[llvm-commits] [llvm] r143785 - /llvm/trunk/docs/GoldPlugin.html

[Peter Collingbourne]

Author: pcc
Date: Fri Nov  4 23:17:28 2011
New Revision: 143785

URL: http://llvm.org/viewvc/llvm-project?rev=143785&view=rev
Log:
Recommend the -flto flag instead of -use-gold-plugin, and update
other aspects of the gold plugin docs to reflect reality.

Modified:
    llvm/trunk/docs/GoldPlugin.html

Modified: llvm/trunk/docs/GoldPlugin.html
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/docs/GoldPlugin.html?rev=143785&r1=143784&r2=143785&view=diff
==============================================================================
--- llvm/trunk/docs/GoldPlugin.html (original)
+++ llvm/trunk/docs/GoldPlugin.html Fri Nov  4 23:17:28 2011
@@ -89,11 +89,11 @@
   <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 @@
 }
 
 --- command lines ---
-$ clang -flto a.c -c -o a.o                 # <-- a.o is LLVM bitcode file
-$ ar q a.a a.o                              # <-- a.a is an archive with LLVM bitcode
-$ clang b.c -c -o b.o                       # <-- b.o is native object file
-$ clang -use-gold-plugin a.a b.o -o main    # <-- link with LLVMgold plugin
+$ clang -flto a.c -c -o a.o      # <-- a.o is LLVM bitcode file
+$ ar q a.a a.o                   # <-- a.a is an archive with LLVM bitcode
+$ clang b.c -c -o b.o            # <-- b.o is native object file
+$ clang -flto a.a b.o -o main    # <-- link with LLVMgold plugin
 </pre>
 
   <p>Gold informs the plugin that foo3 is never referenced outside the IR,
@@ -171,13 +171,12 @@
     <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 @@
      <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>