Converting Makefile to CMake - cmake

Question

I am attempting to replicate the following behaviour in CMake and need a little assistance...
I am compiling using gcc then linking using ld explicity. The original makefile carries out the following:
arm-linux-gcc -MD -Wa,-mcpu=arm7tdmi -Dgcc -c init.S
arm-linux-gcc -MD -Wall -fno-common -fshort-enums -mcpu=arm7tdmi -fno-builtin -mapcs -O2 -c serial.c
arm-linux-gcc -MD -Wall -fno-common -fshort-enums -mcpu=arm7tdmi -fno-builtin -mapcs -O2 -c timer.c
arm-linux-gcc -MD -Wall -fno-common -fshort-enums -mcpu=arm7tdmi -fno-builtin -mapcs -O2 -c amd.c
arm-linux-gcc -MD -Wall -fno-common -fshort-enums -mcpu=arm7tdmi -fno-builtin -mapcs -O2 -c intel.c
arm-linux-gcc -MD -Wall -fno-common -fshort-enums -mcpu=arm7tdmi -fno-builtin -mapcs -O2 -c at25f1024.c
arm-linux-gcc -MD -Wall -fno-common -fshort-enums -mcpu=arm7tdmi -fno-builtin -mapcs -O2 -c sst25vf020.c
arm-linux-gcc -MD -Wall -fno-common -fshort-enums -mcpu=arm7tdmi -fno-builtin -mapcs -O2 -c main.c
arm-linux-ld -q --defsym ROBASE=0x00000000 -T init.lds -o init.elf init.o serial.o timer.o amd.o intel.o at25f1024.o sst25vf020.o main.o
My CMakefileLists.txt looks like this
cmake_minimum_required(VERSION 2.8)
project(bootStage2)
#add_definitions(ROBASE
set(CMAKE_C_FLAGS "-MD -Wall -fno-common -fshort-enums -mcpu=arm7tdmi -fno-builtin -mapcs -O2 -Wl,-q -Wl,--defsym=ROBASE=0x00000000 -T ${bootStage2_SOURCE_DIR}/init.lds")
#add_definitions(ROBASE=0x00000000)
set(SRCFILES
serial.c
timer.c
amd.c
intel.c
at25f1024.c
sst25vf020.c
main.c
)
set(CMAKE_init.elf_LINK_EXECUTABLE "/usr/bob/arm920t/usr/bin/arm-linux-ld")
add_executable( init.elf ${SRCFILES})
SET_TARGET_PROPERTIES(init.elf PROPERTIES LINKER_LANGUAGE C)
add_dependencies( init.elf
assemble_S
)
add_custom_target(assemble_S
COMMAND /usr/bob/arm920t/usr/bin/arm-linux-gcc -MD -Wa,-mcpu=arm7tdmi -Dgcc -c init.S
COMMENT "Assembling init.S"
WORKING_DIRECTORY ${bootStage2_SOURCE_DIR}
If I don't define the linker exe then CMake attempts to use gcc to link and seg faults on linking.
The cmake output complains that there are no files to link against when I tell it to use arm-linux-ld, I'm sure there is a better way of doing this does anyone have any useful hints?
Cheers,
Chris.

Answer 1

The way we found when we have faced this problem some years ago was the following:
We replaced the link-template in cmake (we used our own linker, but it also should work with only adding arguments):
set(CMAKE_CXX_LINK_EXECUTABLE "${LINKER} ... <LINK_FLAGS> <OBJECTS> <LINK_LIBRARIES>")
set(CMAKE_C_LINK_EXECUTABLE ${CMAKE_CXX_LINK_EXECUTABLE})
The ... I omitted our custom arguments. The key here is the <>-elements which are filled in by cmake for each target to be linked.
See also here.