X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=docs%2FGoldPlugin.html;h=68c5cf19280288ced2c771185e39105d4ae58069;hb=a6fd81dd7f6039fbc1a55f6f4d45659fffdd81fb;hp=17a50aca6e9904b418662ab16cdc520d832859a4;hpb=347c7bbcb57f943ea9834e2ffdc6696508c55682;p=oota-llvm.git

diff --git a/docs/GoldPlugin.html b/docs/GoldPlugin.html
index 17a50aca6e9..68c5cf19280 100644
--- a/docs/GoldPlugin.html
+++ b/docs/GoldPlugin.html
@@ -27,7 +27,7 @@
   <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
-LTO via plugins. This is the same system used by the upcoming
+LTO via plugins. This is the same mechanism used by the
 <a href="http://gcc.gnu.org/wiki/LinkTimeOptimization">GCC LTO</a>
 project.</p>
   <p>The LLVM gold plugin implements the
@@ -41,24 +41,31 @@ The same plugin can also be used by other tools such as <tt>ar</tt> and
 <div class="doc_section"><a name="build">How to build it</a></div>
 <!--=========================================================================-->
 <div class="doc_text">
-  <p>You need to build gold with plugin support and build the LLVMgold
-plugin.</p>
+  <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 &#8220;GNU gold&#8221; or else &#8220GNU ld&#8221; if not. If you have
+gold, check for plugin support by running <tt>/usr/bin/ld -plugin</tt>. If it
+complains &#8220missing argument&#8221 then you have plugin support. If not,
+such as an &#8220;unknown option&#8221; error then you will either need to
+build gold or install a version with plugin support.</p>
 <ul>
-  <li>Build gold with plugin support:
+  <li>To build gold with plugin support:
     <pre class="doc_code">
 mkdir binutils
 cd binutils
 cvs -z 9 -d :pserver:anoncvs@sourceware.org:/cvs/src login
 <em>{enter "anoncvs" as the password}</em>
-cvs -z 9 -d :pserver:anoncvs@sourceware.org:/cvs/src co src
+cvs -z 9 -d :pserver:anoncvs@sourceware.org:/cvs/src co binutils
 mkdir build
 cd build
 ../src/configure --enable-gold --enable-plugins
 make all-gold
 </pre>
-    That should leave you with binutils/build/gold/ld-new which supports the
-<tt>-plugin</tt> option.
-
+    That should leave you with <tt>binutils/build/gold/ld-new</tt> which supports the <tt>-plugin</tt> option. It also built would have
+<tt>binutils/build/binutils/ar</tt> and <tt>nm-new</tt> which support plugins
+but don't have a visible -plugin option, instead relying on the gold plugin
+being present in <tt>../lib/bfd-plugins</tt> relative to where the binaries are
+placed.
     <li>Build the LLVMgold plugin: Configure LLVM with
     <tt>--with-binutils-include=/path/to/binutils/src/include</tt> and run
     <tt>make</tt>.
@@ -83,6 +90,11 @@ make all-gold
   passes the <tt>-plugin</tt> option to ld. 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>
 </div>
 
 <!-- ======================================================================= -->
@@ -127,8 +139,9 @@ void foo4(void) {
 
 --- command lines ---
 $ llvm-gcc -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.o b.o -o main # &lt;-- link with LLVMgold plugin
+$ llvm-gcc -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
@@ -140,12 +153,13 @@ $ llvm-gcc -use-gold-plugin a.o b.o -o main # &lt;-- link with LLVMgold plugin
 <div class="doc_section"><a name="lto_autotools">Quickstart for using LTO with autotooled projects</a></div>
 <!--=========================================================================-->
 <div class="doc_text">
-  <p><tt>gold</tt>, <tt>ar</tt> and <tt>nm</tt> all support plugins now, so everything should be
-  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 libLLVMgold.so</a>.</li>
+    <li>Follow the instructions <a href="#build">on how to build LLVMgold.so</a>.</li>
     <li>Install the newly built binutils to <tt>$PREFIX</tt></li>
-    <li>Copy <tt>Release/lib/libLLVMgold.so</tt> to
+    <li>Copy <tt>Release/lib/LLVMgold.so</tt> to
     <tt>$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
@@ -157,7 +171,7 @@ 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
 export CFLAGS="-O4"
-     </pre>
+</pre>
      </li>
      <li>Or you can just set your path:
     <pre class="doc_code">
@@ -166,7 +180,7 @@ export CC="llvm-gcc -use-gold-plugin"
 export CXX="llvm-g++ -use-gold-plugin"
 export RANLIB=/bin/true
 export CFLAGS="-O4"
-     </pre>
+</pre>
      </li>
      <li>Configure &amp; build the project as usual: <tt>./configure &amp;&amp; make &amp;&amp; make check</tt> </li>
    </ul>
@@ -193,7 +207,7 @@ as much as gold could without the plugin.</p>
   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>
-  Last modified: $Date: 2009-01-01 23:10:51 -0800 (Thu, 01 Jan 2009) $
+  Last modified: $Date: 2010-04-16 23:58:21 -0800 (Fri, 16 Apr 2010) $
 </address>
 </body>
 </html>