CODEWITHSUNDEEP
cmake
Chris
Chris

Reputation: 407

Converting Makefile to CMake

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.

Upvotes: 1

Views: 1752

Answers (1)

Patrick B.
Patrick B.

Reputation: 12353

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.

Upvotes: 1

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