I have a CMake script where the final executable is linked with my own linker script:
cmake_minimum_required(VERSION 3.1)
project(test_app)
set(LINKER_SCRIPT "linker.ld")
set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -T ${LINKER_SCRIPT}")
add_executable(${PROJECT_NAME}.elf
main.cpp
startup.cpp
)
How do I make an executable dependent also on the linker script file (trigger linking if linker.ld was changed)?
You can add a LINK_DEPENDS property to your executable target, using set_target_properties. Add the following line after your add_executable command:
set_target_properties(${TARGET_NAME} PROPERTIES LINK_DEPENDS ${LINKER_SCRIPT})
The first argument to set_target_properties is the target name, i.e. the first argument you passed to add_executable.
I found this mail which described three possible ways for forcing an executable to be dependent on a linker script. Its author prefers this way:
CMakeLists.txt:
CMAKE_MINIMUM_REQUIRED(VERSION 2.8 FATAL_ERROR)
PROJECT(LINKERSCRIPT C)
FILE(WRITE main.c "void main(){}")
# dummy.c must exist:
ADD_EXECUTABLE(EXE main.c dummy.c)
# linkerscript must exist:
SET_SOURCE_FILES_PROPERTIES(
dummy.c PROPERTIES OBJECT_DEPENDS ${CMAKE_SOURCE_DIR}/linkerscript
)
Here dummy.c is an empty file, which is listed for the add_executable() command only for make resulted executable dependent on the linker script via the OBJECT_DEPENDS property.
Related
I've been playing around with GCC lately and have been experimenting with the linking options. I'm somewhat confused why the link option -l is necessary when statically linking to an archive file. It seems like you can just toss the .a file as if it were an ordinary object file.
For example, take the following make file:
test1 : main.c libfunc.a
gcc main.c -L. -lfunc -o main.out
test2 : main.c libfunc.a
gcc main.c libfunc.a -o main.out
libfunc.a : func1.c func2.c
gcc func1.c -c
gcc func2.c -c
ar cr libfunc.a func1.o func2.o
Make target test1 uses GCC's linking options to link to the archive file. Target test2 instead just includes the archive file direct. Building and running each output seem to result in the same executable.
There are several ways you can tell gcc what file(s) to use. An argument of the form -lname (or the two arguments -l name) says “Search for a library named name”. Per the GCC documentation, this argument is passed to the linker (typically the ld command). The linker looks for a file with a name like libname.extension, where extension is one of the known library files extensions such as .a or .so, and it looks for files with those names in a list of library directories it has. You can add directories to search with the -L switch.
When the linker finds the library, it uses it just as if you had specified the path, so the end result is the same whether you specify the library with -l or with its path.
By using the path, you can specify libraries that are not in the known library directories or that have unusual names.
Note that the linker does not process libraries the same way as object files. When the linker processes an object file, it incorporates everything in the object file into the output file being constructed. When the linker processes a library file, it incorporates only those modules within the library that provide a symbol definition for a symbol referenced by a prior module and not yet resolved. For example, if you write a program that uses sqrt but does not use sin, then, when the linker processes libm.a after reading your object module, it will take the sqrt module from the library but not the sin module.
I have a C application which is running on Raspberry Pi 3 and currently, I have to build it on PI with Cmake. I am trying to build it on Ubuntu machine. I have added a CMAKE_TOOLCHAIN_FILE as described here.
I could run cmake. -DCMAKE_TOOLCHAIN_FILE without any problem but the "make" command is not successful and it can not find a header file inside one of the external library: "mirsdrapi-rsp". The error message is:
fatal error: mirsdrapi-rsp.h: No such file or directory
#include "mirsdrapi-rsp.h"
^
compilation terminated.
I have created a folder named "lib" and have put the "libmirsdrapi-rsp.so" file inside it.
my CMakeLists.txt is as below:
cmake_minimum_required(VERSION 3.4.1)
set(CMAKE_C_STANDARD 11)
set(CMAKE_CXX_STANDARD 11)
set(CMAKE_C_STANDARD_REQUIRED ON)
set(CMAKE_CXX_STANDARD_REQUIRED ON)
set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -pedantic -Wextra -v -g -D_XOPEN_SOURCE")
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -pedantic -Wextra -v ")
set(CMAKE_EXE_LINKER_FLAGS ${CMAKE_EXE_LINKER_FLAGS} "-v")
set (SDR_API_PATH ${CMAKE_SOURCE_DIR}/lib)
include_directories (include ${SDR_API_PATH})
include_directories("${CMAKE_SOURCE_DIR}/lib")
find_library(mirslocation NAMES mirsdrapi-rsp HINTS ${SDR_API_PATH} NO_CMAKE_FIND_ROOT_PATH)
message(STATUS ${mirslocation})
add_library(mirs STATIC IMPORTED)
set_target_properties(mirs PROPERTIES IMPORTED_LOCATION ${mirslocation})
target_link_libraries (raspberryPiDaemon mirs)
target_link_libraries(raspberryPiDaemon m)
Cmake is printing the right path of the library mirsdrapi-rsp while running "find_library" and as I mentioned I am getting the error message just while running "make" command and not "cmake" command.
My content of CMAKE_TOOLCHAIN_FILE is as below:
# Define our host system
SET(CMAKE_SYSTEM_NAME Linux)
SET(CMAKE_SYSTEM_VERSION 1)
# Define the cross compiler locations
SET(CMAKE_C_COMPILER ${CMAKE_SOURCE_DIR}/../tools-master/arm-bcm2708/arm-rpi-4.9.3-linux-gnueabihf/bin/arm-linux-gnueabihf-gcc)
SET(CMAKE_CXX_COMPILER ${CMAKE_SOURCE_DIR}/../tools-master/arm-bcm2708/arm-rpi-4.9.3-linux-gnueabihf/bin/arm-linux-gnueabihf-gcc)
# Define the sysroot path for the RaspberryPi distribution in our tools folder
SET(CMAKE_FIND_ROOT_PATH ${CMAKE_SOURCE_DIR}/../tools-master/arm-bcm2708/arm-rpi-4.9.3-linux-gnueabihf/arm-linux-gnueabihf/sysroot/SET)
# Use our definitions for compiler tools
SET(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
# Search for libraries and headers in the target directories only
SET(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY BOTH)
SET(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE BOTH)
add_definitions(-Wall -std=c11)
Anybody knows how I can add the header file from mirsdrapi-rsp library to include path?
I guess that you're setting include_directories to the wrong path (it is set 2 times to ${CMAKE_SOURCE_DIR}/lib which must be the folder of libraries not the header files). Check again the correct location of the missing header file.
More precisely: you need to find the path of mirsdrapi-rsp.h and let CMake know it just like for find_library:
find_path(MIRSDRAPI_INCLUDE_DIRS NAMES mirsdrapi-rsp.h PATHS {proper-location})
if (MIRSDRAPI_INCLUDE_DIRS)
target_include_directories(raspberryPiDaemon PRIVATE ${MIRSDRAPI_INCLUDE_DIRS})
endif()
In addition, you can set the INTERFACE_INCLUDE_DIRECTORIES property to the library like this:
set_property(TARGET mirsdrapi-rsp APPEND PROPERTY INTERFACE_INCLUDE_DIRECTORIES ${MIRSDRAPI_INCLUDE_DIRS})
This way, target_include_directories might be unnecessary and target_link_directories should be enough.
I am trying to cross-compile a project for embedded ARM Cortex builds, but I am unable to get the linker working. I want to use armlink, but no files are passed to armlink and hence no .elf file is produced.
My CMakeLists.txt is pretty simple and given below. The failure is shown after that which shows that armlink was invoked by the makefile without any arguments.
Any pointers will help - I searched and read many posts, but they all seem to have more involved requirements.
cmake_minimum_required(VERSION 2.8)
project(test_arm)
enable_language(C ASM)
# Cross-compilation for ARM
SET(CMAKE_C_COMPILER armcc)
SET(CMAKE_LINKER armlink)
SET(CMAKE_C_LINK_EXECUTABLE armlink)
SET(CMAKE_C_FLAGS "--cpu=Cortex-M3")
SET(LINK_FLAGS "--map --ro-base=0x0 --rw-base=0x0008000 --first='boot.o(RESET)' --datacompressor=off")
SET(CMAKE_EXE_LINKER_FLAGS "--map --ro-base=0x0 --rw-base=0x0008000 --first='boot.o(RESET)' --datacompressor=off")
include_directories(../include)
add_executable(blinky blinky.c)
set_target_properties(blinky PROPERTIES LINKER_LANGUAGE C)
The failure is as follows, but I guess it would be obvious to someone given that I have some stupid issue in my CMakeLists:
$ make VERBOSE=1
[100%] Building C object CMakeFiles/blinky.dir/blinky.c.o
/usr/bin/cmake -E cmake_link_script CMakeFiles/blinky.dir/link.txt --verbose=1
armlink
Linking C executable blinky
Product: DS-5 Professional 5.21.0 [5210017]
Component: ARM Compiler 5.05 update 1 (build 106)
Tool: armlink [4d0efa]
For support see http://www.arm.com/support/
Software supplied by: ARM Limited
Usage: armlink option-list input-file-list
where
....
I was expecting the CMake generated Makefile to invoke armlink with something like:
armlink --map --ro-base=0x0 --rw-base=0x0008000 \
--first='boot.o(RESET)' --datacompressor=off \
CMakeFiles/blinky.dir/blinky.c.o -o blinky.elf
Starting with CMake v3.5 you don't need a toolchain anymore for Keil ARM C/C++ compilation tools:
Support was added for the ARM Compiler (arm.com) with compiler id ARMCC.
Just set your C/CXX compiler variables accordingly
cmake -DCMAKE_C_COMPILER:PATH="C:\Program Files (x86)\DS-5\bin\armcc.exe"
-DCMAKE_CXX_COMPILER:PATH="C:\Program Files (x86)\DS-5\bin\armcc.exe"
...
References
ARMCC toolchain support
Add support for the ARM Compiler (arm.com)
CMake Error at CMakeLists.txt:30 (project): No CMAKE_C_COMPILER could be found
From my experience, you cannot set CMAKE_EXE_LINKER_FLAGS in a CMakeLists.txt file. It has to be passed via a CMAKE_TOOLCHAIN_FILE when CMake is invoked the very first time in a build directory.
I don't find any documentation regarding this problem, but there is the cross-compilation with CMake page which you should use it if you do cross-compilation.
For a start, just put your set-calls in a toolchain file and run
cmake -DCMAKE_TOOLCHAIN_FILE=<yourfile.toolchain>
in a clean build directory.
A toolchain file may be a good idea. Here is what I've came up the last time I tried CMake 2.8.10 with the DS-5 toolchain (it could still be optimized, but it should give you a starting point):
INCLUDE(CMakeForceCompiler)
# This one is important
SET(CMAKE_SYSTEM_NAME Generic)
SET(CMAKE_SYSTEM_PROCESSOR arm)
# Specify the cross compiler
SET(CMAKE_C_COMPILER "C:/Program Files (x86)/DS-5/bin/armcc.exe")
SET(CMAKE_CXX_COMPILER "C:/Program Files (x86)/DS-5/bin/armcc.exe")
SET(CMAKE_AR "C:/Program Files (x86)/DS-5/bin/armar.exe" CACHE FILEPATH "Archiver")
#CMAKE_FORCE_C_COMPILER("C:/Program Files (x86)/DS-5/sw/gcc/bin/arm-linux-gnueabihf-gcc.exe" GNU)
#CMAKE_FORCE_CXX_COMPILER("C:/Program Files (x86)/DS-5/sw/gcc/bin/arm-linux-gnueabihf-g++.exe" GNU)
UNSET(CMAKE_C_FLAGS CACHE)
SET(CMAKE_C_FLAGS "--cpu=Cortex-A9 --thumb -Ospace" CACHE STRING "" FORCE)
UNSET(CMAKE_CXX_FLAGS CACHE)
SET(CMAKE_CXX_FLAGS ${CMAKE_C_FLAGS} CACHE STRING "" FORCE)
UNSET(CMAKE_EXE_LINKER_FLAGS CACHE)
SET(CMAKE_EXE_LINKER_FLAGS "" CACHE STRING "" FORCE)
UNSET(CMAKE_AR_FLAGS CACHE)
SET(CMAKE_AR_FLAGS "-p -armcc,-Ospace" CACHE STRING "" FORCE)
# set(CMAKE_C_ARCHIVE_CREATE "<CMAKE_AR> cr <TARGET> <LINK_FLAGS> <OBJECTS>")
SET(CMAKE_C_ARCHIVE_CREATE "<CMAKE_AR> ${CMAKE_AR_FLAGS} -o <TARGET> <OBJECTS>" CACHE STRING "C Archive Create")
# set(CMAKE_CXX_ARCHIVE_CREATE "<CMAKE_AR> cr <TARGET> <LINK_FLAGS> <OBJECTS>")
SET(CMAKE_CXX_ARCHIVE_CREATE "<CMAKE_AR> ${CMAKE_AR_FLAGS} -o <TARGET> <OBJECTS>" CACHE STRING "CXX Archive Create")
include_directories("C:/Program Files (x86)/DS-5/include")
#include_directories("C:/Program Files (x86)/DS-5/sw/gcc/arm-linux-gnueabihf/libc/usr/include/arm-linux-gnueabi")
# Where is the target environment
SET(CMAKE_FIND_ROOT_PATH "C:/Program Files (x86)/DS-5")
# Search for programs in the build host directories
SET(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
# For libraries and headers in the target directories
SET(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
SET(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
Regarding your question
Some failure analysis
What you have tried should work (see also e.g. How do I add a linker or compile flag in a CMake file?). But it seems something goes wrong during the configuration step.
I don't know your command line call for CMake's configuration/generation steps, so some general tips to find the root cause:
You could try calling
cmake.exe --trace ...
to see what went wrong with your CMAKE_EXE_LINKER_FLAGS variable. This will generate a lot of output, so here are some basics on what CMake does:
The project() command will trigger the compiler evaluation
This will write CMAKE_EXE_LINKER_FLAGS into your CMakeCache.txt
You are overwriting it with a local variable (see variable scope docu here)
If you look into share\cmake-2.8\Modules\CMakeCommonLanguageInclude.cmake:
set (CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS_INIT} $ENV{LDFLAGS}"
CACHE STRING "Flags used by the linker.")
You could use CMAKE_EXE_LINKER_FLAGS_INIT, but you have to set it before the project() command or in the toolchain file.
Because you set the link language to C take a look into share\cmake-2.8\Modules\CMakeCInformation.cmake:
if(NOT CMAKE_C_LINK_EXECUTABLE)
set(CMAKE_C_LINK_EXECUTABLE
"<CMAKE_C_COMPILER> <FLAGS> <CMAKE_C_LINK_FLAGS> <LINK_FLAGS> <OBJECTS> -o <TARGET> <LINK_LIBRARIES>")
endif()
So you can use CMAKE_C_LINK_EXECUTABLE to overwrite the complete linker call or you could use CMAKE_C_LINK_FLAGS to set additional flags.
The "official" way
The official way to set the target's linker and compiler flags would be (before CMake 2.8.12):
set_property(TARGET blinky APPEND_STRING PROPERTY COMPILE_FLAGS "--cpu=Cortex-M3")
set_property(TARGET blinky APPEND_STRING PROPERTIES LINK_FLAGS "--map --ro-base=0x0 --rw-base=0x0008000 --first='boot.o(RESET)' --datacompressor=off")
Starting with CMake 2.8.12 it would be something like:
add_compile_options("--cpu=Cortex-M3")
In the root directory of my project, I have a subdirectory for my_lib and another for my_app.
The library my_lib defines tables that populates a section defined by the linker, these tables are not used directly by my_app, so this library is not linked.
To force my_lib to be linked I added the flag --whole-archive as described here.
And it works!
In the CMakelist.txt of the root directory I have the following:
SET(CMAKE_EXE_LINKER_FLAGS "-mmcu=cc430f6137 -Wl,--gc-sections -Wl,--whole-archive -lMY_LIB -Wl,--no-whole-archive")
ADD_SUBDIRECTORY(my_lib)
In the CMakelist.txt of my_lib I have:
ADD_LIBRARY(MY_LIB
my_lib.c
)
TARGET_LINK_LIBRARIES(MY_LIB)
In the CMakelist.txt of my_app I have:
ADD_EXECUTABLE(my_app my_app.c)
TARGET_LINK_LIBRARIES(my_app MY_LIB)
My problem is I just want to use this flag (--whole-archive) if MY_LIB is specified in the TARGET_LINK_LIBRARIES in CMakelist.txt of my_app.
If the the last line TARGET_LINK_LIBRARIES(my_app MY_LIB) is not there, I don't want to add "-Wl,--whole-archive -lMY_LIB -Wl,--no-whole-archive" in the CMAKE_EXE_LINKER_FLAGS.
I tried to remove this flag from the CMakelist.txt in root and add the following into the CMakelist.txt in my_lib subdirectory:
SET_TARGET_PROPERTIES(MY_LIB PROPERTIES CMAKE_EXE_LINKER_FLAGS "-Wl,--whole-archive -lMY_LIB -Wl,--no-whole-archive")
But this does not work.
How can I do this?
The CMake command target_link_libraries allows for specifying both libraries and flags when linking a given target. Instead of directly using the target name MY_LIB in the TARGET_LINK_LIBRARIES call, use a variable that wraps the reference to MY_LIB with the --whole-archive and --no-whole-archive flags:
ADD_LIBRARY(MY_LIB
my_lib.c
)
SET(MY_LIB_LINK_LIBRARIES -Wl,--whole-archive MY_LIB -Wl,--no-whole-archive)
...
ADD_EXECUTABLE(my_app my_app.c)
TARGET_LINK_LIBRARIES(my_app ${MY_LIB_LINK_LIBRARIES})
I am developing a small simulation software that depends on two libraries, the GSL and the libconfig. As a build system, I use CMake. For both the GSL and libconfig, I found cmake files and copied them into the cmake/ directory of my project.
The scenario is the following: I want the project to have several different build types, like debug, release, etc., but also a custom one called cluster, which adds -static to the GCC flags and links against the .a libraries of the GSL and the libconfig, which I assume exist.
My CMakeLists.txt looks like this so far:
# version
SET(PACKAGE_VERSION "1.0")
SET(PACKAGE_NAME "INTERFACE")
PROJECT(interface C CXX)
CMAKE_MINIMUM_REQUIRED(VERSION 2.8)
# dirs -----------------------------------------------------
SET(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_SOURCE_DIR}/cmake")
FIND_PACKAGE(GSL REQUIRED)
INCLUDE_DIRECTORIES(${GSL_INCLUDE_DIRS})
SET(LIBS ${LIBS} ${GSL_LIBRARIES})
FIND_PACKAGE(LibConfig REQUIRED)
INCLUDE_DIRECTORIES(${LIBCONFIG_INCLUDE_DIRS})
SET(LIBS ${LIBS} ${LIBCONFIG_LIBRARIES})
CONFIGURE_FILE("res/config.h.in" "config.h")
INCLUDE_DIRECTORIES(${CMAKE_BINARY_DIR})
SET_DIRECTORY_PROPERTIES(PROPERTIES
ADDITIONAL_MAKE_CLEAN_FILES "config.h"
)
# compilation ----------------------------------------------
ADD_EXECUTABLE( interface
interface.c interface.h config.h
helpers.c
output.c
lattice.c
genetic.c
)
# optional CFLAGS
SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -Wextra -pedantic -std=c99")
SET(CMAKE_C_FLAGS_RELEASE "-O3 -ffast-math")
SET(CMAKE_C_FLAGS_CLUSTER "-O3 -ffast-math -static")
SET(CMAKE_C_FLAGS_DEBUG "-g")
SET(CMAKE_C_FLAGS_PROFILE "-g -ffast-math -pg")
TARGET_LINK_LIBRARIES(interface m ${LIBS})
# installation --------------------------------------------
INSTALL(TARGETS interface DESTINATION bin)
This adds the -static to the compiler, when I use -DCMAKE_BUILD_TYPE=cluster. The thing is, that it still links against the .so versions of the libs, which causes gcc to throw errors. At least the FindLibConfig.cmake scripts sets both a LIBCONFIG_LIBRARY and a LIBCONFIG_STATIC_LIBRARY variable, which I could use.
What is the most elegant or smart way to reach my goal?
Acording to cmake documentation, cmake uses the variable BUILD_SHARED_LIBS to determine the default for add_library().
If you set to ON cmake will assume all add_library() call will be as
add_library(target SHARED lib1 lib2 ...)
For example something like -DBUILD_SHARED_LIBS=ON on the cmake command line may do what you are asking.
I solved it like this:
The User can specify an additional variable -DSTATIC_LINKING=TRUE. Then, the script looks like this. (Only the important parts for the static linking and compilation are shown!)
# determine, whether we want a static binary
SET(STATIC_LINKING FALSE CACHE BOOL "Build a static binary?")
# do we want static libraries?
# When STATIC_LINKING is TRUE, than cmake looks for libraries ending
# with .a. This is for linux only!
IF(STATIC_LINKING)
SET(CMAKE_FIND_LIBRARY_SUFFIXES ".a")
ENDIF(STATIC_LINKING)
# set -static, when STATIC_LINKING is TRUE and set LINK_SEARCH_END_STATIC
# to remove the additional -bdynamic from the linker line.
IF(STATIC_LINKING)
SET(CMAKE_EXE_LINKER_FLAGS "-static")
SET_TARGET_PROPERTIES(surface PROPERTIES
LINK_SEARCH_END_STATIC 1)
ENDIF(STATIC_LINKING)