问题
I am writing c code on my laptop and I would like to cross compile it to ARM v7 architecture using the llvm-clang toolchain.
I am following this website http://llvm.org/docs/HowToCrossCompileLLVM.html using this command to configure cmake:
I am using the following command and getting the following errors (see below). Any idea what is wrong?
Thank you
-------------------------------START----------------------------------------------
cmake -G Ninja /home/user/Desktop/llvm/llvm -DCMAKE_CROSSCOMPILING=True -DCMAKE_INSTALL_PREFIX=/home/user/Desktop/llvm/llvm/new_build -DLLVM_TABLEGEN=/usr/bin/host/llvm-tblgen -DCLANG_TABLEGEN=/usr/bin/host/clang-tblgen -DLLVM_DEFAULT_TARGET_TRIPLE=arm-linux-gnueabihf -DLLVM_TARGET_ARCH=ARM -DLLVM_TARGETS_TO_BUILD=ARM -DCMAKE_CXX_FLAGS='-target armv7a-linux-gnueabihf -mcpu=cortex-a9 -I/usr/arm-linux-gnueabihf/include/c++/4.7.2/arm-linux-gnueabihf/ -I/usr/arm-linux-gnueabihf/include/ -mfloat-abi=hard -ccc-gcc-name arm-linux-gnueabihf-gcc'
------------------------------END-------------------------------------------------
Errors:
-------------------------------START----------------------------------------------
-- The CXX compiler identification is Clang 3.5.0 -- Check for working CXX compiler using: Ninja -- Check for working CXX compiler using: Ninja -- broken CMake Error at /usr/share/cmake-2.8/Modules/CMakeTestCXXCompiler.cmake:54 (message): The C++ compiler "/usr/bin/clang++" is not able to compile a simple test program.
It fails with the following output:
Change Dir: /home/user/Desktop/llvm/llvm/new_build/CMakeFiles/CMakeTmp
Run Build Command:/usr/bin/ninja cmTryCompileExec1541562247
[1/2] Building CXX object
CMakeFiles/cmTryCompileExec1541562247.dir/testCXXCompiler.cxx.o
[2/2] Linking CXX executable cmTryCompileExec1541562247
FAILED: : && /usr/bin/clang++ -target armv7a-linux-gnueabihf
-mcpu=cortex-a9
-I/usr/arm-linux-gnueabihf/include/c++/4.7.2/arm-linux-gnueabihf/
-I/usr/arm-linux-gnueabihf/include/ -mfloat-abi=hard -ccc-gcc-name
arm-linux-gnueabihf-gcc
CMakeFiles/cmTryCompileExec1541562247.dir/testCXXCompiler.cxx.o -o
cmTryCompileExec1541562247 -rdynamic && :
/usr/bin/ld: unrecognised emulation mode: armelf_linux_eabi
Supported emulations: elf_x86_64 elf32_x86_64 elf_i386 i386linux elf_l1om
elf_k1om i386pep i386pe
clang: error: linker command failed with exit code 1 (use -v to see
invocation)
ninja: build stopped: subcommand failed.
CMake will not be able to correctly generate this project.
Call Stack (most recent call first):
CMakeLists.txt:19 (project)
-- Configuring incomplete, errors occurred!
------------------------------END-------------------------------------------------
回答1:
You are using the wrong guide.
The web page you linked is a guide on how to cross-compile LLVM and Clang using LLVM and Clang. But you don't want to compile LLVM itself, you only want to use it. The guide for that is: http://clang.llvm.org/docs/CrossCompilation.html
来源：https://stackoverflow.com/questions/24204199/crosscompile-using-llvm-from-desktop-to-arm