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-<head>
- <title>Getting Started with LLVM System</title>
-</head>
- <body bgcolor="white">
-
-<center>
-<h1>Getting Started with the LLVM System<br>
-<font size="3">By: <a href="mailto:gshi1@uiuc.edu">Guochun Shi</a>, <a
- href="mailto:sabre@nondot.org">Chris Lattner</a> and <a
- href="http://www.cs.uiuc.edu/%7Evadve">Vikram Adve</a> </font></h1>
-</center>
- <!--=====================================================================-->
-
-<h2><a name="Contents">Contents</a></h2>
- <!--=====================================================================-->
-
-<ul>
- <li><a href="#overview">Overview</a> </li>
- <li><a href="#starting">Getting started with LLVM</a>
+ <head>
+ <title>Getting Started with LLVM System</title>
+ </head>
+
+ <body bgcolor=white>
+ <center><h1>Getting Started with the LLVM System<br><font size=3>By: <a
+ href="mailto:gshi1@uiuc.edu">Guochun Shi</a>,
+ <a href="mailto:sabre@nondot.org">Chris Lattner</a>,
+ <a href="mailto:criswell@uiuc.edu">John Criswell</a>,
+ <a href="http://misha.brukman.net">Misha Brukman</a>, and
+ <a href="http://www.cs.uiuc.edu/~vadve">Vikram Adve</a>
+ </font></h1></center>
+
+ <!--=====================================================================-->
+ <h2><a name="Contents">Contents</a></h2>
+ <!--=====================================================================-->
+
+ <ul>
+ <li><a href="#overview">Overview</a>
+ <ol>
+ <li><a href="#requirements">Requirements</a>
+ <ol>
+ <li><a href="#hardware">Hardware</a>
+ <li><a href="#software">Software</a>
+ </ol>
+ </ol>
+ <li><a href="#quickstart">Getting Started Quickly (A Summary)</a>
+ <li><a href="#starting">Getting Started with LLVM</a>
+ <ol>
+ <li><a href="#terminology">Terminology and Notation</tt></a>
+ <li><a href="#environment">Setting Up Your Environment</a>
+ <li><a href="#unpack">Unpacking the LLVM Archives</a>
+ <li><a href="#checkout">Checkout LLVM from CVS</a>
+ <li><a href="#installcf">Install the GCC Front End</a>
+ <li><a href="#config">Local LLVM Configuration</tt></a>
+ <li><a href="#compile">Compiling the LLVM Suite Source Code</a>
+ <li><a href="#objfiles">The Location of LLVM Object Files</tt></a>
+ </ol>
+ <li><a href="#layout">Program layout</a>
+ <ol>
+ <li><a href="#cvsdir"><tt>CVS</tt> directories</a>
+ <li><a href="#include"><tt>llvm/include</tt></a>
+ <li><a href="#lib"><tt>llvm/lib</tt></a>
+ <li><a href="#runtime"><tt>llvm/runtime</tt></a>
+ <li><a href="#test"><tt>llvm/test</tt></a>
+ <li><a href="#tools"><tt>llvm/tools</tt></a>
+ <li><a href="#utils"><tt>llvm/utils</tt></a>
+ </ol>
+ <li><a href="#tutorial">An Example Using the LLVM Tool Chain</a>
+ <li><a href="#problems">Common Problems</a>
+ <li><a href="#links">Links</a>
+ </ul>
+
+
+ <!--=====================================================================-->
+ <center>
+ <h2><a name="overview"><b>Overview</b></a></h2>
+ </center>
+ <hr>
+ <!--=====================================================================-->
+
+ Welcome to LLVM! In order to get started, you first need to know some
+ basic information.
+
+ <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 also contains a test suite that can be used
+ to test the LLVM tools and the GCC front end.
+ <p>
+ The second piece is the GCC front end. This component provides a version
+ of GCC that compiles C and C++ code into LLVM bytecode. Currently, the
+ GCC front end is a modified version of GCC 3.4 (we track the GCC 3.4
+ development). Once compiled into LLVM bytecode, a program can be
+ manipulated with the LLVM tools from the LLVM suite.
+
+ <!--=====================================================================-->
+ <h3><a name="requirements"><b>Requirements</b></a></h3>
+ <!--=====================================================================-->
+
+ Before you begin to use the LLVM system, review the requirements given
+ below. This may save you some trouble by knowing ahead of time what
+ hardware and software you will need.
+
+ <!--=====================================================================-->
+ <h4><a name="hardware"><b>Hardware</b></a></h4>
+ <!--=====================================================================-->
+ LLVM is known to work on the following platforms:
+ <ul>
+ <li> Linux on x86 (Pentium and above)
+ <ul>
+ <li> Approximately 760 MB of Free Disk Space
+ <ul>
+ <li>Source code: 30 MB
+ <li>Object code: 670 MB
+ <li>GCC front end: 60 MB
+ </ul>
+ </ul>
+
+ <p>
+
+ <li> Solaris on SparcV9 (Ultrasparc)
+ <ul>
+ <li> Approximately 1.24 GB of Free Disk Space
+ <ul>
+ <li>Source code: 30 MB
+ <li>Object code: 1000 MB
+ <li>GCC front end: 210 MB
+ </ul>
+ </ul>
+ </ul>
+
+ LLVM <i>may</i> compile on other platforms. The LLVM utilities should work
+ on other platforms, so it should be possible to generate and produce LLVM
+ bytecode on unsupported platforms (although bytecode generated on one
+ platform may not work on another platform). However, the code generators
+ and Just-In-Time (JIT) compilers only generate SparcV9 or x86 machine code.
+ </p>
+
+ <!--=====================================================================-->
+ <h4><a name="software"><b>Software</b></a></h4>
+ <!--=====================================================================-->
+ <p>
+
+ Unpacking the distribution requires the following tools:
+ <dl compact>
+ <dt>
+ <A href="http://www.gnu.org/software/gzip/gzip.html">GNU Zip (gzip)</A>
+ <dt><A href="http://www.gnu.org/software/tar/tar.html">GNU Tar</A>
+ <dd>
+ These tools are needed to uncompress and unarchive the software.
+ Regular Solaris <tt>tar</tt> may work for unpacking the TAR archive but
+ is untested.
+ </dl>
+
+ Compiling LLVM requires that you have several different software packages
+ installed:
+
+ <dl compact>
+ <dt> <A href="http://gcc.gnu.org">GCC</A>
+ <dd>
+ The GNU Compiler Collection must be installed with C and C++ language
+ support. GCC 3.2.x works, and GCC 3.x is generally supported.
+
+ <p>
+ Note that we currently do not support any other C++ compiler.
+ </p>
+
+ <dt> <A href="http://savannah.gnu.org/projects/make">GNU Make</A>
+ <dd>
+ The LLVM build system relies upon GNU Make extensions. Therefore, you
+ will need GNU Make (sometimes known as gmake) to build LLVM.
+ <p>
+
+ <dt> <A href="http://www.gnu.org/software/flex">Flex</A>
+ and
+ <A href="http://www.gnu.org/software/bison/bison.html">Bison</A>
+ <dd>
+ The LLVM source code is built using flex and bison. You will not be
+ able to configure and compile LLVM without them.
+ <p>
+
+ <dt> <A href="http://savannah.gnu.org/projects/m4">GNU M4</A>
+ <dd>
+ If you are installing Bison on your machine for the first time, you
+ will need GNU M4 (version 1.4 or higher).
+ </dl>
+
+ <p>
+ There are some additional tools that you may want to have when working with
+ LLVM:
+ </p>
+
+ <ul>
+ <li><A href="http://www.gnu.org/software/autoconf">GNU Autoconf</A>
+ <li><A href="http://savannah.gnu.org/projects/m4">GNU M4</A>
+ <p>
+ If you want to make changes to the configure scripts, you will need
+ GNU autoconf (2.53 or higher), and consequently, GNU M4 (version 1.4
+ or higher).
+ </p>
+
+ <li><A href="http://www.codesourcery.com/qm/qmtest">QMTest</A>
+ <li><A href="http://www.python.org">Python</A>
+ <p>
+ In order to run the tests in the LLVM test suite, you will need QMTest and
+ a version of the Python interpreter that works with QMTest.
+ </ul>
+
+
+ <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.
+ The <a href"#quickstart">next section</a> gives a short summary for those
+ who are already familiar with the system and want to get started as quickly
+ as possible. A <a href="#starting">complete guide to installation</a> is
+ provided in the subsequent section.
+
+ <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.
+
+ <!--=====================================================================-->
+ <center>
+ <h2><a name="quickstart"><b>Getting Started Quickly (A Summary)</b></a></h2>
+ </center>
+ <hr>
+ <!--=====================================================================-->
+
+ Here's the short story for getting up and running quickly with LLVM:
<ol>
- <li><a href="#quickstart">Getting started quickly (a summary)</a>
- </li>
- <li><a href="#checkout">Checkout LLVM from CVS</a> </li>
- <li><a href="#terminology">Terminology and Notation</a> </li>
- <li><a href="#objfiles">The location for object files</a> </li>
- <li><a href="#config">Local Configuration Options</a> </li>
- <li><a href="#environment">Setting up your environment</a>
- </li>
- <li><a href="#compile">Compiling the source code</a> </li>
+ <li>Install the GCC front end:
+ <ol>
+ <li><tt>cd <i>where-you-want-the-C-front-end-to-live</i></tt>
+ <li><tt>gunzip --stdout cfrontend.<i>platform</i>.tar.gz | tar -xvf
+ -</tt>
+ </ol>
+
+ <p>
+
+ <li>Get the Source Code
+ <ul>
+ <li>With the distributed files:
+ <ol>
+ <li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
+ <li><tt>gunzip --stdout llvm.tar.gz | tar -xvf -</tt>
+ <li><tt>cd llvm</tt>
+ </ol>
+
+ <p>
+
+ <li>With anonymous CVS access:
+ <ol>
+ <li>Find the path to the CVS repository containing LLVM (we'll
+ call this <i>CVSROOTDIR</i>).
+ <li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
+ <li><tt>cvs -d <i>CVSROOTDIR</i> checkout llvm</tt>
+ <li><tt>cd llvm</tt>
+ </ol>
+ </ul>
+ </ul>
+
+ <p>
+
+ <li>Configure the LLVM Build Environment
+ <ol>
+ <li>Change directory to where you want to store the LLVM object
+ files and run <tt>configure</tt> to configure the Makefiles and
+ header files for the default platform.
+ Useful options include:
+ <ul>
+ <li><tt>--with-llvmgccdir=<i>directory</i></tt>
+ <br>
+ Specify where the LLVM GCC frontend is installed.
+ <p>
+
+ <li><tt>--enable-spec2000=<i>directory</i></tt>
+ <br>
+ Enable the SPEC2000 benchmarks for testing. The SPEC2000
+ benchmarks should be available in <tt><i>directory</i></tt>.
+ </ul>
+ </ol>
+
+ <p>
+
+ <li>Build the LLVM Suite
+ <ol>
+ <li>Set your LLVM_LIB_SEARCH_PATH environment variable.
+ <li><tt>gmake -k |& tee gnumake.out
+ # this is csh or tcsh syntax</tt>
+ </ol>
+
+ <p>
+
</ol>
- </li>
- <li><a href="#layout">Program layout</a>
+
+ <p>See <a href="#environment">Setting Up Your Environment</a> on tips to
+ simplify working with the LLVM front-end and compiled tools. See the
+ next section for other useful details in working with LLVM,
+ or go straight to <a href="#layout">Program Layout</a> to learn about the
+ layout of the source code tree.
+
+ <!--=====================================================================-->
+ <center>
+ <h2><a name="starting"><b>Getting Started with LLVM</b></a></h2>
+ </center>
+ <hr>
+ <!--=====================================================================-->
+
+ <!------------------------------------------------------------------------->
+ <h3><a name="terminology">Terminology and Notation</a></h3>
+ <!------------------------------------------------------------------------->
+
+ <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 compact>
+ <dt>CVSROOTDIR
+ <dd>
+ This is the path for the CVS repository containing the LLVM source
+ code. Ask the person responsible for your local LLVM installation to
+ give you this path.
+ <p>
+
+ <dt>SRC_ROOT
+ <dd>
+ This is the top level directory of the LLVM source tree.
+ <p>
+
+ <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).
+ <p>
+
+ <dt>LLVMGCCDIR
+ <dd>
+ This is the where the LLVM GCC Front End is installed.
+ <p>
+ For the pre-built GCC front end binaries, the LLVMGCCDIR is
+ <tt>cfrontend/<i>platform</i>/llvm-gcc</tt>.
+ </dl>
+
+ <!------------------------------------------------------------------------->
+ <h3><a name="environment">Setting Up Your Environment</a></h3>
+ <!------------------------------------------------------------------------->
+
+ <p>
+ In order to compile and use LLVM, you will need to set some environment
+ variables. There are also some shell aliases which you may find useful.
+ You can set these on the command line, or better yet, set them in your
+ <tt>.cshrc</tt> or <tt>.profile</tt>.
+
+ <dl compact>
+ <dt><tt>LLVM_LIB_SEARCH_PATH</tt>=<tt><i>LLVMGCCDIR</i>/llvm-gcc/bytecode-libs</tt>
+ <dd>
+ This environment variable helps the LLVM GCC front end find bytecode
+ libraries that it will need for compilation.
+ <p>
+
+ <dt>alias llvmgcc <i>LLVMGCCDIR</i><tt>/llvm-gcc/bin/gcc</tt>
+ <dt>alias llvmg++ <i>LLVMGCCDIR</i><tt>/llvm-gcc/bin/g++</tt>
+ <dd>
+ This alias allows you to use the LLVM C and C++ front ends without putting
+ them in your <tt>PATH</tt> or typing in their complete pathnames.
+ </dl>
+
+ <!------------------------------------------------------------------------->
+ <h3><a name="unpack">Unpacking the LLVM Archives</a></h3>
+ <!------------------------------------------------------------------------->
+
+ <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 three files. Each
+ file is a TAR archive that is compressed with the gzip program.
+ </p>
+
+ <p> The three files are as follows:
+ <dl compact>
+ <dt>llvm.tar.gz
+ <dd>This is the source code to the LLVM suite.
+ <p>
+
+ <dt>cfrontend.sparc.tar.gz
+ <dd>This is the binary release of the GCC front end for Solaris/Sparc.
+ <p>
+
+ <dt>cfrontend.x86.tar.gz
+ <dd>This is the binary release of the GCC front end for Linux/x86.
+ </dl>
+
+ <!------------------------------------------------------------------------->
+ <h3><a name="checkout">Checkout LLVM from CVS</a></h3>
+ <!------------------------------------------------------------------------->
+
+ <p>If you have access to our CVS repository, you can get a fresh copy of
+ the entire source code. All you need to do is check it out from CVS as
+ follows:
+ <ul>
+ <li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
+ <li><tt>cvs -d <i>CVSROOTDIR</i> checkout llvm</tt></p>
+ </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>
+ Note that the GCC front end is not included in the CVS repository. You
+ should have downloaded the binary distribution for your platform.
+ </p>
+
+ <!------------------------------------------------------------------------->
+ <h3><a name="installcf">Install the GCC Front End</a></h3>
+ <!------------------------------------------------------------------------->
+
+ <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 location must be specified when the LLVM suite is configured.
+ </p>
+
+ <p>
+ To install the GCC front end, do the following:
<ol>
- <li><a href="#cvsdir">CVS directories</a> </li>
- <li><a href="#dd"><tt>Depend</tt>, <tt>Debug</tt>, &
- <tt>Release</tt> directories</a></li>
- <li><a href="#include"><tt>llvm/include</tt></a> </li>
- <li><a href="#lib"><tt>llvm/lib</tt></a> </li>
- <li><a href="#test"><tt>llvm/test</tt></a> </li>
- <li><a href="#tools"><tt>llvm/tools</tt></a> </li>
+ <li><tt>cd <i>where-you-want-the-front-end-to-live</i></tt>
+ <li><tt>gunzip --stdout cfrontend.<i>platform</i>.tar.gz | tar -xvf
+ -</tt>
</ol>
- </li>
- <li><a href="#tutorial">An example using the LLVM tool chain</a>
- </li>
- <li><a href="#links">Links</a> </li>
-</ul>
- <!--=====================================================================-->
-
-<center>
-<h2><a name="overview"><b>Overview</b></a></h2>
- </center>
- <!--=====================================================================-->
-
-<p>The <a href="" starting="">next section</a> of this guide is meant to
-get you up and running with LLVM, and to give you some basic information
-about the LLVM environment. The <a href="" #quickstart="">first subsection</a>
-gives a short summary for those who are already familiar with the system
-and want to get started as quickly as possible. </p>
-<p>The later sections of this guide describe the <a href="" #layout="">general
-layout</a> of 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. <!--=====================================================================-->
+
+ <!------------------------------------------------------------------------->
+ <h3><a name="config">Local LLVM Configuration</a></h3>
+ <!------------------------------------------------------------------------->
+
+ <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>
+ The following environment variables are used by the <tt>configure</tt>
+ script to configure the build system:
</p>
-<center>
-<h2><a name="starting"><b>Getting Started</b></a></h2>
- </center>
- <!--=====================================================================-->
- <!--=====================================================================-->
-
-<h3><a name="quickstart"><b>Getting Started Quickly (A Summary)</b></a></h3>
- <!--=====================================================================-->
- Here's the short story for getting up and running quickly with LLVM:
-
-<ol>
- <li>Find the path to the CVS repository containing LLVM (we'll call
-this <i>CVSROOTDIR</i>). </li>
- <li><tt>cd <i>where-you-want-llvm-to-live</i></tt> </li>
- <li><tt>cvs -d <i>CVSROOTDIR</i> checkout llvm</tt> </li>
- <li><tt>cd llvm</tt> </li>
- <li>Edit <tt>Makefile.config</tt> to set local paths. This includes
- setting the install location of the C frontend and the various paths
- to the C and C++ compilers used to build LLVM itself. </li>
- <li>Set your LLVM_LIB_SEARCH_PATH environment variable. </li>
- <li><tt>gmake -k |& tee gnumake.out # this is
-csh or tcsh syntax</tt> </li>
-</ol>
-
-<p>See <a href="#environment">Setting up your environment</a> on tips to
- simplify working with the LLVM front-end and compiled tools. See the
- other sub-sections below for other useful details in working with LLVM,
- or go straight to <a href="#layout">Program Layout</a> to learn about
-the layout of the source code tree. <!------------------------------------------------------------------------->
+
+ <table border=1>
+ <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>
-<h3><a name="terminology">Terminology and Notation</a></h3>
- <!------------------------------------------------------------------------->
-
-<p>Through 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>
-
-<ul>
-
-</ul>
- <!------------------------------------------------------------------------->
-
-<h3><a name="checkout">Checkout LLVM from CVS</a></h3>
- <!------------------------------------------------------------------------->
-
-<p>Before checking out the source code, you will need to know the path to
- the CVS repository containing LLVM source code (we'll call this <i>CVSROOTDIR</i>
-below). Ask the person responsible for your local LLVM installation
-to give you this path. </p>
-<p>To get a fresh copy of the entire source code, all you need to do
-is check it out from CVS as follows: </p>
-<ul>
- <li><tt>cd <i>where-you-want-llvm-to-live</i></tt> </li>
- <li><tt>cvs -d <i>CVSROOTDIR</i> checkout llvm</tt>
- <p></p>
- </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>
- <!------------------------------------------------------------------------->
-
-<h3><a name="config">Local Configuration Options</a></h3>
- <!------------------------------------------------------------------------->
-
-<p>The file <tt>llvm/Makefile.config</tt> defines the following path
-variables which are specific to a particular installation of LLVM.
- These should need to be modified only once after checking out a copy
- of LLVM (if the default values do not already match your system):
-</p>
-<ul>
-
- <p></p>
- <li><i>CXX</i> = Path to C++ compiler to use.
- <p></p>
- </li>
- <li><i>OBJ_ROOT</i> = Path to the llvm directory where object files
-should be placed. (See the Section on <a href="#objfiles"> The
-location for LLVM object files</a> for more information.)
- <p></p>
- </li>
- <li><i>LLVMGCCDIR</i> = Path to the location of the LLVM front-end
-binaries and associated libraries.
- <p></p>
- </li>
- <li><i>PURIFY</i> = Path to the purify program. </li>
-</ul>
- In addition to settings in this file, you must set a <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 C front-end install. For example,
- <tt>/home/vadve/lattner/local/x86/llvm-gcc/bytecode-libs</tt> is used
-for the X86 version of the C front-end on our research machines.
-<p> <!------------------------------------------------------------------------->
+
+ <dl compact>
+ <dt><i>--with-llvmgccdir=LLVMGCCDIR</i>
+ <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 defaulat (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:
+ <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>
-<h3><a name="objfiles">The location for LLVM object files</a></h3>
- <!------------------------------------------------------------------------->
-
-<p>The LLVM make system sends most output files generated during the build
- into the directory defined by the variable OBJ_ROOT in <tt>llvm/Makefile.config</tt>.
- This can be either just your normal LLVM source tree or some other directory
-writable by you. You may wish to put object files on a different filesystem
-either to keep them from being backed up or to speed up local builds.
- </p>
-<p>If you do not wish to use a different location for object files (i.e.
-building into the source tree directly), just set this variable to ".".</p>
-<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>/llvm-gcc/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>
+
+ <!------------------------------------------------------------------------->
+ <h3><a name="compile">Compiling the LLVM Suite Source Code</a></h3>
+ <!------------------------------------------------------------------------->
+
+ Once you have configured LLVM, you can build it. There are three types of
+ builds:
+
+ <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>
+
+ Once you have LLVM configured, you can build it by entering the
+ <i>OBJ_ROOT</i> directory and issuing the following command:
+ <p>
+ <tt>gmake</tt>
+
+ <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>
+ There are several special targets which are useful when working with the LLVM
+ source code:
+
+ <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>
+
+ It is also possible to override default values from <tt>configure</tt> by
+ declaring variables on the command line. The following are some examples:
+
+ <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>
+
+ 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.
+
+ <!------------------------------------------------------------------------->
+ <h3><a name="objfiles">The Location of LLVM Object Files</a></h3>
+ <!------------------------------------------------------------------------->
+
+ <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>
+ This is accomplished in the typical autoconf manner:
+ <ul>
+ <li>Change directory to where the LLVM object files should live:
+ <p>
+ <tt>cd <i>OBJ_ROOT</i></tt>
+
+ <li>Run the <tt>configure</tt> script found in the LLVM source directory:
+ <p>
+ <tt><i>SRC_ROOT</i>/configure</tt>
+ </ul>
+
+ <p>
+ The LLVM build will place files underneath <i>OBJ_ROOT</i> in directories
+ named after the build type:
</p>
-<h3><a name="environment">Setting up your environment</a></h3>
- <!------------------------------------------------------------------------->
- <i>NOTE: This step is optional but will set up your environment so you
- can use the compiled LLVM tools with as little hassle as possible.</i>)
-
-<p>Add the following lines to your <tt>.cshrc</tt> (or the corresponding
- lines to your <tt>.profile</tt> if you use a bourne shell derivative).
- </p>
-<pre> # Make the C front end easy to use...<br> alias llvmgcc <i>LLVMGCCDIR</i><tt>/bin/llvm-gcc</tt>
-
- # Make the LLVM tools easy to use...
- setenv PATH <i>OBJ_ROOT</i>/llvm/tools/Debug:${PATH}<br> </pre>
- The <tt>llvmgcc</tt> alias is useful because the C compiler is not
- included in the CVS tree you just checked out.
-<p>The other <a href="#tools">LLVM tools</a> are part of the LLVM source
-base and are built when compiling LLVM. They will be built into the
-<tt><i>OBJ_ROOT</i>/tools/Debug</tt> directory.</p>
- <!------------------------------------------------------------------------->
-
-<h3><a name="compile">Compiling the source code</a></h3>
- <!------------------------------------------------------------------------->
-
-<p>Every directory in the LLVM source tree includes a <tt>Makefile</tt> to
- build it and any subdirectories that it contains. These makefiles require
- GNU Make (<tt>gmake)</tt> instead of <tt>make</tt> to build them, but
-can otherwise be used freely. To build the entire LLVM system, just
-enter the top level <tt>llvm</tt> directory and type <tt>gmake</tt>.
- A few minutes later you will hopefully have a freshly compiled toolchain
-waiting for you in <tt><i>OBJ_ROOT</i></tt><tt>/llvm/tools/Debug</tt>.
- If you want to look at the libraries that were compiled, look in <tt><i>OBJ_ROOT</i></tt><tt>/llvm/lib/Debug</tt>.</p>
- If you get an error about the <tt>/localhome</tt> directory, chances
-are good that something has been misconfigured. Follow the instructions
-in the section about <a href="#environment">Setting Up Your Environment.</a>
- <!--=====================================================================-->
-
-<center>
-<h2><a name="layout"><b>Program Layout</b></a></h2>
- </center>
- <!--=====================================================================-->
-
-<p>One useful source of infomation about the LLVM sourcebase 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>
- <!------------------------------------------------------------------------->
-
-<h3><a name="cvsdir"><tt>CVS</tt> directories</a></h3>
- <!------------------------------------------------------------------------->
- Every directory checked out of CVS will contain a <tt>CVS</tt> directory;
- for the most part, these can just be ignored. <!------------------------------------------------------------------------->
-
-<h3><a name="ddr"><tt>Depend</tt>, <tt>Debug</tt>, & <tt>Release</tt>
- directories</a></h3>
- <!------------------------------------------------------------------------->
- If you are building with the "<tt>OBJ_ROOT=.</tt>" option enabled in
-the <tt>Makefile.config</tt> file, most source directories will contain
-two directories, <tt>Depend</tt> and <tt>Debug</tt>. The <tt>Depend</tt>
- directory contains automatically generated dependance files which are
-used during compilation to make sure that source files get rebuilt if
-a header file they use is modified. The <tt>Debug</tt> directory holds
-the object files, library files, and executables that are used for building
-a debug enabled build. The <tt>Release</tt> directory is created to
-hold the same files when the <tt>ENABLE_OPTIMIZED=1</tt> flag is passed
-to <tt>gmake</tt>, causing an optimized built to be performed.
-<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>
+
+ <!--=====================================================================-->
+ <center>
+ <h2><a name="layout"><b>Program Layout</b></a></h2>
+ </center>
+ <hr>
+ <!--=====================================================================-->
+
+ <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>
-<h3><a name="include"><tt>llvm/include</tt></a></h3>
- <!------------------------------------------------------------------------->
- This directory contains public header files exported from the LLVM
- library. The two main subdirectories of this directory are:
-<p> </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>Reoptimizer</tt>, <tt>Target</tt>, <tt>Transforms</tt>, etc...
- </li>
- <li><tt>llvm/include/Support</tt> - This directory contains generic
- support libraries that are independant of LLVM, but are used by LLVM.
- For example, some C++ STL utilities and a Command Line option processing
- library. </li>
-</ol>
- <!------------------------------------------------------------------------->
-
-<h3><a name="lib"><tt>llvm/lib</tt></a></h3>
- <!------------------------------------------------------------------------->
- This directory contains most source files of 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> </p>
-<dl compact="compact">
- <dt><tt>llvm/lib/VMCore/</tt></dt>
- <dd> This directory holds the core LLVM source files that implement
-core classes like Instruction and BasicBlock. </dd>
- <dt><tt>llvm/lib/AsmParser/</tt></dt>
- <dd> This directory holds the source code for the LLVM assembly language
-parser library. </dd>
- <dt><tt>llvm/lib/ByteCode/</tt></dt>
- <dd> This directory holds code for reading and write LLVM bytecode.
- </dd>
- <dt><tt>llvm/lib/CWriter/</tt></dt>
- <dd> This directory implements the LLVM to C converter. </dd>
- <dt><tt>llvm/lib/Analysis/</tt></dt>
- <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>llvm/lib/Transforms/</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 Invarient Code
-Motion, Dead Global Elimination, Pool Allocation, and many others...
- </dd>
- <dt><tt>llvm/lib/Target/</tt></dt>
- <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>
- </dd>
- <dt><tt>llvm/lib/CodeGen/</tt></dt>
- <dd> This directory contains the major parts of the code generator:
-Instruction Selector, Instruction Scheduling, and Register Allocation.
- </dd>
- <dt><tt>llvm/lib/Reoptimizer/</tt></dt>
- <dd> This directory holds code related to the runtime reoptimizer
-framework that is currently under development. </dd>
- <dt><tt>llvm/lib/Support/</tt></dt>
- <dd> This directory contains the source code that corresponds to
-the header files located in <tt>llvm/include/Support/</tt>. </dd>
-</dl>
- <!------------------------------------------------------------------------->
-
-<h3><a name="test"><tt>llvm/test</tt></a></h3>
- <!------------------------------------------------------------------------->
-
-<p>This directory contains regression tests and source code that is used
-to test the LLVM infrastructure...</p>
- <!------------------------------------------------------------------------->
-
-<h3><a name="tools"><tt>llvm/tools</tt></a></h3>
- <!------------------------------------------------------------------------->
-
-<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="compact">
- <dt><tt><b>as</b></tt></dt>
- <dd>The assembler transforms the human readable LLVM assembly to
-LLVM bytecode.
- <p> </p>
- </dd>
- <dt><tt><b>dis</b></tt></dt>
- <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> </p>
- </dd>
- <dt><tt><b>lli</b></tt></dt>
- <dd> <tt>lli</tt> is the LLVM interpreter, which can directly execute
-LLVM bytecode (although very slowly...). In addition to a simple intepreter,
- <tt>lli</tt> is also has debugger and tracing modes (entered by
-specifying <tt>-debug</tt> or <tt>-trace</tt> on the command line,
-respectively).
- <p> </p>
- </dd>
- <dt><tt><b>llc</b></tt></dt>
- <dd> <tt>llc</tt> is the LLVM backend compiler, which translates
-LLVM bytecode to a SPARC assembly file.
- <p> </p>
- </dd>
- <dt><tt><b>llvmgcc</b></tt></dt>
- <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> </p>
+
+ <!------------------------------------------------------------------------->
+ <h3><a name="cvsdir"><tt>CVS</tt> directories</a></h3>
+ <!------------------------------------------------------------------------->
+
+ Every directory checked out of CVS will contain a <tt>CVS</tt> directory;
+ for the most part these can just be ignored.
+
+
+ <!------------------------------------------------------------------------->
+ <h3><a name="include"><tt>llvm/include</tt></a></h3>
+ <!------------------------------------------------------------------------->
+
+ This directory contains public header files exported from the LLVM
+ library. The three main subdirectories of this directory are:<p>
+
<ol>
- <dt><tt><b>gccas</b></tt></dt>
- <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 "wierd" assembler.
- <p> </p>
- </dd>
- <dt><tt><b>gccld</b></tt></dt>
- <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> </p>
- </dd>
+ <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><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><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.
</ol>
- </dd>
- <dt><tt><b>opt</b></tt></dt>
- <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> </p>
- </dd>
- <dt><tt><b>analyze</b></tt></dt>
- <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> </p>
- </dd>
-</dl>
- <!--=====================================================================-->
-
-<h2><a name="tutorial">An example using the LLVM tool chain</a></h2>
- <a name="tutorial"> <!--=====================================================================-->
- </a>
-<ol>
- <a name="tutorial"> <li>First, create a simple C file, name it 'hello.c':
-
- <pre> #include <stdio.h><br> int main() {<br> printf("hello world\n");<br> return 0;<br> }<br> </pre>
- </li>
- <li>Next, compile the C file into a LLVM bytecode file:
- <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>
- <p> </p>
- </li>
- <li>Run the program. To make sure the program ran, execute one of the
- following commands:
- <p> <tt>% ./hello</tt></p>
- <p> or</p>
- <p> <tt>% lli hello.bc</tt></p>
- <p> </p>
- </li>
- <li>Use the <tt>dis</tt> utility to take a look at the LLVM assembly
- code:
- <p> <tt>% dis < hello.bc | less</tt></p>
- <p> </p>
- </li>
- <li>Compile the program to native Sparc assembly using the code generator:
- <p> <tt>% llc hello.bc -o hello.s</tt></p>
- <p> </p>
- </li>
- <li>Assemble the native sparc assemble file into a program:
- <p> <tt>% /opt/SUNWspro/bin/cc -xarch=v9 hello.s -o hello.sparc</tt></p>
- <p> </p>
- </li>
- <li>Execute the native sparc program:
- <p> <tt>% ./hello.sparc</tt></p>
- <p> </p>
- </li>
- </a>
-</ol>
- <a name="tutorial"> <!--=====================================================================-->
- </a>
-<h2><a name="links">Links</a></h2>
- <!--=====================================================================-->
-
-<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>
+
+ <!------------------------------------------------------------------------->
+ <h3><a name="lib"><tt>llvm/lib</tt></a></h3>
+ <!------------------------------------------------------------------------->
+
+ 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
+ Invarient 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>
+
+ <!------------------------------------------------------------------------->
+ <h3><a name="runtime"><tt>llvm/runtime</tt></a></h3>
+ <!------------------------------------------------------------------------->
+
+ <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>
+
+ <!------------------------------------------------------------------------->
+ <h3><a name="test"><tt>llvm/test</tt></a></h3>
+ <!------------------------------------------------------------------------->
+
+ <p>This directory contains regression tests and source code that is used to
+ test the LLVM infrastructure.
+ </p>
+
+ <!------------------------------------------------------------------------->
+ <h3><a name="tools"><tt>llvm/tools</tt></a></h3>
+ <!------------------------------------------------------------------------->
+
+ <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>
+
+ <!------------------------------------------------------------------------->
+ <h3><a name="utils"><tt>llvm/utils</tt></a></h3>
+ <!------------------------------------------------------------------------->
+
+ This directory contains utilities for working with LLVM sourcecode, and some
+ of the utilities are actually required as part of the build process because
+ they are code generators for parts of LLVM infrastructure.
+
+ <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 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>
-<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>
-
-</ul>
+ <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>
+
+ <!--=====================================================================-->
+ <h2>
+ <center><a name="tutorial">An Example Using the LLVM Tool Chain</center>
+ </h2>
+ <hr>
+ <!--=====================================================================-->
+
+ <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>Next, compile the C file into a LLVM bytecode file:<p>
+
+ <tt>% llvmgcc hello.c -o hello</tt><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>Run the program. To make sure the program ran, execute one of the
+ following commands:<p>
-<hr> If you have any questions or run into any snags (or you have any
- additions...), please send an email to <a
- href="mailto:sabre@nondot.org">Chris Lattner</a>.
-<p></p>
- <!-- Created: Mon Jul 1 02:29:02 CDT 2002 --> <!-- hhmts start -->
-Last modified: Tue Jun 3 22:06:43 CDT 2003 <!-- hhmts end --> <br>
-</body>
+ <tt>% ./hello</tt><p>
+
+ or<p>
+
+ <tt>% lli hello.bc</tt><p>
+
+ <li>Use the <tt>llvm-dis</tt> utility to take a look at the LLVM assembly
+ code:<p>
+
+ <tt>% llvm-dis < hello.bc | less</tt><p>
+
+ <li>Compile the program to native Sparc assembly using the code
+ generator (assuming you are currently on a Sparc system):<p>
+
+ <tt>% llc hello.bc -o hello.s</tt><p>
+
+ <li>Assemble the native sparc assemble file into a program:<p>
+
+ <tt>% /opt/SUNWspro/bin/cc -xarch=v9 hello.s -o hello.sparc</tt><p>
+
+ <li>Execute the native sparc program:<p>
+
+ <tt>% ./hello.sparc</tt><p>
+
+ </ol>
+
+
+ <!--=====================================================================-->
+ <h2>
+ <center><a name="problems">Common Problems</a></center>
+ </h2>
+ <hr>
+ <!--=====================================================================-->
+
+ Below are common problems and their remedies:
+
+ <dl compact>
+ <dt><b>When I run configure, it finds the wrong C compiler.</b>
+ <dd>
+ The <tt>configure</tt> script attempts to locate first <tt>gcc</tt> and
+ then <tt>cc</tt>, unless it finds compiler paths set in <tt>CC</tt> and
+ <tt>CXX</tt> for the C and C++ compiler, respectively.
+
+ If <tt>configure</tt> finds the wrong compiler, either adjust your
+ <tt>PATH</tt> environment variable or set <tt>CC</tt> and <tt>CXX</tt>
+ explicitly.
+ <p>
+
+ <dt><b>I compile the code, and I get some error about /localhome</b>.
+ <dd>
+ There are several possible causes for this. The first is that you
+ didn't set a pathname properly when using <tt>configure</tt>, and it
+ defaulted to a pathname that we use on our research machines.
+ <p>
+ Another possibility is that we hardcoded a path in our Makefiles. If
+ you see this, please email the LLVM bug mailing list with the name of
+ the offending Makefile and a description of what is wrong with it.
+
+ <dt><b>The <tt>configure</tt> script finds the right C compiler, but it
+ uses the LLVM linker from a previous build. What do I do?</b>
+ <dd>
+ The <tt>configure</tt> script uses the <tt>PATH</tt> to find
+ executables, so if it's grabbing the wrong linker/assembler/etc, there
+ are two ways to fix it:
+ <ol>
+ <li>Adjust your <tt>PATH</tt> environment variable so that the
+ correct program appears first in the <tt>PATH</tt>. This may work,
+ but may not be convenient when you want them <i>first</i> in your
+ path for other work.
+ <p>
+
+ <li>Run <tt>configure</tt> with an alternative <tt>PATH</tt> that
+ is correct. In a Borne compatible shell, the syntax would be:
+ <p>
+ <tt>PATH=<the path without the bad program> ./configure ...</tt>
+ <p>
+ This is still somewhat inconvenient, but it allows
+ <tt>configure</tt> to do its work without having to adjust your
+ <tt>PATH</tt> permanently.
+ </ol>
+
+ <dt><b>I've upgraded to a new version of LLVM, and I get strange build
+ errors.</b>
+ <dd>
+ Sometimes changes to the LLVM source code alters how the build system
+ works. Changes in libtool, autoconf, or header file dependencies are
+ especially prone to this sort of problem.
+ <p>
+ The best thing to try is to remove the old files and re-build. In most
+ cases, this takes care of the problem. To do this, just type <tt>make
+ clean</tt> and then <tt>make</tt> in the directory that fails to build.
+ <p>
+
+ </dl>
+
+ <!--=====================================================================-->
+ <h2><center><a name="links">Links</a></center></h2>
+ <hr>
+ <!--=====================================================================-->
+
+ <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>
+
+ <hr>
+
+ If you have any questions or run into any snags (or you have any
+ additions...), please send an email to
+ <a href="mailto:sabre@nondot.org">Chris Lattner</a>.</p>
+
+ <!-- Created: Mon Jul 1 02:29:02 CDT 2002 -->
+ <!-- hhmts start -->
+Last modified: Mon Aug 11 13:52:22 CDT 2003
+<!-- hhmts end -->
+ </body>
</html>
projects / oota-llvm.git / blobdiff