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authorPeter Collingbourne <peter@pcc.me.uk>2011-11-05 04:17:28 +0000
committerPeter Collingbourne <peter@pcc.me.uk>2011-11-05 04:17:28 +0000
commit5f73f68d39ef02b6ca4a082e7bc4c64903ed860a (patch)
tree14b09b7b9ef1315a025955324b4dfe152d03351a /docs
parent988fdc5f28692a0c4ee9f1b5f85f51f19272d63f (diff)
Recommend the -flto flag instead of -use-gold-plugin, and update
other aspects of the gold plugin docs to reflect reality. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@143785 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'docs')
-rw-r--r--docs/GoldPlugin.html27
1 files changed, 13 insertions, 14 deletions
diff --git a/docs/GoldPlugin.html b/docs/GoldPlugin.html
index 375dd3c8ca7..2c08bd031b7 100644
--- a/docs/GoldPlugin.html
+++ b/docs/GoldPlugin.html
@@ -89,11 +89,11 @@ placed.
<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>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>Any of these flags will also cause <tt>clang</tt> to look for the
+ gold plugin in the <tt>lib</tt> directory under its prefix and pass 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
@@ -141,10 +141,10 @@ void foo4(void) {
}
--- command lines ---
-$ 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
-$ 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
+$ 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
+$ clang b.c -c -o b.o # &lt;-- b.o is native object file
+$ clang -flto 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,
@@ -171,13 +171,12 @@ $ clang -use-gold-plugin a.a b.o -o main # &lt;-- link with LLVMgold plugin
<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 clang and
binutils):
<pre class="doc_code">
-export CC="$PREFIX/bin/clang -use-gold-plugin"
-export CXX="$PREFIX/bin/clang++ -use-gold-plugin"
+export CC="$PREFIX/bin/clang -flto"
+export CXX="$PREFIX/bin/clang++ -flto"
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
@@ -187,8 +186,8 @@ export CFLAGS="-O4"
<li>Or you can just set your path:
<pre class="doc_code">
export PATH="$PREFIX/bin:$PATH"
-export CC="clang -use-gold-plugin"
-export CXX="clang++ -use-gold-plugin"
+export CC="clang -flto"
+export CXX="clang++ -flto"
export RANLIB=/bin/true
export CFLAGS="-O4"
</pre></li>