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authorBill Wendling <isanbard@gmail.com>2011-09-18 12:37:20 +0000
committerBill Wendling <isanbard@gmail.com>2011-09-18 12:37:20 +0000
commitea55c83e7f6e3a9b1081902ca50a4e12224894c0 (patch)
treef117537d2782eb56c16a904f8c5790c6c5281dd2 /docs
parent91e43fd17a2167ef91150a567a072326ea3a3e29 (diff)
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Remove mention of llvm-gcc/llvm-g++ from doc.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139998 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'docs')
-rw-r--r--docs/GoldPlugin.html63
1 files changed, 36 insertions, 27 deletions
diff --git a/docs/GoldPlugin.html b/docs/GoldPlugin.html
index e25c457..92ba411 100644
--- a/docs/GoldPlugin.html
+++ b/docs/GoldPlugin.html
@@ -75,6 +75,7 @@ placed.
<h2><a name="usage">Usage</a></h2>
<!--=========================================================================-->
<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
@@ -82,19 +83,21 @@ placed.
<tt>ld-new -plugin /path/to/LLVMgold.so</tt> to test it out. Once you're
ready to switch to using gold, backup your existing <tt>/usr/bin/ld</tt>
then replace it with <tt>ld-new</tt>.</p>
- <p>You can produce bitcode files from <tt>llvm-gcc</tt> using
+
+ <p>You can produce bitcode files from <tt>clang</tt> using
<tt>-emit-llvm</tt> or <tt>-flto</tt>, or the <tt>-O4</tt> flag which is
synonymous with <tt>-O3 -flto</tt>.</p>
- <p><tt>llvm-gcc</tt> has a <tt>-use-gold-plugin</tt> option which looks
- for the gold plugin in the same directories as it looks for <tt>cc1</tt> and
- passes the <tt>-plugin</tt> option to ld. It will not look for an alternate
+
+ <p><tt>Clang</tt> has a <tt>-use-gold-plugin</tt> option which looks for the
+ gold plugin in the same directories as it looks for <tt>cc1</tt> and passes
+ the <tt>-plugin</tt> option to <tt>ld</tt>. It will not look for an alternate
linker, which is why you need gold to be the installed system linker in your
path.</p>
+
<p>If you want <tt>ar</tt> and <tt>nm</tt> to work seamlessly as well, install
<tt>LLVMgold.so</tt> to <tt>/usr/lib/bfd-plugins</tt>. If you built your
own gold, be sure to install the <tt>ar</tt> and <tt>nm-new</tt> you built to
- <tt>/usr/bin</tt>.
- <p>
+ <tt>/usr/bin</tt>.<p>
<!-- ======================================================================= -->
<h3>
@@ -137,11 +140,12 @@ void foo4(void) {
}
--- command lines ---
-$ llvm-gcc -flto a.c -c -o a.o # &lt;-- a.o is LLVM bitcode file
+$ clang -flto a.c -c -o a.o # &lt;-- a.o is LLVM bitcode file
$ ar q a.a a.o # &lt;-- a.a is an archive with LLVM bitcode
-$ llvm-gcc b.c -c -o b.o # &lt;-- b.o is native object file
-$ llvm-gcc -use-gold-plugin a.a b.o -o main # &lt;-- link with LLVMgold plugin
+$ clang b.c -c -o b.o # &lt;-- b.o is native object file
+$ clang -use-gold-plugin a.a b.o -o main # &lt;-- link with LLVMgold plugin
</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="LinkTimeOptimization.html#example1">libLTO
@@ -158,20 +162,21 @@ $ llvm-gcc -use-gold-plugin a.a b.o -o main # &lt;-- link with LLVMgold plugin
</h2>
<!--=========================================================================-->
<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>
+ <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>
+
<ul>
<li>Follow the instructions <a href="#build">on how to build LLVMgold.so</a>.</li>
<li>Install the newly built binutils to <tt>$PREFIX</tt></li>
<li>Copy <tt>Release/lib/LLVMgold.so</tt> to
- <tt>$PREFIX/libexec/gcc/x86_64-unknown-linux-gnu/4.2.1/</tt> and
- <tt>$PREFIX/lib/bfd-plugins/</tt></li>
- <li>Set environment variables (<tt>$PREFIX</tt> is where you installed llvm-gcc and
- binutils):
- <pre class="doc_code">
-export CC="$PREFIX/bin/llvm-gcc -use-gold-plugin"
-export CXX="$PREFIX/bin/llvm-g++ -use-gold-plugin"
+ <tt>$PREFIX/libexec/gcc/x86_64-unknown-linux-gnu/4.2.1/</tt> and
+ <tt>$PREFIX/lib/bfd-plugins/</tt></li>
+ <li>Set environment variables (<tt>$PREFIX</tt> is where you installed clang and
+ binutils):
+<pre class="doc_code">
+export CC="$PREFIX/bin/clang -use-gold-plugin"
+export CXX="$PREFIX/bin/clang++ -use-gold-plugin"
export AR="$PREFIX/bin/ar"
export NM="$PREFIX/bin/nm"
export RANLIB=/bin/true #ranlib is not needed, and doesn't support .bc files in .a
@@ -179,18 +184,22 @@ export CFLAGS="-O4"
</pre>
</li>
<li>Or you can just set your path:
- <pre class="doc_code">
+<pre class="doc_code">
export PATH="$PREFIX/bin:$PATH"
-export CC="llvm-gcc -use-gold-plugin"
-export CXX="llvm-g++ -use-gold-plugin"
+export CC="clang -use-gold-plugin"
+export CXX="clang++ -use-gold-plugin"
export RANLIB=/bin/true
export CFLAGS="-O4"
-</pre>
- </li>
- <li>Configure &amp; build the project as usual: <tt>./configure &amp;&amp; make &amp;&amp; make check</tt> </li>
+</pre></li>
+ <li>Configure &amp; build the project as usual:
+<pre class="doc_code">
+% ./configure &amp;&amp; make &amp;&amp; make check
+</pre></li>
</ul>
- <p> The environment variable settings may work for non-autotooled projects
- too, but you may need to set the <tt>LD</tt> environment variable as well.</p>
+
+ <p>The environment variable settings may work for non-autotooled projects
+ too, but you may need to set the <tt>LD</tt> environment variable as
+ well.</p>
</div>
<!--=========================================================================-->