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	Also, have tools output -help-hidden rather than refer to --help-hidden, for consistency, and likewise adjust documentation. This doesn't change every mention of --help, only those which seemed clearly safe. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96578 91177308-0d34-0410-b5e6-96231b3b80d8
		
			
				
	
	
		
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			65 KiB
		
	
	
	
		
			HTML
		
	
	
	
	
	
			
		
		
	
	
			1680 lines
		
	
	
		
			65 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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  <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
 | 
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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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 | 
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<div class="doc_title">
 | 
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  Getting Started with the LLVM System  
 | 
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</div>
 | 
						|
 | 
						|
<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>
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						|
      <li><a href="#software">Software</a></li>
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						|
      <li><a href="#brokengcc">Broken versions of GCC and other tools</a></li>
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						|
    </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="#installcf">Install the GCC Front End</a></li>
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						|
      <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>
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						|
      <li><a href="#objfiles">The Location of LLVM Object Files</a></li>
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						|
      <li><a href="#optionalconfig">Optional Configuration Items</a></li>
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    </ol></li>
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						|
 | 
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  <li><a href="#layout">Program layout</a>
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    <ol>
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      <li><a href="#examples"><tt>llvm/examples</tt></a></li>
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      <li><a href="#include"><tt>llvm/include</tt></a></li>
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      <li><a href="#lib"><tt>llvm/lib</tt></a></li>
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      <li><a href="#projects"><tt>llvm/projects</tt></a></li>
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      <li><a href="#runtime"><tt>llvm/runtime</tt></a></li>
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      <li><a href="#test"><tt>llvm/test</tt></a></li>
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						|
      <li><a href="#llvmtest"><tt>llvm-test</tt></a></li>
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						|
      <li><a href="#tools"><tt>llvm/tools</tt></a></li>
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      <li><a href="#utils"><tt>llvm/utils</tt></a></li>
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						|
      <li><a href="#win32"><tt>llvm/win32</tt></a></li>
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    </ol></li>
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						|
 | 
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  <li><a href="#tutorial">An Example Using the LLVM Tool Chain</a>
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      <ol>
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         <li><a href="#tutorial4">Example with llvm-gcc4</a></li>
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      </ol>
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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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<div class="doc_author">
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  <p>Written by: 
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    <a href="mailto:criswell@uiuc.edu">John Criswell</a>, 
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    <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>.
 | 
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  </p>
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</div>
 | 
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 | 
						|
 | 
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<!-- *********************************************************************** -->
 | 
						|
<div class="doc_section">
 | 
						|
  <a name="overview"><b>Overview</b></a>
 | 
						|
</div>
 | 
						|
<!-- *********************************************************************** -->
 | 
						|
 | 
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<div class="doc_text">
 | 
						|
 | 
						|
<p>Welcome to LLVM! In order to get started, you first need to know some
 | 
						|
basic information.</p>
 | 
						|
 | 
						|
<p>First, LLVM comes in two 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 a test suite 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>
 | 
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There is a third, optional piece called llvm-test.  It is a suite of programs
 | 
						|
with a testing harness that can be used to further test LLVM's functionality
 | 
						|
and performance.
 | 
						|
</p>
 | 
						|
 | 
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</div>
 | 
						|
 | 
						|
<!-- *********************************************************************** -->
 | 
						|
<div class="doc_section">
 | 
						|
  <a name="quickstart"><b>Getting Started Quickly (A Summary)</b></a>
 | 
						|
</div>
 | 
						|
<!-- *********************************************************************** -->
 | 
						|
 | 
						|
<div class="doc_text">
 | 
						|
 | 
						|
<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):</li>
 | 
						|
    <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>
 | 
						|
    </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 the testsuite 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
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						|
         # 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>
 | 
						|
 | 
						|
<!-- *********************************************************************** -->
 | 
						|
<div class="doc_section">
 | 
						|
  <a name="requirements"><b>Requirements</b></a>
 | 
						|
</div>
 | 
						|
<!-- *********************************************************************** -->
 | 
						|
 | 
						|
<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>
 | 
						|
 | 
						|
</div>
 | 
						|
 | 
						|
<!-- ======================================================================= -->
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<div class="doc_subsection">
 | 
						|
  <a name="hardware"><b>Hardware</b></a>
 | 
						|
</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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 | 
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<table cellpadding="3" summary="Known LLVM platforms">
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<tr>
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  <th>OS</th>
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						|
  <th>Arch</th>
 | 
						|
  <th>Compilers</th>
 | 
						|
</tr>
 | 
						|
<tr>
 | 
						|
  <td>AuroraUX</td>
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						|
  <td>x86<sup><a href="#pf_1">1</a></sup></td>
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						|
  <td>GCC</td>
 | 
						|
</tr>
 | 
						|
<tr>
 | 
						|
  <td>Linux</td>
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						|
  <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>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>,
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						|
     <a href="#pf_8">8</a>, <a href="#pf_10">10</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>
 | 
						|
</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">In general, LLVM modules requiring dynamic linking can
 | 
						|
    not be built on Windows. However, you can build LLVM tools using
 | 
						|
    <i>"make tools-only"</i>.</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>
 | 
						|
 | 
						|
<!-- ======================================================================= -->
 | 
						|
<div class="doc_subsection"><a name="software"><b>Software</b></a></div>
 | 
						|
<div class="doc_text">
 | 
						|
  <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>
 | 
						|
 | 
						|
    <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 (2.59), and consequently, GNU M4 (version 1.4 
 | 
						|
      or higher). You will also need automake (1.9.2). 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>
 | 
						|
 | 
						|
<!-- ======================================================================= -->
 | 
						|
<div class="doc_subsection">
 | 
						|
  <a name="brokengcc">Broken versions of GCC and other tools</a>
 | 
						|
</div>
 | 
						|
 | 
						|
<div class="doc_text">
 | 
						|
 | 
						|
<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>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 class="doc_section">
 | 
						|
  <a name="starting"><b>Getting Started with LLVM</b></a>
 | 
						|
</div>
 | 
						|
<!-- *********************************************************************** -->
 | 
						|
 | 
						|
<div class="doc_text">
 | 
						|
 | 
						|
<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>
 | 
						|
</div>
 | 
						|
 | 
						|
<!-- ======================================================================= -->
 | 
						|
<div class="doc_subsection">
 | 
						|
  <a name="terminology">Terminology and Notation</a>
 | 
						|
</div>
 | 
						|
 | 
						|
<div class="doc_text">
 | 
						|
 | 
						|
<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>
 | 
						|
 | 
						|
<!-- ======================================================================= -->
 | 
						|
<div class="doc_subsection">
 | 
						|
  <a name="environment">Setting Up Your Environment</a>
 | 
						|
</div>
 | 
						|
 | 
						|
<div class="doc_text">
 | 
						|
 | 
						|
<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>
 | 
						|
 | 
						|
<!-- ======================================================================= -->
 | 
						|
<div class="doc_subsection">
 | 
						|
  <a name="unpack">Unpacking the LLVM Archives</a>
 | 
						|
</div>
 | 
						|
 | 
						|
<div class="doc_text">
 | 
						|
 | 
						|
<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>
 | 
						|
 | 
						|
<!-- ======================================================================= -->
 | 
						|
<div class="doc_subsection">
 | 
						|
  <a name="checkout">Checkout LLVM from Subversion</a>
 | 
						|
</div>
 | 
						|
 | 
						|
<div class="doc_text">
 | 
						|
 | 
						|
<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 2.6: <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 llvm-test
 | 
						|
</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>
 | 
						|
 | 
						|
<!-- ======================================================================= -->
 | 
						|
<div class="doc_subsection">
 | 
						|
  <a name="installcf">Install the GCC Front End</a>
 | 
						|
</div>
 | 
						|
 | 
						|
<div class="doc_text">
 | 
						|
 | 
						|
<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 testsuite 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 llvm-test.  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 
 | 
						|
llvm-test 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>
 | 
						|
 | 
						|
<!-- ======================================================================= -->
 | 
						|
<div class="doc_subsection">
 | 
						|
  <a name="config">Local LLVM Configuration</a>
 | 
						|
</div>
 | 
						|
 | 
						|
<div class="doc_text">
 | 
						|
 | 
						|
  <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>
 | 
						|
 | 
						|
<!-- ======================================================================= -->
 | 
						|
<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>
 | 
						|
    <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>
 | 
						|
 | 
						|
<!-- ======================================================================= -->
 | 
						|
<div class="doc_subsection">
 | 
						|
  <a name="cross-compile">Cross-Compiling LLVM</a>
 | 
						|
</div>
 | 
						|
 | 
						|
<div class="doc_text">
 | 
						|
  <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>
 | 
						|
 | 
						|
<!-- ======================================================================= -->
 | 
						|
<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>
 | 
						|
 | 
						|
      <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
 | 
						|
  <dd>
 | 
						|
  <dl>
 | 
						|
    <dt>Tools
 | 
						|
    <dd><tt><i>OBJ_ROOT</i>/Debug/bin</tt>
 | 
						|
    <dt>Libraries
 | 
						|
    <dd><tt><i>OBJ_ROOT</i>/Debug/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>
 | 
						|
 | 
						|
<!-- ======================================================================= -->
 | 
						|
<div class="doc_subsection">
 | 
						|
  <a name="optionalconfig">Optional Configuration Items</a>
 | 
						|
</div>
 | 
						|
 | 
						|
<div class="doc_text">
 | 
						|
 | 
						|
<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>
 | 
						|
</p>
 | 
						|
 | 
						|
<div class="doc_code">
 | 
						|
<pre>
 | 
						|
$ sudo update-binfmts --install llvm /path/to/lli --magic 'BC'
 | 
						|
</pre>
 | 
						|
</div>
 | 
						|
 | 
						|
</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.org/doxygen/">http://llvm.org/doxygen/</a></tt>.
 | 
						|
The following is a brief introduction to code layout:</p>
 | 
						|
 | 
						|
</div>
 | 
						|
 | 
						|
<!-- ======================================================================= -->
 | 
						|
<div class="doc_subsection"><a name="examples"><tt>llvm/examples</tt></a></div>
 | 
						|
<div class="doc_text">
 | 
						|
  <p>This directory contains some simple examples of how to use the LLVM IR and
 | 
						|
  JIT.</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>
 | 
						|
 | 
						|
<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>
 | 
						|
 | 
						|
<!-- ======================================================================= -->
 | 
						|
<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>
 | 
						|
  <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/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/Support/</tt>.</dd>
 | 
						|
 | 
						|
  <dt><tt><b>llvm/lib/System/</b></tt></dt>
 | 
						|
  <dd>This directory contains the operating system abstraction layer that
 | 
						|
  shields LLVM from platform-specific coding.</dd>
 | 
						|
</dl>
 | 
						|
 | 
						|
</div>
 | 
						|
 | 
						|
<!-- ======================================================================= -->
 | 
						|
<div class="doc_subsection"><a name="projects"><tt>llvm/projects</tt></a></div>
 | 
						|
<div class="doc_text">
 | 
						|
  <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>
 | 
						|
 | 
						|
<!-- ======================================================================= -->
 | 
						|
<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 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>
 | 
						|
 | 
						|
<!-- ======================================================================= -->
 | 
						|
<div class="doc_subsection"><a name="test"><tt>llvm/test</tt></a></div>
 | 
						|
<div class="doc_text">
 | 
						|
  <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>
 | 
						|
 | 
						|
<!-- ======================================================================= -->
 | 
						|
<div class="doc_subsection"><a name="llvmtest"><tt>test-suite</tt></a></div>
 | 
						|
<div class="doc_text">
 | 
						|
  <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>
 | 
						|
 | 
						|
<!-- ======================================================================= -->
 | 
						|
<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.  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>llvmc</b></tt></dt>
 | 
						|
  <dd>The LLVM Compiler Driver. This program can
 | 
						|
  be configured to utilize both LLVM and non-LLVM compilation tools to enable
 | 
						|
  pre-processing, translation, optimization, assembly, and linking of programs
 | 
						|
  all from one command line. <tt>llvmc</tt> also takes care of processing the
 | 
						|
  dependent libraries found in bitcode. This reduces the need to get the
 | 
						|
  traditional <tt>-l<name></tt> options right on the command line. Please
 | 
						|
  note that this tool, while functional, is still experimental and not feature
 | 
						|
  complete.</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. 
 | 
						|
  This is the linker invoked by <tt>llvmc</tt>. It performsn 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>
 | 
						|
 | 
						|
<!-- ======================================================================= -->
 | 
						|
<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>
 | 
						|
  <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 class="doc_subsection"><a name="win32"><tt>llvm/win32</tt></a></div>
 | 
						|
<div class="doc_text">
 | 
						|
  <p>This directory contains build scripts and project files for use with 
 | 
						|
  Visual C++. This allows developers on Windows to build LLVM without the need
 | 
						|
  for Cygwin. The contents of this directory should be considered experimental
 | 
						|
  at this time.
 | 
						|
  </p>
 | 
						|
</div>
 | 
						|
<!-- *********************************************************************** -->
 | 
						|
<div class="doc_section">
 | 
						|
  <a name="tutorial">An Example Using the LLVM Tool Chain</a>
 | 
						|
</div>
 | 
						|
<!-- *********************************************************************** -->
 | 
						|
 | 
						|
<div class="doc_text">
 | 
						|
<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>
 | 
						|
</div>
 | 
						|
 | 
						|
<!-- ======================================================================= -->
 | 
						|
<div class="doc_subsection"><a name="tutorial4">Example with llvm-gcc4</a></div>
 | 
						|
 | 
						|
<div class="doc_text">
 | 
						|
 | 
						|
<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 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> 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>
 | 
						|
 | 
						|
<!-- *********************************************************************** -->
 | 
						|
 | 
						|
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  <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>
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  Last modified: $Date$
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