CMAKE separate Linker and Compiler Flags - eclipse

Question

Right now my toolchain.cmake looks loke this:
CMAKE_FORCE_C_COMPILER(arm-none-eabi-gcc GNU)
CMAKE_FORCE_CXX_COMPILER(arm-none-eabi-gcc GNU)
SET(CMAKE_ASM_COMPILER arm-none-eabi-as)
SET(CMAKE_OBJCOPY arm-none-eabi-objcopy CACHE INTERNAL "objcopy" FORCE)
SET(CMAKE_OBJDUMP arm-none-eabi-objdump CACHE INTERNAL "objdump" FORCE)
# Compiler Flags
SET(MCU_FLAGS "-mcpu=cortex-m3 -mthumb")
SET(CMAKE_BUILD_FLAGS "-O2 -g -mfpu=vfp -mfloat-abi=soft -Wa,-meabi=5 -ffunction-sections -fno-common -pedantic -Wall -Wextra -Wno-missing-field-initializers")
SET(CMAKE_C_FLAGS "${MCU_FLAGS} ${CMAKE_BUILD_FLAGS}" CACHE INTERNAL "c compiler flags")
SET(CMAKE_CXX_FLAGS ${CMAKE_C_FLAGS} CACHE INTERNAL "cxx compiler flags")
SET(CMAKE_ASM_FLAGS "-g -mcpu=cortex-m3 -mthumb -mfpu=vfp -mfloat-abi=soft -meabi=5 -warn" CACHE INTERNAL "asm compiler flags")
SET(CMAKE_EXE_LINKER_FLAGS "-mcpu=cortex-m3 -mthumb -Wall -Wextra -Wno-missing-field-initializers -g -nostartfiles -Wl,-T1.ld,-M=1.map,--gc-sections" CACHE INTERNAL "exe link flags")
The problem is that CMake passes to the Linker additionally the Compiler-flags! Is there any way to separate these two?
Another thing is if I use another compiler-tool-chain (Like Fujitsu Softtune) how can I tell CMake explicitly to take a Linker and not the compiler to Link objects?
Thanks
So i finally solved it. for evryone else with the same problem, i changed CMakelists as follow:
add_executable(${PROJECT_NAME} ${PROJECT_SOURCES})
SET_TARGET_PROPERTIES(${PROJECT_NAME} PROPERTIES LINKER_LANGUAGE C CXX ASM)
SET_TARGET_PROPERTIES(${PROJECT_NAME} PROPERTIES LINK_FLAGS "${LD_FLAGS_STR} -m ${PROJECT_NAME}.map")
set(CMAKE_C_LINK_EXECUTABLE "FLNK907S.EXE -o <TARGET> <LINK_FLAGS> <OBJECTS>")
and it works fine...
where ${LD_FLAGS_STR} is just the list of my linker flags (own variable). and LNK907S.EXE is the name of Linker i 'm using (Fujitsu).

Answer 1

Try using SET_TARGET_PROPERTIES to set the link flags, respectively:
SET(MCU_FLAGS "-mcpu=cortex-m3 -mthumb")
SET(CMAKE_BUILD_FLAGS "-O2 -g -mfpu=vfp -mfloat-abi=soft -Wa,-meabi=5 -ffunction-sections -fno-common -pedantic -Wall -Wextra -Wno-missing-field-initializers")
SET(CMAKE_C_FLAGS "${MCU_FLAGS} ${CMAKE_BUILD_FLAGS}")
SET(CMAKE_CXX_FLAGS ${CMAKE_C_FLAGS})
SET(CMAKE_ASM_FLAGS "-g -mcpu=cortex-m3 -mthumb -mfpu=vfp -mfloat-abi=soft -meabi=5 -warn")
SET_TARGET_PROPERTIES(FOO PROPERTIES LINK_FLAGS "-mcpu=cortex-m3 -mthumb -Wall -Wextra -Wno-missing-field-initializers -g -nostartfiles -Wl,-T1.ld,-M=1.map,--gc-sections")
Here, I have assumed your excutable is called "FOO". Note that the link libaries are specified on a per-target basis. If you need special compiler flags for the target only, you can use COMPILE_FLAGS in SET_TARGET_PROPERTIES as well.

Answer 2

With newer versions of cmake, using generator expressions [1] has been my preferred approach.
target_compile_options(${TARGET_NAME}
PRIVATE
$<$<COMPILE_LANGUAGE:C>:${C_DEFS} ${C_FLAGS}>
$<$<COMPILE_LANGUAGE:ASM>:${ASM_FLAGS}>)
[1] https://cmake.org/cmake/help/latest/manual/cmake-generator-expressions.7.html