</head>
<body>
-<div class="doc_title">
+<h1>
Getting Started with the LLVM System
-</div>
+</h1>
<ul>
<li><a href="#overview">Overview</a>
<!-- *********************************************************************** -->
-<div class="doc_section">
- <a name="overview"><b>Overview</b></a>
-</div>
+<h2>
+ <a name="overview">Overview</a>
+</h2>
<!-- *********************************************************************** -->
-<div class="doc_text">
+<div>
<p>Welcome to LLVM! In order to get started, you first need to know some
basic information.</p>
</div>
<!-- *********************************************************************** -->
-<div class="doc_section">
- <a name="quickstart"><b>Getting Started Quickly (A Summary)</b></a>
-</div>
+<h2>
+ <a name="quickstart">Getting Started Quickly (A Summary)</a>
+</h2>
<!-- *********************************************************************** -->
-<div class="doc_text">
+<div>
<p>Here's the short story for getting up and running quickly with LLVM:</p>
<li>Read the documentation.</li>
<li>Remember that you were warned twice about reading the documentation.</li>
<li>Install the llvm-gcc-4.2 front end if you intend to compile C or C++
- (see <a href="#installcf">Install the GCC Front End</a> for details):</li>
+ (see <a href="#installcf">Install the GCC Front End</a> for details):
<ol>
<li><tt>cd <i>where-you-want-the-C-front-end-to-live</i></tt></li>
<li><tt>gunzip --stdout llvm-gcc-4.2-<i>version</i>-<i>platform</i>.tar.gz | tar -xvf -</tt></li>
</div>
<!-- *********************************************************************** -->
-<div class="doc_section">
- <a name="requirements"><b>Requirements</b></a>
-</div>
+<h2>
+ <a name="requirements">Requirements</a>
+</h2>
<!-- *********************************************************************** -->
-<div class="doc_text">
+<div>
<p>Before you begin to use the LLVM system, review the requirements given below.
This may save you some trouble by knowing ahead of time what hardware and
software you will need.</p>
-</div>
-
<!-- ======================================================================= -->
-<div class="doc_subsection">
- <a name="hardware"><b>Hardware</b></a>
-</div>
+<h3>
+ <a name="hardware">Hardware</a>
+</h3>
-<div class="doc_text">
+<div>
<p>LLVM is known to work on the following platforms:</p>
ActivePerl, as these have Windows-specifics that will cause the
build to fail.</a></li>
<li><a name="pf_11">To use LLVM modules on Win32-based system,
- you may configure LLVM with <i>"--enable-shared"</i>.</li>
+ you may configure LLVM with <i>"--enable-shared"</i>.</a></li>
<li><a name="pf_12">To compile SPU backend, you need to add
- <tt>"LDFLAGS=-Wl,--stack,16777216"</tt> to configure.</li>
+ <tt>"LDFLAGS=-Wl,--stack,16777216"</tt> to configure.</a></li>
</ol>
</div>
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection"><a name="software"><b>Software</b></a></div>
-<div class="doc_text">
+<h3>
+ <a name="software">Software</a>
+</h3>
+<div>
<p>Compiling LLVM requires that you have several software packages
installed. The table below lists those required packages. The Package column
is the usual name for the software package that LLVM depends on. The Version
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="brokengcc">Broken versions of GCC and other tools</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>LLVM is very demanding of the host C++ compiler, and as such tends to expose
bugs in the compiler. In particular, several versions of GCC crash when trying
-to compile LLVM. We routinely use GCC 3.3.3, 3.4.0, and Apple 4.0.1
-successfully with them (however, see important notes below). Other versions
-of GCC will probably work as well. GCC versions listed
+to compile LLVM. We routinely use GCC 4.2 (and higher) or Clang.
+Other versions of GCC will probably work as well. GCC versions listed
here are known to not work. If you are using one of these versions, please try
to upgrade your GCC to something more recent. If you run into a problem with a
version of GCC not listed here, please <a href="mailto:llvmdev@cs.uiuc.edu">let
</div>
-
+</div>
<!-- *********************************************************************** -->
-<div class="doc_section">
- <a name="starting"><b>Getting Started with LLVM</b></a>
-</div>
+<h2>
+ <a name="starting">Getting Started with LLVM</a>
+</h2>
<!-- *********************************************************************** -->
-<div class="doc_text">
+<div>
<p>The remainder of this guide is meant to get you up and running with
LLVM and to give you some basic information about the LLVM environment.</p>
href="#tutorial">simple example</a> using the LLVM tool chain, and <a
href="#links">links</a> to find more information about LLVM or to get
help via e-mail.</p>
-</div>
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="terminology">Terminology and Notation</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>Throughout this manual, the following names are used to denote paths
specific to the local system and working environment. <i>These are not
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="environment">Setting Up Your Environment</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>
In order to compile and use LLVM, you may need to set some environment
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="unpack">Unpacking the LLVM Archives</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>
If you have the LLVM distribution, you will need to unpack it before you
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="checkout">Checkout LLVM from Subversion</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>If you have access to our Subversion repository, you can get a fresh copy of
the entire source code. All you need to do is check it out from Subversion as
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="git_mirror">GIT mirror</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>GIT mirrors are available for a number of LLVM subprojects. These mirrors
sync automatically with each Subversion commit and contain all necessary
git-svn marks (so, you can recreate git-svn metadata locally). Note that right
now mirrors reflect only <tt>trunk</tt> for each project. You can do the
- read-only GIT clone of LLVM via:
-<pre>
-% git clone http://llvm.org/git/llvm.git
+ read-only GIT clone of LLVM via:</p>
+
+<pre class="doc_code">
+git clone http://llvm.org/git/llvm.git
+</pre>
+
+<p>If you want to check out clang too, run:</p>
+
+<pre class="doc_code">
+git clone http://llvm.org/git/llvm.git
+cd llvm/tools
+git clone http://llvm.org/git/clang.git
+</pre>
+
+<p>
+Since the upstream repository is in Subversion, you should use
+<tt>"git pull --rebase"</tt>
+instead of <tt>"git pull"</tt> to avoid generating a non-linear
+history in your clone.
+To configure <tt>"git pull"</tt> to pass <tt>--rebase</tt> by default
+on the master branch, run the following command:
+</p>
+
+<pre class="doc_code">
+git config branch.master.rebase true
+</pre>
+
+<h4>Sending patches with Git</h4>
+<div>
+<p>
+Please read <a href="DeveloperPolicy.html#patches">Developer Policy</a>, too.
+</p>
+
+<p>
+Assume <tt>master</tt> points the upstream and <tt>mybranch</tt> points your
+working branch, and <tt>mybranch</tt> is rebased onto <tt>master</tt>.
+At first you may check sanity of whitespaces:
+</p>
+
+<pre class="doc_code">
+git diff --check master..mybranch
+</pre>
+
+<p>
+The easiest way to generate a patch is as below:
+</p>
+
+<pre class="doc_code">
+git diff master..mybranch > /path/to/mybranch.diff
+</pre>
+
+<p>
+It is a little different from svn-generated diff. git-diff-generated diff has
+prefixes like <tt>a/</tt> and <tt>b/</tt>. Don't worry, most developers might
+know it could be accepted with <tt>patch -p1 -N</tt>.
+</p>
+
+<p>
+But you may generate patchset with git-format-patch. It generates
+by-each-commit patchset. To generate patch files to attach to your article:
+</p>
+
+<pre class="doc_code">
+git format-patch --no-attach master..mybranch -o /path/to/your/patchset
+</pre>
+
+<p>
+If you would like to send patches directly, you may use git-send-email or
+git-imap-send. Here is an example to generate the patchset in Gmail's [Drafts].
+</p>
+
+<pre class="doc_code">
+git format-patch --attach master..mybranch --stdout | git imap-send
</pre>
+
+<p>
+Then, your .git/config should have [imap] sections.
</p>
+<pre class="doc_code">
+[imap]
+ host = imaps://imap.gmail.com
+ user = <em>your.gmail.account</em>@gmail.com
+ pass = <em>himitsu!</em>
+ port = 993
+ sslverify = false
+; in English
+ folder = "[Gmail]/Drafts"
+; example for Japanese, "Modified UTF-7" encoded.
+ folder = "[Gmail]/&Tgtm+DBN-"
+; example for Traditional Chinese
+ folder = "[Gmail]/&g0l6Pw-"
+</pre>
+
+</div>
+
+<h4>For developers to work with git-svn</h4>
+<div>
+
+<p>To set up clone from which you can submit code using
+ <tt>git-svn</tt>, run:</p>
+
+<pre class="doc_code">
+git clone http://llvm.org/git/llvm.git
+cd llvm
+git svn init https://llvm.org/svn/llvm-project/llvm/trunk --username=<username>
+git config svn-remote.svn.fetch :refs/remotes/origin/master
+git svn rebase -l # -l avoids fetching ahead of the git mirror.
+
+# If you have clang too:
+cd tools
+git clone http://llvm.org/git/clang.git
+cd clang
+git svn init https://llvm.org/svn/llvm-project/cfe/trunk --username=<username>
+git config svn-remote.svn.fetch :refs/remotes/origin/master
+git svn rebase -l
+</pre>
+
+<p>To update this clone without generating git-svn tags that conflict
+with the upstream git repo, run:</p>
+
+<pre class="doc_code">
+git fetch && (cd tools/clang && git fetch) # Get matching revisions of both trees.
+git checkout master
+git svn rebase -l
+(cd tools/clang &&
+ git checkout master &&
+ git svn rebase -l)
+</pre>
+
+<p>This leaves your working directories on their master branches, so
+you'll need to <tt>checkout</tt> each working branch individually and
+<tt>rebase</tt> it on top of its parent branch. (Note: This script is
+intended for relative newbies to git. If you have more experience,
+you can likely improve on it.)</p>
+
+<p>The git-svn metadata can get out of sync after you mess around with
+branches and <code>dcommit</code>. When that happens, <code>git svn
+dcommit</code> stops working, complaining about files with uncommitted
+changes. The fix is to rebuild the metadata:</p>
+
+<pre class="doc_code">
+rm -rf .git/svn
+git svn rebase -l
+</pre>
+
+</div>
+
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="installcf">Install the GCC Front End</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>Before configuring and compiling the LLVM suite (or if you want to use just the LLVM
GCC front end) you can optionally extract the front end from the binary distribution.
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="config">Local LLVM Configuration</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>Once checked out from the Subversion repository, the LLVM suite source
code must be
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="compile">Compiling the LLVM Suite Source Code</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>Once you have configured LLVM, you can build it. There are three types of
builds:</p>
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="cross-compile">Cross-Compiling LLVM</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>It is possible to cross-compile LLVM itself. That is, you can create LLVM
executables and libraries to be hosted on a platform different from the
platform where they are build (a Canadian Cross build). To configure a
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="objfiles">The Location of LLVM Object Files</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>The LLVM build system is capable of sharing a single LLVM source tree among
several LLVM builds. Hence, it is possible to build LLVM for several different
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="optionalconfig">Optional Configuration Items</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>
If you're running on a Linux system that supports the "<a
<p>
This allows you to execute LLVM bitcode files directly. On Debian, you
-can also use this command instead of the 'echo' command above:</p>
+can also use this command instead of the 'echo' command above:
</p>
<div class="doc_code">
</div>
-<!-- *********************************************************************** -->
-<div class="doc_section">
- <a name="layout"><b>Program Layout</b></a>
</div>
+
+<!-- *********************************************************************** -->
+<h2>
+ <a name="layout">Program Layout</a>
+</h2>
<!-- *********************************************************************** -->
-<div class="doc_text">
+<div>
<p>One useful source of information about the LLVM source base is the LLVM <a
href="http://www.doxygen.org/">doxygen</a> documentation available at <tt><a
href="http://llvm.org/doxygen/">http://llvm.org/doxygen/</a></tt>.
The following is a brief introduction to code layout:</p>
-</div>
-
<!-- ======================================================================= -->
-<div class="doc_subsection"><a name="examples"><tt>llvm/examples</tt></a></div>
-<div class="doc_text">
+<h3>
+ <a name="examples"><tt>llvm/examples</tt></a>
+</h3>
+
+<div>
<p>This directory contains some simple examples of how to use the LLVM IR and
JIT.</p>
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection"><a name="include"><tt>llvm/include</tt></a></div>
-<div class="doc_text">
+<h3>
+ <a name="include"><tt>llvm/include</tt></a>
+</h3>
+
+<div>
<p>This directory contains public header files exported from the LLVM
library. The three main subdirectories of this directory are:</p>
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection"><a name="lib"><tt>llvm/lib</tt></a></div>
-<div class="doc_text">
+<h3>
+ <a name="lib"><tt>llvm/lib</tt></a>
+</h3>
+
+<div>
<p>This directory contains most of the source files of the LLVM system. In LLVM,
almost all code exists in libraries, making it very easy to share code among the
at runtime in both interpreted and JIT compiled fashions.</dd>
<dt><tt><b>llvm/lib/Support/</b></tt></dt>
- <dd> This directory contains the source code that corresponds to the header
- files located in <tt>llvm/include/Support/</tt>.</dd>
-
- <!--FIXME: obsoleted -->
- <dt><tt><b>llvm/lib/System/</b></tt></dt>
- <dd>This directory contains the operating system abstraction layer that
- shields LLVM from platform-specific coding.</dd>
+ <dd> This directory contains the source code that corresponds to the header
+ files located in <tt>llvm/include/ADT/</tt>
+ and <tt>llvm/include/Support/</tt>.</dd>
</dl>
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection"><a name="projects"><tt>llvm/projects</tt></a></div>
-<div class="doc_text">
+<h3>
+ <a name="projects"><tt>llvm/projects</tt></a>
+</h3>
+
+<div>
<p>This directory contains projects that are not strictly part of LLVM but are
shipped with LLVM. This is also the directory where you should create your own
LLVM-based projects. See <tt>llvm/projects/sample</tt> for an example of how
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection"><a name="runtime"><tt>llvm/runtime</tt></a></div>
-<div class="doc_text">
+<h3>
+ <a name="runtime"><tt>llvm/runtime</tt></a>
+</h3>
+
+<div>
<p>This directory contains libraries which are compiled into LLVM bitcode and
used when linking programs with the GCC front end. Most of these libraries are
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection"><a name="test"><tt>llvm/test</tt></a></div>
-<div class="doc_text">
+<h3>
+ <a name="test"><tt>llvm/test</tt></a>
+</h3>
+
+<div>
<p>This directory contains feature and regression tests and other basic sanity
checks on the LLVM infrastructure. These are intended to run quickly and cover
a lot of territory without being exhaustive.</p>
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection"><a name="test-suite"><tt>test-suite</tt></a></div>
-<div class="doc_text">
+<h3>
+ <a name="test-suite"><tt>test-suite</tt></a>
+</h3>
+
+<div>
<p>This is not a directory in the normal llvm module; it is a separate
Subversion
module that must be checked out (usually to <tt>projects/test-suite</tt>).
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection"><a name="tools"><tt>llvm/tools</tt></a></div>
-<div class="doc_text">
+<h3>
+ <a name="tools"><tt>llvm/tools</tt></a>
+</h3>
+
+<div>
<p>The <b>tools</b> directory contains the executables built out of the
libraries above, which form the main part of the user interface. You can
href="HowToSubmitABug.html">HowToSubmitABug.html</a> for more information
on using <tt>bugpoint</tt>.</dd>
- <dt><tt><b>llvmc</b></tt></dt>
- <dd>The LLVM Compiler Driver. This program can
- be configured to utilize both LLVM and non-LLVM compilation tools to enable
- pre-processing, translation, optimization, assembly, and linking of programs
- all from one command line. <tt>llvmc</tt> also takes care of processing the
- dependent libraries found in bitcode. This reduces the need to get the
- traditional <tt>-l<name></tt> options right on the command line. Please
- note that this tool, while functional, is still experimental and not feature
- complete.</dd>
-
<dt><tt><b>llvm-ar</b></tt></dt>
<dd>The archiver produces an archive containing
the given LLVM bitcode files, optionally with an index for faster
<dt><tt><b>llvm-ld</b></tt></dt>
<dd><tt>llvm-ld</tt> is a general purpose and extensible linker for LLVM.
- This is the linker invoked by <tt>llvmc</tt>. It performs standard link time
- optimizations and allows optimization modules to be loaded and run so that
- language specific optimizations can be applied at link time.</dd>
+ It performs standard link time optimizations and allows optimization
+ modules to be loaded and run so that language specific optimizations can
+ be applied at link time.</dd>
<dt><tt><b>llvm-link</b></tt></dt>
<dd><tt>llvm-link</tt>, not surprisingly, links multiple LLVM modules into
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection"><a name="utils"><tt>llvm/utils</tt></a></div>
-<div class="doc_text">
+<h3>
+ <a name="utils"><tt>llvm/utils</tt></a>
+</h3>
+
+<div>
<p>This directory contains utilities for working with LLVM source code, and some
of the utilities are actually required as part of the build process because they
</div>
+</div>
+
<!-- *********************************************************************** -->
-<div class="doc_section">
+<h2>
<a name="tutorial">An Example Using the LLVM Tool Chain</a>
-</div>
+</h2>
<!-- *********************************************************************** -->
-<div class="doc_text">
+<div>
<p>This section gives an example of using LLVM. llvm-gcc3 is now obsolete,
so we only include instructions for llvm-gcc4.
</p>
the '--emit-llvm' flag is needed to produce LLVM bitcode output. For <i>makefiles</i> and
<i>configure</i> scripts, the CFLAGS variable needs '--emit-llvm' to produce bitcode
output.</p>
-</div>
<!-- ======================================================================= -->
-<div class="doc_subsection"><a name="tutorial4">Example with llvm-gcc4</a></div>
+<h3>
+ <a name="tutorial4">Example with llvm-gcc4</a>
+</h3>
-<div class="doc_text">
+<div>
<ol>
<li><p>First, create a simple C file, name it 'hello.c':</p>
</div>
+</div>
<!-- *********************************************************************** -->
-<div class="doc_section">
+<h2>
<a name="problems">Common Problems</a>
-</div>
+</h2>
<!-- *********************************************************************** -->
-<div class="doc_text">
+<div>
<p>If you are having problems building or using LLVM, or if you have any other
general questions about LLVM, please consult the <a href="FAQ.html">Frequently
</div>
<!-- *********************************************************************** -->
-<div class="doc_section">
+<h2>
<a name="links">Links</a>
-</div>
+</h2>
<!-- *********************************************************************** -->
-<div class="doc_text">
+<div>
<p>This document is just an <b>introduction</b> on how to use LLVM to do
some simple things... there are many more interesting and complicated things
projects / oota-llvm.git / blobdiff