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| |
| <h1> |
| Getting Started with the LLVM System |
| </h1> |
| |
| <ul> |
| <li><a href="#overview">Overview</a> |
| <li><a href="#quickstart">Getting Started Quickly (A Summary)</a> |
| <li><a href="#requirements">Requirements</a> |
| <ol> |
| <li><a href="#hardware">Hardware</a></li> |
| <li><a href="#software">Software</a></li> |
| <li><a href="#brokengcc">Broken versions of GCC and other tools</a></li> |
| </ol></li> |
| |
| <li><a href="#starting">Getting Started with LLVM</a> |
| <ol> |
| <li><a href="#terminology">Terminology and Notation</a></li> |
| <li><a href="#environment">Setting Up Your Environment</a></li> |
| <li><a href="#unpack">Unpacking the LLVM Archives</a></li> |
| <li><a href="#checkout">Checkout LLVM from Subversion</a></li> |
| <li><a href="#git_mirror">LLVM GIT mirror</a></li> |
| <li><a href="#installcf">Install the GCC Front End</a></li> |
| <li><a href="#config">Local LLVM Configuration</a></li> |
| <li><a href="#compile">Compiling the LLVM Suite Source Code</a></li> |
| <li><a href="#cross-compile">Cross-Compiling LLVM</a></li> |
| <li><a href="#objfiles">The Location of LLVM Object Files</a></li> |
| <li><a href="#optionalconfig">Optional Configuration Items</a></li> |
| </ol></li> |
| |
| <li><a href="#layout">Program layout</a> |
| <ol> |
| <li><a href="#examples"><tt>llvm/examples</tt></a></li> |
| <li><a href="#include"><tt>llvm/include</tt></a></li> |
| <li><a href="#lib"><tt>llvm/lib</tt></a></li> |
| <li><a href="#projects"><tt>llvm/projects</tt></a></li> |
| <li><a href="#runtime"><tt>llvm/runtime</tt></a></li> |
| <li><a href="#test"><tt>llvm/test</tt></a></li> |
| <li><a href="#test-suite"><tt>test-suite</tt></a></li> |
| <li><a href="#tools"><tt>llvm/tools</tt></a></li> |
| <li><a href="#utils"><tt>llvm/utils</tt></a></li> |
| </ol></li> |
| |
| <li><a href="#tutorial">An Example Using the LLVM Tool Chain</a> |
| <ol> |
| <li><a href="#tutorial4">Example with llvm-gcc4</a></li> |
| </ol> |
| <li><a href="#problems">Common Problems</a> |
| <li><a href="#links">Links</a> |
| </ul> |
| |
| <div class="doc_author"> |
| <p>Written by: |
| <a href="mailto:criswell@uiuc.edu">John Criswell</a>, |
| <a href="mailto:sabre@nondot.org">Chris Lattner</a>, |
| <a href="http://misha.brukman.net/">Misha Brukman</a>, |
| <a href="http://www.cs.uiuc.edu/~vadve">Vikram Adve</a>, and |
| <a href="mailto:gshi1@uiuc.edu">Guochun Shi</a>. |
| </p> |
| </div> |
| |
| |
| <!-- *********************************************************************** --> |
| <h2> |
| <a name="overview">Overview</a> |
| </h2> |
| <!-- *********************************************************************** --> |
| |
| <div> |
| |
| <p>Welcome to LLVM! In order to get started, you first need to know some |
| basic information.</p> |
| |
| <p>First, LLVM comes in three pieces. The first piece is the LLVM |
| suite. This contains all of the tools, libraries, and header files |
| needed to use the low level virtual machine. It contains an |
| assembler, disassembler, bitcode analyzer and bitcode optimizer. It |
| also contains basic regression tests that can be used to test the LLVM |
| tools and the GCC front end.</p> |
| |
| <p>The second piece is the GCC front end. This component provides a version of |
| GCC that compiles C and C++ code into LLVM bitcode. Currently, the GCC front |
| end uses the GCC parser to convert code to LLVM. Once |
| compiled into LLVM bitcode, a program can be manipulated with the LLVM tools |
| from the LLVM suite.</p> |
| |
| <p> |
| There is a third, optional piece called Test Suite. It is a suite of programs |
| with a testing harness that can be used to further test LLVM's functionality |
| and performance. |
| </p> |
| |
| </div> |
| |
| <!-- *********************************************************************** --> |
| <h2> |
| <a name="quickstart">Getting Started Quickly (A Summary)</a> |
| </h2> |
| <!-- *********************************************************************** --> |
| |
| <div> |
| |
| <p>Here's the short story for getting up and running quickly with LLVM:</p> |
| |
| <ol> |
| <li>Read the documentation.</li> |
| <li>Read the documentation.</li> |
| <li>Remember that you were warned twice about reading the documentation.</li> |
| <li>Install the llvm-gcc-4.2 front end if you intend to compile C or C++ |
| (see <a href="#installcf">Install the GCC Front End</a> for details): |
| <ol> |
| <li><tt>cd <i>where-you-want-the-C-front-end-to-live</i></tt></li> |
| <li><tt>gunzip --stdout llvm-gcc-4.2-<i>version</i>-<i>platform</i>.tar.gz | tar -xvf -</tt></li> |
| <li><tt><i>install-binutils-binary-from-MinGW</i></tt> (Windows only)</li> |
| <li>Note: If the binary extension is "<tt>.bz</tt>" use <tt>bunzip2</tt> instead of <tt>gunzip</tt>.</li> |
| <li>Note: On Windows, use <a href="http://www.7-zip.org/">7-Zip</a> or a similar archiving tool.</li> |
| <li>Add <tt>llvm-gcc</tt>'s "<tt>bin</tt>" directory to your <tt>PATH</tt> environment variable.</li> |
| </ol></li> |
| |
| <li>Get the LLVM Source Code |
| <ul> |
| <li>With the distributed files (or use <a href="#checkout">SVN</a>): |
| <ol> |
| <li><tt>cd <i>where-you-want-llvm-to-live</i></tt> |
| <li><tt>gunzip --stdout llvm-<i>version</i>.tar.gz | tar -xvf -</tt> |
| </ol></li> |
| |
| </ul></li> |
| |
| <li><b>[Optional]</b> Get the Test Suite Source Code |
| <ul> |
| <li>With the distributed files (or use <a href="#checkout">SVN</a>): |
| <ol> |
| <li><tt>cd <i>where-you-want-llvm-to-live</i></tt> |
| <li><tt>cd llvm/projects</tt> |
| <li><tt>gunzip --stdout llvm-test-<i>version</i>.tar.gz | tar -xvf -</tt> |
| <li><tt>mv llvm-test-<i>version</i> test-suite</tt> |
| </ol></li> |
| |
| </ul></li> |
| |
| |
| <li>Configure the LLVM Build Environment |
| <ol> |
| <li><tt>cd <i>where-you-want-to-build-llvm</i></tt></li> |
| <li><tt><i>/path/to/llvm/</i>configure [options]</tt><br> |
| Some common options: |
| |
| <ul> |
| <li><tt>--prefix=<i>directory</i></tt> |
| <p>Specify for <i>directory</i> the full pathname of where you |
| want the LLVM tools and libraries to be installed (default |
| <tt>/usr/local</tt>).</p></li> |
| <li><tt>--with-llvmgccdir=<i>directory</i></tt> |
| <p>Optionally, specify for <i>directory</i> the full pathname of the |
| C/C++ front end installation to use with this LLVM configuration. If |
| not specified, the PATH will be searched. This is only needed if you |
| want to run test-suite or do some special kinds of LLVM builds.</p></li> |
| <li><tt>--enable-spec2000=<i>directory</i></tt> |
| <p>Enable the SPEC2000 benchmarks for testing. The SPEC2000 |
| benchmarks should be available in |
| <tt><i>directory</i></tt>.</p></li> |
| </ul> |
| </ol></li> |
| |
| <li>Build the LLVM Suite: |
| <ol> |
| <li><tt>gmake -k |& tee gnumake.out |
| # this is csh or tcsh syntax</tt></li> |
| <li>If you get an "internal compiler error (ICE)" or test failures, see |
| <a href="#brokengcc">below</a>.</li> |
| </ol> |
| |
| </ol> |
| |
| <p>Consult the <a href="#starting">Getting Started with LLVM</a> section for |
| detailed information on configuring and compiling LLVM. See <a |
| href="#environment">Setting Up Your Environment</a> for tips that simplify |
| working with the GCC front end and LLVM tools. Go to <a href="#layout">Program |
| Layout</a> to learn about the layout of the source code tree.</p> |
| |
| </div> |
| |
| <!-- *********************************************************************** --> |
| <h2> |
| <a name="requirements">Requirements</a> |
| </h2> |
| <!-- *********************************************************************** --> |
| |
| <div> |
| |
| <p>Before you begin to use the LLVM system, review the requirements given below. |
| This may save you some trouble by knowing ahead of time what hardware and |
| software you will need.</p> |
| |
| <!-- ======================================================================= --> |
| <h3> |
| <a name="hardware">Hardware</a> |
| </h3> |
| |
| <div> |
| |
| <p>LLVM is known to work on the following platforms:</p> |
| |
| <table cellpadding="3" summary="Known LLVM platforms"> |
| <tr> |
| <th>OS</th> |
| <th>Arch</th> |
| <th>Compilers</th> |
| </tr> |
| <tr> |
| <td>AuroraUX</td> |
| <td>x86<sup><a href="#pf_1">1</a></sup></td> |
| <td>GCC</td> |
| </tr> |
| <tr> |
| <td>Linux</td> |
| <td>x86<sup><a href="#pf_1">1</a></sup></td> |
| <td>GCC</td> |
| </tr> |
| <tr> |
| <td>Linux</td> |
| <td>amd64</td> |
| <td>GCC</td> |
| </tr> |
| <tr> |
| <td>Solaris</td> |
| <td>V9 (Ultrasparc)</td> |
| <td>GCC</td> |
| </tr> |
| <tr> |
| <td>FreeBSD</td> |
| <td>x86<sup><a href="#pf_1">1</a></sup></td> |
| <td>GCC</td> |
| </tr> |
| <tr> |
| <td>FreeBSD</td> |
| <td>amd64</td> |
| <td>GCC</td> |
| </tr> |
| <tr> |
| <td>MacOS X<sup><a href="#pf_2">2</a></sup></td> |
| <td>PowerPC</td> |
| <td>GCC</td> |
| </tr> |
| <tr> |
| <td>MacOS X<sup><a href="#pf_2">2</a>,<a href="#pf_9">9</a></sup></td> |
| <td>x86</td> |
| <td>GCC</td> |
| </tr> |
| <tr> |
| <td>Cygwin/Win32</td> |
| <td>x86<sup><a href="#pf_1">1</a>,<a href="#pf_8">8</a>, |
| <a href="#pf_11">11</a></sup></td> |
| <td>GCC 3.4.X, binutils 2.20</td> |
| </tr> |
| <tr> |
| <td>MinGW/Win32</td> |
| <td>x86<sup><a href="#pf_1">1</a>,<a href="#pf_6">6</a>, |
| <a href="#pf_8">8</a>, <a href="#pf_10">10</a>, |
| <a href="#pf_11">11</a></sup></td> |
| <td>GCC 3.4.X, binutils 2.20</td> |
| </tr> |
| </table> |
| |
| <p>LLVM has partial support for the following platforms:</p> |
| |
| <table summary="LLVM partial platform support"> |
| <tr> |
| <th>OS</th> |
| <th>Arch</th> |
| <th>Compilers</th> |
| </tr> |
| <tr> |
| <td>Windows</td> |
| <td>x86<sup><a href="#pf_1">1</a></sup></td> |
| <td>Visual Studio 2005 SP1 or higher<sup><a href="#pf_4">4</a>,<a href="#pf_5">5</a></sup></td> |
| <tr> |
| <td>AIX<sup><a href="#pf_3">3</a>,<a href="#pf_4">4</a></sup></td> |
| <td>PowerPC</td> |
| <td>GCC</td> |
| </tr> |
| <tr> |
| <td>Linux<sup><a href="#pf_3">3</a>,<a href="#pf_5">5</a></sup></td> |
| <td>PowerPC</td> |
| <td>GCC</td> |
| </tr> |
| |
| <tr> |
| <td>Linux<sup><a href="#pf_7">7</a></sup></td> |
| <td>Alpha</td> |
| <td>GCC</td> |
| </tr> |
| <tr> |
| <td>Linux<sup><a href="#pf_7">7</a></sup></td> |
| <td>Itanium (IA-64)</td> |
| <td>GCC</td> |
| </tr> |
| <tr> |
| <td>HP-UX<sup><a href="#pf_7">7</a></sup></td> |
| <td>Itanium (IA-64)</td> |
| <td>HP aCC</td> |
| </tr> |
| <tr> |
| <td>Windows x64</td> |
| <td>x86-64</td> |
| <td>mingw-w64's GCC-4.5.x<sup><a href="#pf_12">12</a></sup></td> |
| </tr> |
| </table> |
| |
| <p><b>Notes:</b></p> |
| |
| <div class="doc_notes"> |
| <ol> |
| <li><a name="pf_1">Code generation supported for Pentium processors and |
| up</a></li> |
| <li><a name="pf_2">Code generation supported for 32-bit ABI only</a></li> |
| <li><a name="pf_3">No native code generation</a></li> |
| <li><a name="pf_4">Build is not complete: one or more tools do not link or function</a></li> |
| <li><a name="pf_5">The GCC-based C/C++ frontend does not build</a></li> |
| <li><a name="pf_6">The port is done using the MSYS shell.</a></li> |
| <li><a name="pf_7">Native code generation exists but is not complete.</a></li> |
| <li><a name="pf_8">Binutils 2.20 or later is required to build the assembler |
| generated by LLVM properly.</a></li> |
| <li><a name="pf_9">XCode 2.5 and gcc 4.0.1</a> (Apple Build 5370) will trip |
| internal LLVM assert messages when compiled for Release at optimization |
| levels greater than 0 (i.e., <i>"-O1"</i> and higher). |
| Add <i>OPTIMIZE_OPTION="-O0"</i> to the build command line |
| if compiling for LLVM Release or bootstrapping the LLVM toolchain.</li> |
| <li><a name="pf_10">For MSYS/MinGW on Windows, be sure to install the MSYS |
| version of the perl package, and be sure it appears in your path |
| before any Windows-based versions such as Strawberry Perl and |
| ActivePerl, as these have Windows-specifics that will cause the |
| build to fail.</a></li> |
| <li><a name="pf_11">To use LLVM modules on Win32-based system, |
| you may configure LLVM with <i>"--enable-shared"</i>.</a></li> |
| <li><a name="pf_12">To compile SPU backend, you need to add |
| <tt>"LDFLAGS=-Wl,--stack,16777216"</tt> to configure.</a></li> |
| </ol> |
| </div> |
| |
| <p>Note that you will need about 1-3 GB of space for a full LLVM build in Debug |
| mode, depending on the system (it is so large because of all the debugging |
| information and the fact that the libraries are statically linked into multiple |
| tools). If you do not need many of the tools and you are space-conscious, you |
| can pass <tt>ONLY_TOOLS="tools you need"</tt> to make. The Release build |
| requires considerably less space.</p> |
| |
| <p>The LLVM suite <i>may</i> compile on other platforms, but it is not |
| guaranteed to do so. If compilation is successful, the LLVM utilities should be |
| able to assemble, disassemble, analyze, and optimize LLVM bitcode. Code |
| generation should work as well, although the generated native code may not work |
| on your platform.</p> |
| |
| <p>The GCC front end is not very portable at the moment. If you want to get it |
| to work on another platform, you can download a copy of the source and <a |
| href="GCCFEBuildInstrs.html">try to compile it</a> on your platform.</p> |
| |
| </div> |
| |
| <!-- ======================================================================= --> |
| <h3> |
| <a name="software">Software</a> |
| </h3> |
| <div> |
| <p>Compiling LLVM requires that you have several software packages |
| installed. The table below lists those required packages. The Package column |
| is the usual name for the software package that LLVM depends on. The Version |
| column provides "known to work" versions of the package. The Notes column |
| describes how LLVM uses the package and provides other details.</p> |
| <table summary="Packages required to compile LLVM"> |
| <tr><th>Package</th><th>Version</th><th>Notes</th></tr> |
| |
| <tr> |
| <td><a href="http://savannah.gnu.org/projects/make">GNU Make</a></td> |
| <td>3.79, 3.79.1</td> |
| <td>Makefile/build processor</td> |
| </tr> |
| |
| <tr> |
| <td><a href="http://gcc.gnu.org/">GCC</a></td> |
| <td>3.4.2</td> |
| <td>C/C++ compiler<sup><a href="#sf1">1</a></sup></td> |
| </tr> |
| |
| <tr> |
| <td><a href="http://www.gnu.org/software/texinfo/">TeXinfo</a></td> |
| <td>4.5</td> |
| <td>For building the CFE</td> |
| </tr> |
| |
| <tr> |
| <td><a href="http://subversion.tigris.org/project_packages.html">SVN</a></td> |
| <td>≥1.3</td> |
| <td>Subversion access to LLVM<sup><a href="#sf2">2</a></sup></td> |
| </tr> |
| |
| <!-- FIXME: |
| Do we support dg? |
| Are DejaGnu and expect obsolete? |
| Shall we mention Python? --> |
| |
| <tr> |
| <td><a href="http://savannah.gnu.org/projects/dejagnu">DejaGnu</a></td> |
| <td>1.4.2</td> |
| <td>Automated test suite<sup><a href="#sf3">3</a></sup></td> |
| </tr> |
| |
| <tr> |
| <td><a href="http://www.tcl.tk/software/tcltk/">tcl</a></td> |
| <td>8.3, 8.4</td> |
| <td>Automated test suite<sup><a href="#sf3">3</a></sup></td> |
| </tr> |
| |
| <tr> |
| <td><a href="http://expect.nist.gov/">expect</a></td> |
| <td>5.38.0</td> |
| <td>Automated test suite<sup><a href="#sf3">3</a></sup></td> |
| </tr> |
| |
| <tr> |
| <td><a href="http://www.perl.com/download.csp">perl</a></td> |
| <td>≥5.6.0</td> |
| <td>Nightly tester, utilities</td> |
| </tr> |
| |
| <tr> |
| <td><a href="http://savannah.gnu.org/projects/m4">GNU M4</a> |
| <td>1.4</td> |
| <td>Macro processor for configuration<sup><a href="#sf4">4</a></sup></td> |
| </tr> |
| |
| <tr> |
| <td><a href="http://www.gnu.org/software/autoconf/">GNU Autoconf</a></td> |
| <td>2.60</td> |
| <td>Configuration script builder<sup><a href="#sf4">4</a></sup></td> |
| </tr> |
| |
| <tr> |
| <td><a href="http://www.gnu.org/software/automake/">GNU Automake</a></td> |
| <td>1.9.6</td> |
| <td>aclocal macro generator<sup><a href="#sf4">4</a></sup></td> |
| </tr> |
| |
| <tr> |
| <td><a href="http://savannah.gnu.org/projects/libtool">libtool</a></td> |
| <td>1.5.22</td> |
| <td>Shared library manager<sup><a href="#sf4">4</a></sup></td> |
| </tr> |
| |
| </table> |
| |
| <p><b>Notes:</b></p> |
| <div class="doc_notes"> |
| <ol> |
| <li><a name="sf1">Only the C and C++ languages are needed so there's no |
| need to build the other languages for LLVM's purposes.</a> See |
| <a href="#brokengcc">below</a> for specific version info.</li> |
| <li><a name="sf2">You only need Subversion if you intend to build from the |
| latest LLVM sources. If you're working from a release distribution, you |
| don't need Subversion.</a></li> |
| <li><a name="sf3">Only needed if you want to run the automated test |
| suite in the <tt>llvm/test</tt> directory.</a></li> |
| <li><a name="sf4">If you want to make changes to the configure scripts, |
| you will need GNU autoconf (2.60), and consequently, GNU M4 (version 1.4 |
| or higher). You will also need automake (1.9.6). We only use aclocal |
| from that package.</a></li> |
| </ol> |
| </div> |
| |
| <p>Additionally, your compilation host is expected to have the usual |
| plethora of Unix utilities. Specifically:</p> |
| <ul> |
| <li><b>ar</b> - archive library builder</li> |
| <li><b>bzip2*</b> - bzip2 command for distribution generation</li> |
| <li><b>bunzip2*</b> - bunzip2 command for distribution checking</li> |
| <li><b>chmod</b> - change permissions on a file</li> |
| <li><b>cat</b> - output concatenation utility</li> |
| <li><b>cp</b> - copy files</li> |
| <li><b>date</b> - print the current date/time </li> |
| <li><b>echo</b> - print to standard output</li> |
| <li><b>egrep</b> - extended regular expression search utility</li> |
| <li><b>find</b> - find files/dirs in a file system</li> |
| <li><b>grep</b> - regular expression search utility</li> |
| <li><b>gzip*</b> - gzip command for distribution generation</li> |
| <li><b>gunzip*</b> - gunzip command for distribution checking</li> |
| <li><b>install</b> - install directories/files </li> |
| <li><b>mkdir</b> - create a directory</li> |
| <li><b>mv</b> - move (rename) files</li> |
| <li><b>ranlib</b> - symbol table builder for archive libraries</li> |
| <li><b>rm</b> - remove (delete) files and directories</li> |
| <li><b>sed</b> - stream editor for transforming output</li> |
| <li><b>sh</b> - Bourne shell for make build scripts</li> |
| <li><b>tar</b> - tape archive for distribution generation</li> |
| <li><b>test</b> - test things in file system</li> |
| <li><b>unzip*</b> - unzip command for distribution checking</li> |
| <li><b>zip*</b> - zip command for distribution generation</li> |
| </ul> |
| </div> |
| |
| <!-- ======================================================================= --> |
| <h3> |
| <a name="brokengcc">Broken versions of GCC and other tools</a> |
| </h3> |
| |
| <div> |
| |
| <p>LLVM is very demanding of the host C++ compiler, and as such tends to expose |
| bugs in the compiler. In particular, several versions of GCC crash when trying |
| to compile LLVM. We routinely use GCC 3.3.3, 3.4.0, and Apple 4.0.1 |
| successfully with them (however, see important notes below). Other versions |
| of GCC will probably work as well. GCC versions listed |
| here are known to not work. If you are using one of these versions, please try |
| to upgrade your GCC to something more recent. If you run into a problem with a |
| version of GCC not listed here, please <a href="mailto:llvmdev@cs.uiuc.edu">let |
| us know</a>. Please use the "<tt>gcc -v</tt>" command to find out which version |
| of GCC you are using. |
| </p> |
| |
| <p><b>GCC versions prior to 3.0</b>: GCC 2.96.x and before had several |
| problems in the STL that effectively prevent it from compiling LLVM. |
| </p> |
| |
| <p><b>GCC 3.2.2 and 3.2.3</b>: These versions of GCC fails to compile LLVM with |
| a bogus template error. This was fixed in later GCCs.</p> |
| |
| <p><b>GCC 3.3.2</b>: This version of GCC suffered from a <a |
| href="http://gcc.gnu.org/PR13392">serious bug</a> which causes it to crash in |
| the "<tt>convert_from_eh_region_ranges_1</tt>" GCC function.</p> |
| |
| <p><b>Cygwin GCC 3.3.3</b>: The version of GCC 3.3.3 commonly shipped with |
| Cygwin does not work. Please <a href="GCCFEBuildInstrs.html#cygwin">upgrade |
| to a newer version</a> if possible.</p> |
| <p><b>SuSE GCC 3.3.3</b>: The version of GCC 3.3.3 shipped with SuSE 9.1 (and |
| possibly others) does not compile LLVM correctly (it appears that exception |
| handling is broken in some cases). Please download the FSF 3.3.3 or upgrade |
| to a newer version of GCC.</p> |
| <p><b>GCC 3.4.0 on linux/x86 (32-bit)</b>: GCC miscompiles portions of the |
| code generator, causing an infinite loop in the llvm-gcc build when built |
| with optimizations enabled (i.e. a release build).</p> |
| <p><b>GCC 3.4.2 on linux/x86 (32-bit)</b>: GCC miscompiles portions of the |
| code generator at -O3, as with 3.4.0. However gcc 3.4.2 (unlike 3.4.0) |
| correctly compiles LLVM at -O2. A work around is to build release LLVM |
| builds with "make ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O2 ..."</p> |
| <p><b>GCC 3.4.x on X86-64/amd64</b>: GCC <a href="http://llvm.org/PR1056"> |
| miscompiles portions of LLVM</a>.</p> |
| <p><b>GCC 3.4.4 (CodeSourcery ARM 2005q3-2)</b>: this compiler miscompiles LLVM |
| when building with optimizations enabled. It appears to work with |
| "<tt>make ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O1</tt>" or build a debug |
| build.</p> |
| <p><b>IA-64 GCC 4.0.0</b>: The IA-64 version of GCC 4.0.0 is known to |
| miscompile LLVM.</p> |
| <p><b>Apple Xcode 2.3</b>: GCC crashes when compiling LLVM at -O3 (which is the |
| default with ENABLE_OPTIMIZED=1. To work around this, build with |
| "ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O2".</p> |
| <p><b>GCC 4.1.1</b>: GCC fails to build LLVM with template concept check errors |
| compiling some files. At the time of this writing, GCC mainline (4.2) |
| did not share the problem.</p> |
| <p><b>GCC 4.1.1 on X86-64/amd64</b>: GCC <a href="http://llvm.org/PR1063"> |
| miscompiles portions of LLVM</a> when compiling llvm itself into 64-bit |
| code. LLVM will appear to mostly work but will be buggy, e.g. failing |
| portions of its testsuite.</p> |
| <p><b>GCC 4.1.2 on OpenSUSE</b>: Seg faults during libstdc++ build and on x86_64 |
| platforms compiling md5.c gets a mangled constant.</p> |
| <p><b>GCC 4.1.2 (20061115 (prerelease) (Debian 4.1.1-21)) on Debian</b>: Appears |
| to miscompile parts of LLVM 2.4. One symptom is ValueSymbolTable complaining |
| about symbols remaining in the table on destruction.</p> |
| <p><b>GCC 4.1.2 20071124 (Red Hat 4.1.2-42)</b>: Suffers from the same symptoms |
| as the previous one. It appears to work with ENABLE_OPTIMIZED=0 (the default).</p> |
| <p><b>Cygwin GCC 4.3.2 20080827 (beta) 2</b>: |
| Users <a href="http://llvm.org/PR4145">reported</a> various problems related |
| with link errors when using this GCC version.</p> |
| <p><b>Debian GCC 4.3.2 on X86</b>: Crashes building some files in LLVM 2.6.</p> |
| <p><b>GCC 4.3.3 (Debian 4.3.3-10) on ARM</b>: Miscompiles parts of LLVM 2.6 |
| when optimizations are turned on. The symptom is an infinite loop in |
| FoldingSetImpl::RemoveNode while running the code generator.</p> |
| <p><b>GCC 4.3.5 and GCC 4.4.5 on ARM</b>: These can miscompile <tt>value >> |
| 1</tt> even at -O0. A test failure in <tt>test/Assembler/alignstack.ll</tt> is |
| one symptom of the problem. |
| <p><b>GNU ld 2.16.X</b>. Some 2.16.X versions of the ld linker will produce very |
| long warning messages complaining that some ".gnu.linkonce.t.*" symbol was |
| defined in a discarded section. You can safely ignore these messages as they are |
| erroneous and the linkage is correct. These messages disappear using ld |
| 2.17.</p> |
| |
| <p><b>GNU binutils 2.17</b>: Binutils 2.17 contains <a |
| href="http://sourceware.org/bugzilla/show_bug.cgi?id=3111">a bug</a> which |
| causes huge link times (minutes instead of seconds) when building LLVM. We |
| recommend upgrading to a newer version (2.17.50.0.4 or later).</p> |
| |
| <p><b>GNU Binutils 2.19.1 Gold</b>: This version of Gold contained |
| <a href="http://sourceware.org/bugzilla/show_bug.cgi?id=9836">a bug</a> |
| which causes intermittent failures when building LLVM with position independent |
| code. The symptom is an error about cyclic dependencies. We recommend |
| upgrading to a newer version of Gold.</p> |
| |
| </div> |
| |
| </div> |
| |
| <!-- *********************************************************************** --> |
| <h2> |
| <a name="starting">Getting Started with LLVM</a> |
| </h2> |
| <!-- *********************************************************************** --> |
| |
| <div> |
| |
| <p>The remainder of this guide is meant to get you up and running with |
| LLVM and to give you some basic information about the LLVM environment.</p> |
| |
| <p>The later sections of this guide describe the <a |
| href="#layout">general layout</a> of the the LLVM source tree, a <a |
| href="#tutorial">simple example</a> using the LLVM tool chain, and <a |
| href="#links">links</a> to find more information about LLVM or to get |
| help via e-mail.</p> |
| |
| <!-- ======================================================================= --> |
| <h3> |
| <a name="terminology">Terminology and Notation</a> |
| </h3> |
| |
| <div> |
| |
| <p>Throughout this manual, the following names are used to denote paths |
| specific to the local system and working environment. <i>These are not |
| environment variables you need to set but just strings used in the rest |
| of this document below</i>. In any of the examples below, simply replace |
| each of these names with the appropriate pathname on your local system. |
| All these paths are absolute:</p> |
| |
| <dl> |
| <dt>SRC_ROOT |
| <dd> |
| This is the top level directory of the LLVM source tree. |
| <br><br> |
| |
| <dt>OBJ_ROOT |
| <dd> |
| This is the top level directory of the LLVM object tree (i.e. the |
| tree where object files and compiled programs will be placed. It |
| can be the same as SRC_ROOT). |
| <br><br> |
| |
| <dt>LLVMGCCDIR |
| <dd> |
| This is where the LLVM GCC Front End is installed. |
| <p> |
| For the pre-built GCC front end binaries, the LLVMGCCDIR is |
| <tt>llvm-gcc/<i>platform</i>/llvm-gcc</tt>. |
| </dl> |
| |
| </div> |
| |
| <!-- ======================================================================= --> |
| <h3> |
| <a name="environment">Setting Up Your Environment</a> |
| </h3> |
| |
| <div> |
| |
| <p> |
| In order to compile and use LLVM, you may need to set some environment |
| variables. |
| |
| <dl> |
| <dt><tt>LLVM_LIB_SEARCH_PATH</tt>=<tt>/path/to/your/bitcode/libs</tt></dt> |
| <dd>[Optional] This environment variable helps LLVM linking tools find the |
| locations of your bitcode libraries. It is provided only as a |
| convenience since you can specify the paths using the -L options of the |
| tools and the C/C++ front-end will automatically use the bitcode files |
| installed in its |
| <tt>lib</tt> directory.</dd> |
| </dl> |
| |
| </div> |
| |
| <!-- ======================================================================= --> |
| <h3> |
| <a name="unpack">Unpacking the LLVM Archives</a> |
| </h3> |
| |
| <div> |
| |
| <p> |
| If you have the LLVM distribution, you will need to unpack it before you |
| can begin to compile it. LLVM is distributed as a set of two files: the LLVM |
| suite and the LLVM GCC front end compiled for your platform. There is an |
| additional test suite that is optional. Each file is a TAR archive that is |
| compressed with the gzip program. |
| </p> |
| |
| <p>The files are as follows, with <em>x.y</em> marking the version number: |
| <dl> |
| <dt><tt>llvm-x.y.tar.gz</tt></dt> |
| <dd>Source release for the LLVM libraries and tools.<br></dd> |
| |
| <dt><tt>llvm-test-x.y.tar.gz</tt></dt> |
| <dd>Source release for the LLVM test-suite.</dd> |
| |
| <dt><tt>llvm-gcc-4.2-x.y.source.tar.gz</tt></dt> |
| <dd>Source release of the llvm-gcc-4.2 front end. See README.LLVM in the root |
| directory for build instructions.<br></dd> |
| |
| <dt><tt>llvm-gcc-4.2-x.y-platform.tar.gz</tt></dt> |
| <dd>Binary release of the llvm-gcc-4.2 front end for a specific platform.<br></dd> |
| |
| </dl> |
| |
| </div> |
| |
| <!-- ======================================================================= --> |
| <h3> |
| <a name="checkout">Checkout LLVM from Subversion</a> |
| </h3> |
| |
| <div> |
| |
| <p>If you have access to our Subversion repository, you can get a fresh copy of |
| the entire source code. All you need to do is check it out from Subversion as |
| follows:</p> |
| |
| <ul> |
| <li><tt>cd <i>where-you-want-llvm-to-live</i></tt></li> |
| <li>Read-Only: <tt>svn co http://llvm.org/svn/llvm-project/llvm/trunk llvm</tt></li> |
| <li>Read-Write:<tt>svn co https://user@llvm.org/svn/llvm-project/llvm/trunk |
| llvm</tt></li> |
| </ul> |
| |
| |
| <p>This will create an '<tt>llvm</tt>' directory in the current |
| directory and fully populate it with the LLVM source code, Makefiles, |
| test directories, and local copies of documentation files.</p> |
| |
| <p>If you want to get a specific release (as opposed to the most recent |
| revision), you can checkout it from the '<tt>tags</tt>' directory (instead of |
| '<tt>trunk</tt>'). The following releases are located in the following |
| subdirectories of the '<tt>tags</tt>' directory:</p> |
| |
| <ul> |
| <li>Release 2.9: <b>RELEASE_29/final</b></li> |
| <li>Release 2.8: <b>RELEASE_28</b></li> |
| <li>Release 2.7: <b>RELEASE_27</b></li> |
| <li>Release 2.6: <b>RELEASE_26</b></li> |
| <li>Release 2.5: <b>RELEASE_25</b></li> |
| <li>Release 2.4: <b>RELEASE_24</b></li> |
| <li>Release 2.3: <b>RELEASE_23</b></li> |
| <li>Release 2.2: <b>RELEASE_22</b></li> |
| <li>Release 2.1: <b>RELEASE_21</b></li> |
| <li>Release 2.0: <b>RELEASE_20</b></li> |
| <li>Release 1.9: <b>RELEASE_19</b></li> |
| <li>Release 1.8: <b>RELEASE_18</b></li> |
| <li>Release 1.7: <b>RELEASE_17</b></li> |
| <li>Release 1.6: <b>RELEASE_16</b></li> |
| <li>Release 1.5: <b>RELEASE_15</b></li> |
| <li>Release 1.4: <b>RELEASE_14</b></li> |
| <li>Release 1.3: <b>RELEASE_13</b></li> |
| <li>Release 1.2: <b>RELEASE_12</b></li> |
| <li>Release 1.1: <b>RELEASE_11</b></li> |
| <li>Release 1.0: <b>RELEASE_1</b></li> |
| </ul> |
| |
| <p>If you would like to get the LLVM test suite (a separate package as of 1.4), |
| you get it from the Subversion repository:</p> |
| |
| <div class="doc_code"> |
| <pre> |
| % cd llvm/projects |
| % svn co http://llvm.org/svn/llvm-project/test-suite/trunk test-suite |
| </pre> |
| </div> |
| |
| <p>By placing it in the <tt>llvm/projects</tt>, it will be automatically |
| configured by the LLVM configure script as well as automatically updated when |
| you run <tt>svn update</tt>.</p> |
| |
| <p>If you would like to get the GCC front end source code, you can also get it |
| and build it yourself. Please follow <a href="GCCFEBuildInstrs.html">these |
| instructions</a> to successfully get and build the LLVM GCC front-end.</p> |
| |
| </div> |
| |
| <!-- ======================================================================= --> |
| <h3> |
| <a name="git_mirror">GIT mirror</a> |
| </h3> |
| |
| <div> |
| |
| <p>GIT mirrors are available for a number of LLVM subprojects. These mirrors |
| sync automatically with each Subversion commit and contain all necessary |
| git-svn marks (so, you can recreate git-svn metadata locally). Note that right |
| now mirrors reflect only <tt>trunk</tt> for each project. You can do the |
| read-only GIT clone of LLVM via:</p> |
| |
| <pre class="doc_code"> |
| git clone http://llvm.org/git/llvm.git |
| </pre> |
| |
| <p>If you want to check out clang too, run:</p> |
| |
| <pre class="doc_code"> |
| git clone http://llvm.org/git/llvm.git |
| cd llvm/tools |
| git clone http://llvm.org/git/clang.git |
| </pre> |
| |
| <p> |
| Since the upstream repository is in Subversion, you should use |
| <tt>"git pull --rebase"</tt> |
| instead of <tt>"git pull"</tt> to avoid generating a non-linear |
| history in your clone. |
| To configure <tt>"git pull"</tt> to pass <tt>--rebase</tt> by default |
| on the master branch, run the following command: |
| </p> |
| |
| <pre class="doc_code"> |
| git config branch.master.rebase true |
| </pre> |
| |
| <h4>Sending patches with Git</h4> |
| <div> |
| <p> |
| Please read <a href="DeveloperPolicy.html#patches">Developer Policy</a>, too. |
| </p> |
| |
| <p> |
| Assume <tt>master</tt> points the upstream and <tt>mybranch</tt> points your |
| working branch, and <tt>mybranch</tt> is rebased onto <tt>master</tt>. |
| At first you may check sanity of whitespaces: |
| </p> |
| |
| <pre class="doc_code"> |
| git diff --check master..mybranch |
| </pre> |
| |
| <p> |
| The easiest way to generate a patch is as below: |
| </p> |
| |
| <pre class="doc_code"> |
| git diff master..mybranch > /path/to/mybranch.diff |
| </pre> |
| |
| <p> |
| It is a little different from svn-generated diff. git-diff-generated diff has |
| prefixes like <tt>a/</tt> and <tt>b/</tt>. Don't worry, most developers might |
| know it could be accepted with <tt>patch -p1 -N</tt>. |
| </p> |
| |
| <p> |
| But you may generate patchset with git-format-patch. It generates |
| by-each-commit patchset. To generate patch files to attach to your article: |
| </p> |
| |
| <pre class="doc_code"> |
| git format-patch --no-attach master..mybranch -o /path/to/your/patchset |
| </pre> |
| |
| <p> |
| If you would like to send patches directly, you may use git-send-email or |
| git-imap-send. Here is an example to generate the patchset in Gmail's [Drafts]. |
| </p> |
| |
| <pre class="doc_code"> |
| git format-patch --attach master..mybranch --stdout | git imap-send |
| </pre> |
| |
| <p> |
| Then, your .git/config should have [imap] sections. |
| </p> |
| |
| <pre class="doc_code"> |
| [imap] |
| host = imaps://imap.gmail.com |
| user = <em>your.gmail.account</em>@gmail.com |
| pass = <em>himitsu!</em> |
| port = 993 |
| sslverify = false |
| ; in English |
| folder = "[Gmail]/Drafts" |
| ; example for Japanese, "Modified UTF-7" encoded. |
| folder = "[Gmail]/&Tgtm+DBN-" |
| </pre> |
| |
| </div> |
| |
| <h4>For developers to work with git-svn</h4> |
| <div> |
| |
| <p>To set up clone from which you can submit code using |
| <tt>git-svn</tt>, run:</p> |
| |
| <pre class="doc_code"> |
| git clone http://llvm.org/git/llvm.git |
| cd llvm |
| git svn init https://llvm.org/svn/llvm-project/llvm/trunk --username=<username> |
| git config svn-remote.svn.fetch :refs/remotes/origin/master |
| git svn rebase -l # -l avoids fetching ahead of the git mirror. |
| |
| # If you have clang too: |
| cd tools |
| git clone http://llvm.org/git/clang.git |
| cd clang |
| git svn init https://llvm.org/svn/llvm-project/cfe/trunk --username=<username> |
| git config svn-remote.svn.fetch :refs/remotes/origin/master |
| git svn rebase -l |
| </pre> |
| |
| <p>To update this clone without generating git-svn tags that conflict |
| with the upstream git repo, run:</p> |
| |
| <pre class="doc_code"> |
| git fetch && (cd tools/clang && git fetch) # Get matching revisions of both trees. |
| git checkout master |
| git svn rebase -l |
| (cd tools/clang && |
| git checkout master && |
| git svn rebase -l) |
| </pre> |
| |
| <p>This leaves your working directories on their master branches, so |
| you'll need to <tt>checkout</tt> each working branch individually and |
| <tt>rebase</tt> it on top of its parent branch. (Note: This script is |
| intended for relative newbies to git. If you have more experience, |
| you can likely improve on it.)</p> |
| |
| <p>The git-svn metadata can get out of sync after you mess around with |
| branches and <code>dcommit</code>. When that happens, <code>git svn |
| dcommit</code> stops working, complaining about files with uncommitted |
| changes. The fix is to rebuild the metadata:</p> |
| |
| <pre class="doc_code"> |
| rm -rf .git/svn |
| git svn rebase -l |
| </pre> |
| |
| </div> |
| |
| </div> |
| |
| <!-- ======================================================================= --> |
| <h3> |
| <a name="installcf">Install the GCC Front End</a> |
| </h3> |
| |
| <div> |
| |
| <p>Before configuring and compiling the LLVM suite (or if you want to use just the LLVM |
| GCC front end) you can optionally extract the front end from the binary distribution. |
| It is used for running the LLVM test-suite and for compiling C/C++ programs. Note that |
| you can optionally <a href="GCCFEBuildInstrs.html">build llvm-gcc yourself</a> after building the |
| main LLVM repository.</p> |
| |
| <p>To install the GCC front end, do the following (on Windows, use an archival tool |
| like <a href="http://www.7-zip.org/">7-zip</a> that understands gzipped tars):</p> |
| |
| <ol> |
| <li><tt>cd <i>where-you-want-the-front-end-to-live</i></tt></li> |
| <li><tt>gunzip --stdout llvm-gcc-4.2-<i>version</i>-<i>platform</i>.tar.gz | tar -xvf |
| -</tt></li> |
| </ol> |
| |
| <p>Once the binary is uncompressed, if you're using a *nix-based system, add a symlink for |
| <tt>llvm-gcc</tt> and <tt>llvm-g++</tt> to some directory in your path. If you're using a |
| Windows-based system, add the <tt>bin</tt> subdirectory of your front end installation directory |
| to your <tt>PATH</tt> environment variable. For example, if you uncompressed the binary to |
| <tt>c:\llvm-gcc</tt>, add <tt>c:\llvm-gcc\bin</tt> to your <tt>PATH</tt>.</p> |
| |
| <p>If you now want to build LLVM from source, when you configure LLVM, it will |
| automatically detect <tt>llvm-gcc</tt>'s presence (if it is in your path) enabling its |
| use in test-suite. Note that you can always build or install <tt>llvm-gcc</tt> at any |
| point after building the main LLVM repository: just reconfigure llvm and |
| test-suite will pick it up. |
| </p> |
| |
| <p>As a convenience for Windows users, the front end binaries for MinGW/x86 include |
| versions of the required w32api and mingw-runtime binaries. The last remaining step for |
| Windows users is to simply uncompress the binary binutils package from |
| <a href="http://mingw.org/">MinGW</a> into your front end installation directory. While the |
| front end installation steps are not quite the same as a typical manual MinGW installation, |
| they should be similar enough to those who have previously installed MinGW on Windows systems.</p> |
| |
| <p>To install binutils on Windows:</p> |
| |
| <ol> |
| <li><tt><i>download GNU Binutils from <a href="http://sourceforge.net/projects/mingw/files/">MinGW Downloads</a></i></tt></li> |
| <li><tt>cd <i>where-you-uncompressed-the-front-end</i></tt></li> |
| <li><tt><i>uncompress archived binutils directories (not the tar file) into the current directory</i></tt></li> |
| </ol> |
| |
| <p>The binary versions of the LLVM GCC front end may not suit all of your needs. For |
| example, the binary distribution may include an old version of a system header |
| file, not "fix" a header file that needs to be fixed for GCC, or it may be linked with |
| libraries not available on your system. In cases like these, you may want to try |
| <a href="GCCFEBuildInstrs.html">building the GCC front end from source</a>. Thankfully, |
| this is much easier now than it was in the past.</p> |
| |
| <p>We also do not currently support updating of the GCC front end by manually overlaying |
| newer versions of the w32api and mingw-runtime binary packages that may become available |
| from MinGW. At this time, it's best to think of the MinGW LLVM GCC front end binary as |
| a self-contained convenience package that requires Windows users to simply download and |
| uncompress the GNU Binutils binary package from the MinGW project.</p> |
| |
| <p>Regardless of your platform, if you discover that installing the LLVM GCC front end |
| binaries is not as easy as previously described, or you would like to suggest improvements, |
| please let us know how you would like to see things improved by dropping us a note on our |
| <a href="http://llvm.org/docs/#maillist">mailing list</a>.</p> |
| |
| </div> |
| |
| <!-- ======================================================================= --> |
| <h3> |
| <a name="config">Local LLVM Configuration</a> |
| </h3> |
| |
| <div> |
| |
| <p>Once checked out from the Subversion repository, the LLVM suite source |
| code must be |
| configured via the <tt>configure</tt> script. This script sets variables in the |
| various <tt>*.in</tt> files, most notably <tt>llvm/Makefile.config</tt> and |
| <tt>llvm/include/Config/config.h</tt>. It also populates <i>OBJ_ROOT</i> with |
| the Makefiles needed to begin building LLVM.</p> |
| |
| <p>The following environment variables are used by the <tt>configure</tt> |
| script to configure the build system:</p> |
| |
| <table summary="LLVM configure script environment variables"> |
| <tr><th>Variable</th><th>Purpose</th></tr> |
| <tr> |
| <td>CC</td> |
| <td>Tells <tt>configure</tt> which C compiler to use. By default, |
| <tt>configure</tt> will look for the first GCC C compiler in |
| <tt>PATH</tt>. Use this variable to override |
| <tt>configure</tt>'s default behavior.</td> |
| </tr> |
| <tr> |
| <td>CXX</td> |
| <td>Tells <tt>configure</tt> which C++ compiler to use. By default, |
| <tt>configure</tt> will look for the first GCC C++ compiler in |
| <tt>PATH</tt>. Use this variable to override |
| <tt>configure</tt>'s default behavior.</td> |
| </tr> |
| </table> |
| |
| <p>The following options can be used to set or enable LLVM specific options:</p> |
| |
| <dl> |
| <dt><i>--with-llvmgccdir</i></dt> |
| <dd>Path to the LLVM C/C++ FrontEnd to be used with this LLVM configuration. |
| The value of this option should specify the full pathname of the C/C++ Front |
| End to be used. If this option is not provided, the PATH will be searched for |
| a program named <i>llvm-gcc</i> and the C/C++ FrontEnd install directory will |
| be inferred from the path found. If the option is not given, and no llvm-gcc |
| can be found in the path then a warning will be produced by |
| <tt>configure</tt> indicating this situation. LLVM may still be built with |
| the <tt>tools-only</tt> target but attempting to build the runtime libraries |
| will fail as these libraries require llvm-gcc and llvm-g++. See |
| <a href="#installcf">Install the GCC Front End</a> for details on installing |
| the C/C++ Front End. See |
| <a href="GCCFEBuildInstrs.html">Bootstrapping the LLVM C/C++ Front-End</a> |
| for details on building the C/C++ Front End.</dd> |
| <dt><i>--with-tclinclude</i></dt> |
| <dd>Path to the tcl include directory under which <tt>tclsh</tt> can be |
| found. Use this if you have multiple tcl installations on your machine and you |
| want to use a specific one (8.x) for LLVM. LLVM only uses tcl for running the |
| dejagnu based test suite in <tt>llvm/test</tt>. If you don't specify this |
| option, the LLVM configure script will search for the tcl 8.4 and 8.3 |
| releases. |
| <br><br> |
| </dd> |
| <dt><i>--enable-optimized</i></dt> |
| <dd> |
| Enables optimized compilation (debugging symbols are removed |
| and GCC optimization flags are enabled). Note that this is the default |
| setting if you are using the LLVM distribution. The default behavior |
| of an Subversion checkout is to use an unoptimized build (also known as a |
| debug build). |
| <br><br> |
| </dd> |
| <dt><i>--enable-debug-runtime</i></dt> |
| <dd> |
| Enables debug symbols in the runtime libraries. The default is to strip |
| debug symbols from the runtime libraries. |
| </dd> |
| <dt><i>--enable-jit</i></dt> |
| <dd> |
| Compile the Just In Time (JIT) compiler functionality. This is not |
| available |
| on all platforms. The default is dependent on platform, so it is best |
| to explicitly enable it if you want it. |
| <br><br> |
| </dd> |
| <dt><i>--enable-targets=</i><tt>target-option</tt></dt> |
| <dd>Controls which targets will be built and linked into llc. The default |
| value for <tt>target_options</tt> is "all" which builds and links all |
| available targets. The value "host-only" can be specified to build only a |
| native compiler (no cross-compiler targets available). The "native" target is |
| selected as the target of the build host. You can also specify a comma |
| separated list of target names that you want available in llc. The target |
| names use all lower case. The current set of targets is: <br> |
| <tt>alpha, ia64, powerpc, skeleton, sparc, x86</tt>. |
| <br><br></dd> |
| <dt><i>--enable-doxygen</i></dt> |
| <dd>Look for the doxygen program and enable construction of doxygen based |
| documentation from the source code. This is disabled by default because |
| generating the documentation can take a long time and producess 100s of |
| megabytes of output.</dd> |
| <dt><i>--with-udis86</i></dt> |
| <dd>LLVM can use external disassembler library for various purposes (now it's |
| used only for examining code produced by JIT). This option will enable usage |
| of <a href="http://udis86.sourceforge.net/">udis86</a> x86 (both 32 and 64 |
| bits) disassembler library.</dd> |
| </dl> |
| |
| <p>To configure LLVM, follow these steps:</p> |
| |
| <ol> |
| <li><p>Change directory into the object root directory:</p> |
| |
| <div class="doc_code"><pre>% cd <i>OBJ_ROOT</i></pre></div></li> |
| |
| <li><p>Run the <tt>configure</tt> script located in the LLVM source |
| tree:</p> |
| |
| <div class="doc_code"> |
| <pre>% <i>SRC_ROOT</i>/configure --prefix=/install/path [other options]</pre> |
| </div></li> |
| </ol> |
| |
| </div> |
| |
| <!-- ======================================================================= --> |
| <h3> |
| <a name="compile">Compiling the LLVM Suite Source Code</a> |
| </h3> |
| |
| <div> |
| |
| <p>Once you have configured LLVM, you can build it. There are three types of |
| builds:</p> |
| |
| <dl> |
| <dt>Debug Builds |
| <dd> |
| These builds are the default when one is using an Subversion checkout and |
| types <tt>gmake</tt> (unless the <tt>--enable-optimized</tt> option was |
| used during configuration). The build system will compile the tools and |
| libraries with debugging information. To get a Debug Build using the |
| LLVM distribution the <tt>--disable-optimized</tt> option must be passed |
| to <tt>configure</tt>. |
| <br><br> |
| |
| <dt>Release (Optimized) Builds |
| <dd> |
| These builds are enabled with the <tt>--enable-optimized</tt> option to |
| <tt>configure</tt> or by specifying <tt>ENABLE_OPTIMIZED=1</tt> on the |
| <tt>gmake</tt> command line. For these builds, the build system will |
| compile the tools and libraries with GCC optimizations enabled and strip |
| debugging information from the libraries and executables it generates. |
| Note that Release Builds are default when using an LLVM distribution. |
| <br><br> |
| |
| <dt>Profile Builds |
| <dd> |
| These builds are for use with profiling. They compile profiling |
| information into the code for use with programs like <tt>gprof</tt>. |
| Profile builds must be started by specifying <tt>ENABLE_PROFILING=1</tt> |
| on the <tt>gmake</tt> command line. |
| </dl> |
| |
| <p>Once you have LLVM configured, you can build it by entering the |
| <i>OBJ_ROOT</i> directory and issuing the following command:</p> |
| |
| <div class="doc_code"><pre>% gmake</pre></div> |
| |
| <p>If the build fails, please <a href="#brokengcc">check here</a> to see if you |
| are using a version of GCC that is known not to compile LLVM.</p> |
| |
| <p> |
| If you have multiple processors in your machine, you may wish to use some of |
| the parallel build options provided by GNU Make. For example, you could use the |
| command:</p> |
| |
| <div class="doc_code"><pre>% gmake -j2</pre></div> |
| |
| <p>There are several special targets which are useful when working with the LLVM |
| source code:</p> |
| |
| <dl> |
| <dt><tt>gmake clean</tt> |
| <dd> |
| Removes all files generated by the build. This includes object files, |
| generated C/C++ files, libraries, and executables. |
| <br><br> |
| |
| <dt><tt>gmake dist-clean</tt> |
| <dd> |
| Removes everything that <tt>gmake clean</tt> does, but also removes files |
| generated by <tt>configure</tt>. It attempts to return the source tree to the |
| original state in which it was shipped. |
| <br><br> |
| |
| <dt><tt>gmake install</tt> |
| <dd> |
| Installs LLVM header files, libraries, tools, and documentation in a |
| hierarchy |
| under $PREFIX, specified with <tt>./configure --prefix=[dir]</tt>, which |
| defaults to <tt>/usr/local</tt>. |
| <br><br> |
| |
| <dt><tt>gmake -C runtime install-bytecode</tt> |
| <dd> |
| Assuming you built LLVM into $OBJDIR, when this command is run, it will |
| install bitcode libraries into the GCC front end's bitcode library |
| directory. If you need to update your bitcode libraries, |
| this is the target to use once you've built them. |
| <br><br> |
| </dl> |
| |
| <p>Please see the <a href="MakefileGuide.html">Makefile Guide</a> for further |
| details on these <tt>make</tt> targets and descriptions of other targets |
| available.</p> |
| |
| <p>It is also possible to override default values from <tt>configure</tt> by |
| declaring variables on the command line. The following are some examples:</p> |
| |
| <dl> |
| <dt><tt>gmake ENABLE_OPTIMIZED=1</tt> |
| <dd> |
| Perform a Release (Optimized) build. |
| <br><br> |
| |
| <dt><tt>gmake ENABLE_OPTIMIZED=1 DISABLE_ASSERTIONS=1</tt> |
| <dd> |
| Perform a Release (Optimized) build without assertions enabled. |
| <br><br> |
| |
| <dt><tt>gmake ENABLE_OPTIMIZED=0</tt> |
| <dd> |
| Perform a Debug build. |
| <br><br> |
| |
| <dt><tt>gmake ENABLE_PROFILING=1</tt> |
| <dd> |
| Perform a Profiling build. |
| <br><br> |
| |
| <dt><tt>gmake VERBOSE=1</tt> |
| <dd> |
| Print what <tt>gmake</tt> is doing on standard output. |
| <br><br> |
| |
| <dt><tt>gmake TOOL_VERBOSE=1</tt></dt> |
| <dd>Ask each tool invoked by the makefiles to print out what it is doing on |
| the standard output. This also implies <tt>VERBOSE=1</tt>. |
| <br><br></dd> |
| </dl> |
| |
| <p>Every directory in the LLVM object tree includes a <tt>Makefile</tt> to build |
| it and any subdirectories that it contains. Entering any directory inside the |
| LLVM object tree and typing <tt>gmake</tt> should rebuild anything in or below |
| that directory that is out of date.</p> |
| |
| </div> |
| |
| <!-- ======================================================================= --> |
| <h3> |
| <a name="cross-compile">Cross-Compiling LLVM</a> |
| </h3> |
| |
| <div> |
| <p>It is possible to cross-compile LLVM itself. That is, you can create LLVM |
| executables and libraries to be hosted on a platform different from the |
| platform where they are build (a Canadian Cross build). To configure a |
| cross-compile, supply the configure script with <tt>--build</tt> and |
| <tt>--host</tt> options that are different. The values of these options must |
| be legal target triples that your GCC compiler supports.</p> |
| |
| <p>The result of such a build is executables that are not runnable on |
| on the build host (--build option) but can be executed on the compile host |
| (--host option).</p> |
| </div> |
| |
| <!-- ======================================================================= --> |
| <h3> |
| <a name="objfiles">The Location of LLVM Object Files</a> |
| </h3> |
| |
| <div> |
| |
| <p>The LLVM build system is capable of sharing a single LLVM source tree among |
| several LLVM builds. Hence, it is possible to build LLVM for several different |
| platforms or configurations using the same source tree.</p> |
| |
| <p>This is accomplished in the typical autoconf manner:</p> |
| |
| <ul> |
| <li><p>Change directory to where the LLVM object files should live:</p> |
| |
| <div class="doc_code"><pre>% cd <i>OBJ_ROOT</i></pre></div></li> |
| |
| <li><p>Run the <tt>configure</tt> script found in the LLVM source |
| directory:</p> |
| |
| <div class="doc_code"><pre>% <i>SRC_ROOT</i>/configure</pre></div></li> |
| </ul> |
| |
| <p>The LLVM build will place files underneath <i>OBJ_ROOT</i> in directories |
| named after the build type:</p> |
| |
| <dl> |
| <dt>Debug Builds with assertions enabled (the default) |
| <dd> |
| <dl> |
| <dt>Tools |
| <dd><tt><i>OBJ_ROOT</i>/Debug+Asserts/bin</tt> |
| <dt>Libraries |
| <dd><tt><i>OBJ_ROOT</i>/Debug+Asserts/lib</tt> |
| </dl> |
| <br><br> |
| |
| <dt>Release Builds |
| <dd> |
| <dl> |
| <dt>Tools |
| <dd><tt><i>OBJ_ROOT</i>/Release/bin</tt> |
| <dt>Libraries |
| <dd><tt><i>OBJ_ROOT</i>/Release/lib</tt> |
| </dl> |
| <br><br> |
| |
| <dt>Profile Builds |
| <dd> |
| <dl> |
| <dt>Tools |
| <dd><tt><i>OBJ_ROOT</i>/Profile/bin</tt> |
| <dt>Libraries |
| <dd><tt><i>OBJ_ROOT</i>/Profile/lib</tt> |
| </dl> |
| </dl> |
| |
| </div> |
| |
| <!-- ======================================================================= --> |
| <h3> |
| <a name="optionalconfig">Optional Configuration Items</a> |
| </h3> |
| |
| <div> |
| |
| <p> |
| If you're running on a Linux system that supports the "<a |
| href="http://www.tat.physik.uni-tuebingen.de/~rguenth/linux/binfmt_misc.html">binfmt_misc</a>" |
| module, and you have root access on the system, you can set your system up to |
| execute LLVM bitcode files directly. To do this, use commands like this (the |
| first command may not be required if you are already using the module):</p> |
| |
| <div class="doc_code"> |
| <pre> |
| $ mount -t binfmt_misc none /proc/sys/fs/binfmt_misc |
| $ echo ':llvm:M::BC::/path/to/lli:' > /proc/sys/fs/binfmt_misc/register |
| $ chmod u+x hello.bc (if needed) |
| $ ./hello.bc |
| </pre> |
| </div> |
| |
| <p> |
| This allows you to execute LLVM bitcode files directly. On Debian, you |
| can also use this command instead of the 'echo' command above: |
| </p> |
| |
| <div class="doc_code"> |
| <pre> |
| $ sudo update-binfmts --install llvm /path/to/lli --magic 'BC' |
| </pre> |
| </div> |
| |
| </div> |
| |
| </div> |
| |
| <!-- *********************************************************************** --> |
| <h2> |
| <a name="layout">Program Layout</a> |
| </h2> |
| <!-- *********************************************************************** --> |
| |
| <div> |
| |
| <p>One useful source of information about the LLVM source base is the LLVM <a |
| href="http://www.doxygen.org/">doxygen</a> documentation available at <tt><a |
| href="http://llvm.org/doxygen/">http://llvm.org/doxygen/</a></tt>. |
| The following is a brief introduction to code layout:</p> |
| |
| <!-- ======================================================================= --> |
| <h3> |
| <a name="examples"><tt>llvm/examples</tt></a> |
| </h3> |
| |
| <div> |
| <p>This directory contains some simple examples of how to use the LLVM IR and |
| JIT.</p> |
| </div> |
| |
| <!-- ======================================================================= --> |
| <h3> |
| <a name="include"><tt>llvm/include</tt></a> |
| </h3> |
| |
| <div> |
| |
| <p>This directory contains public header files exported from the LLVM |
| library. The three main subdirectories of this directory are:</p> |
| |
| <dl> |
| <dt><tt><b>llvm/include/llvm</b></tt></dt> |
| <dd>This directory contains all of the LLVM specific header files. This |
| directory also has subdirectories for different portions of LLVM: |
| <tt>Analysis</tt>, <tt>CodeGen</tt>, <tt>Target</tt>, <tt>Transforms</tt>, |
| etc...</dd> |
| |
| <dt><tt><b>llvm/include/llvm/Support</b></tt></dt> |
| <dd>This directory contains generic support libraries that are provided with |
| LLVM but not necessarily specific to LLVM. For example, some C++ STL utilities |
| and a Command Line option processing library store their header files here. |
| </dd> |
| |
| <dt><tt><b>llvm/include/llvm/Config</b></tt></dt> |
| <dd>This directory contains header files configured by the <tt>configure</tt> |
| script. They wrap "standard" UNIX and C header files. Source code can |
| include these header files which automatically take care of the conditional |
| #includes that the <tt>configure</tt> script generates.</dd> |
| </dl> |
| </div> |
| |
| <!-- ======================================================================= --> |
| <h3> |
| <a name="lib"><tt>llvm/lib</tt></a> |
| </h3> |
| |
| <div> |
| |
| <p>This directory contains most of the source files of the LLVM system. In LLVM, |
| almost all code exists in libraries, making it very easy to share code among the |
| different <a href="#tools">tools</a>.</p> |
| |
| <dl> |
| <dt><tt><b>llvm/lib/VMCore/</b></tt></dt> |
| <dd> This directory holds the core LLVM source files that implement core |
| classes like Instruction and BasicBlock.</dd> |
| |
| <dt><tt><b>llvm/lib/AsmParser/</b></tt></dt> |
| <dd>This directory holds the source code for the LLVM assembly language parser |
| library.</dd> |
| |
| <dt><tt><b>llvm/lib/BitCode/</b></tt></dt> |
| <dd>This directory holds code for reading and write LLVM bitcode.</dd> |
| |
| <dt><tt><b>llvm/lib/Analysis/</b></tt><dd>This directory contains a variety of |
| different program analyses, such as Dominator Information, Call Graphs, |
| Induction Variables, Interval Identification, Natural Loop Identification, |
| etc.</dd> |
| |
| <dt><tt><b>llvm/lib/Transforms/</b></tt></dt> |
| <dd> This directory contains the source code for the LLVM to LLVM program |
| transformations, such as Aggressive Dead Code Elimination, Sparse Conditional |
| Constant Propagation, Inlining, Loop Invariant Code Motion, Dead Global |
| Elimination, and many others.</dd> |
| |
| <dt><tt><b>llvm/lib/Target/</b></tt></dt> |
| <dd> This directory contains files that describe various target architectures |
| for code generation. For example, the <tt>llvm/lib/Target/X86</tt> |
| directory holds the X86 machine description while |
| <tt>llvm/lib/Target/CBackend</tt> implements the LLVM-to-C converter.</dd> |
| |
| <dt><tt><b>llvm/lib/CodeGen/</b></tt></dt> |
| <dd> This directory contains the major parts of the code generator: Instruction |
| Selector, Instruction Scheduling, and Register Allocation.</dd> |
| |
| <dt><tt><b>llvm/lib/MC/</b></tt></dt> |
| <dd>(FIXME: T.B.D.)</dd> |
| |
| <!--FIXME: obsoleted --> |
| <dt><tt><b>llvm/lib/Debugger/</b></tt></dt> |
| <dd> This directory contains the source level debugger library that makes |
| it possible to instrument LLVM programs so that a debugger could identify |
| source code locations at which the program is executing.</dd> |
| |
| <dt><tt><b>llvm/lib/ExecutionEngine/</b></tt></dt> |
| <dd> This directory contains libraries for executing LLVM bitcode directly |
| at runtime in both interpreted and JIT compiled fashions.</dd> |
| |
| <dt><tt><b>llvm/lib/Support/</b></tt></dt> |
| <dd> This directory contains the source code that corresponds to the header |
| files located in <tt>llvm/include/ADT/</tt> |
| and <tt>llvm/include/Support/</tt>.</dd> |
| </dl> |
| |
| </div> |
| |
| <!-- ======================================================================= --> |
| <h3> |
| <a name="projects"><tt>llvm/projects</tt></a> |
| </h3> |
| |
| <div> |
| <p>This directory contains projects that are not strictly part of LLVM but are |
| shipped with LLVM. This is also the directory where you should create your own |
| LLVM-based projects. See <tt>llvm/projects/sample</tt> for an example of how |
| to set up your own project.</p> |
| </div> |
| |
| <!-- ======================================================================= --> |
| <h3> |
| <a name="runtime"><tt>llvm/runtime</tt></a> |
| </h3> |
| |
| <div> |
| |
| <p>This directory contains libraries which are compiled into LLVM bitcode and |
| used when linking programs with the GCC front end. Most of these libraries are |
| skeleton versions of real libraries; for example, libc is a stripped down |
| version of glibc.</p> |
| |
| <p>Unlike the rest of the LLVM suite, this directory needs the LLVM GCC front |
| end to compile.</p> |
| |
| </div> |
| |
| <!-- ======================================================================= --> |
| <h3> |
| <a name="test"><tt>llvm/test</tt></a> |
| </h3> |
| |
| <div> |
| <p>This directory contains feature and regression tests and other basic sanity |
| checks on the LLVM infrastructure. These are intended to run quickly and cover |
| a lot of territory without being exhaustive.</p> |
| </div> |
| |
| <!-- ======================================================================= --> |
| <h3> |
| <a name="test-suite"><tt>test-suite</tt></a> |
| </h3> |
| |
| <div> |
| <p>This is not a directory in the normal llvm module; it is a separate |
| Subversion |
| module that must be checked out (usually to <tt>projects/test-suite</tt>). |
| This |
| module contains a comprehensive correctness, performance, and benchmarking |
| test |
| suite for LLVM. It is a separate Subversion module because not every LLVM |
| user is |
| interested in downloading or building such a comprehensive test suite. For |
| further details on this test suite, please see the |
| <a href="TestingGuide.html">Testing Guide</a> document.</p> |
| </div> |
| |
| <!-- ======================================================================= --> |
| <h3> |
| <a name="tools"><tt>llvm/tools</tt></a> |
| </h3> |
| |
| <div> |
| |
| <p>The <b>tools</b> directory contains the executables built out of the |
| libraries above, which form the main part of the user interface. You can |
| always get help for a tool by typing <tt>tool_name -help</tt>. The |
| following is a brief introduction to the most important tools. More detailed |
| information is in the <a href="CommandGuide/index.html">Command Guide</a>.</p> |
| |
| <dl> |
| |
| <dt><tt><b>bugpoint</b></tt></dt> |
| <dd><tt>bugpoint</tt> is used to debug |
| optimization passes or code generation backends by narrowing down the |
| given test case to the minimum number of passes and/or instructions that |
| still cause a problem, whether it is a crash or miscompilation. See <a |
| href="HowToSubmitABug.html">HowToSubmitABug.html</a> for more information |
| on using <tt>bugpoint</tt>.</dd> |
| |
| <dt><tt><b>llvm-ar</b></tt></dt> |
| <dd>The archiver produces an archive containing |
| the given LLVM bitcode files, optionally with an index for faster |
| lookup.</dd> |
| |
| <dt><tt><b>llvm-as</b></tt></dt> |
| <dd>The assembler transforms the human readable LLVM assembly to LLVM |
| bitcode.</dd> |
| |
| <dt><tt><b>llvm-dis</b></tt></dt> |
| <dd>The disassembler transforms the LLVM bitcode to human readable |
| LLVM assembly.</dd> |
| |
| <dt><tt><b>llvm-ld</b></tt></dt> |
| <dd><tt>llvm-ld</tt> is a general purpose and extensible linker for LLVM. |
| It performs standard link time optimizations and allows optimization |
| modules to be loaded and run so that language specific optimizations can |
| be applied at link time.</dd> |
| |
| <dt><tt><b>llvm-link</b></tt></dt> |
| <dd><tt>llvm-link</tt>, not surprisingly, links multiple LLVM modules into |
| a single program.</dd> |
| |
| <dt><tt><b>lli</b></tt></dt> |
| <dd><tt>lli</tt> is the LLVM interpreter, which |
| can directly execute LLVM bitcode (although very slowly...). For architectures |
| that support it (currently x86, Sparc, and PowerPC), by default, <tt>lli</tt> |
| will function as a Just-In-Time compiler (if the functionality was compiled |
| in), and will execute the code <i>much</i> faster than the interpreter.</dd> |
| |
| <dt><tt><b>llc</b></tt></dt> |
| <dd> <tt>llc</tt> is the LLVM backend compiler, which |
| translates LLVM bitcode to a native code assembly file or to C code (with |
| the -march=c option).</dd> |
| |
| <dt><tt><b>llvm-gcc</b></tt></dt> |
| <dd><tt>llvm-gcc</tt> is a GCC-based C frontend that has been retargeted to |
| use LLVM as its backend instead of GCC's RTL backend. It can also emit LLVM |
| bitcode or assembly (with the <tt>-emit-llvm</tt> option) instead of the |
| usual machine code output. It works just like any other GCC compiler, |
| taking the typical <tt>-c, -S, -E, -o</tt> options that are typically used. |
| Additionally, the the source code for <tt>llvm-gcc</tt> is available as a |
| separate Subversion module.</dd> |
| |
| <dt><tt><b>opt</b></tt></dt> |
| <dd><tt>opt</tt> reads LLVM bitcode, applies a series of LLVM to LLVM |
| transformations (which are specified on the command line), and then outputs |
| the resultant bitcode. The '<tt>opt -help</tt>' command is a good way to |
| get a list of the program transformations available in LLVM.<br> |
| <dd><tt>opt</tt> can also be used to run a specific analysis on an input |
| LLVM bitcode file and print out the results. It is primarily useful for |
| debugging analyses, or familiarizing yourself with what an analysis does.</dd> |
| </dl> |
| </div> |
| |
| <!-- ======================================================================= --> |
| <h3> |
| <a name="utils"><tt>llvm/utils</tt></a> |
| </h3> |
| |
| <div> |
| |
| <p>This directory contains utilities for working with LLVM source code, and some |
| of the utilities are actually required as part of the build process because they |
| are code generators for parts of LLVM infrastructure.</p> |
| |
| <dl> |
| <dt><tt><b>codegen-diff</b></tt> <dd><tt>codegen-diff</tt> is a script |
| that finds differences between code that LLC generates and code that LLI |
| generates. This is a useful tool if you are debugging one of them, |
| assuming that the other generates correct output. For the full user |
| manual, run <tt>`perldoc codegen-diff'</tt>.<br><br> |
| |
| <dt><tt><b>emacs/</b></tt> <dd>The <tt>emacs</tt> directory contains |
| syntax-highlighting files which will work with Emacs and XEmacs editors, |
| providing syntax highlighting support for LLVM assembly files and TableGen |
| description files. For information on how to use the syntax files, consult |
| the <tt>README</tt> file in that directory.<br><br> |
| |
| <dt><tt><b>getsrcs.sh</b></tt> <dd>The <tt>getsrcs.sh</tt> script finds |
| and outputs all non-generated source files, which is useful if one wishes |
| to do a lot of development across directories and does not want to |
| individually find each file. One way to use it is to run, for example: |
| <tt>xemacs `utils/getsources.sh`</tt> from the top of your LLVM source |
| tree.<br><br> |
| |
| <dt><tt><b>llvmgrep</b></tt></dt> |
| <dd>This little tool performs an "egrep -H -n" on each source file in LLVM and |
| passes to it a regular expression provided on <tt>llvmgrep</tt>'s command |
| line. This is a very efficient way of searching the source base for a |
| particular regular expression.</dd> |
| |
| <dt><tt><b>makellvm</b></tt> <dd>The <tt>makellvm</tt> script compiles all |
| files in the current directory and then compiles and links the tool that |
| is the first argument. For example, assuming you are in the directory |
| <tt>llvm/lib/Target/Sparc</tt>, if <tt>makellvm</tt> is in your path, |
| simply running <tt>makellvm llc</tt> will make a build of the current |
| directory, switch to directory <tt>llvm/tools/llc</tt> and build it, |
| causing a re-linking of LLC.<br><br> |
| |
| <dt><tt><b>NewNightlyTest.pl</b></tt> and |
| <tt><b>NightlyTestTemplate.html</b></tt> <dd>These files are used in a |
| cron script to generate nightly status reports of the functionality of |
| tools, and the results can be seen by following the appropriate link on |
| the <a href="http://llvm.org/">LLVM homepage</a>.<br><br> |
| |
| <dt><tt><b>TableGen/</b></tt> <dd>The <tt>TableGen</tt> directory contains |
| the tool used to generate register descriptions, instruction set |
| descriptions, and even assemblers from common TableGen description |
| files.<br><br> |
| |
| <dt><tt><b>vim/</b></tt> <dd>The <tt>vim</tt> directory contains |
| syntax-highlighting files which will work with the VIM editor, providing |
| syntax highlighting support for LLVM assembly files and TableGen |
| description files. For information on how to use the syntax files, consult |
| the <tt>README</tt> file in that directory.<br><br> |
| |
| </dl> |
| |
| </div> |
| |
| </div> |
| |
| <!-- *********************************************************************** --> |
| <h2> |
| <a name="tutorial">An Example Using the LLVM Tool Chain</a> |
| </h2> |
| <!-- *********************************************************************** --> |
| |
| <div> |
| <p>This section gives an example of using LLVM. llvm-gcc3 is now obsolete, |
| so we only include instructions for llvm-gcc4. |
| </p> |
| |
| <p><b>Note:</b> The <i>gcc4</i> frontend's invocation is <b><i>considerably different</i></b> |
| from the previous <i>gcc3</i> frontend. In particular, the <i>gcc4</i> frontend <b><i>does not</i></b> |
| create bitcode by default: <i>gcc4</i> produces native code. As the example below illustrates, |
| the '--emit-llvm' flag is needed to produce LLVM bitcode output. For <i>makefiles</i> and |
| <i>configure</i> scripts, the CFLAGS variable needs '--emit-llvm' to produce bitcode |
| output.</p> |
| |
| <!-- ======================================================================= --> |
| <h3> |
| <a name="tutorial4">Example with llvm-gcc4</a> |
| </h3> |
| |
| <div> |
| |
| <ol> |
| <li><p>First, create a simple C file, name it 'hello.c':</p> |
| |
| <div class="doc_code"> |
| <pre> |
| #include <stdio.h> |
| |
| int main() { |
| printf("hello world\n"); |
| return 0; |
| } |
| </pre></div></li> |
| |
| <li><p>Next, compile the C file into a native executable:</p> |
| |
| <div class="doc_code"><pre>% llvm-gcc hello.c -o hello</pre></div> |
| |
| <p>Note that llvm-gcc works just like GCC by default. The standard -S and |
| -c arguments work as usual (producing a native .s or .o file, |
| respectively).</p></li> |
| |
| <li><p>Next, compile the C file into a LLVM bitcode file:</p> |
| |
| <div class="doc_code"> |
| <pre>% llvm-gcc -O3 -emit-llvm hello.c -c -o hello.bc</pre></div> |
| |
| <p>The -emit-llvm option can be used with the -S or -c options to emit an |
| LLVM ".ll" or ".bc" file (respectively) for the code. This allows you |
| to use the <a href="CommandGuide/index.html">standard LLVM tools</a> on |
| the bitcode file.</p> |
| |
| <p>Unlike llvm-gcc3, llvm-gcc4 correctly responds to -O[0123] arguments. |
| </p></li> |
| |
| <li><p>Run the program in both forms. To run the program, use:</p> |
| |
| <div class="doc_code"><pre>% ./hello</pre></div> |
| |
| <p>and</p> |
| |
| <div class="doc_code"><pre>% lli hello.bc</pre></div> |
| |
| <p>The second examples shows how to invoke the LLVM JIT, <a |
| href="CommandGuide/html/lli.html">lli</a>.</p></li> |
| |
| <li><p>Use the <tt>llvm-dis</tt> utility to take a look at the LLVM assembly |
| code:</p> |
| |
| <div class="doc_code"> |
| <pre>llvm-dis < hello.bc | less</pre> |
| </div></li> |
| |
| <li><p>Compile the program to native assembly using the LLC code |
| generator:</p> |
| |
| <div class="doc_code"><pre>% llc hello.bc -o hello.s</pre></div></li> |
| |
| <li><p>Assemble the native assembly language file into a program:</p> |
| |
| <div class="doc_code"> |
| <pre> |
| <b>Solaris:</b> % /opt/SUNWspro/bin/cc -xarch=v9 hello.s -o hello.native |
| |
| <b>Others:</b> % gcc hello.s -o hello.native |
| </pre> |
| </div></li> |
| |
| <li><p>Execute the native code program:</p> |
| |
| <div class="doc_code"><pre>% ./hello.native</pre></div> |
| |
| <p>Note that using llvm-gcc to compile directly to native code (i.e. when |
| the -emit-llvm option is not present) does steps 6/7/8 for you.</p> |
| </li> |
| |
| </ol> |
| |
| </div> |
| |
| </div> |
| |
| <!-- *********************************************************************** --> |
| <h2> |
| <a name="problems">Common Problems</a> |
| </h2> |
| <!-- *********************************************************************** --> |
| |
| <div> |
| |
| <p>If you are having problems building or using LLVM, or if you have any other |
| general questions about LLVM, please consult the <a href="FAQ.html">Frequently |
| Asked Questions</a> page.</p> |
| |
| </div> |
| |
| <!-- *********************************************************************** --> |
| <h2> |
| <a name="links">Links</a> |
| </h2> |
| <!-- *********************************************************************** --> |
| |
| <div> |
| |
| <p>This document is just an <b>introduction</b> on how to use LLVM to do |
| some simple things... there are many more interesting and complicated things |
| that you can do that aren't documented here (but we'll gladly accept a patch |
| if you want to write something up!). For more information about LLVM, check |
| out:</p> |
| |
| <ul> |
| <li><a href="http://llvm.org/">LLVM homepage</a></li> |
| <li><a href="http://llvm.org/doxygen/">LLVM doxygen tree</a></li> |
| <li><a href="http://llvm.org/docs/Projects.html">Starting a Project |
| that Uses LLVM</a></li> |
| </ul> |
| |
| </div> |
| |
| <!-- *********************************************************************** --> |
| |
| <hr> |
| <address> |
| <a href="http://jigsaw.w3.org/css-validator/check/referer"><img |
| src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a> |
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| src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a> |
| |
| <a href="mailto:sabre@nondot.org">Chris Lattner</a><br> |
| <a href="http://llvm.x10sys.com/rspencer/">Reid Spencer</a><br> |
| <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br> |
| Last modified: $Date$ |
| </address> |
| </body> |
| </html> |