Cross Compiling with Cmake

[rafal1137]

I have followed this GUIDE:
https://github.com/abhiTronix/raspberry-pi-cross-compilers/wiki/Raspberry-Pi-GCC-Cross-Compiler-ARM-Toolchains-CMake-Usage-Guide/17f85af96eafabab415351a21d8d653bd3feca5c#build-dummy-hello-world-project

I have added those to my cmake file.

            include_directories(${SYSROOT_PATH}/usr/include/arm-linux-gnueabihf)
            link_directories(${SYSROOT_PATH}/usr/lib/arm-linux-gnueabihf)

Have rasbian rootfs with correct linking.

My Toolchain Cmake file. Is a bit different from the guide posted there. But that should not be an issue.

if("$ENV{RASPBIAN_ROOTFS}" STREQUAL "")
	message(FATAL_ERROR "Define the RASPBIAN_ROOTFS environment variable to point to the raspbian rootfs.")
else()
	set(SYSROOT_PATH "$ENV{RASPBIAN_ROOTFS}")
endif()
set(TOOLCHAIN_HOST "arm-linux-gnueabihf")

message(STATUS "Using sysroot path: ${SYSROOT_PATH}")

set(TOOLCHAIN_CC "${TOOLCHAIN_HOST}-gcc")
set(TOOLCHAIN_CXX "${TOOLCHAIN_HOST}-g++")
set(TOOLCHAIN_LD "${TOOLCHAIN_HOST}-ld")
set(TOOLCHAIN_AR "${TOOLCHAIN_HOST}-ar")
set(TOOLCHAIN_RANLIB "${TOOLCHAIN_HOST}-ranlib")
set(TOOLCHAIN_STRIP "${TOOLCHAIN_HOST}-strip")
set(TOOLCHAIN_NM "${TOOLCHAIN_HOST}-nm")

set(CMAKE_CROSSCOMPILING TRUE)
set(CMAKE_SYSROOT "${SYSROOT_PATH}")

# Define name of the target system
set(CMAKE_SYSTEM_NAME "Linux")
set(CMAKE_SYSTEM_PROCESSOR "armv7l")

# Define the compiler
set(CMAKE_C_COMPILER ${TOOLCHAIN_CC})
set(CMAKE_CXX_COMPILER ${TOOLCHAIN_CXX})
set(CMAKE_C_COMPILER_WORKS 1)
set(CMAKE_CXX_COMPILER_WORKS 1)

set(CMAKE_PREFIX_PATH "${CMAKE_PREFIX_PATH};${SYSROOT_PATH}/usr/lib/${TOOLCHAIN_HOST}")
set(CMAKE_FIND_ROOT_PATH "${CMAKE_INSTALL_PREFIX};${CMAKE_PREFIX_PATH};${CMAKE_SYSROOT}")

# 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)
set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY)

But when I want to compile it. It fails.

Those are the errors/issues I am getting during complilation

/lib/ld-linux-armhf.so.3: No such file or directory

This one comes at linking procedure

/opt/cross-pi-gcc/bin/../lib/gcc/arm-linux-gnueabihf/10.2.0/../../../../arm-linux-gnueabihf/bin/ld: cannot find crti.o: No such file or directory
collect2: error: ld returned 1 exit status

[abhiTronix]

@rafal1137 Please remove set(CMAKE_SYSROOT "${SYSROOT_PATH}") and set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER) lines from your Toolchain Cmake file and try again. Make sure you clean up build directory before trying again.

[abhiTronix]

@rafal1137 Please test it and report back here, check if this fixes your issue. Good luck.

[abhiTronix]

@rafal1137 For more information on why CMAKE_FIND_ROOT_PATH is preferred for cross compiling, see here: https://stackoverflow.com/a/34077078

[rafal1137]

@abhiTronix
So I did followed your suggestion there to remove those 2 lines but my project in short might depend on CMAKE_SYSROOT being set.
Because after testing those changes.

CMake Error at /usr/share/cmake-3.13/Modules/FindX11.cmake:429 (message):
  Could not find X11
....
-- Configuring incomplete, errors occurred!

[abhiTronix]

@rafal1137 Did you made following symlinks before syncing sysroot with RPi?

sudo ln -sf -r /usr/include/arm-linux-gnueabihf/asm /usr/include
sudo ln -sf -r /usr/include/arm-linux-gnueabihf/gnu /usr/include
sudo ln -sf -r /usr/include/arm-linux-gnueabihf/bits /usr/include
sudo ln -sf -r /usr/include/arm-linux-gnueabihf/sys /usr/include
sudo ln -sf -r /usr/include/arm-linux-gnueabihf/openssl /usr/include
sudo ln -sf /usr/lib/arm-linux-gnueabihf/crtn.o /usr/lib/crtn.o
sudo ln -sf /usr/lib/arm-linux-gnueabihf/crt1.o /usr/lib/crt1.o
sudo ln -sf /usr/lib/arm-linux-gnueabihf/crti.o /usr/lib/crti.o

Also, check this comment: #69 (reply in thread)

[abhiTronix]

Also, can you test without CMAKE_FIND_ROOT_PATH and CMAKE_PREFIX_PATH as following toolchain cmake configuration:

if("$ENV{RASPBIAN_ROOTFS}" STREQUAL "")
	message(FATAL_ERROR "Define the RASPBIAN_ROOTFS environment variable to point to the raspbian rootfs.")
else()
	set(SYSROOT_PATH "$ENV{RASPBIAN_ROOTFS}")
endif()
set(TOOLCHAIN_HOST "arm-linux-gnueabihf")

message(STATUS "Using sysroot path: ${SYSROOT_PATH}")

set(TOOLCHAIN_CC "${TOOLCHAIN_HOST}-gcc")
set(TOOLCHAIN_CXX "${TOOLCHAIN_HOST}-g++")
set(TOOLCHAIN_LD "${TOOLCHAIN_HOST}-ld")
set(TOOLCHAIN_AR "${TOOLCHAIN_HOST}-ar")
set(TOOLCHAIN_RANLIB "${TOOLCHAIN_HOST}-ranlib")
set(TOOLCHAIN_STRIP "${TOOLCHAIN_HOST}-strip")
set(TOOLCHAIN_NM "${TOOLCHAIN_HOST}-nm")

set(CMAKE_CROSSCOMPILING TRUE)
set(CMAKE_SYSROOT "${SYSROOT_PATH}")

# Define name of the target system
set(CMAKE_SYSTEM_NAME "Linux")
set(CMAKE_SYSTEM_PROCESSOR "armv7l")

# Define the compiler
set(CMAKE_C_COMPILER ${TOOLCHAIN_CC})
set(CMAKE_CXX_COMPILER ${TOOLCHAIN_CXX})
set(CMAKE_C_COMPILER_WORKS 1)
set(CMAKE_CXX_COMPILER_WORKS 1)

# 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)
set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY)

but keep CMAKE_SYSROOT and CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER as previous.

[rafal1137]

@abhiTronix

@rafal1137 Did you made following symlinks before syncing sysroot with RPi?

sudo ln -sf -r /usr/include/arm-linux-gnueabihf/asm /usr/include
sudo ln -sf -r /usr/include/arm-linux-gnueabihf/gnu /usr/include
sudo ln -sf -r /usr/include/arm-linux-gnueabihf/bits /usr/include
sudo ln -sf -r /usr/include/arm-linux-gnueabihf/sys /usr/include
sudo ln -sf -r /usr/include/arm-linux-gnueabihf/openssl /usr/include
sudo ln -sf /usr/lib/arm-linux-gnueabihf/crtn.o /usr/lib/crtn.o
sudo ln -sf /usr/lib/arm-linux-gnueabihf/crt1.o /usr/lib/crt1.o
sudo ln -sf /usr/lib/arm-linux-gnueabihf/crti.o /usr/lib/crti.o

Also, check this comment: #69 (reply in thread)

This may be tricky because I do not own RPI hardware. I did used 3rd Party sh script to download raspbian.iso and rsync. I can do only run rapsbian on docker. I have tried to ssh into it but I had no experience with docker before back then.

PS: Or will it work when doing those symlinks in rootfs ?

Also, can you test without CMAKE_FIND_ROOT_PATH and CMAKE_PREFIX_PATH as following toolchain cmake configuration:

if("$ENV{RASPBIAN_ROOTFS}" STREQUAL "")
	message(FATAL_ERROR "Define the RASPBIAN_ROOTFS environment variable to point to the raspbian rootfs.")
else()
	set(SYSROOT_PATH "$ENV{RASPBIAN_ROOTFS}")
endif()
set(TOOLCHAIN_HOST "arm-linux-gnueabihf")

message(STATUS "Using sysroot path: ${SYSROOT_PATH}")

set(TOOLCHAIN_CC "${TOOLCHAIN_HOST}-gcc")
set(TOOLCHAIN_CXX "${TOOLCHAIN_HOST}-g++")
set(TOOLCHAIN_LD "${TOOLCHAIN_HOST}-ld")
set(TOOLCHAIN_AR "${TOOLCHAIN_HOST}-ar")
set(TOOLCHAIN_RANLIB "${TOOLCHAIN_HOST}-ranlib")
set(TOOLCHAIN_STRIP "${TOOLCHAIN_HOST}-strip")
set(TOOLCHAIN_NM "${TOOLCHAIN_HOST}-nm")

set(CMAKE_CROSSCOMPILING TRUE)
set(CMAKE_SYSROOT "${SYSROOT_PATH}")

# Define name of the target system
set(CMAKE_SYSTEM_NAME "Linux")
set(CMAKE_SYSTEM_PROCESSOR "armv7l")

# Define the compiler
set(CMAKE_C_COMPILER ${TOOLCHAIN_CC})
set(CMAKE_CXX_COMPILER ${TOOLCHAIN_CXX})
set(CMAKE_C_COMPILER_WORKS 1)
set(CMAKE_CXX_COMPILER_WORKS 1)

# 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)
set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY)

but keep CMAKE_SYSROOT and CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER as previous.

Tried that one with no luck.

[abhiTronix]

This may be tricky because I do not own RPI hardware. I did used 3rd Party sh script to download raspbian.iso and rsync. I can do only run rapsbian on docker. I have tried to ssh into it but I had no experience with docker before back then.

PS: Or will it work when doing those symlinks in rootfs ?

@rafal1137 Ok this was the actual problem. Yes, it won't work without these symlinks, see this comment #69 (reply in thread)

[abhiTronix]

@rafal1137 Can you try these commands after setting correct RASPBIAN_ROOTFS environment variable value:

sudo ln -sf -r "$RASPBIAN_ROOTFS"/usr/include/arm-linux-gnueabihf/asm "$RASPBIAN_ROOTFS"/usr/include
sudo ln -sf -r "$RASPBIAN_ROOTFS"/usr/include/arm-linux-gnueabihf/gnu "$RASPBIAN_ROOTFS"/usr/include
sudo ln -sf -r "$RASPBIAN_ROOTFS"/usr/include/arm-linux-gnueabihf/bits "$RASPBIAN_ROOTFS"/usr/include
sudo ln -sf -r "$RASPBIAN_ROOTFS"/usr/include/arm-linux-gnueabihf/sys "$RASPBIAN_ROOTFS"/usr/include
sudo ln -sf -r "$RASPBIAN_ROOTFS"/usr/include/arm-linux-gnueabihf/openssl "$RASPBIAN_ROOTFS"/usr/include
sudo ln -sf "$RASPBIAN_ROOTFS"/usr/lib/arm-linux-gnueabihf/crtn.o "$RASPBIAN_ROOTFS"/usr/lib/crtn.o
sudo ln -sf "$RASPBIAN_ROOTFS"/usr/lib/arm-linux-gnueabihf/crt1.o "$RASPBIAN_ROOTFS"/usr/lib/crt1.o
sudo ln -sf "$RASPBIAN_ROOTFS"/usr/lib/arm-linux-gnueabihf/crti.o "$RASPBIAN_ROOTFS"/usr/lib/crti.o

and see if it works?

[rafal1137]

@rafal1137 Can you try these commands after setting correct RASPBIAN_ROOTFS environment variable value:

sudo ln -sf -r "$RASPBIAN_ROOTFS"/usr/include/arm-linux-gnueabihf/asm "$RASPBIAN_ROOTFS"/usr/include
sudo ln -sf -r "$RASPBIAN_ROOTFS"/usr/include/arm-linux-gnueabihf/gnu "$RASPBIAN_ROOTFS"/usr/include
sudo ln -sf -r "$RASPBIAN_ROOTFS"/usr/include/arm-linux-gnueabihf/bits "$RASPBIAN_ROOTFS"/usr/include
sudo ln -sf -r "$RASPBIAN_ROOTFS"/usr/include/arm-linux-gnueabihf/sys "$RASPBIAN_ROOTFS"/usr/include
sudo ln -sf -r "$RASPBIAN_ROOTFS"/usr/include/arm-linux-gnueabihf/openssl "$RASPBIAN_ROOTFS"/usr/include
sudo ln -sf "$RASPBIAN_ROOTFS"/usr/lib/arm-linux-gnueabihf/crtn.o "$RASPBIAN_ROOTFS"/usr/lib/crtn.o
sudo ln -sf "$RASPBIAN_ROOTFS"/usr/lib/arm-linux-gnueabihf/crt1.o "$RASPBIAN_ROOTFS"/usr/lib/crt1.o
sudo ln -sf "$RASPBIAN_ROOTFS"/usr/lib/arm-linux-gnueabihf/crti.o "$RASPBIAN_ROOTFS"/usr/lib/crti.o

and see if it works?

Well I did went another way to make those symlinks. Now it started to compile again.
But its still fails because it still complains about

/lib/ld-linux-armhf.so.3: No such file or directory
Exiting!

[rafal1137]

@abhiTronix ^
Just to ping you.