I am trying to import a library in CMake the modern way like shown in this thread: How do I add a library path in cmake?
The goal is to build a RTEMS test program. I'm building on a Ubuntu 20.04 machine, and I am cross compiling for an ARM target with the arm/stm32h7 BSP.
The libraries are located inside an external lib folder. I almost got the build process working, however CMake appears to do something which breaks the linking process. I propably did the mistake but I have problems figuring it out.
This is the basic setup of my CMake file, after I set up everything for cross compilation of RTEMS binaries:
...
# Here comes application stuff again
add_executable(${CMAKE_PROJECT_NAME} init.c led.c stm32h7xx_nucleo.c)
set(RTEMS_LIB_NAME "rtems_${RTEMS_ARCH_NAME}_${RTEMS_BSP_NAME}")
add_library(${RTEMS_LIB_NAME} SHARED IMPORTED)
set_target_properties(${RTEMS_LIB_NAME} PROPERTIES
IMPORTED_LOCATION ${RTEMS_BSP_LIB_PATH}
INTERFACE_INCLUDE_DIRECTORIES ${RTEMS_BSP_INC_PATH}
)
#target_link_directories(${RTEMS_LIB_NAME} INTERFACE
# ${RTEMS_BSP_LIB_PATH}
#)
#target_include_directories(${RTEMS_LIB_NAME} INTERFACE
# ${RTEMS_BSP_INC_PATH}
#)
target_link_options(${RTEMS_LIB_NAME} INTERFACE
# -I${RTEMS_BSP_INC_PATH}
# -B${RTEMS_BSP_LIB_PATH}
-Wl,--gc-sections
-Wl,-Bstatic
-Wl,-Bdynamic
-qrtems
)
target_link_libraries(${CMAKE_PROJECT_NAME} ${RTEMS_LIB_NAME})
Building the individual source files appears to work fine. The raw link command attempted by CMake will be the following:
/home/rmueller/Documents/RTEMS/toolchain/rtems/6/bin/arm-rtems6-gcc
-mthumb -mcpu=cortex-m7 -mfpu=fpv5-d16 -mfloat-abi=hard
-Wl,--gc-sections -Wl,-Bstatic -Wl,-Bdynamic
-qrtems CMakeFiles/blinky.dir/init.c.o CMakeFiles/blinky.dir/led.c.o CMakeFiles/blinky.dir/stm32h7xx_nucleo.c.o
-o blinky -Wl,-rpath,/home/rmueller/Documents/RTEMS/toolchain/rtems
/6/arm-rtems6/stm32h7 /home/rmueller/Documents/RTEMS/toolchain/rtems/6/arm-rtems6/stm32h7/lib
And I get the error:
./../../../arm-rtems6/bin/ld: cannot open linker script file linkcmds: No such file or directory
This is propably because the libraries are not in the search path somehow. I then found out that the following command links the binary properly:
/home/rmueller/Documents/RTEMS/toolchain/rtems/6/bin/arm-rtems6-gcc
-mthumb -mcpu=cortex-m7 -mfpu=fpv5-d16 -mfloat-abi=hard
-Wl,--gc-sections -Wl,-Bstatic -Wl,-Bdynamic
-qrtems CMakeFiles/blinky.dir/init.c.o CMakeFiles/blinky.dir/led.c.o
CMakeFiles/blinky.dir/stm32h7xx_nucleo.c.o -o blinky
-L/home/rmueller/Documents/RTEMS/toolchain/rtems/6/arm-rtems6/stm32h7/lib
Is the way to import the library wrong? I could just add the -L flag manually to my build target using commands like target_link_options , but I was thinking it would be nice if the search path could just be an interface requirement when linking the RTEMS library.
UPDATE: I think I found one error: I imported the library path as a SHARED library and it propably has to be imported as STATIC.
THe command now looks like this:
/home/rmueller/Documents/RTEMS/toolchain/rtems/6/bin/arm-rtems6-gcc -mthumb
-mcpu=cortex-m7 -mfpu=fpv5-d16 -mfloat-abi=hard -Wl,--gc-sections -Wl,-Bstatic -Wl,-Bdynamic -qrtems
CMakeFiles/blinky.dir/init.c.o CMakeFiles/blinky.dir/led.c.o CMakeFiles/blinky.dir/stm32h7xx_nucleo.c.o
-o blinky /home/rmueller/Documents/RTEMS/toolchain/rtems/6/arm-rtems6/stm32h7/lib
UPDATE2:
I solved the problem. There was still a little syntax error, I think the quotes were missing. The command to set the library properties looks like this now :
set_target_properties(${RTEMS_LIB_NAME} PROPERTIES
IMPORTED_LOCATION "${RTEMS_BSP_LIB_PATH}"
INTERFACE_INCLUDE_DIRECTORIES "${RTEMS_BSP_INC_PATH}"
)
And the binary is linked properly :-)
UPDATE3:
And it has stopped working again. This is really weird. The -L flag appears to be missing..
Kind Regards
Robin
