Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 1 | ==================================== |
| 2 | Getting Started with the LLVM System |
| 3 | ==================================== |
| 4 | |
Sean Silva | 7d31849 | 2012-12-20 03:32:39 +0000 | [diff] [blame] | 5 | .. contents:: |
| 6 | :local: |
| 7 | |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 8 | Overview |
| 9 | ======== |
| 10 | |
| 11 | Welcome to LLVM! In order to get started, you first need to know some basic |
| 12 | information. |
| 13 | |
| 14 | First, LLVM comes in three pieces. The first piece is the LLVM suite. This |
| 15 | contains all of the tools, libraries, and header files needed to use LLVM. It |
| 16 | contains an assembler, disassembler, bitcode analyzer and bitcode optimizer. It |
| 17 | also contains basic regression tests that can be used to test the LLVM tools and |
| 18 | the Clang front end. |
| 19 | |
| 20 | The second piece is the `Clang <http://clang.llvm.org/>`_ front end. This |
| 21 | component compiles C, C++, Objective C, and Objective C++ code into LLVM |
| 22 | bitcode. Once compiled into LLVM bitcode, a program can be manipulated with the |
| 23 | LLVM tools from the LLVM suite. |
| 24 | |
| 25 | There is a third, optional piece called Test Suite. It is a suite of programs |
| 26 | with a testing harness that can be used to further test LLVM's functionality |
| 27 | and performance. |
| 28 | |
| 29 | Getting Started Quickly (A Summary) |
| 30 | =================================== |
| 31 | |
| 32 | The LLVM Getting Started documentation may be out of date. So, the `Clang |
| 33 | Getting Started <http://clang.llvm.org/get_started.html>`_ page might also be a |
| 34 | good place to start. |
| 35 | |
| 36 | Here's the short story for getting up and running quickly with LLVM: |
| 37 | |
| 38 | #. Read the documentation. |
| 39 | #. Read the documentation. |
| 40 | #. Remember that you were warned twice about reading the documentation. |
| 41 | #. Checkout LLVM: |
| 42 | |
| 43 | * ``cd where-you-want-llvm-to-live`` |
| 44 | * ``svn co http://llvm.org/svn/llvm-project/llvm/trunk llvm`` |
| 45 | |
| 46 | #. Checkout Clang: |
| 47 | |
| 48 | * ``cd where-you-want-llvm-to-live`` |
| 49 | * ``cd llvm/tools`` |
| 50 | * ``svn co http://llvm.org/svn/llvm-project/cfe/trunk clang`` |
| 51 | |
| 52 | #. Checkout Compiler-RT: |
| 53 | |
| 54 | * ``cd where-you-want-llvm-to-live`` |
| 55 | * ``cd llvm/projects`` |
| 56 | * ``svn co http://llvm.org/svn/llvm-project/compiler-rt/trunk compiler-rt`` |
| 57 | |
| 58 | #. Get the Test Suite Source Code **[Optional]** |
| 59 | |
| 60 | * ``cd where-you-want-llvm-to-live`` |
| 61 | * ``cd llvm/projects`` |
| 62 | * ``svn co http://llvm.org/svn/llvm-project/test-suite/trunk test-suite`` |
| 63 | |
| 64 | #. Configure and build LLVM and Clang: |
| 65 | |
| 66 | * ``cd where-you-want-to-build-llvm`` |
| 67 | * ``mkdir build`` (for building without polluting the source dir) |
| 68 | * ``cd build`` |
| 69 | * ``../llvm/configure [options]`` |
| 70 | Some common options: |
| 71 | |
Dmitri Gribenko | 8b2bcf4 | 2013-01-05 18:10:06 +0000 | [diff] [blame] | 72 | * ``--prefix=directory`` --- Specify for *directory* the full pathname of |
| 73 | where you want the LLVM tools and libraries to be installed (default |
| 74 | ``/usr/local``). |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 75 | |
Dmitri Gribenko | 8b2bcf4 | 2013-01-05 18:10:06 +0000 | [diff] [blame] | 76 | * ``--enable-optimized`` --- Compile with optimizations enabled (default |
| 77 | is NO). |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 78 | |
Dmitri Gribenko | 8b2bcf4 | 2013-01-05 18:10:06 +0000 | [diff] [blame] | 79 | * ``--enable-assertions`` --- Compile with assertion checks enabled |
| 80 | (default is YES). |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 81 | |
| 82 | * ``make [-j]`` --- The ``-j`` specifies the number of jobs (commands) to run |
| 83 | simultaneously. This builds both LLVM and Clang for Debug+Asserts mode. |
Rui Ueyama | e0f26bc | 2013-05-22 18:09:39 +0000 | [diff] [blame] | 84 | The ``--enable-optimized`` configure option is used to specify a Release |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 85 | build. |
| 86 | |
| 87 | * ``make check-all`` --- This run the regression tests to ensure everything |
| 88 | is in working order. |
Dmitri Gribenko | 8b2bcf4 | 2013-01-05 18:10:06 +0000 | [diff] [blame] | 89 | |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 90 | * ``make update`` --- This command is used to update all the svn repositories |
| 91 | at once, rather then having to ``cd`` into the individual repositories and |
| 92 | running ``svn update``. |
| 93 | |
| 94 | * It is also possible to use CMake instead of the makefiles. With CMake it is |
NAKAMURA Takumi | 51434aa | 2012-11-27 23:34:28 +0000 | [diff] [blame] | 95 | possible to generate project files for several IDEs: Xcode, Eclipse CDT4, |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 96 | CodeBlocks, Qt-Creator (use the CodeBlocks generator), KDevelop3. |
| 97 | |
| 98 | * If you get an "internal compiler error (ICE)" or test failures, see |
| 99 | `below`. |
| 100 | |
| 101 | Consult the `Getting Started with LLVM`_ section for detailed information on |
| 102 | configuring and compiling LLVM. See `Setting Up Your Environment`_ for tips |
| 103 | that simplify working with the Clang front end and LLVM tools. Go to `Program |
| 104 | Layout`_ to learn about the layout of the source code tree. |
| 105 | |
| 106 | Requirements |
| 107 | ============ |
| 108 | |
| 109 | Before you begin to use the LLVM system, review the requirements given below. |
| 110 | This may save you some trouble by knowing ahead of time what hardware and |
| 111 | software you will need. |
| 112 | |
| 113 | Hardware |
| 114 | -------- |
| 115 | |
| 116 | LLVM is known to work on the following platforms: |
| 117 | |
| 118 | +-----------------+----------------------+-------------------------+ |
| 119 | |OS | Arch | Compilers | |
| 120 | +=================+======================+=========================+ |
| 121 | |AuroraUX | x86\ :sup:`1` | GCC | |
| 122 | +-----------------+----------------------+-------------------------+ |
| 123 | |Linux | x86\ :sup:`1` | GCC | |
| 124 | +-----------------+----------------------+-------------------------+ |
| 125 | |Linux | amd64 | GCC | |
| 126 | +-----------------+----------------------+-------------------------+ |
Renato Golin | 37527d1 | 2013-02-26 17:23:13 +0000 | [diff] [blame] | 127 | |Linux | ARM\ :sup:`13` | GCC | |
| 128 | +-----------------+----------------------+-------------------------+ |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 129 | |Solaris | V9 (Ultrasparc) | GCC | |
| 130 | +-----------------+----------------------+-------------------------+ |
| 131 | |FreeBSD | x86\ :sup:`1` | GCC | |
| 132 | +-----------------+----------------------+-------------------------+ |
| 133 | |FreeBSD | amd64 | GCC | |
| 134 | +-----------------+----------------------+-------------------------+ |
| 135 | |MacOS X\ :sup:`2`| PowerPC | GCC | |
| 136 | +-----------------+----------------------+-------------------------+ |
| 137 | |MacOS X\ :sup:`9`| x86 | GCC | |
| 138 | +-----------------+----------------------+-------------------------+ |
| 139 | |Cygwin/Win32 | x86\ :sup:`1, 8, 11` | GCC 3.4.X, binutils 2.20| |
| 140 | +-----------------+----------------------+-------------------------+ |
| 141 | |
| 142 | LLVM has partial support for the following platforms: |
| 143 | |
| 144 | +-------------------+----------------------+-------------------------------------------+ |
| 145 | |OS | Arch | Compilers | |
| 146 | +===================+======================+===========================================+ |
| 147 | | Windows | x86\ :sup:`1` | Visual Studio 2000 or higher\ :sup:`4,5` | |
| 148 | +-------------------+----------------------+-------------------------------------------+ |
| 149 | | AIX\ :sup:`3,4` | PowerPC | GCC | |
| 150 | +-------------------+----------------------+-------------------------------------------+ |
| 151 | | Linux\ :sup:`3,5` | PowerPC | GCC | |
| 152 | +-------------------+----------------------+-------------------------------------------+ |
| 153 | | Linux\ :sup:`7` | Alpha | GCC | |
| 154 | +-------------------+----------------------+-------------------------------------------+ |
| 155 | | Linux\ :sup:`7` | Itanium (IA-64) | GCC | |
| 156 | +-------------------+----------------------+-------------------------------------------+ |
| 157 | | HP-UX\ :sup:`7` | Itanium (IA-64) | HP aCC | |
| 158 | +-------------------+----------------------+-------------------------------------------+ |
| 159 | | Windows x64 | x86-64 | mingw-w64's GCC-4.5.x\ :sup:`12` | |
| 160 | +-------------------+----------------------+-------------------------------------------+ |
| 161 | |
| 162 | .. note:: |
| 163 | |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 164 | #. Code generation supported for Pentium processors and up |
| 165 | #. Code generation supported for 32-bit ABI only |
| 166 | #. No native code generation |
| 167 | #. Build is not complete: one or more tools do not link or function |
| 168 | #. The GCC-based C/C++ frontend does not build |
| 169 | #. The port is done using the MSYS shell. |
| 170 | #. Native code generation exists but is not complete. |
| 171 | #. Binutils 2.20 or later is required to build the assembler generated by LLVM properly. |
| 172 | #. Xcode 2.5 and gcc 4.0.1 (Apple Build 5370) will trip internal LLVM assert |
| 173 | messages when compiled for Release at optimization levels greater than 0 |
| 174 | (i.e., ``-O1`` and higher). Add ``OPTIMIZE_OPTION="-O0"`` to the build |
| 175 | command line if compiling for LLVM Release or bootstrapping the LLVM |
| 176 | toolchain. |
| 177 | #. For MSYS/MinGW on Windows, be sure to install the MSYS version of the perl |
| 178 | package, and be sure it appears in your path before any Windows-based |
| 179 | versions such as Strawberry Perl and ActivePerl, as these have |
| 180 | Windows-specifics that will cause the build to fail. |
| 181 | #. To use LLVM modules on Win32-based system, you may configure LLVM |
| 182 | with ``--enable-shared``. |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 183 | #. To compile SPU backend, you need to add ``LDFLAGS=-Wl,--stack,16777216`` to |
| 184 | configure. |
Renato Golin | 37527d1 | 2013-02-26 17:23:13 +0000 | [diff] [blame] | 185 | #. MCJIT not working well pre-v7, old JIT engine not supported any more. |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 186 | |
| 187 | Note that you will need about 1-3 GB of space for a full LLVM build in Debug |
| 188 | mode, depending on the system (it is so large because of all the debugging |
| 189 | information and the fact that the libraries are statically linked into multiple |
| 190 | tools). If you do not need many of the tools and you are space-conscious, you |
| 191 | can pass ``ONLY_TOOLS="tools you need"`` to make. The Release build requires |
| 192 | considerably less space. |
| 193 | |
| 194 | The LLVM suite *may* compile on other platforms, but it is not guaranteed to do |
| 195 | so. If compilation is successful, the LLVM utilities should be able to |
| 196 | assemble, disassemble, analyze, and optimize LLVM bitcode. Code generation |
| 197 | should work as well, although the generated native code may not work on your |
| 198 | platform. |
| 199 | |
| 200 | Software |
| 201 | -------- |
| 202 | |
| 203 | Compiling LLVM requires that you have several software packages installed. The |
| 204 | table below lists those required packages. The Package column is the usual name |
| 205 | for the software package that LLVM depends on. The Version column provides |
| 206 | "known to work" versions of the package. The Notes column describes how LLVM |
| 207 | uses the package and provides other details. |
| 208 | |
| 209 | +--------------------------------------------------------------+-----------------+---------------------------------------------+ |
| 210 | | Package | Version | Notes | |
| 211 | +==============================================================+=================+=============================================+ |
| 212 | | `GNU Make <http://savannah.gnu.org/projects/make>`_ | 3.79, 3.79.1 | Makefile/build processor | |
| 213 | +--------------------------------------------------------------+-----------------+---------------------------------------------+ |
| 214 | | `GCC <http://gcc.gnu.org/>`_ | 3.4.2 | C/C++ compiler\ :sup:`1` | |
| 215 | +--------------------------------------------------------------+-----------------+---------------------------------------------+ |
| 216 | | `TeXinfo <http://www.gnu.org/software/texinfo/>`_ | 4.5 | For building the CFE | |
| 217 | +--------------------------------------------------------------+-----------------+---------------------------------------------+ |
| 218 | | `SVN <http://subversion.tigris.org/project_packages.html>`_ | >=1.3 | Subversion access to LLVM\ :sup:`2` | |
| 219 | +--------------------------------------------------------------+-----------------+---------------------------------------------+ |
Dmitri Gribenko | 55c6f0c | 2013-01-18 19:27:43 +0000 | [diff] [blame] | 220 | | `python <http://www.python.org/>`_ | >=2.4 | Automated test suite\ :sup:`3` | |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 221 | +--------------------------------------------------------------+-----------------+---------------------------------------------+ |
| 222 | | `perl <http://www.perl.com/download.csp>`_ | >=5.6.0 | Utilities | |
| 223 | +--------------------------------------------------------------+-----------------+---------------------------------------------+ |
| 224 | | `GNU M4 <http://savannah.gnu.org/projects/m4>`_ | 1.4 | Macro processor for configuration\ :sup:`4` | |
| 225 | +--------------------------------------------------------------+-----------------+---------------------------------------------+ |
| 226 | | `GNU Autoconf <http://www.gnu.org/software/autoconf/>`_ | 2.60 | Configuration script builder\ :sup:`4` | |
| 227 | +--------------------------------------------------------------+-----------------+---------------------------------------------+ |
| 228 | | `GNU Automake <http://www.gnu.org/software/automake/>`_ | 1.9.6 | aclocal macro generator\ :sup:`4` | |
| 229 | +--------------------------------------------------------------+-----------------+---------------------------------------------+ |
| 230 | | `libtool <http://savannah.gnu.org/projects/libtool>`_ | 1.5.22 | Shared library manager\ :sup:`4` | |
| 231 | +--------------------------------------------------------------+-----------------+---------------------------------------------+ |
Alexey Samsonov | ee03c94 | 2013-04-23 08:28:39 +0000 | [diff] [blame] | 232 | | `zlib <http://zlib.net>`_ | >=1.2.3.4 | Compression library\ :sup:`5` | |
| 233 | +--------------------------------------------------------------+-----------------+---------------------------------------------+ |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 234 | |
| 235 | .. note:: |
| 236 | |
| 237 | #. Only the C and C++ languages are needed so there's no need to build the |
| 238 | other languages for LLVM's purposes. See `below` for specific version |
| 239 | info. |
| 240 | #. You only need Subversion if you intend to build from the latest LLVM |
| 241 | sources. If you're working from a release distribution, you don't need |
| 242 | Subversion. |
| 243 | #. Only needed if you want to run the automated test suite in the |
| 244 | ``llvm/test`` directory. |
| 245 | #. If you want to make changes to the configure scripts, you will need GNU |
| 246 | autoconf (2.60), and consequently, GNU M4 (version 1.4 or higher). You |
| 247 | will also need automake (1.9.6). We only use aclocal from that package. |
Alexey Samsonov | ee03c94 | 2013-04-23 08:28:39 +0000 | [diff] [blame] | 248 | #. Optional, adds compression/uncompression capabilities to selected LLVM |
| 249 | tools. |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 250 | |
| 251 | Additionally, your compilation host is expected to have the usual plethora of |
| 252 | Unix utilities. Specifically: |
| 253 | |
| 254 | * **ar** --- archive library builder |
| 255 | * **bzip2** --- bzip2 command for distribution generation |
| 256 | * **bunzip2** --- bunzip2 command for distribution checking |
| 257 | * **chmod** --- change permissions on a file |
| 258 | * **cat** --- output concatenation utility |
| 259 | * **cp** --- copy files |
| 260 | * **date** --- print the current date/time |
| 261 | * **echo** --- print to standard output |
| 262 | * **egrep** --- extended regular expression search utility |
| 263 | * **find** --- find files/dirs in a file system |
| 264 | * **grep** --- regular expression search utility |
| 265 | * **gzip** --- gzip command for distribution generation |
| 266 | * **gunzip** --- gunzip command for distribution checking |
| 267 | * **install** --- install directories/files |
| 268 | * **mkdir** --- create a directory |
| 269 | * **mv** --- move (rename) files |
| 270 | * **ranlib** --- symbol table builder for archive libraries |
| 271 | * **rm** --- remove (delete) files and directories |
| 272 | * **sed** --- stream editor for transforming output |
| 273 | * **sh** --- Bourne shell for make build scripts |
| 274 | * **tar** --- tape archive for distribution generation |
| 275 | * **test** --- test things in file system |
| 276 | * **unzip** --- unzip command for distribution checking |
| 277 | * **zip** --- zip command for distribution generation |
| 278 | |
| 279 | .. _below: |
| 280 | .. _check here: |
| 281 | |
| 282 | Broken versions of GCC and other tools |
| 283 | -------------------------------------- |
| 284 | |
| 285 | LLVM is very demanding of the host C++ compiler, and as such tends to expose |
| 286 | bugs in the compiler. In particular, several versions of GCC crash when trying |
| 287 | to compile LLVM. We routinely use GCC 4.2 (and higher) or Clang. Other |
| 288 | versions of GCC will probably work as well. GCC versions listed here are known |
| 289 | to not work. If you are using one of these versions, please try to upgrade your |
| 290 | GCC to something more recent. If you run into a problem with a version of GCC |
| 291 | not listed here, please `let us know <mailto:llvmdev@cs.uiuc.edu>`_. Please use |
| 292 | the "``gcc -v``" command to find out which version of GCC you are using. |
| 293 | |
| 294 | **GCC versions prior to 3.0**: GCC 2.96.x and before had several problems in the |
| 295 | STL that effectively prevent it from compiling LLVM. |
| 296 | |
| 297 | **GCC 3.2.2 and 3.2.3**: These versions of GCC fails to compile LLVM with a |
| 298 | bogus template error. This was fixed in later GCCs. |
| 299 | |
| 300 | **GCC 3.3.2**: This version of GCC suffered from a `serious bug |
| 301 | <http://gcc.gnu.org/PR13392>`_ which causes it to crash in the |
| 302 | "``convert_from_eh_region_ranges_1``" GCC function. |
| 303 | |
| 304 | **Cygwin GCC 3.3.3**: The version of GCC 3.3.3 commonly shipped with Cygwin does |
| 305 | not work. |
| 306 | |
| 307 | **SuSE GCC 3.3.3**: The version of GCC 3.3.3 shipped with SuSE 9.1 (and possibly |
| 308 | others) does not compile LLVM correctly (it appears that exception handling is |
| 309 | broken in some cases). Please download the FSF 3.3.3 or upgrade to a newer |
| 310 | version of GCC. |
| 311 | |
| 312 | **GCC 3.4.0 on linux/x86 (32-bit)**: GCC miscompiles portions of the code |
| 313 | generator, causing an infinite loop in the llvm-gcc build when built with |
| 314 | optimizations enabled (i.e. a release build). |
| 315 | |
| 316 | **GCC 3.4.2 on linux/x86 (32-bit)**: GCC miscompiles portions of the code |
| 317 | generator at -O3, as with 3.4.0. However gcc 3.4.2 (unlike 3.4.0) correctly |
| 318 | compiles LLVM at -O2. A work around is to build release LLVM builds with |
| 319 | "``make ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O2 ...``" |
| 320 | |
| 321 | **GCC 3.4.x on X86-64/amd64**: GCC `miscompiles portions of LLVM |
Sean Silva | 59ccfb0 | 2012-10-07 18:49:28 +0000 | [diff] [blame] | 322 | <http://llvm.org/PR1056>`__. |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 323 | |
| 324 | **GCC 3.4.4 (CodeSourcery ARM 2005q3-2)**: this compiler miscompiles LLVM when |
| 325 | building with optimizations enabled. It appears to work with "``make |
| 326 | ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O1``" or build a debug build. |
| 327 | |
| 328 | **IA-64 GCC 4.0.0**: The IA-64 version of GCC 4.0.0 is known to miscompile LLVM. |
| 329 | |
| 330 | **Apple Xcode 2.3**: GCC crashes when compiling LLVM at -O3 (which is the |
| 331 | default with ENABLE_OPTIMIZED=1. To work around this, build with |
| 332 | "``ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O2``". |
| 333 | |
| 334 | **GCC 4.1.1**: GCC fails to build LLVM with template concept check errors |
| 335 | compiling some files. At the time of this writing, GCC mainline (4.2) did not |
| 336 | share the problem. |
| 337 | |
| 338 | **GCC 4.1.1 on X86-64/amd64**: GCC `miscompiles portions of LLVM |
Sean Silva | 59ccfb0 | 2012-10-07 18:49:28 +0000 | [diff] [blame] | 339 | <http://llvm.org/PR1063>`__ when compiling llvm itself into 64-bit code. LLVM |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 340 | will appear to mostly work but will be buggy, e.g. failing portions of its |
| 341 | testsuite. |
| 342 | |
| 343 | **GCC 4.1.2 on OpenSUSE**: Seg faults during libstdc++ build and on x86_64 |
| 344 | platforms compiling md5.c gets a mangled constant. |
| 345 | |
| 346 | **GCC 4.1.2 (20061115 (prerelease) (Debian 4.1.1-21)) on Debian**: Appears to |
| 347 | miscompile parts of LLVM 2.4. One symptom is ValueSymbolTable complaining about |
| 348 | symbols remaining in the table on destruction. |
| 349 | |
| 350 | **GCC 4.1.2 20071124 (Red Hat 4.1.2-42)**: Suffers from the same symptoms as the |
| 351 | previous one. It appears to work with ENABLE_OPTIMIZED=0 (the default). |
| 352 | |
| 353 | **Cygwin GCC 4.3.2 20080827 (beta) 2**: Users `reported |
| 354 | <http://llvm.org/PR4145>`_ various problems related with link errors when using |
| 355 | this GCC version. |
| 356 | |
| 357 | **Debian GCC 4.3.2 on X86**: Crashes building some files in LLVM 2.6. |
| 358 | |
| 359 | **GCC 4.3.3 (Debian 4.3.3-10) on ARM**: Miscompiles parts of LLVM 2.6 when |
| 360 | optimizations are turned on. The symptom is an infinite loop in |
| 361 | ``FoldingSetImpl::RemoveNode`` while running the code generator. |
| 362 | |
| 363 | **SUSE 11 GCC 4.3.4**: Miscompiles LLVM, causing crashes in ValueHandle logic. |
| 364 | |
| 365 | **GCC 4.3.5 and GCC 4.4.5 on ARM**: These can miscompile ``value >> 1`` even at |
| 366 | ``-O0``. A test failure in ``test/Assembler/alignstack.ll`` is one symptom of |
| 367 | the problem. |
| 368 | |
Renato Golin | 86ab766 | 2013-02-26 13:32:40 +0000 | [diff] [blame] | 369 | **GCC 4.6.3 on ARM**: Miscompiles ``llvm-readobj`` at ``-O3``. A test failure |
| 370 | in ``test/Object/readobj-shared-object.test`` is one symptom of the problem. |
| 371 | |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 372 | **GNU ld 2.16.X**. Some 2.16.X versions of the ld linker will produce very long |
| 373 | warning messages complaining that some "``.gnu.linkonce.t.*``" symbol was |
| 374 | defined in a discarded section. You can safely ignore these messages as they are |
| 375 | erroneous and the linkage is correct. These messages disappear using ld 2.17. |
| 376 | |
| 377 | **GNU binutils 2.17**: Binutils 2.17 contains `a bug |
Sean Silva | 59ccfb0 | 2012-10-07 18:49:28 +0000 | [diff] [blame] | 378 | <http://sourceware.org/bugzilla/show_bug.cgi?id=3111>`__ which causes huge link |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 379 | times (minutes instead of seconds) when building LLVM. We recommend upgrading |
| 380 | to a newer version (2.17.50.0.4 or later). |
| 381 | |
| 382 | **GNU Binutils 2.19.1 Gold**: This version of Gold contained `a bug |
Sean Silva | 59ccfb0 | 2012-10-07 18:49:28 +0000 | [diff] [blame] | 383 | <http://sourceware.org/bugzilla/show_bug.cgi?id=9836>`__ which causes |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 384 | intermittent failures when building LLVM with position independent code. The |
| 385 | symptom is an error about cyclic dependencies. We recommend upgrading to a |
| 386 | newer version of Gold. |
| 387 | |
Dmitri Gribenko | be0ffd1 | 2013-01-06 21:23:27 +0000 | [diff] [blame] | 388 | **Clang 3.0 with libstdc++ 4.7.x**: a few Linux distributions (Ubuntu 12.10, |
| 389 | Fedora 17) have both Clang 3.0 and libstdc++ 4.7 in their repositories. Clang |
| 390 | 3.0 does not implement a few builtins that are used in this library. We |
| 391 | recommend using the system GCC to compile LLVM and Clang in this case. |
| 392 | |
Dmitri Gribenko | a1e7530 | 2013-01-07 12:17:44 +0000 | [diff] [blame] | 393 | **Clang 3.0 on Mageia 2**. There's a packaging issue: Clang can not find at |
| 394 | least some (``cxxabi.h``) libstdc++ headers. |
| 395 | |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 396 | .. _Getting Started with LLVM: |
| 397 | |
| 398 | Getting Started with LLVM |
| 399 | ========================= |
| 400 | |
| 401 | The remainder of this guide is meant to get you up and running with LLVM and to |
| 402 | give you some basic information about the LLVM environment. |
| 403 | |
| 404 | The later sections of this guide describe the `general layout`_ of the LLVM |
| 405 | source tree, a `simple example`_ using the LLVM tool chain, and `links`_ to find |
| 406 | more information about LLVM or to get help via e-mail. |
| 407 | |
| 408 | Terminology and Notation |
| 409 | ------------------------ |
| 410 | |
| 411 | Throughout this manual, the following names are used to denote paths specific to |
| 412 | the local system and working environment. *These are not environment variables |
| 413 | you need to set but just strings used in the rest of this document below*. In |
| 414 | any of the examples below, simply replace each of these names with the |
| 415 | appropriate pathname on your local system. All these paths are absolute: |
| 416 | |
| 417 | ``SRC_ROOT`` |
| 418 | |
| 419 | This is the top level directory of the LLVM source tree. |
| 420 | |
| 421 | ``OBJ_ROOT`` |
| 422 | |
| 423 | This is the top level directory of the LLVM object tree (i.e. the tree where |
| 424 | object files and compiled programs will be placed. It can be the same as |
| 425 | SRC_ROOT). |
| 426 | |
| 427 | .. _Setting Up Your Environment: |
| 428 | |
| 429 | Setting Up Your Environment |
| 430 | --------------------------- |
| 431 | |
| 432 | In order to compile and use LLVM, you may need to set some environment |
| 433 | variables. |
| 434 | |
| 435 | ``LLVM_LIB_SEARCH_PATH=/path/to/your/bitcode/libs`` |
| 436 | |
| 437 | [Optional] This environment variable helps LLVM linking tools find the |
| 438 | locations of your bitcode libraries. It is provided only as a convenience |
| 439 | since you can specify the paths using the -L options of the tools and the |
| 440 | C/C++ front-end will automatically use the bitcode files installed in its |
| 441 | ``lib`` directory. |
| 442 | |
| 443 | Unpacking the LLVM Archives |
| 444 | --------------------------- |
| 445 | |
| 446 | If you have the LLVM distribution, you will need to unpack it before you can |
| 447 | begin to compile it. LLVM is distributed as a set of two files: the LLVM suite |
| 448 | and the LLVM GCC front end compiled for your platform. There is an additional |
| 449 | test suite that is optional. Each file is a TAR archive that is compressed with |
| 450 | the gzip program. |
| 451 | |
| 452 | The files are as follows, with *x.y* marking the version number: |
| 453 | |
| 454 | ``llvm-x.y.tar.gz`` |
| 455 | |
| 456 | Source release for the LLVM libraries and tools. |
| 457 | |
| 458 | ``llvm-test-x.y.tar.gz`` |
| 459 | |
| 460 | Source release for the LLVM test-suite. |
| 461 | |
| 462 | ``llvm-gcc-4.2-x.y.source.tar.gz`` |
| 463 | |
| 464 | Source release of the llvm-gcc-4.2 front end. See README.LLVM in the root |
| 465 | directory for build instructions. |
| 466 | |
| 467 | ``llvm-gcc-4.2-x.y-platform.tar.gz`` |
| 468 | |
| 469 | Binary release of the llvm-gcc-4.2 front end for a specific platform. |
| 470 | |
Sean Silva | 8a0f3f7 | 2013-01-10 06:39:37 +0000 | [diff] [blame] | 471 | .. _checkout: |
| 472 | |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 473 | Checkout LLVM from Subversion |
| 474 | ----------------------------- |
| 475 | |
| 476 | If you have access to our Subversion repository, you can get a fresh copy of the |
| 477 | entire source code. All you need to do is check it out from Subversion as |
| 478 | follows: |
| 479 | |
| 480 | * ``cd where-you-want-llvm-to-live`` |
| 481 | * Read-Only: ``svn co http://llvm.org/svn/llvm-project/llvm/trunk llvm`` |
| 482 | * Read-Write:``svn co https://user@llvm.org/svn/llvm-project/llvm/trunk llvm`` |
| 483 | |
| 484 | This will create an '``llvm``' directory in the current directory and fully |
| 485 | populate it with the LLVM source code, Makefiles, test directories, and local |
| 486 | copies of documentation files. |
| 487 | |
| 488 | If you want to get a specific release (as opposed to the most recent revision), |
| 489 | you can checkout it from the '``tags``' directory (instead of '``trunk``'). The |
| 490 | following releases are located in the following subdirectories of the '``tags``' |
| 491 | directory: |
| 492 | |
| 493 | * Release 3.1: **RELEASE_31/final** |
| 494 | * Release 3.0: **RELEASE_30/final** |
| 495 | * Release 2.9: **RELEASE_29/final** |
| 496 | * Release 2.8: **RELEASE_28** |
| 497 | * Release 2.7: **RELEASE_27** |
| 498 | * Release 2.6: **RELEASE_26** |
| 499 | * Release 2.5: **RELEASE_25** |
| 500 | * Release 2.4: **RELEASE_24** |
| 501 | * Release 2.3: **RELEASE_23** |
| 502 | * Release 2.2: **RELEASE_22** |
| 503 | * Release 2.1: **RELEASE_21** |
| 504 | * Release 2.0: **RELEASE_20** |
| 505 | * Release 1.9: **RELEASE_19** |
| 506 | * Release 1.8: **RELEASE_18** |
| 507 | * Release 1.7: **RELEASE_17** |
| 508 | * Release 1.6: **RELEASE_16** |
| 509 | * Release 1.5: **RELEASE_15** |
| 510 | * Release 1.4: **RELEASE_14** |
| 511 | * Release 1.3: **RELEASE_13** |
| 512 | * Release 1.2: **RELEASE_12** |
| 513 | * Release 1.1: **RELEASE_11** |
| 514 | * Release 1.0: **RELEASE_1** |
| 515 | |
| 516 | If you would like to get the LLVM test suite (a separate package as of 1.4), you |
| 517 | get it from the Subversion repository: |
| 518 | |
Dmitri Gribenko | 527036d | 2012-12-12 13:56:37 +0000 | [diff] [blame] | 519 | .. code-block:: console |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 520 | |
| 521 | % cd llvm/projects |
| 522 | % svn co http://llvm.org/svn/llvm-project/test-suite/trunk test-suite |
| 523 | |
| 524 | By placing it in the ``llvm/projects``, it will be automatically configured by |
| 525 | the LLVM configure script as well as automatically updated when you run ``svn |
| 526 | update``. |
| 527 | |
Thomas Schwinge | 7f5f06b | 2013-03-28 18:06:20 +0000 | [diff] [blame] | 528 | Git Mirror |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 529 | ---------- |
| 530 | |
Thomas Schwinge | 7f5f06b | 2013-03-28 18:06:20 +0000 | [diff] [blame] | 531 | Git mirrors are available for a number of LLVM subprojects. These mirrors sync |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 532 | automatically with each Subversion commit and contain all necessary git-svn |
| 533 | marks (so, you can recreate git-svn metadata locally). Note that right now |
Thomas Schwinge | 7f5f06b | 2013-03-28 18:06:20 +0000 | [diff] [blame] | 534 | mirrors reflect only ``trunk`` for each project. You can do the read-only Git |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 535 | clone of LLVM via: |
| 536 | |
Dmitri Gribenko | 527036d | 2012-12-12 13:56:37 +0000 | [diff] [blame] | 537 | .. code-block:: console |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 538 | |
| 539 | % git clone http://llvm.org/git/llvm.git |
| 540 | |
| 541 | If you want to check out clang too, run: |
| 542 | |
Dmitri Gribenko | 527036d | 2012-12-12 13:56:37 +0000 | [diff] [blame] | 543 | .. code-block:: console |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 544 | |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 545 | % cd llvm/tools |
| 546 | % git clone http://llvm.org/git/clang.git |
| 547 | |
Tobias Grosser | 9c22886 | 2013-03-24 15:15:19 +0000 | [diff] [blame] | 548 | If you want to check out compiler-rt too, run: |
| 549 | |
| 550 | .. code-block:: console |
| 551 | |
| 552 | % cd llvm/projects |
| 553 | % git clone http://llvm.org/git/compiler-rt.git |
| 554 | |
| 555 | If you want to check out the Test Suite Source Code (optional), run: |
| 556 | |
| 557 | .. code-block:: console |
| 558 | |
| 559 | % cd llvm/projects |
| 560 | % git clone http://llvm.org/git/test-suite.git |
| 561 | |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 562 | Since the upstream repository is in Subversion, you should use ``git |
| 563 | pull --rebase`` instead of ``git pull`` to avoid generating a non-linear history |
| 564 | in your clone. To configure ``git pull`` to pass ``--rebase`` by default on the |
| 565 | master branch, run the following command: |
| 566 | |
Dmitri Gribenko | 527036d | 2012-12-12 13:56:37 +0000 | [diff] [blame] | 567 | .. code-block:: console |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 568 | |
| 569 | % git config branch.master.rebase true |
| 570 | |
| 571 | Sending patches with Git |
| 572 | ^^^^^^^^^^^^^^^^^^^^^^^^ |
| 573 | |
NAKAMURA Takumi | df60867 | 2012-10-11 01:10:27 +0000 | [diff] [blame] | 574 | Please read `Developer Policy <DeveloperPolicy.html#one-off-patches>`_, too. |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 575 | |
| 576 | Assume ``master`` points the upstream and ``mybranch`` points your working |
| 577 | branch, and ``mybranch`` is rebased onto ``master``. At first you may check |
| 578 | sanity of whitespaces: |
| 579 | |
Dmitri Gribenko | 527036d | 2012-12-12 13:56:37 +0000 | [diff] [blame] | 580 | .. code-block:: console |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 581 | |
| 582 | % git diff --check master..mybranch |
| 583 | |
| 584 | The easiest way to generate a patch is as below: |
| 585 | |
Dmitri Gribenko | 527036d | 2012-12-12 13:56:37 +0000 | [diff] [blame] | 586 | .. code-block:: console |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 587 | |
| 588 | % git diff master..mybranch > /path/to/mybranch.diff |
| 589 | |
| 590 | It is a little different from svn-generated diff. git-diff-generated diff has |
| 591 | prefixes like ``a/`` and ``b/``. Don't worry, most developers might know it |
| 592 | could be accepted with ``patch -p1 -N``. |
| 593 | |
| 594 | But you may generate patchset with git-format-patch. It generates by-each-commit |
| 595 | patchset. To generate patch files to attach to your article: |
| 596 | |
Dmitri Gribenko | 527036d | 2012-12-12 13:56:37 +0000 | [diff] [blame] | 597 | .. code-block:: console |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 598 | |
| 599 | % git format-patch --no-attach master..mybranch -o /path/to/your/patchset |
| 600 | |
| 601 | If you would like to send patches directly, you may use git-send-email or |
| 602 | git-imap-send. Here is an example to generate the patchset in Gmail's [Drafts]. |
| 603 | |
Dmitri Gribenko | 527036d | 2012-12-12 13:56:37 +0000 | [diff] [blame] | 604 | .. code-block:: console |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 605 | |
| 606 | % git format-patch --attach master..mybranch --stdout | git imap-send |
| 607 | |
| 608 | Then, your .git/config should have [imap] sections. |
| 609 | |
Sean Silva | 426fe8b | 2012-11-20 12:36:27 +0000 | [diff] [blame] | 610 | .. code-block:: ini |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 611 | |
| 612 | [imap] |
| 613 | host = imaps://imap.gmail.com |
| 614 | user = your.gmail.account@gmail.com |
| 615 | pass = himitsu! |
| 616 | port = 993 |
| 617 | sslverify = false |
| 618 | ; in English |
| 619 | folder = "[Gmail]/Drafts" |
| 620 | ; example for Japanese, "Modified UTF-7" encoded. |
NAKAMURA Takumi | cea9264 | 2012-10-11 01:10:37 +0000 | [diff] [blame] | 621 | folder = "[Gmail]/&Tgtm+DBN-" |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 622 | ; example for Traditional Chinese |
NAKAMURA Takumi | cea9264 | 2012-10-11 01:10:37 +0000 | [diff] [blame] | 623 | folder = "[Gmail]/&g0l6Pw-" |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 624 | |
| 625 | For developers to work with git-svn |
| 626 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ |
| 627 | |
| 628 | To set up clone from which you can submit code using ``git-svn``, run: |
| 629 | |
Dmitri Gribenko | 527036d | 2012-12-12 13:56:37 +0000 | [diff] [blame] | 630 | .. code-block:: console |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 631 | |
| 632 | % git clone http://llvm.org/git/llvm.git |
| 633 | % cd llvm |
| 634 | % git svn init https://llvm.org/svn/llvm-project/llvm/trunk --username=<username> |
| 635 | % git config svn-remote.svn.fetch :refs/remotes/origin/master |
| 636 | % git svn rebase -l # -l avoids fetching ahead of the git mirror. |
| 637 | |
| 638 | # If you have clang too: |
| 639 | % cd tools |
| 640 | % git clone http://llvm.org/git/clang.git |
| 641 | % cd clang |
| 642 | % git svn init https://llvm.org/svn/llvm-project/cfe/trunk --username=<username> |
| 643 | % git config svn-remote.svn.fetch :refs/remotes/origin/master |
| 644 | % git svn rebase -l |
| 645 | |
Tobias Grosser | 9c22886 | 2013-03-24 15:15:19 +0000 | [diff] [blame] | 646 | Likewise for compiler-rt and test-suite. |
| 647 | |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 648 | To update this clone without generating git-svn tags that conflict with the |
Thomas Schwinge | 7f5f06b | 2013-03-28 18:06:20 +0000 | [diff] [blame] | 649 | upstream Git repo, run: |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 650 | |
Dmitri Gribenko | 527036d | 2012-12-12 13:56:37 +0000 | [diff] [blame] | 651 | .. code-block:: console |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 652 | |
| 653 | % git fetch && (cd tools/clang && git fetch) # Get matching revisions of both trees. |
| 654 | % git checkout master |
| 655 | % git svn rebase -l |
| 656 | % (cd tools/clang && |
| 657 | git checkout master && |
| 658 | git svn rebase -l) |
| 659 | |
Tobias Grosser | 9c22886 | 2013-03-24 15:15:19 +0000 | [diff] [blame] | 660 | Likewise for compiler-rt and test-suite. |
| 661 | |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 662 | This leaves your working directories on their master branches, so you'll need to |
| 663 | ``checkout`` each working branch individually and ``rebase`` it on top of its |
Renato Golin | e36291a | 2013-01-06 00:14:27 +0000 | [diff] [blame] | 664 | parent branch. |
| 665 | |
Michael Gottesman | e1f0790 | 2013-04-26 01:04:45 +0000 | [diff] [blame] | 666 | For those who wish to be able to update an llvm repo/revert patches easily using |
| 667 | git-svn, please look in the directory for the scripts ``git-svnup`` and |
| 668 | ``git-svnrevert``. |
Michael Gottesman | 7e4aeba | 2013-01-25 19:31:09 +0000 | [diff] [blame] | 669 | |
Michael Gottesman | e1f0790 | 2013-04-26 01:04:45 +0000 | [diff] [blame] | 670 | To perform the aforementioned update steps go into your source directory and |
| 671 | just type ``git-svnup`` or ``git svnup`` and everything will just work. |
Michael Gottesman | 7e4aeba | 2013-01-25 19:31:09 +0000 | [diff] [blame] | 672 | |
Michael Gottesman | e1f0790 | 2013-04-26 01:04:45 +0000 | [diff] [blame] | 673 | If one wishes to revert a commit with git-svn, but do not want the git hash to |
| 674 | escape into the commit message, one can use the script ``git-svnrevert`` or |
| 675 | ``git svnrevert`` which will take in the git hash for the commit you want to |
| 676 | revert, look up the appropriate svn revision, and output a message where all |
| 677 | references to the git hash have been replaced with the svn revision. |
Michael Gottesman | 7e4aeba | 2013-01-25 19:31:09 +0000 | [diff] [blame] | 678 | |
Michael Gottesman | e1f0790 | 2013-04-26 01:04:45 +0000 | [diff] [blame] | 679 | To commit back changes via git-svn, use ``git svn dcommit``: |
Renato Golin | e36291a | 2013-01-06 00:14:27 +0000 | [diff] [blame] | 680 | |
| 681 | .. code-block:: console |
| 682 | |
| 683 | % git svn dcommit |
| 684 | |
| 685 | Note that git-svn will create one SVN commit for each Git commit you have pending, |
| 686 | so squash and edit each commit before executing ``dcommit`` to make sure they all |
| 687 | conform to the coding standards and the developers' policy. |
| 688 | |
| 689 | On success, ``dcommit`` will rebase against the HEAD of SVN, so to avoid conflict, |
| 690 | please make sure your current branch is up-to-date (via fetch/rebase) before |
| 691 | proceeding. |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 692 | |
| 693 | The git-svn metadata can get out of sync after you mess around with branches and |
| 694 | ``dcommit``. When that happens, ``git svn dcommit`` stops working, complaining |
| 695 | about files with uncommitted changes. The fix is to rebuild the metadata: |
| 696 | |
Dmitri Gribenko | 527036d | 2012-12-12 13:56:37 +0000 | [diff] [blame] | 697 | .. code-block:: console |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 698 | |
| 699 | % rm -rf .git/svn |
| 700 | % git svn rebase -l |
| 701 | |
Renato Golin | e36291a | 2013-01-06 00:14:27 +0000 | [diff] [blame] | 702 | Please, refer to the Git-SVN manual (``man git-svn``) for more information. |
| 703 | |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 704 | Local LLVM Configuration |
| 705 | ------------------------ |
| 706 | |
| 707 | Once checked out from the Subversion repository, the LLVM suite source code must |
| 708 | be configured via the ``configure`` script. This script sets variables in the |
| 709 | various ``*.in`` files, most notably ``llvm/Makefile.config`` and |
| 710 | ``llvm/include/Config/config.h``. It also populates *OBJ_ROOT* with the |
| 711 | Makefiles needed to begin building LLVM. |
| 712 | |
| 713 | The following environment variables are used by the ``configure`` script to |
| 714 | configure the build system: |
| 715 | |
| 716 | +------------+-----------------------------------------------------------+ |
| 717 | | Variable | Purpose | |
| 718 | +============+===========================================================+ |
| 719 | | CC | Tells ``configure`` which C compiler to use. By default, | |
Dmitri Gribenko | 8b2bcf4 | 2013-01-05 18:10:06 +0000 | [diff] [blame] | 720 | | | ``configure`` will check ``PATH`` for ``clang`` and GCC C | |
| 721 | | | compilers (in this order). Use this variable to override | |
| 722 | | | ``configure``\'s default behavior. | |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 723 | +------------+-----------------------------------------------------------+ |
| 724 | | CXX | Tells ``configure`` which C++ compiler to use. By | |
Dmitri Gribenko | 8b2bcf4 | 2013-01-05 18:10:06 +0000 | [diff] [blame] | 725 | | | default, ``configure`` will check ``PATH`` for | |
| 726 | | | ``clang++`` and GCC C++ compilers (in this order). Use | |
| 727 | | | this variable to override ``configure``'s default | |
| 728 | | | behavior. | |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 729 | +------------+-----------------------------------------------------------+ |
| 730 | |
| 731 | The following options can be used to set or enable LLVM specific options: |
| 732 | |
| 733 | ``--enable-optimized`` |
| 734 | |
| 735 | Enables optimized compilation (debugging symbols are removed and GCC |
| 736 | optimization flags are enabled). Note that this is the default setting if you |
| 737 | are using the LLVM distribution. The default behavior of an Subversion |
| 738 | checkout is to use an unoptimized build (also known as a debug build). |
| 739 | |
| 740 | ``--enable-debug-runtime`` |
| 741 | |
| 742 | Enables debug symbols in the runtime libraries. The default is to strip debug |
| 743 | symbols from the runtime libraries. |
| 744 | |
| 745 | ``--enable-jit`` |
| 746 | |
| 747 | Compile the Just In Time (JIT) compiler functionality. This is not available |
| 748 | on all platforms. The default is dependent on platform, so it is best to |
| 749 | explicitly enable it if you want it. |
| 750 | |
| 751 | ``--enable-targets=target-option`` |
| 752 | |
| 753 | Controls which targets will be built and linked into llc. The default value |
| 754 | for ``target_options`` is "all" which builds and links all available targets. |
| 755 | The value "host-only" can be specified to build only a native compiler (no |
| 756 | cross-compiler targets available). The "native" target is selected as the |
| 757 | target of the build host. You can also specify a comma separated list of |
| 758 | target names that you want available in llc. The target names use all lower |
| 759 | case. The current set of targets is: |
| 760 | |
| 761 | ``arm, cpp, hexagon, mblaze, mips, mipsel, msp430, powerpc, ptx, sparc, spu, |
Ulrich Weigand | 735ab83 | 2013-05-06 16:22:34 +0000 | [diff] [blame] | 762 | systemz, x86, x86_64, xcore``. |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 763 | |
| 764 | ``--enable-doxygen`` |
| 765 | |
| 766 | Look for the doxygen program and enable construction of doxygen based |
| 767 | documentation from the source code. This is disabled by default because |
| 768 | generating the documentation can take a long time and producess 100s of |
| 769 | megabytes of output. |
| 770 | |
| 771 | ``--with-udis86`` |
| 772 | |
| 773 | LLVM can use external disassembler library for various purposes (now it's used |
| 774 | only for examining code produced by JIT). This option will enable usage of |
| 775 | `udis86 <http://udis86.sourceforge.net/>`_ x86 (both 32 and 64 bits) |
| 776 | disassembler library. |
| 777 | |
| 778 | To configure LLVM, follow these steps: |
| 779 | |
| 780 | #. Change directory into the object root directory: |
| 781 | |
Dmitri Gribenko | 527036d | 2012-12-12 13:56:37 +0000 | [diff] [blame] | 782 | .. code-block:: console |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 783 | |
| 784 | % cd OBJ_ROOT |
| 785 | |
| 786 | #. Run the ``configure`` script located in the LLVM source tree: |
| 787 | |
Dmitri Gribenko | 527036d | 2012-12-12 13:56:37 +0000 | [diff] [blame] | 788 | .. code-block:: console |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 789 | |
| 790 | % SRC_ROOT/configure --prefix=/install/path [other options] |
| 791 | |
| 792 | Compiling the LLVM Suite Source Code |
| 793 | ------------------------------------ |
| 794 | |
| 795 | Once you have configured LLVM, you can build it. There are three types of |
| 796 | builds: |
| 797 | |
| 798 | Debug Builds |
| 799 | |
| 800 | These builds are the default when one is using an Subversion checkout and |
| 801 | types ``gmake`` (unless the ``--enable-optimized`` option was used during |
| 802 | configuration). The build system will compile the tools and libraries with |
| 803 | debugging information. To get a Debug Build using the LLVM distribution the |
| 804 | ``--disable-optimized`` option must be passed to ``configure``. |
| 805 | |
| 806 | Release (Optimized) Builds |
| 807 | |
| 808 | These builds are enabled with the ``--enable-optimized`` option to |
| 809 | ``configure`` or by specifying ``ENABLE_OPTIMIZED=1`` on the ``gmake`` command |
| 810 | line. For these builds, the build system will compile the tools and libraries |
| 811 | with GCC optimizations enabled and strip debugging information from the |
| 812 | libraries and executables it generates. Note that Release Builds are default |
| 813 | when using an LLVM distribution. |
| 814 | |
| 815 | Profile Builds |
| 816 | |
| 817 | These builds are for use with profiling. They compile profiling information |
| 818 | into the code for use with programs like ``gprof``. Profile builds must be |
| 819 | started by specifying ``ENABLE_PROFILING=1`` on the ``gmake`` command line. |
| 820 | |
| 821 | Once you have LLVM configured, you can build it by entering the *OBJ_ROOT* |
| 822 | directory and issuing the following command: |
| 823 | |
Dmitri Gribenko | 527036d | 2012-12-12 13:56:37 +0000 | [diff] [blame] | 824 | .. code-block:: console |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 825 | |
| 826 | % gmake |
| 827 | |
| 828 | If the build fails, please `check here`_ to see if you are using a version of |
| 829 | GCC that is known not to compile LLVM. |
| 830 | |
| 831 | If you have multiple processors in your machine, you may wish to use some of the |
| 832 | parallel build options provided by GNU Make. For example, you could use the |
| 833 | command: |
| 834 | |
Dmitri Gribenko | 527036d | 2012-12-12 13:56:37 +0000 | [diff] [blame] | 835 | .. code-block:: console |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 836 | |
| 837 | % gmake -j2 |
| 838 | |
| 839 | There are several special targets which are useful when working with the LLVM |
| 840 | source code: |
| 841 | |
| 842 | ``gmake clean`` |
| 843 | |
| 844 | Removes all files generated by the build. This includes object files, |
| 845 | generated C/C++ files, libraries, and executables. |
| 846 | |
| 847 | ``gmake dist-clean`` |
| 848 | |
| 849 | Removes everything that ``gmake clean`` does, but also removes files generated |
| 850 | by ``configure``. It attempts to return the source tree to the original state |
| 851 | in which it was shipped. |
| 852 | |
| 853 | ``gmake install`` |
| 854 | |
| 855 | Installs LLVM header files, libraries, tools, and documentation in a hierarchy |
| 856 | under ``$PREFIX``, specified with ``./configure --prefix=[dir]``, which |
| 857 | defaults to ``/usr/local``. |
| 858 | |
| 859 | ``gmake -C runtime install-bytecode`` |
| 860 | |
| 861 | Assuming you built LLVM into $OBJDIR, when this command is run, it will |
| 862 | install bitcode libraries into the GCC front end's bitcode library directory. |
| 863 | If you need to update your bitcode libraries, this is the target to use once |
| 864 | you've built them. |
| 865 | |
| 866 | Please see the `Makefile Guide <MakefileGuide.html>`_ for further details on |
| 867 | these ``make`` targets and descriptions of other targets available. |
| 868 | |
| 869 | It is also possible to override default values from ``configure`` by declaring |
| 870 | variables on the command line. The following are some examples: |
| 871 | |
| 872 | ``gmake ENABLE_OPTIMIZED=1`` |
| 873 | |
| 874 | Perform a Release (Optimized) build. |
| 875 | |
| 876 | ``gmake ENABLE_OPTIMIZED=1 DISABLE_ASSERTIONS=1`` |
| 877 | |
| 878 | Perform a Release (Optimized) build without assertions enabled. |
| 879 | |
| 880 | ``gmake ENABLE_OPTIMIZED=0`` |
| 881 | |
| 882 | Perform a Debug build. |
| 883 | |
| 884 | ``gmake ENABLE_PROFILING=1`` |
| 885 | |
| 886 | Perform a Profiling build. |
| 887 | |
| 888 | ``gmake VERBOSE=1`` |
| 889 | |
| 890 | Print what ``gmake`` is doing on standard output. |
| 891 | |
| 892 | ``gmake TOOL_VERBOSE=1`` |
| 893 | |
| 894 | Ask each tool invoked by the makefiles to print out what it is doing on |
| 895 | the standard output. This also implies ``VERBOSE=1``. |
| 896 | |
| 897 | Every directory in the LLVM object tree includes a ``Makefile`` to build it and |
| 898 | any subdirectories that it contains. Entering any directory inside the LLVM |
| 899 | object tree and typing ``gmake`` should rebuild anything in or below that |
| 900 | directory that is out of date. |
| 901 | |
Joel Jones | b92ef12 | 2012-11-15 21:15:08 +0000 | [diff] [blame] | 902 | This does not apply to building the documentation. |
| 903 | LLVM's (non-Doxygen) documentation is produced with the |
| 904 | `Sphinx <http://sphinx-doc.org/>`_ documentation generation system. |
| 905 | There are some HTML documents that have not yet been converted to the new |
| 906 | system (which uses the easy-to-read and easy-to-write |
| 907 | `reStructuredText <http://sphinx-doc.org/rest.html>`_ plaintext markup |
| 908 | language). |
| 909 | The generated documentation is built in the ``SRC_ROOT/docs`` directory using |
| 910 | a special makefile. |
| 911 | For instructions on how to install Sphinx, see |
| 912 | `Sphinx Introduction for LLVM Developers |
| 913 | <http://lld.llvm.org/sphinx_intro.html>`_. |
| 914 | After following the instructions there for installing Sphinx, build the LLVM |
| 915 | HTML documentation by doing the following: |
| 916 | |
Dmitri Gribenko | 527036d | 2012-12-12 13:56:37 +0000 | [diff] [blame] | 917 | .. code-block:: console |
Joel Jones | b92ef12 | 2012-11-15 21:15:08 +0000 | [diff] [blame] | 918 | |
| 919 | $ cd SRC_ROOT/docs |
| 920 | $ make -f Makefile.sphinx |
| 921 | |
| 922 | This creates a ``_build/html`` sub-directory with all of the HTML files, not |
| 923 | just the generated ones. |
| 924 | This directory corresponds to ``llvm.org/docs``. |
| 925 | For example, ``_build/html/SphinxQuickstartTemplate.html`` corresponds to |
| 926 | ``llvm.org/docs/SphinxQuickstartTemplate.html``. |
| 927 | The :doc:`SphinxQuickstartTemplate` is useful when creating a new document. |
| 928 | |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 929 | Cross-Compiling LLVM |
| 930 | -------------------- |
| 931 | |
| 932 | It is possible to cross-compile LLVM itself. That is, you can create LLVM |
| 933 | executables and libraries to be hosted on a platform different from the platform |
Joel Jones | b92ef12 | 2012-11-15 21:15:08 +0000 | [diff] [blame] | 934 | where they are built (a Canadian Cross build). To configure a cross-compile, |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 935 | supply the configure script with ``--build`` and ``--host`` options that are |
| 936 | different. The values of these options must be legal target triples that your |
| 937 | GCC compiler supports. |
| 938 | |
| 939 | The result of such a build is executables that are not runnable on on the build |
| 940 | host (--build option) but can be executed on the compile host (--host option). |
| 941 | |
| 942 | The Location of LLVM Object Files |
| 943 | --------------------------------- |
| 944 | |
| 945 | The LLVM build system is capable of sharing a single LLVM source tree among |
| 946 | several LLVM builds. Hence, it is possible to build LLVM for several different |
| 947 | platforms or configurations using the same source tree. |
| 948 | |
| 949 | This is accomplished in the typical autoconf manner: |
| 950 | |
| 951 | * Change directory to where the LLVM object files should live: |
| 952 | |
Dmitri Gribenko | 527036d | 2012-12-12 13:56:37 +0000 | [diff] [blame] | 953 | .. code-block:: console |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 954 | |
| 955 | % cd OBJ_ROOT |
| 956 | |
| 957 | * Run the ``configure`` script found in the LLVM source directory: |
| 958 | |
Dmitri Gribenko | 527036d | 2012-12-12 13:56:37 +0000 | [diff] [blame] | 959 | .. code-block:: console |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 960 | |
| 961 | % SRC_ROOT/configure |
| 962 | |
| 963 | The LLVM build will place files underneath *OBJ_ROOT* in directories named after |
| 964 | the build type: |
| 965 | |
| 966 | Debug Builds with assertions enabled (the default) |
| 967 | |
| 968 | Tools |
| 969 | |
| 970 | ``OBJ_ROOT/Debug+Asserts/bin`` |
| 971 | |
| 972 | Libraries |
| 973 | |
| 974 | ``OBJ_ROOT/Debug+Asserts/lib`` |
| 975 | |
| 976 | Release Builds |
| 977 | |
| 978 | Tools |
| 979 | |
| 980 | ``OBJ_ROOT/Release/bin`` |
| 981 | |
| 982 | Libraries |
| 983 | |
| 984 | ``OBJ_ROOT/Release/lib`` |
| 985 | |
| 986 | Profile Builds |
| 987 | |
| 988 | Tools |
| 989 | |
| 990 | ``OBJ_ROOT/Profile/bin`` |
| 991 | |
| 992 | Libraries |
| 993 | |
| 994 | ``OBJ_ROOT/Profile/lib`` |
| 995 | |
| 996 | Optional Configuration Items |
| 997 | ---------------------------- |
| 998 | |
| 999 | If you're running on a Linux system that supports the `binfmt_misc |
Dmitri Gribenko | 9409a64 | 2013-03-25 17:08:25 +0000 | [diff] [blame] | 1000 | <http://en.wikipedia.org/wiki/binfmt_misc>`_ |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 1001 | module, and you have root access on the system, you can set your system up to |
| 1002 | execute LLVM bitcode files directly. To do this, use commands like this (the |
| 1003 | first command may not be required if you are already using the module): |
| 1004 | |
Dmitri Gribenko | 527036d | 2012-12-12 13:56:37 +0000 | [diff] [blame] | 1005 | .. code-block:: console |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 1006 | |
| 1007 | % mount -t binfmt_misc none /proc/sys/fs/binfmt_misc |
| 1008 | % echo ':llvm:M::BC::/path/to/lli:' > /proc/sys/fs/binfmt_misc/register |
| 1009 | % chmod u+x hello.bc (if needed) |
| 1010 | % ./hello.bc |
| 1011 | |
| 1012 | This allows you to execute LLVM bitcode files directly. On Debian, you can also |
| 1013 | use this command instead of the 'echo' command above: |
| 1014 | |
Dmitri Gribenko | 527036d | 2012-12-12 13:56:37 +0000 | [diff] [blame] | 1015 | .. code-block:: console |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 1016 | |
| 1017 | % sudo update-binfmts --install llvm /path/to/lli --magic 'BC' |
| 1018 | |
| 1019 | .. _Program Layout: |
| 1020 | .. _general layout: |
| 1021 | |
| 1022 | Program Layout |
| 1023 | ============== |
| 1024 | |
| 1025 | One useful source of information about the LLVM source base is the LLVM `doxygen |
| 1026 | <http://www.doxygen.org/>`_ documentation available at |
| 1027 | `<http://llvm.org/doxygen/>`_. The following is a brief introduction to code |
| 1028 | layout: |
| 1029 | |
| 1030 | ``llvm/examples`` |
| 1031 | ----------------- |
| 1032 | |
| 1033 | This directory contains some simple examples of how to use the LLVM IR and JIT. |
| 1034 | |
| 1035 | ``llvm/include`` |
| 1036 | ---------------- |
| 1037 | |
| 1038 | This directory contains public header files exported from the LLVM library. The |
| 1039 | three main subdirectories of this directory are: |
| 1040 | |
| 1041 | ``llvm/include/llvm`` |
| 1042 | |
| 1043 | This directory contains all of the LLVM specific header files. This directory |
| 1044 | also has subdirectories for different portions of LLVM: ``Analysis``, |
| 1045 | ``CodeGen``, ``Target``, ``Transforms``, etc... |
| 1046 | |
| 1047 | ``llvm/include/llvm/Support`` |
| 1048 | |
| 1049 | This directory contains generic support libraries that are provided with LLVM |
| 1050 | but not necessarily specific to LLVM. For example, some C++ STL utilities and |
| 1051 | a Command Line option processing library store their header files here. |
| 1052 | |
| 1053 | ``llvm/include/llvm/Config`` |
| 1054 | |
| 1055 | This directory contains header files configured by the ``configure`` script. |
| 1056 | They wrap "standard" UNIX and C header files. Source code can include these |
| 1057 | header files which automatically take care of the conditional #includes that |
| 1058 | the ``configure`` script generates. |
| 1059 | |
| 1060 | ``llvm/lib`` |
| 1061 | ------------ |
| 1062 | |
| 1063 | This directory contains most of the source files of the LLVM system. In LLVM, |
| 1064 | almost all code exists in libraries, making it very easy to share code among the |
| 1065 | different `tools`_. |
| 1066 | |
| 1067 | ``llvm/lib/VMCore/`` |
| 1068 | |
| 1069 | This directory holds the core LLVM source files that implement core classes |
| 1070 | like Instruction and BasicBlock. |
| 1071 | |
| 1072 | ``llvm/lib/AsmParser/`` |
| 1073 | |
| 1074 | This directory holds the source code for the LLVM assembly language parser |
| 1075 | library. |
| 1076 | |
Michael Liao | 0262db3 | 2013-06-11 18:09:21 +0000 | [diff] [blame^] | 1077 | ``llvm/lib/Bitcode/`` |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 1078 | |
| 1079 | This directory holds code for reading and write LLVM bitcode. |
| 1080 | |
| 1081 | ``llvm/lib/Analysis/`` |
| 1082 | |
| 1083 | This directory contains a variety of different program analyses, such as |
| 1084 | Dominator Information, Call Graphs, Induction Variables, Interval |
| 1085 | Identification, Natural Loop Identification, etc. |
| 1086 | |
| 1087 | ``llvm/lib/Transforms/`` |
| 1088 | |
| 1089 | This directory contains the source code for the LLVM to LLVM program |
| 1090 | transformations, such as Aggressive Dead Code Elimination, Sparse Conditional |
| 1091 | Constant Propagation, Inlining, Loop Invariant Code Motion, Dead Global |
| 1092 | Elimination, and many others. |
| 1093 | |
| 1094 | ``llvm/lib/Target/`` |
| 1095 | |
| 1096 | This directory contains files that describe various target architectures for |
| 1097 | code generation. For example, the ``llvm/lib/Target/X86`` directory holds the |
| 1098 | X86 machine description while ``llvm/lib/Target/ARM`` implements the ARM |
| 1099 | backend. |
| 1100 | |
| 1101 | ``llvm/lib/CodeGen/`` |
| 1102 | |
| 1103 | This directory contains the major parts of the code generator: Instruction |
| 1104 | Selector, Instruction Scheduling, and Register Allocation. |
| 1105 | |
| 1106 | ``llvm/lib/MC/`` |
| 1107 | |
| 1108 | (FIXME: T.B.D.) |
| 1109 | |
| 1110 | ``llvm/lib/Debugger/`` |
| 1111 | |
| 1112 | This directory contains the source level debugger library that makes it |
| 1113 | possible to instrument LLVM programs so that a debugger could identify source |
| 1114 | code locations at which the program is executing. |
| 1115 | |
| 1116 | ``llvm/lib/ExecutionEngine/`` |
| 1117 | |
| 1118 | This directory contains libraries for executing LLVM bitcode directly at |
| 1119 | runtime in both interpreted and JIT compiled fashions. |
| 1120 | |
| 1121 | ``llvm/lib/Support/`` |
| 1122 | |
| 1123 | This directory contains the source code that corresponds to the header files |
| 1124 | located in ``llvm/include/ADT/`` and ``llvm/include/Support/``. |
| 1125 | |
| 1126 | ``llvm/projects`` |
| 1127 | ----------------- |
| 1128 | |
| 1129 | This directory contains projects that are not strictly part of LLVM but are |
| 1130 | shipped with LLVM. This is also the directory where you should create your own |
| 1131 | LLVM-based projects. See ``llvm/projects/sample`` for an example of how to set |
| 1132 | up your own project. |
| 1133 | |
| 1134 | ``llvm/runtime`` |
| 1135 | ---------------- |
| 1136 | |
| 1137 | This directory contains libraries which are compiled into LLVM bitcode and used |
| 1138 | when linking programs with the Clang front end. Most of these libraries are |
| 1139 | skeleton versions of real libraries; for example, libc is a stripped down |
| 1140 | version of glibc. |
| 1141 | |
| 1142 | Unlike the rest of the LLVM suite, this directory needs the LLVM GCC front end |
| 1143 | to compile. |
| 1144 | |
| 1145 | ``llvm/test`` |
| 1146 | ------------- |
| 1147 | |
| 1148 | This directory contains feature and regression tests and other basic sanity |
| 1149 | checks on the LLVM infrastructure. These are intended to run quickly and cover a |
| 1150 | lot of territory without being exhaustive. |
| 1151 | |
| 1152 | ``test-suite`` |
| 1153 | -------------- |
| 1154 | |
| 1155 | This is not a directory in the normal llvm module; it is a separate Subversion |
| 1156 | module that must be checked out (usually to ``projects/test-suite``). This |
| 1157 | module contains a comprehensive correctness, performance, and benchmarking test |
| 1158 | suite for LLVM. It is a separate Subversion module because not every LLVM user |
| 1159 | is interested in downloading or building such a comprehensive test suite. For |
Sean Silva | ac99eed | 2012-11-14 21:09:30 +0000 | [diff] [blame] | 1160 | further details on this test suite, please see the :doc:`Testing Guide |
| 1161 | <TestingGuide>` document. |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 1162 | |
| 1163 | .. _tools: |
| 1164 | |
| 1165 | ``llvm/tools`` |
| 1166 | -------------- |
| 1167 | |
| 1168 | The **tools** directory contains the executables built out of the libraries |
| 1169 | above, which form the main part of the user interface. You can always get help |
| 1170 | for a tool by typing ``tool_name -help``. The following is a brief introduction |
| 1171 | to the most important tools. More detailed information is in |
| 1172 | the `Command Guide <CommandGuide/index.html>`_. |
| 1173 | |
| 1174 | ``bugpoint`` |
| 1175 | |
| 1176 | ``bugpoint`` is used to debug optimization passes or code generation backends |
| 1177 | by narrowing down the given test case to the minimum number of passes and/or |
| 1178 | instructions that still cause a problem, whether it is a crash or |
| 1179 | miscompilation. See `<HowToSubmitABug.html>`_ for more information on using |
| 1180 | ``bugpoint``. |
| 1181 | |
| 1182 | ``llvm-ar`` |
| 1183 | |
| 1184 | The archiver produces an archive containing the given LLVM bitcode files, |
| 1185 | optionally with an index for faster lookup. |
| 1186 | |
| 1187 | ``llvm-as`` |
| 1188 | |
| 1189 | The assembler transforms the human readable LLVM assembly to LLVM bitcode. |
| 1190 | |
| 1191 | ``llvm-dis`` |
| 1192 | |
| 1193 | The disassembler transforms the LLVM bitcode to human readable LLVM assembly. |
| 1194 | |
| 1195 | ``llvm-link`` |
| 1196 | |
| 1197 | ``llvm-link``, not surprisingly, links multiple LLVM modules into a single |
| 1198 | program. |
| 1199 | |
| 1200 | ``lli`` |
| 1201 | |
| 1202 | ``lli`` is the LLVM interpreter, which can directly execute LLVM bitcode |
| 1203 | (although very slowly...). For architectures that support it (currently x86, |
| 1204 | Sparc, and PowerPC), by default, ``lli`` will function as a Just-In-Time |
| 1205 | compiler (if the functionality was compiled in), and will execute the code |
| 1206 | *much* faster than the interpreter. |
| 1207 | |
| 1208 | ``llc`` |
| 1209 | |
| 1210 | ``llc`` is the LLVM backend compiler, which translates LLVM bitcode to a |
| 1211 | native code assembly file or to C code (with the ``-march=c`` option). |
| 1212 | |
| 1213 | ``opt`` |
| 1214 | |
| 1215 | ``opt`` reads LLVM bitcode, applies a series of LLVM to LLVM transformations |
| 1216 | (which are specified on the command line), and then outputs the resultant |
| 1217 | bitcode. The '``opt -help``' command is a good way to get a list of the |
| 1218 | program transformations available in LLVM. |
| 1219 | |
| 1220 | ``opt`` can also be used to run a specific analysis on an input LLVM bitcode |
| 1221 | file and print out the results. It is primarily useful for debugging |
| 1222 | analyses, or familiarizing yourself with what an analysis does. |
| 1223 | |
| 1224 | ``llvm/utils`` |
| 1225 | -------------- |
| 1226 | |
| 1227 | This directory contains utilities for working with LLVM source code, and some of |
| 1228 | the utilities are actually required as part of the build process because they |
| 1229 | are code generators for parts of LLVM infrastructure. |
| 1230 | |
| 1231 | |
| 1232 | ``codegen-diff`` |
| 1233 | |
| 1234 | ``codegen-diff`` is a script that finds differences between code that LLC |
| 1235 | generates and code that LLI generates. This is a useful tool if you are |
| 1236 | debugging one of them, assuming that the other generates correct output. For |
| 1237 | the full user manual, run ```perldoc codegen-diff'``. |
| 1238 | |
| 1239 | ``emacs/`` |
| 1240 | |
| 1241 | The ``emacs`` directory contains syntax-highlighting files which will work |
| 1242 | with Emacs and XEmacs editors, providing syntax highlighting support for LLVM |
| 1243 | assembly files and TableGen description files. For information on how to use |
| 1244 | the syntax files, consult the ``README`` file in that directory. |
| 1245 | |
| 1246 | ``getsrcs.sh`` |
| 1247 | |
| 1248 | The ``getsrcs.sh`` script finds and outputs all non-generated source files, |
| 1249 | which is useful if one wishes to do a lot of development across directories |
| 1250 | and does not want to individually find each file. One way to use it is to run, |
| 1251 | for example: ``xemacs `utils/getsources.sh``` from the top of your LLVM source |
| 1252 | tree. |
| 1253 | |
| 1254 | ``llvmgrep`` |
| 1255 | |
| 1256 | This little tool performs an ``egrep -H -n`` on each source file in LLVM and |
| 1257 | passes to it a regular expression provided on ``llvmgrep``'s command |
| 1258 | line. This is a very efficient way of searching the source base for a |
| 1259 | particular regular expression. |
| 1260 | |
| 1261 | ``makellvm`` |
| 1262 | |
| 1263 | The ``makellvm`` script compiles all files in the current directory and then |
| 1264 | compiles and links the tool that is the first argument. For example, assuming |
| 1265 | you are in the directory ``llvm/lib/Target/Sparc``, if ``makellvm`` is in your |
| 1266 | path, simply running ``makellvm llc`` will make a build of the current |
| 1267 | directory, switch to directory ``llvm/tools/llc`` and build it, causing a |
| 1268 | re-linking of LLC. |
| 1269 | |
| 1270 | ``TableGen/`` |
| 1271 | |
| 1272 | The ``TableGen`` directory contains the tool used to generate register |
| 1273 | descriptions, instruction set descriptions, and even assemblers from common |
| 1274 | TableGen description files. |
| 1275 | |
| 1276 | ``vim/`` |
| 1277 | |
| 1278 | The ``vim`` directory contains syntax-highlighting files which will work with |
| 1279 | the VIM editor, providing syntax highlighting support for LLVM assembly files |
| 1280 | and TableGen description files. For information on how to use the syntax |
| 1281 | files, consult the ``README`` file in that directory. |
| 1282 | |
| 1283 | .. _simple example: |
| 1284 | |
| 1285 | An Example Using the LLVM Tool Chain |
| 1286 | ==================================== |
| 1287 | |
| 1288 | This section gives an example of using LLVM with the Clang front end. |
| 1289 | |
| 1290 | Example with clang |
| 1291 | ------------------ |
| 1292 | |
| 1293 | #. First, create a simple C file, name it 'hello.c': |
| 1294 | |
Sean Silva | a8759dd | 2012-10-10 17:07:23 +0000 | [diff] [blame] | 1295 | .. code-block:: c |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 1296 | |
| 1297 | #include <stdio.h> |
| 1298 | |
| 1299 | int main() { |
| 1300 | printf("hello world\n"); |
| 1301 | return 0; |
| 1302 | } |
| 1303 | |
| 1304 | #. Next, compile the C file into a native executable: |
| 1305 | |
Dmitri Gribenko | 527036d | 2012-12-12 13:56:37 +0000 | [diff] [blame] | 1306 | .. code-block:: console |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 1307 | |
| 1308 | % clang hello.c -o hello |
| 1309 | |
| 1310 | .. note:: |
| 1311 | |
| 1312 | Clang works just like GCC by default. The standard -S and -c arguments |
| 1313 | work as usual (producing a native .s or .o file, respectively). |
| 1314 | |
| 1315 | #. Next, compile the C file into a LLVM bitcode file: |
| 1316 | |
Dmitri Gribenko | 527036d | 2012-12-12 13:56:37 +0000 | [diff] [blame] | 1317 | .. code-block:: console |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 1318 | |
| 1319 | % clang -O3 -emit-llvm hello.c -c -o hello.bc |
| 1320 | |
| 1321 | The -emit-llvm option can be used with the -S or -c options to emit an LLVM |
| 1322 | ``.ll`` or ``.bc`` file (respectively) for the code. This allows you to use |
| 1323 | the `standard LLVM tools <CommandGuide/index.html>`_ on the bitcode file. |
| 1324 | |
| 1325 | #. Run the program in both forms. To run the program, use: |
| 1326 | |
Dmitri Gribenko | 527036d | 2012-12-12 13:56:37 +0000 | [diff] [blame] | 1327 | .. code-block:: console |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 1328 | |
| 1329 | % ./hello |
| 1330 | |
| 1331 | and |
| 1332 | |
Dmitri Gribenko | 527036d | 2012-12-12 13:56:37 +0000 | [diff] [blame] | 1333 | .. code-block:: console |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 1334 | |
| 1335 | % lli hello.bc |
| 1336 | |
Dmitri Gribenko | c796af6 | 2012-11-18 10:32:14 +0000 | [diff] [blame] | 1337 | The second examples shows how to invoke the LLVM JIT, :doc:`lli |
| 1338 | <CommandGuide/lli>`. |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 1339 | |
| 1340 | #. Use the ``llvm-dis`` utility to take a look at the LLVM assembly code: |
| 1341 | |
Dmitri Gribenko | 527036d | 2012-12-12 13:56:37 +0000 | [diff] [blame] | 1342 | .. code-block:: console |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 1343 | |
| 1344 | % llvm-dis < hello.bc | less |
| 1345 | |
| 1346 | #. Compile the program to native assembly using the LLC code generator: |
| 1347 | |
Dmitri Gribenko | 527036d | 2012-12-12 13:56:37 +0000 | [diff] [blame] | 1348 | .. code-block:: console |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 1349 | |
| 1350 | % llc hello.bc -o hello.s |
| 1351 | |
| 1352 | #. Assemble the native assembly language file into a program: |
| 1353 | |
Dmitri Gribenko | 527036d | 2012-12-12 13:56:37 +0000 | [diff] [blame] | 1354 | .. code-block:: console |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 1355 | |
Dmitri Gribenko | 527036d | 2012-12-12 13:56:37 +0000 | [diff] [blame] | 1356 | % /opt/SUNWspro/bin/cc -xarch=v9 hello.s -o hello.native # On Solaris |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 1357 | |
Dmitri Gribenko | 527036d | 2012-12-12 13:56:37 +0000 | [diff] [blame] | 1358 | % gcc hello.s -o hello.native # On others |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 1359 | |
| 1360 | #. Execute the native code program: |
| 1361 | |
Dmitri Gribenko | 527036d | 2012-12-12 13:56:37 +0000 | [diff] [blame] | 1362 | .. code-block:: console |
Bill Wendling | f93c55a | 2012-10-07 07:10:13 +0000 | [diff] [blame] | 1363 | |
| 1364 | % ./hello.native |
| 1365 | |
| 1366 | Note that using clang to compile directly to native code (i.e. when the |
| 1367 | ``-emit-llvm`` option is not present) does steps 6/7/8 for you. |
| 1368 | |
| 1369 | Common Problems |
| 1370 | =============== |
| 1371 | |
| 1372 | If you are having problems building or using LLVM, or if you have any other |
| 1373 | general questions about LLVM, please consult the `Frequently Asked |
| 1374 | Questions <FAQ.html>`_ page. |
| 1375 | |
| 1376 | .. _links: |
| 1377 | |
| 1378 | Links |
| 1379 | ===== |
| 1380 | |
| 1381 | This document is just an **introduction** on how to use LLVM to do some simple |
| 1382 | things... there are many more interesting and complicated things that you can do |
| 1383 | that aren't documented here (but we'll gladly accept a patch if you want to |
| 1384 | write something up!). For more information about LLVM, check out: |
| 1385 | |
| 1386 | * `LLVM Homepage <http://llvm.org/>`_ |
| 1387 | * `LLVM Doxygen Tree <http://llvm.org/doxygen/>`_ |
| 1388 | * `Starting a Project that Uses LLVM <http://llvm.org/docs/Projects.html>`_ |