not
>added as subdirectory to the top level (super build) CMakeLists.txt).
>
>best regards,
>
>Torsten
>
>P.S.:
>$ cmake --version
>cmake version 3.14.3