</head>
<body>
-<div class="doc_title">LLVM gold plugin</div>
+<h1>LLVM gold plugin</h1>
<ol>
<li><a href="#introduction">Introduction</a></li>
<li><a href="#build">How to build it</a></li>
<div class="doc_author">Written by Nick Lewycky</div>
<!--=========================================================================-->
-<div class="doc_section"><a name="introduction">Introduction</a></div>
+<h2><a name="introduction">Introduction</a></h2>
<!--=========================================================================-->
-<div class="doc_text">
+<div>
<p>Building with link time optimization requires cooperation from the
system linker. LTO support on Linux systems requires that you use
the <a href="http://sourceware.org/binutils">gold linker</a> which supports
<p>The LLVM gold plugin implements the
<a href="http://gcc.gnu.org/wiki/whopr/driver">gold plugin interface</a>
on top of
-<a href="http://llvm.org/docs/LinkTimeOptimization.html#lto">libLTO</a>.
+<a href="LinkTimeOptimization.html#lto">libLTO</a>.
The same plugin can also be used by other tools such as <tt>ar</tt> and
<tt>nm</tt>.
</div>
<!--=========================================================================-->
-<div class="doc_section"><a name="build">How to build it</a></div>
+<h2><a name="build">How to build it</a></h2>
<!--=========================================================================-->
-<div class="doc_text">
+<div>
<p>You need to have gold with plugin support and build the LLVMgold
plugin. Check whether you have gold running <tt>/usr/bin/ld -v</tt>. It will
report “GNU gold” or else “GNU ld” if not. If you have
</ul>
</div>
<!--=========================================================================-->
-<div class="doc_section"><a name="usage">Usage</a></div>
+<h2><a name="usage">Usage</a></h2>
<!--=========================================================================-->
-<div class="doc_text">
+<div>
<p>The linker takes a <tt>-plugin</tt> option that points to the path of
the plugin <tt>.so</tt> file. To find out what link command <tt>gcc</tt>
would run in a given situation, run <tt>gcc -v <em>[...]</em></tt> and look
own gold, be sure to install the <tt>ar</tt> and <tt>nm-new</tt> you built to
<tt>/usr/bin</tt>.
<p>
-</div>
<!-- ======================================================================= -->
-<div class="doc_subsection">
+<h3>
<a name="example1">Example of link time optimization</a>
-</div>
+</h3>
-<div class="doc_text">
+<div>
<p>The following example shows a worked example of the gold plugin mixing
LLVM bitcode and native code.
<pre class="doc_code">
</pre>
<p>Gold informs the plugin that foo3 is never referenced outside the IR,
leading LLVM to delete that function. However, unlike in the
- <a href="http://llvm.org/docs/LinkTimeOptimization.html#example1">libLTO
+ <a href="LinkTimeOptimization.html#example1">libLTO
example</a> gold does not currently eliminate foo4.</p>
</div>
+</div>
+
<!--=========================================================================-->
-<div class="doc_section"><a name="lto_autotools">Quickstart for using LTO with autotooled projects</a></div>
+<h2>
+ <a name="lto_autotools">
+ Quickstart for using LTO with autotooled projects
+ </a>
+</h2>
<!--=========================================================================-->
-<div class="doc_text">
+<div>
<p>Once your system <tt>ld</tt>, <tt>ar</tt> and <tt>nm</tt> all support LLVM
bitcode, everything is in place for an easy to use LTO build of autotooled
projects:</p>
</div>
<!--=========================================================================-->
-<div class="doc_section"><a name="licensing">Licensing</a></div>
+<h2><a name="licensing">Licensing</a></h2>
<!--=========================================================================-->
-<div class="doc_text">
+<div>
<p>Gold is licensed under the GPLv3. LLVMgold uses the interface file
<tt>plugin-api.h</tt> from gold which means that the resulting LLVMgold.so
binary is also GPLv3. This can still be used to link non-GPLv3 programs just
<a href="http://validator.w3.org/check/referer"><img
src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
<a href="mailto:nicholas@metrix.on.ca">Nick Lewycky</a><br>
- <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
+ <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
Last modified: $Date: 2010-04-16 23:58:21 -0800 (Fri, 16 Apr 2010) $
</address>
</body>
projects / oota-llvm.git / blobdiff