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1098 lines
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HTML
1098 lines
38 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
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"http://www.w3.org/TR/html4/strict.dtd">
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<html>
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<head>
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<title>Getting Started with LLVM System</title>
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<link rel="stylesheet" href="llvm.css" type="text/css">
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</head>
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<body>
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<div class="doc_title">
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Getting Started with the LLVM System
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</div>
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<ul>
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<li><a href="#overview">Overview</a>
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<li><a href="#quickstart">Getting Started Quickly (A Summary)</a>
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<li><a href="#requirements">Requirements</a>
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<ol>
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<li><a href="#hardware">Hardware</a>
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<li><a href="#software">Software</a>
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</ol></li>
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<li><a href="#starting">Getting Started with LLVM</a>
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<ol>
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<li><a href="#terminology">Terminology and Notation</a>
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<li><a href="#environment">Setting Up Your Environment</a>
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<li><a href="#unpack">Unpacking the LLVM Archives</a>
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<li><a href="#checkout">Checkout LLVM from CVS</a>
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<li><a href="#installcf">Install the GCC Front End</a>
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<li><a href="#config">Local LLVM Configuration</a>
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<li><a href="#compile">Compiling the LLVM Suite Source Code</a>
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<li><a href="#objfiles">The Location of LLVM Object Files</a>
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</ol></li>
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<li><a href="#layout">Program layout</a>
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<ol>
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<li><a href="#cvsdir"><tt>CVS</tt> directories</a>
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<li><a href="#include"><tt>llvm/include</tt></a>
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<li><a href="#lib"><tt>llvm/lib</tt></a>
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<li><a href="#runtime"><tt>llvm/runtime</tt></a>
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<li><a href="#test"><tt>llvm/test</tt></a>
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<li><a href="#tools"><tt>llvm/tools</tt></a>
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<li><a href="#utils"><tt>llvm/utils</tt></a>
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</ol></li>
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<li><a href="#tutorial">An Example Using the LLVM Tool Chain</a>
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<li><a href="#problems">Common Problems</a>
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<li><a href="#links">Links</a>
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</ul>
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<p>By:
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<a href="mailto:gshi1@uiuc.edu">Guochun Shi</a>,
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<a href="mailto:sabre@nondot.org">Chris Lattner</a>,
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<a href="mailto:criswell@uiuc.edu">John Criswell</a>,
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<a href="http://misha.brukman.net">Misha Brukman</a>, and
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<a href="http://www.cs.uiuc.edu/~vadve">Vikram Adve</a>.</p>
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<!-- *********************************************************************** -->
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<div class="doc_section">
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<a name="overview"><b>Overview</b></a>
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</div>
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<!-- *********************************************************************** -->
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<div class="doc_text">
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<p>Welcome to LLVM! In order to get started, you first need to know some
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basic information.</p>
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<p>First, LLVM comes in two pieces. The first piece is the LLVM suite. This
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contains all of the tools, libraries, and header files needed to use the low
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level virtual machine. It contains an assembler, disassembler, bytecode
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analyzer, and bytecode optimizer. It also contains a test suite that can be
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used to test the LLVM tools and the GCC front end.</p>
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<p>The second piece is the GCC front end. This component provides a version of
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GCC that compiles C and C++ code into LLVM bytecode. Currently, the GCC front
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end is a modified version of GCC 3.4 (we track the GCC 3.4 development). Once
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compiled into LLVM bytecode, a program can be manipulated with the LLVM tools
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from the LLVM suite.</p>
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</div>
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<!-- *********************************************************************** -->
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<div class="doc_section">
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<a name="quickstart"><b>Getting Started Quickly (A Summary)</b></a>
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</div>
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<!-- *********************************************************************** -->
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<div class="doc_text">
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<p>Here's the short story for getting up and running quickly with LLVM:</p>
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<ol>
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<li>Install the GCC front end:
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<ol>
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<li><tt>cd <i>where-you-want-the-C-front-end-to-live</i></tt>
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<li><tt>gunzip --stdout cfrontend.<i>platform</i>.tar.gz | tar -xvf -</tt>
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<li><b>Sparc Only:</b><br>
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<tt>cd cfrontend/sparc<br>
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./fixheaders</tt>
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</ol></li>
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<li>Get the Source Code
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<ul>
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<li>With the distributed files:
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<ol>
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<li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
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<li><tt>gunzip --stdout llvm.tar.gz | tar -xvf -</tt>
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<li><tt>cd llvm</tt>
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</ol></li>
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<li>With anonymous CVS access:
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<ol>
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<li><tt>cd <i>where-you-want-llvm-to-live</i></tt></li>
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<li><tt>cvs -d
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:pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm login</tt></li>
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<li>Hit the return key when prompted for the password.
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<li><tt>cvs -z3 -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm
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co llvm</tt></li>
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<li><tt>cd llvm</tt></li>
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</ol></li>
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</ul></li>
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<li>Configure the LLVM Build Environment
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<ol>
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<li>Change directory to where you want to store the LLVM object
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files and run <tt>configure</tt> to configure the Makefiles and
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header files for the default platform. Useful options include:
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<ul>
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<li><tt>--with-llvmgccdir=<i>directory</i></tt>
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<p>Specify where the LLVM GCC frontend is installed.</p></li>
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<li><tt>--enable-spec2000=<i>directory</i></tt>
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<p>Enable the SPEC2000 benchmarks for testing. The SPEC2000
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benchmarks should be available in
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<tt><i>directory</i></tt>.</p></li>
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</ul>
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</ol></li>
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<li>Build the LLVM Suite:
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<ol>
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<li>Set your LLVM_LIB_SEARCH_PATH environment variable.
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<li><tt>gmake -k |& tee gnumake.out
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# this is csh or tcsh syntax</tt>
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</ol>
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</ol>
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<p>Consult the <a href="starting">Getting Started with LLVM</a> section for
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detailed information on configuring and compiling LLVM. See <a
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href="#environment">Setting Up Your Environment</a> for tips that simplify
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working with the GCC front end and LLVM tools. Go to <a href="#layout">Program
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Layout</a> to learn about the layout of the source code tree.</p>
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</div>
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<!-- *********************************************************************** -->
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<div class="doc_section">
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<a name="requirements"><b>Requirements</b></a>
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</div>
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<!-- *********************************************************************** -->
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<div class="doc_text">
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<p>Before you begin to use the LLVM system, review the requirements given below.
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This may save you some trouble by knowing ahead of time what hardware and
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software you will need.</p>
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</div>
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<!-- ======================================================================= -->
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<div class="doc_subsection">
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<a name="hardware"><b>Hardware</b></a>
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</div>
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<div class="doc_text">
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<p>LLVM is known to work on the following platforms:</p>
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<ul>
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<li>Linux on x86 (Pentium and above)
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<ul>
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<li>Approximately 760 MB of Free Disk Space
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<ul>
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<li>Source code: 30 MB</li>
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<li>Object code: 670 MB</li>
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<li>GCC front end: 60 MB</li>
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</ul></li>
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</ul></li>
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<li>Solaris on SparcV9 (Ultrasparc)
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<ul>
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<li>Approximately 1.24 GB of Free Disk Space
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<ul>
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<li>Source code: 30 MB</li>
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<li>Object code: 1000 MB</li>
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<li>GCC front end: 210 MB</li>
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</ul></li>
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</ul></li>
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</ul>
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<p>The LLVM suite <i>may</i> compile on other platforms, but it is not
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guaranteed to do so. If compilation is successful, the LLVM utilities should be
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able to assemble, disassemble, analyze, and optimize LLVM bytecode. Code
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generation should work as well, although the generated native code may not work
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on your platform.</p>
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<p>The GCC front end is not very portable at the moment. If you want to get it
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to work on another platform, you can download a copy of the source and try to
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compile it on your platform.</p>
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</div>
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<!-- ======================================================================= -->
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<div class="doc_subsection">
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<a name="software"><b>Software</b></a>
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</div>
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<div class="doc_text">
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<p>Compiling LLVM requires that you have several software packages
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installed:</p>
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<ul>
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<li><a href="http://gcc.gnu.org">GCC 3.x with C and C++ language
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support</a></li>
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<li><a href="http://savannah.gnu.org/projects/make">GNU Make</a></li>
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<li><a href="http://www.gnu.org/software/flex">Flex</a></li>
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<li><a href="http://www.gnu.org/software/bison/bison.html">Bison</a></li>
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</ul>
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<p>There are some additional tools that you may want to have when working with
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LLVM:</p>
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<ul>
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<li><A href="http://www.gnu.org/software/autoconf">GNU Autoconf</A>
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<li><A href="http://savannah.gnu.org/projects/m4">GNU M4</A>
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<p>If you want to make changes to the configure scripts, you will need GNU
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autoconf (2.57 or higher), and consequently, GNU M4 (version 1.4 or
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higher).</p></li>
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<li><A href="http://www.codesourcery.com/qm/qmtest">QMTest</A></li>
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<li><A href="http://www.python.org">Python</A>
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<p>These are needed to use the LLVM test suite.</p></li>
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</ul>
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<p>The remainder of this guide is meant to get you up and running with
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LLVM and to give you some basic information about the LLVM environment.
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A <a href="#starting">complete guide to installation</a> is provided in the
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next section.</p>
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<p>The later sections of this guide describe the <a
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href="#layout">general layout</a> of the the LLVM source tree, a <a
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href="#tutorial">simple example</a> using the LLVM tool chain, and <a
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href="#links">links</a> to find more information about LLVM or to get
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help via e-mail.</p>
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</div>
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<!-- *********************************************************************** -->
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<div class="doc_section">
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<a name="starting"><b>Getting Started with LLVM</b></a>
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|
</div>
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<!-- *********************************************************************** -->
|
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<!-- ======================================================================= -->
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<div class="doc_subsection">
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<a name="terminology">Terminology and Notation</a>
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</div>
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<div class="doc_text">
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<p>Throughout this manual, the following names are used to denote paths
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specific to the local system and working environment. <i>These are not
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environment variables you need to set but just strings used in the rest
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of this document below</i>. In any of the examples below, simply replace
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each of these names with the appropriate pathname on your local system.
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All these paths are absolute:</p>
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<dl compact>
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<dt>SRC_ROOT
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<dd>
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This is the top level directory of the LLVM source tree.
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<p>
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<dt>OBJ_ROOT
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<dd>
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This is the top level directory of the LLVM object tree (i.e. the
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tree where object files and compiled programs will be placed. It
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can be the same as SRC_ROOT).
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<p>
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<dt>LLVMGCCDIR
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<dd>
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This is the where the LLVM GCC Front End is installed.
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<p>
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For the pre-built GCC front end binaries, the LLVMGCCDIR is
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<tt>cfrontend/<i>platform</i>/llvm-gcc</tt>.
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</dl>
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</div>
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<!-- ======================================================================= -->
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<div class="doc_subsection">
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<a name="environment">Setting Up Your Environment</a>
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</div>
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<div class="doc_text">
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<p>
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In order to compile and use LLVM, you will need to set some environment
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variables. There are also some shell aliases which you may find useful.
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You can set these on the command line, or better yet, set them in your
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<tt>.cshrc</tt> or <tt>.profile</tt>.
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<dl compact>
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<dt><tt>LLVM_LIB_SEARCH_PATH</tt>=<tt><i>LLVMGCCDIR</i>/bytecode-libs</tt>
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<dd>
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This environment variable helps the LLVM GCC front end find bytecode
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libraries that it will need for compilation.
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<p>
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<dt>alias llvmgcc <i>LLVMGCCDIR</i><tt>/bin/gcc</tt>
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<dt>alias llvmg++ <i>LLVMGCCDIR</i><tt>/bin/g++</tt>
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<dd>
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This alias allows you to use the LLVM C and C++ front ends without putting
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them in your <tt>PATH</tt> or typing in their complete pathnames.
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</dl>
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</div>
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<!-- ======================================================================= -->
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<div class="doc_subsection">
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<a name="unpack">Unpacking the LLVM Archives</a></h3>
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</div>
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<div class="doc_text">
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<p>
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If you have the LLVM distribution, you will need to unpack it before you
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can begin to compile it. LLVM is distributed as a set of three files. Each
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file is a TAR archive that is compressed with the gzip program.
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</p>
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<p> The three files are as follows:
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<dl compact>
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<dt>llvm.tar.gz
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<dd>This is the source code to the LLVM suite.
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<p>
|
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<dt>cfrontend.sparc.tar.gz
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<dd>This is the binary release of the GCC front end for Solaris/Sparc.
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<p>
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<dt>cfrontend.x86.tar.gz
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<dd>This is the binary release of the GCC front end for Linux/x86.
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</dl>
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</div>
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<!-- ======================================================================= -->
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<div class="doc_subsection">
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<a name="checkout">Checkout LLVM from CVS</a></h3>
|
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</div>
|
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<div class="doc_text">
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<p>If you have access to our CVS repository, you can get a fresh copy of
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the entire source code. All you need to do is check it out from CVS as
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follows:</p>
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<ul>
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<li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
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<li><tt>cvs -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm login</tt>
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<li>Hit the return key when prompted for the password.
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<li><tt>cvs -z3 -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm co
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llvm</tt>
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</ul>
|
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|
<p>This will create an '<tt>llvm</tt>' directory in the current
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directory and fully populate it with the LLVM source code, Makefiles,
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test directories, and local copies of documentation files.</p>
|
|
|
|
<p>Note that the GCC front end is not included in the CVS repository. You
|
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should have downloaded the binary distribution for your platform.</p>
|
|
|
|
</div>
|
|
|
|
<!-- ======================================================================= -->
|
|
<div class="doc_subsection">
|
|
<a name="installcf">Install the GCC Front End</a></h3>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
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|
<p>Before configuring and compiling the LLVM suite, you need to extract the LLVM
|
|
GCC front end from the binary distribution. It is used for building the
|
|
bytecode libraries later used by the GCC front end for linking programs, and its
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|
location must be specified when the LLVM suite is configured.</p>
|
|
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|
<p>To install the GCC front end, do the following:</p>
|
|
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|
<ol>
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<li><tt>cd <i>where-you-want-the-front-end-to-live</i></tt></li>
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|
<li><tt>gunzip --stdout cfrontend.<i>platform</i>.tar.gz | tar -xvf
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-</tt></li>
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|
</ol>
|
|
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|
<p>If you are on a Sparc/Solaris machine, you will need to fix the header
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files:</p>
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<p><tt>cd cfrontend/sparc<br>
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./fixheaders</tt></p>
|
|
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|
<p>The binary versions of the GCC front end may not suit all of your needs. For
|
|
example, the binary distribution may include an old version of a system header
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|
file, not "fix" a header file that needs to be fixed for GCC, or it may be
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|
linked with libraries not available on your system.</p>
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|
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|
<p>In cases like these, you may want to try <a
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href="CFEBuildInstrs.html">building the GCC front end from source.</a> This is
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|
not for the faint of heart, so be forewarned.</p>
|
|
|
|
</div>
|
|
|
|
<!-- ======================================================================= -->
|
|
<div class="doc_subsection">
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|
<a name="config">Local LLVM Configuration</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<p>Once checked out from the CVS repository, the LLVM suite source code must be
|
|
configured via the <tt>configure</tt> script. This script sets variables in
|
|
<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 build LLVM.</p>
|
|
|
|
<p>The following environment variables are used by the <tt>configure</tt>
|
|
script to configure the build system:</p>
|
|
|
|
<table border=1>
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|
<tr>
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|
<th>Variable</th>
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<th>Purpose</th>
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</tr>
|
|
|
|
<tr>
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|
<td>CC</td>
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|
<td>Tells <tt>configure</tt> which C compiler to use. By default,
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|
<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>
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|
<td>CXX</td>
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<td>Tells <tt>configure</tt> which C++ compiler to use. By default,
|
|
<tt>configure</tt> will look for the first GCC C++ compiler in
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|
<tt>PATH</tt>. Use this variable to override
|
|
<tt>configure</tt>'s default behavior.</td>
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|
</tr>
|
|
</table>
|
|
|
|
<p>The following options can be used to set or enable LLVM specific options:</p>
|
|
|
|
<dl compact>
|
|
<dt><i>--with-llvmgccdir=LLVMGCCDIR</i>
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|
<dd>
|
|
Path to the location where the LLVM C front end binaries and
|
|
associated libraries will be installed.
|
|
<p>
|
|
<dt><i>--enable-optimized</i>
|
|
<dd>
|
|
Enables optimized compilation by default (debugging symbols are removed
|
|
and GCC optimization flags are enabled). The default is to use an
|
|
unoptimized build (also known as a debug build).
|
|
<p>
|
|
<dt><i>--enable-jit</i>
|
|
<dd>
|
|
Compile the Just In Time (JIT) 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.
|
|
<p>
|
|
<dt><i>--enable-spec2000</i>
|
|
<dt><i>--enable-spec2000=<<tt>directory</tt>></i>
|
|
<dd>
|
|
Enable the use of SPEC2000 when testing LLVM. This is disabled by default
|
|
(unless <tt>configure</tt> finds SPEC2000 installed). By specifying
|
|
<tt>directory</tt>, you can tell configure where to find the SPEC2000
|
|
benchmarks. If <tt>directory</tt> is left unspecified, <tt>configure</tt>
|
|
uses the default value
|
|
<tt>/home/vadve/shared/benchmarks/speccpu2000/benchspec</tt>.
|
|
</dl>
|
|
|
|
<p>To configure LLVM, follow these steps:</p>
|
|
|
|
<ol>
|
|
<li>Change directory into the object root directory:
|
|
<br>
|
|
<tt>cd <i>OBJ_ROOT</i></tt>
|
|
<p>
|
|
|
|
<li>Run the <tt>configure</tt> script located in the LLVM source tree:
|
|
<br>
|
|
<tt><i>SRC_ROOT</i>/configure</tt>
|
|
<p>
|
|
</ol>
|
|
|
|
<p>In addition to running <tt>configure</tt>, you must set the
|
|
<tt>LLVM_LIB_SEARCH_PATH</tt> environment variable in your startup scripts.
|
|
This environment variable is used to locate "system" libraries like
|
|
"<tt>-lc</tt>" and "<tt>-lm</tt>" when linking. This variable should be set to
|
|
the absolute path for the bytecode-libs subdirectory of the GCC front end
|
|
install, or <i>LLVMGCCDIR</i>/bytecode-libs. For example, one might set
|
|
<tt>LLVM_LIB_SEARCH_PATH</tt> to
|
|
<tt>/home/vadve/lattner/local/x86/llvm-gcc/bytecode-libs</tt> for the X86
|
|
version of the GCC front end on our research machines.</p>
|
|
|
|
</div>
|
|
|
|
<!-- ======================================================================= -->
|
|
<div class="doc_subsection">
|
|
<a name="compile">Compiling the LLVM Suite Source Code</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<p>Once you have configured LLVM, you can build it. There are three types of
|
|
builds:</p>
|
|
|
|
<dl compact>
|
|
<dt>Debug Builds
|
|
<dd>
|
|
These builds are the default when one 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.
|
|
<p>
|
|
|
|
<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.
|
|
<p>
|
|
|
|
<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>
|
|
|
|
<p><tt>gmake</tt></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>
|
|
|
|
<p><tt>gmake -j2</tt></p>
|
|
|
|
<p>There are several special targets which are useful when working with the LLVM
|
|
source code:</p>
|
|
|
|
<dl compact>
|
|
<dt><tt>gmake clean</tt>
|
|
<dd>
|
|
Removes all files generated by the build. This includes object files,
|
|
generated C/C++ files, libraries, and executables.
|
|
<p>
|
|
|
|
<dt><tt>gmake distclean</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.
|
|
<p>
|
|
|
|
<dt><tt>gmake install</tt>
|
|
<dd>
|
|
Installs LLVM files into the proper location. For the most part,
|
|
this does nothing, but it does install bytecode libraries into the
|
|
GCC front end's bytecode library directory. If you need to update
|
|
your bytecode libraries, this is the target to use once you've built
|
|
them.
|
|
<p>
|
|
</dl>
|
|
|
|
<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 compact>
|
|
<dt><tt>gmake ENABLE_OPTIMIZED=1</tt>
|
|
<dd>
|
|
Perform a Release (Optimized) build.
|
|
<p>
|
|
|
|
<dt><tt>gmake ENABLE_PROFILING=1</tt>
|
|
<dd>
|
|
Perform a Profiling build.
|
|
<p>
|
|
|
|
<dt><tt>gmake VERBOSE=1</tt>
|
|
<dd>
|
|
Print what <tt>gmake</tt> is doing on standard output.
|
|
<p>
|
|
</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>
|
|
|
|
<!-- ======================================================================= -->
|
|
<div class="doc_subsection">
|
|
<a name="objfiles">The Location of LLVM Object Files</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<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>
|
|
|
|
<p><tt>cd <i>OBJ_ROOT</i></tt></p></li>
|
|
|
|
<li><p>Run the <tt>configure</tt> script found in the LLVM source
|
|
directory:</p>
|
|
|
|
<p><tt><i>SRC_ROOT</i>/configure</tt></p></li>
|
|
</ul>
|
|
|
|
<p>The LLVM build will place files underneath <i>OBJ_ROOT</i> in directories
|
|
named after the build type:</p>
|
|
|
|
<dl compact>
|
|
<dt>Debug Builds
|
|
<dd>
|
|
<dl compact>
|
|
<dt>Tools
|
|
<dd><tt><i>OBJ_ROOT</i>/tools/Debug</tt>
|
|
<dt>Libraries
|
|
<dd><tt><i>OBJ_ROOT</i>/lib/Debug</tt>
|
|
</dl>
|
|
<p>
|
|
|
|
<dt>Release Builds
|
|
<dd>
|
|
<dl compact>
|
|
<dt>Tools
|
|
<dd><tt><i>OBJ_ROOT</i>/tools/Release</tt>
|
|
<dt>Libraries
|
|
<dd><tt><i>OBJ_ROOT</i>/lib/Release</tt>
|
|
</dl>
|
|
<p>
|
|
|
|
<dt>Profile Builds
|
|
<dd>
|
|
<dl compact>
|
|
<dt>Tools
|
|
<dd><tt><i>OBJ_ROOT</i>/tools/Profile</tt>
|
|
<dt>Libraries
|
|
<dd><tt><i>OBJ_ROOT</i>/lib/Profile</tt>
|
|
</dl>
|
|
</dl>
|
|
|
|
</div>
|
|
|
|
<!-- *********************************************************************** -->
|
|
<div class="doc_section">
|
|
<a name="layout"><b>Program Layout</b></a>
|
|
</div>
|
|
<!-- *********************************************************************** -->
|
|
|
|
<div class="doc_text">
|
|
|
|
<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.cs.uiuc.edu/doxygen/">http://llvm.cs.uiuc.edu/doxygen/</a></tt>.
|
|
The following is a brief introduction to code layout:</p>
|
|
|
|
</div>
|
|
|
|
<!-- ======================================================================= -->
|
|
<div class="doc_subsection">
|
|
<a name="cvsdir"><tt>CVS</tt> directories</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<p>Every directory checked out of CVS will contain a <tt>CVS</tt> directory; for
|
|
the most part these can just be ignored.</p>
|
|
|
|
</div>
|
|
|
|
<!-- ======================================================================= -->
|
|
<div class="doc_subsection">
|
|
<a name="include"><tt>llvm/include</tt></a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<p>This directory contains public header files exported from the LLVM
|
|
library. The three main subdirectories of this directory are:</p>
|
|
|
|
<ol>
|
|
<li><tt>llvm/include/llvm</tt> - 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...</li>
|
|
|
|
<li><tt>llvm/include/Support</tt> - This directory contains generic
|
|
support libraries that are independent of LLVM, but are used by LLVM.
|
|
For example, some C++ STL utilities and a Command Line option processing
|
|
library store their header files here.</li>
|
|
|
|
<li><tt>llvm/include/Config</tt> - 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.</li>
|
|
</ol>
|
|
|
|
</div>
|
|
|
|
<!-- ======================================================================= -->
|
|
<div class="doc_subsection">
|
|
<a name="lib"><tt>llvm/lib</tt></a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<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 compact>
|
|
<dt><tt>llvm/lib/VMCore/</tt><dd> This directory holds the core LLVM
|
|
source files that implement core classes like Instruction and BasicBlock.
|
|
|
|
<dt><tt>llvm/lib/AsmParser/</tt><dd> This directory holds the source code
|
|
for the LLVM assembly language parser library.
|
|
|
|
<dt><tt>llvm/lib/ByteCode/</tt><dd> This directory holds code for reading
|
|
and write LLVM bytecode.
|
|
|
|
<dt><tt>llvm/lib/CWriter/</tt><dd> This directory implements the LLVM to C
|
|
converter.
|
|
|
|
<dt><tt>llvm/lib/Analysis/</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...
|
|
|
|
<dt><tt>llvm/lib/Transforms/</tt><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...
|
|
|
|
<dt><tt>llvm/lib/Target/</tt><dd> This directory contains files that
|
|
describe various target architectures for code generation. For example,
|
|
the llvm/lib/Target/Sparc directory holds the Sparc machine
|
|
description.<br>
|
|
|
|
<dt><tt>llvm/lib/CodeGen/</tt><dd> This directory contains the major parts
|
|
of the code generator: Instruction Selector, Instruction Scheduling, and
|
|
Register Allocation.
|
|
|
|
<dt><tt>llvm/lib/Support/</tt><dd> This directory contains the source code
|
|
that corresponds to the header files located in
|
|
<tt>llvm/include/Support/</tt>.
|
|
</dl>
|
|
|
|
</div>
|
|
|
|
<!-- ======================================================================= -->
|
|
<div class="doc_subsection">
|
|
<a name="runtime"><tt>llvm/runtime</tt></a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<p>This directory contains libraries which are compiled into LLVM bytecode 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>
|
|
|
|
<!-- ======================================================================= -->
|
|
<div class="doc_subsection">
|
|
<a name="test"><tt>llvm/test</tt></a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<p>This directory contains regression tests and source code that is used to test
|
|
the LLVM infrastructure.</p>
|
|
|
|
</div>
|
|
|
|
<!-- ======================================================================= -->
|
|
<div class="doc_subsection">
|
|
<a name="tools"><tt>llvm/tools</tt></a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<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.</p>
|
|
|
|
<dl compact>
|
|
<dt>
|
|
|
|
<dt><tt><b>analyze</b></tt><dd> <tt>analyze</tt> is used to run a specific
|
|
analysis on an input LLVM bytecode file and print out the results. It is
|
|
primarily useful for debugging analyses, or familiarizing yourself with
|
|
what an analysis does.<p>
|
|
|
|
<dt><tt><b>bugpoint</b></tt><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>.<p>
|
|
|
|
<dt><tt><b>llvm-ar</b></tt><dd>The archiver produces an archive containing
|
|
the given LLVM bytecode files, optionally with an index for faster
|
|
lookup.<p>
|
|
|
|
<dt><tt><b>llvm-as</b></tt><dd>The assembler transforms the human readable
|
|
LLVM assembly to LLVM bytecode.<p>
|
|
|
|
<dt><tt><b>llvm-dis</b></tt><dd>The disassembler transforms the LLVM
|
|
bytecode to human readable LLVM assembly. Additionally, it can convert
|
|
LLVM bytecode to C, which is enabled with the <tt>-c</tt> option.<p>
|
|
|
|
<dt><tt><b>llvm-link</b></tt><dd> <tt>llvm-link</tt>, not surprisingly,
|
|
links multiple LLVM modules into a single program.<p>
|
|
|
|
<dt><tt><b>lli</b></tt><dd> <tt>lli</tt> is the LLVM interpreter, which
|
|
can directly execute LLVM bytecode (although very slowly...). In addition
|
|
to a simple interpreter, <tt>lli</tt> also has a tracing mode (entered by
|
|
specifying <tt>-trace</tt> on the command line). Finally, for
|
|
architectures that support it (currently only x86 and Sparc), 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.<p>
|
|
|
|
<dt><tt><b>llc</b></tt><dd> <tt>llc</tt> is the LLVM backend compiler,
|
|
which translates LLVM bytecode to a SPARC or x86 assembly file.<p>
|
|
|
|
<dt><tt><b>llvmgcc</b></tt><dd> <tt>llvmgcc</tt> is a GCC-based C frontend
|
|
that has been retargeted to emit LLVM code as the 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. The source code for the
|
|
<tt>llvmgcc</tt> tool is currently not included in the LLVM CVS tree
|
|
because it is quite large and not very interesting.<p>
|
|
|
|
<ol>
|
|
<dt><tt><b>gccas</b></tt><dd> This tool is invoked by the
|
|
<tt>llvmgcc</tt> frontend as the "assembler" part of the compiler. This
|
|
tool actually assembles LLVM assembly to LLVM bytecode,
|
|
performs a variety of optimizations, and outputs LLVM bytecode. Thus
|
|
when you invoke <tt>llvmgcc -c x.c -o x.o</tt>, you are causing
|
|
<tt>gccas</tt> to be run, which writes the <tt>x.o</tt> file (which is
|
|
an LLVM bytecode file that can be disassembled or manipulated just like
|
|
any other bytecode file). The command line interface to <tt>gccas</tt>
|
|
is designed to be as close as possible to the <b>system</b>
|
|
`<tt>as</tt>' utility so that the gcc frontend itself did not have to be
|
|
modified to interface to a "weird" assembler.<p>
|
|
|
|
<dt><tt><b>gccld</b></tt><dd> <tt>gccld</tt> links together several LLVM
|
|
bytecode files into one bytecode file and does some optimization. It is
|
|
the linker invoked by the GCC frontend when multiple .o files need to be
|
|
linked together. Like <tt>gccas</tt>, the command line interface of
|
|
<tt>gccld</tt> is designed to match the system linker, to aid
|
|
interfacing with the GCC frontend.<p>
|
|
</ol>
|
|
|
|
<dt><tt><b>opt</b></tt><dd> <tt>opt</tt> reads LLVM bytecode, applies a
|
|
series of LLVM to LLVM transformations (which are specified on the command
|
|
line), and then outputs the resultant bytecode. The '<tt>opt --help</tt>'
|
|
command is a good way to get a list of the program transformations
|
|
available in LLVM.<p>
|
|
|
|
</dl>
|
|
|
|
</div>
|
|
|
|
<!-- ======================================================================= -->
|
|
<div class="doc_subsection">
|
|
<a name="utils"><tt>llvm/utils</tt></a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<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 compact>
|
|
<td><tt><b>Burg/</b></tt><dd> <tt>Burg</tt> is an instruction selector
|
|
generator -- it builds trees on which it then performs pattern-matching to
|
|
select instructions according to the patterns the user has specified. Burg
|
|
is currently used in the Sparc V9 backend.<p>
|
|
|
|
<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>.<p>
|
|
|
|
<dt><tt><b>cvsupdate</b></tt><dd> <tt>cvsupdate</tt> is a script that will
|
|
update your CVS tree, but produce a much cleaner and more organized output
|
|
than simply running <tt>`cvs -z3 up -dP'</tt> will. For example, it will group
|
|
together all the new and updated files and modified files in separate
|
|
sections, so you can see at a glance what has changed. If you are at the
|
|
top of your LLVM CVS tree, running <tt>utils/cvsupdate</tt> is the
|
|
preferred way of updating the tree.<p>
|
|
|
|
<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.<p>
|
|
|
|
<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.<p>
|
|
|
|
<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.<p>
|
|
|
|
<dt><tt><b>NightlyTest.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.cs.uiuc.edu/">LLVM homepage</a>.<p>
|
|
|
|
<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.<p>
|
|
|
|
<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.<p>
|
|
|
|
</dl>
|
|
|
|
</div>
|
|
|
|
<!-- *********************************************************************** -->
|
|
<div class="doc_section">
|
|
<a name="tutorial">An Example Using the LLVM Tool Chain</a>
|
|
</div>
|
|
<!-- *********************************************************************** -->
|
|
|
|
<div class="doc_text">
|
|
|
|
<ol>
|
|
<li>First, create a simple C file, name it 'hello.c':
|
|
<pre>
|
|
#include <stdio.h>
|
|
int main() {
|
|
printf("hello world\n");
|
|
return 0;
|
|
}
|
|
</pre></li>
|
|
|
|
<li><p>Next, compile the C file into a LLVM bytecode file:</p>
|
|
<p><tt>% llvmgcc hello.c -o hello</tt></p>
|
|
|
|
<p>This will create two result files: <tt>hello</tt> and
|
|
<tt>hello.bc</tt>. The <tt>hello.bc</tt> is the LLVM bytecode that
|
|
corresponds the the compiled program and the library facilities that it
|
|
required. <tt>hello</tt> is a simple shell script that runs the bytecode
|
|
file with <tt>lli</tt>, making the result directly executable.</p></li>
|
|
|
|
<li><p>Run the program. To make sure the program ran, execute one of the
|
|
following commands:</p>
|
|
|
|
<p><tt>% ./hello</tt></p>
|
|
|
|
<p>or</p>
|
|
|
|
<p><tt>% lli hello.bc</tt></p></li>
|
|
|
|
<li><p>Use the <tt>llvm-dis</tt> utility to take a look at the LLVM assembly
|
|
code:</p>
|
|
|
|
<p><tt>% llvm-dis < hello.bc | less</tt><p></li>
|
|
|
|
<li><p>Compile the program to native Sparc assembly using the code
|
|
generator (assuming you are currently on a Sparc system):</p>
|
|
|
|
<p><tt>% llc hello.bc -o hello.s</tt></p>
|
|
|
|
<li><p>Assemble the native sparc assemble file into a program:</p>
|
|
|
|
<p><tt>% /opt/SUNWspro/bin/cc -xarch=v9 hello.s -o hello.sparc</tt></p>
|
|
|
|
<li><p>Execute the native sparc program:</p>
|
|
|
|
<p><tt>% ./hello.sparc</tt></p></li>
|
|
|
|
</ol>
|
|
|
|
</div>
|
|
|
|
<!-- *********************************************************************** -->
|
|
<div class="doc_section">
|
|
<a name="problems">Common Problems</a>
|
|
</div>
|
|
<!-- *********************************************************************** -->
|
|
|
|
<div class="doc_text">
|
|
|
|
<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>
|
|
|
|
<!-- *********************************************************************** -->
|
|
<div class="doc_section">
|
|
<a name="links">Links</a>
|
|
</div>
|
|
<!-- *********************************************************************** -->
|
|
|
|
<div class="doc_text">
|
|
|
|
<p>This document is just an <b>introduction</b> to 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.cs.uiuc.edu/">LLVM homepage</a></li>
|
|
<li><a href="http://llvm.cs.uiuc.edu/doxygen/">LLVM doxygen tree</a></li>
|
|
<li><a href="http://llvm.cs.uiuc.edu/docs/Projects.html">Starting a Project
|
|
that Uses LLVM</a></li>
|
|
</ul>
|
|
|
|
</div>
|
|
|
|
<!-- *********************************************************************** -->
|
|
|
|
<hr>
|
|
<div class="doc_footer">
|
|
<address><a href="mailto:sabre@nondot.org">Chris Lattner</a></address>
|
|
<a href="http://llvm.cs.uiuc.edu">The LLVM Compiler Infrastructure</a>
|
|
<br>
|
|
Last modified: $Date$
|
|
</div>
|
|
|
|
</body>
|
|
</html>
|