Linux: Stop installing the gold linker as /usr/bin/ld. Ask users to pass -B/usr/local/gold/bin in...

build/install-build-deps.sh

 #!/bin/bash -e
 
 # Copyright (c) 2011 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # Script to install everything needed to build chromium (well, ideally, anyway)
 # See http://code.google.com/p/chromium/wiki/LinuxBuildInstructions
 # and http://code.google.com/p/chromium/wiki/LinuxBuild64Bit
 
@@ skipping 42 matching lines @@
   test -f $BINUTILS.tar.bz2 || wget $BINUTILS_URL
   if test "`sha1sum $BINUTILS.tar.bz2|cut -d' ' -f1`" != "$BINUTILS_SHA1"
   then
     echo Bad sha1sum for $BINUTILS.tar.bz2
     exit 1
   fi
 
   tar -xjvf $BINUTILS.tar.bz2
   cd $BINUTILS
   ./configure --prefix=/usr/local/gold --enable-gold --enable-threads
-  make maybe-all-binutils maybe-all-gold -j4
+  NCPU=`cat /proc/cpuinfo |grep ^processor|wc -l`
+  make maybe-all-binutils maybe-all-gold -j${NCPU}
   if sudo make maybe-install-binutils maybe-install-gold
   then
     # Still need to figure out graceful way of pointing gyp to use
     # /usr/local/gold/bin/ld without requiring him to set environment
     # variables.  That will go into bootstrap-linux.sh when it's ready.

[Evan Martin, 2011/07/13 20:37:38]

FWIW, there is no bootstrap-linux.sh.

-    echo "Installing gold as /usr/bin/ld."
-    echo "To uninstall, do 'cd /usr/bin; sudo rm ld; sudo mv ld.orig ld'"
-    test -f /usr/bin/ld && test ! -f /usr/bin/ld.orig && \
-        sudo mv /usr/bin/ld /usr/bin/ld.orig
+    test -f /usr/local/gold/bin/ld && test -f /usr/local/gold/bin/ld.gold && \
+        sudo mv /usr/local/gold/bin/ld.gold /usr/local/gold/bin/ld
     sudo strip /usr/local/gold/bin/ld
-    sudo ln -fs /usr/local/gold/bin/ld /usr/bin/ld.gold
-    sudo ln -fs /usr/bin/ld.gold /usr/bin/ld
   else
     echo "make install failed, not installing gold"
   fi
 }
 
 if ! egrep -q \
     'Ubuntu (10\.04|10\.10|11\.04|lucid|maverick|natty)' \
     /etc/issue; then
   echo "Only Ubuntu 10.04 (lucid) through 11.04 (natty) are currently" \
       "supported" >&2
@@ skipping 156 matching lines @@
 fi
 
 # Some operating systems already ship gold (on recent Debian and
 # Ubuntu you can do "apt-get install binutils-gold" to get it), but
 # older releases didn't.  Additionally, gold 2.20 (included in Ubuntu
 # Lucid) makes binaries that just segfault, and 2.20.1 does not support
 # --map-whole-files.
 # So install from source if we don't have a good version.
 
 case `ld --version` in
+*gold*2.2[1-9].*)
+  echo "*** Warning ***"
+  echo "If the default linker is gold, linking may fail for:"
+  echo "the Linux kernel, kernel modules, Valgrind, and Wine."
+  echo "If you previously installed gold as the default linker,"
+  echo "you can restore the original linker by running:"
+  echo "'cd /usr/bin; sudo rm ld; sudo mv ld.orig ld'"
+  echo
+  ;;
+esac
+
+case `/usr/local/gold/bin/ld --version` in
 *gold*2.2[1-9].*) ;;
 * )
   if test "$do_inst_gold" = ""
   then
-    echo "Gold is a new linker that links Chrome 5x faster than ld."
-    echo "Don't use it if you need to link other apps (e.g. valgrind, wine)"
-    echo -n "REPLACE SYSTEM LINKER ld with gold and back up ld? (y/N) "
+    echo "Gold is a new linker that links Chrome 5x faster than GNU ld."
+    echo -n "*** To use the gold linker, "
+    echo "you must pass -B/usr/local/gold/bin/ to g++ ***"
+    echo -n "Install the gold linker? (y/N) "
     if yes_no 1; then
       do_inst_gold=1
     fi
   fi
   if test "$do_inst_gold" = "1"
   then
     # If the system provides a good version of gold, just install it.
     if apt-cache show binutils-gold | grep -Eq 'Version: 2.2[1-9].*'; then
       echo "Installing binutils-gold. Backing up ld as ld.single."
       sudo apt-get install binutils-gold
     else
-      # FIXME: avoid installing as /usr/bin/ld
-      echo "Building binutils. Backing up ld as ld.orig."
+      echo "Building binutils with gold..."
       install_gold || exit 99
     fi
   else
     echo "Not installing gold."
   fi
 esac
 
 # Install 32bit backwards compatibility support for 64bit systems
 if [ "$(uname -m)" = "x86_64" ]; then
   if test "$do_inst_lib32" = ""
@@ skipping 171 matching lines @@
              sed -e 's/[.]so[.][0-9].*/.so/' |
              sort -u); do
     [ "x${i##*/}" = "xld-linux.so" ] && continue
     [ -r "$i" ] && continue
     j="$(ls "$i."* | sed -e 's/.*[.]so[.]\([^.]*\)$/\1/;t;d' |
          sort -n | tail -n 1)"
     [ -r "$i.$j" ] || continue
     sudo ln -s "${i##*/}.$j" "$i"
   done
 fi