<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
- <title>Specification for LLVM system code</title>
+ <title>Getting Started with LLVM System</title>
</head>
- <body>
- <h1>Specification for LLVM system</h1>
- <h1><a name="index">Index</a></h1>
+ <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="#cvs">Checkout LLVM from CVS</a>
- <li><a href="#compilerun">Compile and Run</a>
+ <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><a href="#software">Software</a>
+ </ol>
+
+ <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="#d&d">Depend and Debug directories</a></li>
- <li><a href="#include">llvm/include</a>
- <li><a href="#lib">llvm/lib</a>
- <li><a href="#test">llvm/test</a>
- <li><a href="#tools">llvm/tools</a>
- </ol>
- <li> <a href="#tutorial"> simple example for using tools</li>
+ <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>
- <h2><a name="tools">Checkout LLVM from CVS</a></h2>
- <p>
- <dl>
- <dt>cvs root directory:<dd> /home/vadve/vadve/Research/DynOpt/CVSRepository<br>
- <dt>project name:<dd> llvm
+
+
+ <!--=====================================================================-->
+ <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 contains an assembler, disassembler,
+ bytecode analyzer, and bytecode optimizer. 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.
+
+ <!--=====================================================================-->
+ <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>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><tt>cd <i>where-you-want-llvm-to-live</i></tt>
+ <li><tt>cvs -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm login</tt>
+ <li>Hit the return key when prompted for the password.
+ <li><tt>cvs -z3 -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm co 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>
+
+ <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.
+
+ <!--=====================================================================-->
+ <center>
+ <h2><a name="requirements"><b>Requirements</b></a></h2>
+ </center>
+ <hr>
+ <!--=====================================================================-->
+
+ 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.
+
+ <!--=====================================================================-->
+ <h3><a name="hardware"><b>Hardware</b></a></h3>
+ <!--=====================================================================-->
+ 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>
+
+ 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
+ bytecode. Code generation should work as well, although the generated
+ native code may not work on your platform.
+ <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 always request
+ <a href="mailto:llvm-request@zion.cs.uiuc.edu">a copy of the source</a>
+ and try to compile it on your platform.
+ </p>
+
+ <!--=====================================================================-->
+ <h3><a name="software"><b>Software</b></a></h3>
+ <!--=====================================================================-->
+ <p>
+
+ Compiling LLVM requires that you have several software packages installed:
+
+ <ul compact>
+ <li>
+ <a href="http://gcc.gnu.org">GCC 3.x with C and C++ language support</a>
+
+ <li>
+ <a href="http://savannah.gnu.org/projects/make">GNU Make</a>
+
+ <li>
+ <a href="http://www.gnu.org/software/flex">Flex</a>
+
+ <li>
+ <a href="http://www.gnu.org/software/bison/bison.html">Bison</a>
+ </ul>
+
+ <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 (2.57 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>
+ These are needed to use the LLVM test suite.
+ </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.
+ A <a href="#starting">complete guide to installation</a> is provided in the
+ next 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="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>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>
-
- For those who are not familar with cvs, there are two steps you should do:<br>
+
+ <!------------------------------------------------------------------------->
+ <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 :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm login</tt>
+ <li>Hit the return key when prompted for the password.
+ <li><tt>cvs -z3 -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm co llvm</tt>
+ </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>
- set CVSROOT. Add the following line into the .cshrc file in your home directory if you are using tcsh or csh:<br>
- <i>setenv CVSROOT /home/vadve/vadve/Research/DynOpt/CVSRepository</i>
- </li>
- <li>
- check out. Go to the directory you want to store LLVM, type <br>
- <i>cvs checkout llvm</i>
- </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>
-
- note: the c front-end implementation is not in cvs. If you want to use it, you can use excutable in Chris Lattner's directory<br>
- <dd><i>/home/vadve/lattner/cvs/gcc_install/bin/gcc</i><br>
- a brief usage of this gcc and other tools are introduced later. To read it now, click <a href="#tutorial">here</a>.
-
- <h2><a name="compilerun">Compile and Run</a></h2>
- There is a makefile in each directory. You can simple type <i>gmake</i> in the <b>~/llvm</b> directory to compile all the files or you can type <i>gmake</i> in the certain directory to compile all files and subdirectories in that directory.<br>
- You might want to add the the following directory into your path:<br>
- <dd><i>llvm/tools/Debug</i><br>
- so you can run tools in any directory. If you are using csh or tcsh, add <br>
- <dd><i>setenv PATH llvm/tools/Debug:${PATH}</i><br>
- at the end of the file .cshrc in your home directory.
-
- </dl>
- <h2><a name="layout">Program Layout</a></h2>
- Many useful infomation can be obtained from the LLVM doxygen tree available at <a href="http://llvm.cs.uiuc.edu/doxygen/"><i>http://llvm.cs.uiuc.edu/doxygen/ </i><br></a>
- The following is a brief introduction to code layout:
-
- <h3><a name="d&d">Depend and Debug directories</a></h3>
- Most directories contain these two directories. The depend directory contains dependance files which will be used during complilation. The debug directory contains object files, library files or executables after compilation.
- <h3><a name="include">llvm/include</a></h3>
- This directory contains common head files supporting the LLVM library. Specific head files which are only used by certain directory are place in that directory instead of here.
- <h3><a name="lib">llvm/lib</a></h3>
- This directory contains most important files of LLVM system. <br>
- <dl compact>
-
- <dt>llvm/lib/transforms/<dd> This directory contains files and directories for transforming one representation to another representation.
- <dt>llvm/lib/Target/<dd> This directory contains files and directories for target machine. The files under llvm/lib/Target describe the common property for any target machine. The directory llvm/lib/Target/Sparc describe the sparc machine specification. <br>
-
- <dt>llvm/lib/Analysis/<dd> This directory contains files and directories for doing all kinds of data and control analysis.
- <dt>llvm/lib/AsmParser/<dd> This directory contains files and directories for parsing the llvm assemly files.
- <dt>llvm/lib/ByteCode/<dd> This directory contains files and directories for reading and write LLVM bytecode.
- <dt>llvm/lib/CWrite/<dd> This directory contains files and directories for writing c files as output.
- <dt>llvm/lib/CodeGen/<dd> This directory contains files and directories for instruction selection, instruction scheduling and register allocation.
- <dt>llvm/lib/Reoptimizer<dd> This directory contains files and directories for all kinds of optimizations, e.g. dead code elimination, Loop Invariant Code Motion, etc.
+
+ <!------------------------------------------------------------------------->
+ <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>
+
+ <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>
+
+ <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 default (debugging symbols are removed
+ and GCC optimization flags are enabled). The default is to use an
+ unoptimized build (also known as a debug build).
+ <p>
+ <dt><i>--enable-jit</i>
+ <dd>
+ Compile the Just In Time (JIT) functionality. This is not available
+ on all platforms. The default is dependent on platform, so it is best
+ to explicitly enable it if you want it.
+ <p>
+ <dt><i>--enable-spec2000</i>
+ <dt><i>--enable-spec2000=<<tt>directory</tt>></i>
+ <dd>
+ Enable the use of SPEC2000 when testing LLVM. This is disabled by default
+ (unless <tt>configure</tt> finds SPEC2000 installed). By specifying
+ <tt>directory</tt>, you can tell configure where to find the SPEC2000
+ benchmarks. If <tt>directory</tt> is left unspecified, <tt>configure</tt>
+ uses the default value
+ <tt>/home/vadve/shared/benchmarks/speccpu2000/benchspec</tt>.
+ </dl>
+
+ <p>
+ To configure LLVM, follow these steps:
+ <ol>
+ <li>Change directory into the object root directory:
+ <br>
+ <tt>cd <i>OBJ_ROOT</i></tt>
+ <p>
+
+ <li>Run the <tt>configure</tt> script located in the LLVM source tree:
+ <br>
+ <tt><i>SRC_ROOT</i>/configure</tt>
+ <p>
+ </ol>
+ </p>
+
+ In addition to running <tt>configure</tt>, you must set the
+ <tt>LLVM_LIB_SEARCH_PATH</tt> environment variable in your startup scripts.
+ This environment variable is used to locate "system" libraries like
+ "<tt>-lc</tt>" and "<tt>-lm</tt>" when linking. This variable should be set
+ to the absolute path for the bytecode-libs subdirectory of the GCC front end
+ install, or <i>LLVMGCCDIR</i>/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>
+
+ <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="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>
+ <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>
+
+ <!------------------------------------------------------------------------->
+ <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
+ Invariant Code Motion, Dead Global Elimination, and many others...
+
+ <dt><tt>llvm/lib/Target/</tt><dd> This directory contains files that
+ describe various target architectures for code generation. For example,
+ the llvm/lib/Target/Sparc directory holds the Sparc machine
+ description.<br>
- <dt>llvm/lib/Support/<dd> This directory contains some files and directories supporting the library, e.g. commandline processor and statistic reporter.
- <dt>llvm/lib/VMCore/<dd> This directory contains files and directories for implementing the virtual machine instruction set.
- </dl>
- <h3><a name="test">llvm/test</a></h3>
- This directory contains llvm assembly and other files to test the llvm library.
-
- <h3><a name="tools">llvm/tools</a></h3>
- <p> The <b>tools</b> directory contains many tools. You can always get help by typing <i>command_name --help </i>. The following is a brief introduction to each tool.
+ <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><i>analyze</i><dd> ???
- <dt><i>as</i><dd>llvm .ll -> .bc assembler
- <br>The assembler transfroms the human readable assembly to llvm bytecode.
- <dt><i>dis</i><dd>llvm .bc -> .ll disassembler
- <br>The disassembler transfroms the llvm bytecode to human readable assembly.
- <dt><i>extract</i><dd> ???
- <dt><i>gccas</i><dd>llvm .ll -> .bc assembler
- <br>The assembler transfroms the human readable assembly to llvm bytecode.
- <dt><i>gccld</i><dd>many llvm bytecode -> llvm bytecode + optimizations
- <br> gccld links many llvm bytecode files into one bytecode file and does some optimization.
- <dt><i>link</i><dd>many llvm bytecode -> llvm bytecode
- <br> <i>link</i> takes many llvm bytecode files and link them into one llvm bytecode file.
- <dt><i>llc</i><dd>llvm bytecode -> SPARC assembly
- <br> <i>llc</i> takes a llvm bytecode file and output a SPARC assembly file.
- <dt><i>lli</i><dd>llvm interpreter
- <br><i>lli</i> reads a llvm bytecode file and execute it.
- <dt><i>opt</i><dd>llvm .bc -> .bc modular optimizer
- <br> <i>opt</i> reads llvm bytecode and do certain optimization, then output llvm bytecode .
- </dl>
-
- <h2><a name="tutorial">tutorial for using tools</h2>
- <ul>
- <li>create a simple c file:<br>
- <pre>
- hello.c
-
- int main() {
- printf("hello world\n");
- return 0;
- }
- </pre>
- </li>
- <li>compile the c file into a llvm bytecode file<br>
- <i>% alias llvmgcc /home/vadve/lattner/cvs/gcc_install/bin/gcc</i><br>
- <i>% llvmgcc hello.c </i><br>
- there will be two output files: <b>a.out</b> and <b>a.out.bc</b>. The file <b>a.out</b> is a shell script and <b>a.out.bc</b> is the llvm bytecode. You can run a.out to excute or directly call the interpreter: <br>
- % <i>lli a.out.bc</i><br>
- <li> dissembler and assembler <br>
- read llvm bytecode and output human readable llvm assembly<br>
- %<i>dis a.out.bc -o hello.ll</i><br>
- read human readable llvm assembly code and output llvm bytecode<br>
- %<i>as hello.ll -o hello.bc</i>
- </li>
- <li> compile to sparc assembly<br>
- <i>%llc hello.bc -o hello.s</i>
- </li>
- </ul>
- <h2><a name="links">Links</a></h2>
- <ul>
- <li><a href="http://llvm.cs.uiuc.edu/">LLVM homepage</a></li>
- <li><a href="http://tank.cs.uiuc.edu/doxygen/">LLVM doxygen tree</a></li>
- </ul>
- <hr>
- If you have any question, please send an email to <a href="mailto:lattner@uiuc.edu">Lattner Chris Arthur</a> or <a href="mailto:gshi1@uiuc.edu">Guochun Shi</a>. <p>
+ <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 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.
+
+ <dl compact>
+ <td><tt><b>Burg/</b></tt><dd> <tt>Burg</tt> is an instruction selector
+ generator -- it builds trees on which it then performs pattern-matching to
+ select instructions according to the patterns the user has specified. Burg
+ is currently used in the Sparc V9 backend.<p>
+
+ <dt><tt><b>codegen-diff</b></tt><dd> <tt>codegen-diff</tt> is a script
+ that finds differences between code that LLC generates and code that LLI
+ generates. This is a useful tool if you are debugging one of them,
+ assuming that the other generates correct output. For the full user
+ manual, run <tt>`perldoc codegen-diff'</tt>.<p>
+
+ <dt><tt><b>cvsupdate</b></tt><dd> <tt>cvsupdate</tt> is a script that will
+ update your CVS tree, but produce a much cleaner and more organized output
+ than simply running <tt>`cvs -z3 up -dP'</tt> will. For example, it will group
+ together all the new and updated files and modified files in separate
+ sections, so you can see at a glance what has changed. If you are at the
+ top of your LLVM CVS tree, running <tt>utils/cvsupdate</tt> is the
+ preferred way of updating the tree.<p>
+
+ <dt><tt><b>emacs/</b></tt><dd> The <tt>emacs</tt> directory contains
+ syntax-highlighting files which will work with Emacs and XEmacs editors,
+ providing syntax highlighting support for LLVM assembly files and TableGen
+ description files. For information on how to use the syntax files, consult
+ the <tt>README</tt> file in that directory.<p>
+
+ <dt><tt><b>getsrcs.sh</b></tt><dd> The <tt>getsrcs.sh</tt> script finds
+ and outputs all non-generated source files, which is useful if one wishes
+ to do a lot of development across directories and does not want to
+ individually find each file. One way to use it is to run, for example:
+ <tt>xemacs `utils/getsources.sh`</tt> from the top of your LLVM source
+ tree.<p>
+
+ <dt><tt><b>makellvm</b></tt><dd> The <tt>makellvm</tt> script compiles all
+ files in the current directory and then compiles and links the tool that
+ is the first argument. For example, assuming you are in the directory
+ <tt>llvm/lib/Target/Sparc</tt>, if <tt>makellvm</tt> is in your path,
+ simply running <tt>makellvm llc</tt> will make a build of the current
+ directory, switch to directory <tt>llvm/tools/llc</tt> and build it,
+ causing a re-linking of LLC.<p>
+
+ <dt><tt><b>NightlyTest.pl</b></tt> and
+ <tt><b>NightlyTestTemplate.html</b></tt><dd> These files are used in a
+ cron script to generate nightly status reports of the functionality of
+ tools, and the results can be seen by following the appropriate link on
+ the <a href="http://llvm.cs.uiuc.edu/">LLVM homepage</a>.<p>
+
+ <dt><tt><b>TableGen/</b></tt><dd> The <tt>TableGen</tt> directory contains
+ the tool used to generate register descriptions, instruction set
+ descriptions, and even assemblers from common TableGen description
+ files.<p>
+
+ <dt><tt><b>vim/</b></tt><dd> The <tt>vim</tt> directory contains
+ syntax-highlighting files which will work with the VIM editor, providing
+ syntax highlighting support for LLVM assembly files and TableGen
+ description files. For information on how to use the syntax files, consult
+ the <tt>README</tt> file in that directory.<p>
+
+ </dl>
+
+ <!--=====================================================================-->
+ <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>
+
+ <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>
+ <!--=====================================================================-->
+
+ 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.
+
+ <!--=====================================================================-->
+ <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: Wed Jul 17 17:55:16 CDT 2002
+Last modified: Mon Aug 11 13:52:22 CDT 2003
<!-- hhmts end -->
</body>
</html>
projects / oota-llvm.git / blobdiff