1 ================================================================== 2 Getting Started with the LLVM System using Microsoft Visual Studio 3 ================================================================== 4 5 .. contents:: 6 :local: 7 8 9 Overview 10 ======== 11 Welcome to LLVM on Windows! This document only covers LLVM on Windows using 12 Visual Studio, not mingw or cygwin. In order to get started, you first need to 13 know some basic information. 14 15 There are many different projects that compose LLVM. The first is the LLVM 16 suite. This contains all of the tools, libraries, and header files needed to 17 use LLVM. It contains an assembler, disassembler, 18 bitcode analyzer and bitcode optimizer. It also contains a test suite that can 19 be used to test the LLVM tools. 20 21 Another useful project on Windows is `Clang <http://clang.llvm.org/>`_. 22 Clang is a C family ([Objective]C/C++) compiler. Clang mostly works on 23 Windows, but does not currently understand all of the Microsoft extensions 24 to C and C++. Because of this, clang cannot parse the C++ standard library 25 included with Visual Studio, nor parts of the Windows Platform SDK. However, 26 most standard C programs do compile. Clang can be used to emit bitcode, 27 directly emit object files or even linked executables using Visual Studio's 28 ``link.exe``. 29 30 The large LLVM test suite cannot be run on the Visual Studio port at this 31 time. 32 33 Most of the tools build and work. ``bugpoint`` does build, but does 34 not work. 35 36 Additional information about the LLVM directory structure and tool chain 37 can be found on the main `Getting Started <GettingStarted.html>`_ page. 38 39 40 Requirements 41 ============ 42 Before you begin to use the LLVM system, review the requirements given 43 below. This may save you some trouble by knowing ahead of time what hardware 44 and software you will need. 45 46 Hardware 47 -------- 48 Any system that can adequately run Visual Studio 2008 is fine. The LLVM 49 source tree and object files, libraries and executables will consume 50 approximately 3GB. 51 52 Software 53 -------- 54 You will need Visual Studio 2008 or higher. Earlier versions of Visual 55 Studio have bugs, are not completely compatible, or do not support the C++ 56 standard well enough. 57 58 You will also need the `CMake <http://www.cmake.org/>`_ build system since it 59 generates the project files you will use to build with. 60 61 If you would like to run the LLVM tests you will need `Python 62 <http://www.python.org/>`_. Versions 2.4-2.7 are known to work. You will need 63 `GnuWin32 <http://gnuwin32.sourceforge.net/>`_ tools, too. 64 65 Do not install the LLVM directory tree into a path containing spaces (e.g. 66 ``C:\Documents and Settings\...``) as the configure step will fail. 67 68 69 Getting Started 70 =============== 71 Here's the short story for getting up and running quickly with LLVM: 72 73 1. Read the documentation. 74 2. Seriously, read the documentation. 75 3. Remember that you were warned twice about reading the documentation. 76 4. Get the Source Code 77 78 * With the distributed files: 79 80 1. ``cd <where-you-want-llvm-to-live>`` 81 2. ``gunzip --stdout llvm-VERSION.tar.gz | tar -xvf -`` 82 (*or use WinZip*) 83 3. ``cd llvm`` 84 85 * With anonymous Subversion access: 86 87 1. ``cd <where-you-want-llvm-to-live>`` 88 2. ``svn co http://llvm.org/svn/llvm-project/llvm/trunk llvm`` 89 3. ``cd llvm`` 90 91 5. Use `CMake <http://www.cmake.org/>`_ to generate up-to-date project files: 92 93 * Once CMake is installed then the simplest way is to just start the 94 CMake GUI, select the directory where you have LLVM extracted to, and 95 the default options should all be fine. One option you may really 96 want to change, regardless of anything else, might be the 97 ``CMAKE_INSTALL_PREFIX`` setting to select a directory to INSTALL to 98 once compiling is complete, although installation is not mandatory for 99 using LLVM. Another important option is ``LLVM_TARGETS_TO_BUILD``, 100 which controls the LLVM target architectures that are included on the 101 build. 102 * See the `LLVM CMake guide <CMake.html>`_ for detailed information about 103 how to configure the LLVM build. 104 105 6. Start Visual Studio 106 107 * In the directory you created the project files will have an ``llvm.sln`` 108 file, just double-click on that to open Visual Studio. 109 110 7. Build the LLVM Suite: 111 112 * The projects may still be built individually, but to build them all do 113 not just select all of them in batch build (as some are meant as 114 configuration projects), but rather select and build just the 115 ``ALL_BUILD`` project to build everything, or the ``INSTALL`` project, 116 which first builds the ``ALL_BUILD`` project, then installs the LLVM 117 headers, libs, and other useful things to the directory set by the 118 ``CMAKE_INSTALL_PREFIX`` setting when you first configured CMake. 119 * The Fibonacci project is a sample program that uses the JIT. Modify the 120 project's debugging properties to provide a numeric command line argument 121 or run it from the command line. The program will print the 122 corresponding fibonacci value. 123 124 8. Test LLVM on Visual Studio: 125 126 * If ``%PATH%`` does not contain GnuWin32, you may specify 127 ``LLVM_LIT_TOOLS_DIR`` on CMake for the path to GnuWin32. 128 * You can run LLVM tests by merely building the project "check". The test 129 results will be shown in the VS output window. 130 131 .. FIXME: Is it up-to-date? 132 133 9. Test LLVM: 134 135 * The LLVM tests can be run by changing directory to the llvm source 136 directory and running: 137 138 .. code-block:: bat 139 140 C:\..\llvm> llvm-lit test 141 142 Note that quite a few of these test will fail. 143 144 A specific test or test directory can be run with: 145 146 .. code-block:: bat 147 148 C:\..\llvm> llvm-lit test/path/to/test 149 150 151 An Example Using the LLVM Tool Chain 152 ==================================== 153 154 1. First, create a simple C file, name it '``hello.c``': 155 156 .. code-block:: c 157 158 #include <stdio.h> 159 int main() { 160 printf("hello world\n"); 161 return 0; 162 } 163 164 2. Next, compile the C file into a LLVM bitcode file: 165 166 .. code-block:: bat 167 168 C:\..> clang -c hello.c -emit-llvm -o hello.bc 169 170 This will create the result file ``hello.bc`` which is the LLVM bitcode 171 that corresponds the compiled program and the library facilities that 172 it required. You can execute this file directly using ``lli`` tool, 173 compile it to native assembly with the ``llc``, optimize or analyze it 174 further with the ``opt`` tool, etc. 175 176 Alternatively you can directly output an executable with clang with: 177 178 .. code-block:: bat 179 180 C:\..> clang hello.c -o hello.exe 181 182 The ``-o hello.exe`` is required because clang currently outputs ``a.out`` 183 when neither ``-o`` nor ``-c`` are given. 184 185 3. Run the program using the just-in-time compiler: 186 187 .. code-block:: bat 188 189 C:\..> lli hello.bc 190 191 4. Use the ``llvm-dis`` utility to take a look at the LLVM assembly code: 192 193 .. code-block:: bat 194 195 C:\..> llvm-dis < hello.bc | more 196 197 5. Compile the program to object code using the LLC code generator: 198 199 .. code-block:: bat 200 201 C:\..> llc -filetype=obj hello.bc 202 203 6. Link to binary using Microsoft link: 204 205 .. code-block:: bat 206 207 C:\..> link hello.obj -defaultlib:libcmt 208 209 7. Execute the native code program: 210 211 .. code-block:: bat 212 213 C:\..> hello.exe 214 215 216 Common Problems 217 =============== 218 If you are having problems building or using LLVM, or if you have any other 219 general questions about LLVM, please consult the `Frequently Asked Questions 220 <FAQ.html>`_ page. 221 222 223 Links 224 ===== 225 This document is just an **introduction** to how to use LLVM to do some simple 226 things... there are many more interesting and complicated things that you can 227 do that aren't documented here (but we'll gladly accept a patch if you want to 228 write something up!). For more information about LLVM, check out: 229 230 * `LLVM homepage <http://llvm.org/>`_ 231 * `LLVM doxygen tree <http://llvm.org/doxygen/>`_ 232 233
