clang: a C language family frontend for LLVM

编译LLVM

http://clang.llvm.org/get_started.html

http://clang.llvm.org/

On Unix-like Systems

Note: as an experimental setup, you can use a single checkout with all the projects, and an easy CMake invocation, see the LLVM Doc "For developers to work with a git monorepo"

If you would like to check out and build Clang, the current procedure is as follows:

1. Get the required tools.
   • See Getting Started with the LLVM System - Requirements.
   • Note also that Python is needed for running the test suite. Get it at: http://www.python.org/download
   • Standard build process uses CMake. Get it at: http://www.cmake.org/download
2. Check out LLVM:
   • Change directory to where you want the llvm directory placed.
   • svn co http://llvm.org/svn/llvm-project/llvm/trunk llvm
3. Check out Clang:
   • cd llvm/tools
   • svn co http://llvm.org/svn/llvm-project/cfe/trunk clang
   • cd ../..
4. Check out extra Clang tools: (optional)
   • cd llvm/tools/clang/tools
   • svn co http://llvm.org/svn/llvm-project/clang-tools-extra/trunk extra
   • cd ../../../..
5. Check out Compiler-RT (optional):
   • cd llvm/projects
   • svn co http://llvm.org/svn/llvm-project/compiler-rt/trunk compiler-rt
   • cd ../..
6. Check out libcxx: (only required to build and run Compiler-RT tests on OS X, optional otherwise)
   • cd llvm/projects
   • svn co http://llvm.org/svn/llvm-project/libcxx/trunk libcxx
   • cd ../..
7. Build LLVM and Clang:
   • mkdir build (in-tree build is not supported)
   • cd build
   • cmake -G "Unix Makefiles" ../llvm
   • make
   • This builds both LLVM and Clang for debug mode.
   • Note: For subsequent Clang development, you can just run make clang.
   • CMake allows you to generate project files for several IDEs: Xcode, Eclipse CDT4, CodeBlocks, Qt-Creator (use the CodeBlocks generator), KDevelop3. For more details see Building LLVM with CMake page.
8. If you intend to use Clang's C++ support, you may need to tell it how to find your C++ standard library headers. In general, Clang will detect the best version of libstdc++ headers available and use them - it will look both for system installations of libstdc++ as well as installations adjacent to Clang itself. If your configuration fits neither of these scenarios, you can use the -DGCC_INSTALL_PREFIX cmake option to tell Clang where the gcc containing the desired libstdc++ is installed.
9. Try it out (assuming you add llvm/build/bin to your path):
   • clang --help
   • clang file.c -fsyntax-only (check for correctness)
   • clang file.c -S -emit-llvm -o - (print out unoptimized llvm code)
   • clang file.c -S -emit-llvm -o - -O3
   • clang file.c -S -O3 -o - (output native machine code)
10. Run the testsuite:
    • make check-clang