re PR driver/46944 (gcc should accept -fuse-linker-plugin only if linker handles -plugin)

	PR lto/46944
	* configure.ac (gcc_cv_gld_major_version, gcc_cv_gld_minor):
	Handle in-tree gold.
	(ld_vers): Extract binutils version for gold.
	(gcc_cv_ld_hidden): Handle gold here.
	(gcc_cv_lto_plugin): Determine level of linker plugin support.
	* configure: Regenerate.
	* config.in: Regenerate.
	* gcc.c: Only use LTO plugin if HAVE_LTO_PLUGIN > 0, reject
	-fuse-linker-plugin otherwise.
	(LINK_PLUGIN_SPEC): Define.  Extract from LINK_COMMAND_SPEC.
	(LINK_COMMAND_SPEC): Use it.
	(main): Only look for LTOPLUGINSONAME if HAVE_LTO_PLUGIN > 0.

From-SVN: r171039

gcc/ChangeLog

+2011-03-16  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>
+
+	PR lto/46944
+	* configure.ac (gcc_cv_gld_major_version, gcc_cv_gld_minor):
+	Handle in-tree gold.
+	(ld_vers): Extract binutils version for gold.
+	(gcc_cv_ld_hidden): Handle gold here.
+	(gcc_cv_lto_plugin): Determine level of linker plugin support.
+	* configure: Regenerate.
+	* config.in: Regenerate.
+	* gcc.c: Only use LTO plugin if HAVE_LTO_PLUGIN > 0, reject
+	-fuse-linker-plugin otherwise.
+	(LINK_PLUGIN_SPEC): Define.  Extract from LINK_COMMAND_SPEC.
+	(LINK_COMMAND_SPEC): Use it.
+	(main): Only look for LTOPLUGINSONAME if HAVE_LTO_PLUGIN > 0.
+
 2011-03-16  Jakub Jelinek  <jakub@redhat.com>
 
 	* emit-rtl.c (try_split): Don't call copy_call_info debug hook.

gcc/config.in

@@ -1252,7 +1252,7 @@
 #endif
 
 
-/* Define if your linker supports plugin. */
+/* Define to the level of your linker's plugin support. */
 #ifndef USED_FOR_TARGET
 #undef HAVE_LTO_PLUGIN
 #endif

gcc/configure

@@ -21096,7 +21096,8 @@ esac
 
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking what linker to use" >&5
 $as_echo_n "checking what linker to use... " >&6; }
-if test "$gcc_cv_ld" = ../ld/ld-new$build_exeext; then
+if test "$gcc_cv_ld" = ../ld/ld-new$build_exeext \
+   || test "$gcc_cv_ld" = ../gold/ld-new$build_exeext; then
 	# Single tree build which includes ld.  We want to prefer it
 	# over whatever linker top-level may have detected, since
 	# we'll use what we're building after installation anyway.
@@ -21108,6 +21109,8 @@ $as_echo "newly built ld" >&6; }
 	    || grep 'EMUL = .*linux' ../ld/Makefile \
 	    || grep 'EMUL = .*lynx' ../ld/Makefile) > /dev/null; then
 	  in_tree_ld_is_elf=yes
+	elif test "$ld_is_gold" = yes; then
+	  in_tree_ld_is_elf=yes
 	fi
 	for f in $gcc_cv_ld_bfd_srcdir/configure $gcc_cv_ld_gld_srcdir/configure $gcc_cv_ld_gld_srcdir/configure.in $gcc_cv_ld_gld_srcdir/Makefile.in
 	do
@@ -21716,11 +21719,23 @@ fi
 
 if test $in_tree_ld != yes ; then
   ld_ver=`$gcc_cv_ld --version 2>/dev/null | sed 1q`
-  if test x"$ld_is_gold" = xyes; then
-    gcc_cv_ld_hidden=yes
-  elif echo "$ld_ver" | grep GNU > /dev/null; then
-    ld_vers=`echo $ld_ver | sed -n \
-	-e 's,^.*[	 ]\([0-9][0-9]*\.[0-9][0-9]*.*\)$,\1,p'`
+  if echo "$ld_ver" | grep GNU > /dev/null; then
+    if test x"$ld_is_gold" = xyes; then
+      # GNU gold --version looks like this:
+      #
+      # GNU gold (GNU Binutils 2.21.51.20110225) 1.11
+      #
+      # We extract the binutils version which is more familiar and specific
+      # than the gold version.
+      ld_vers=`echo $ld_ver | sed -n \
+	  -e 's,^[^)]*[	 ]\([0-9][0-9]*\.[0-9][0-9]*[^)]*\)) .*$,\1,p'`
+    else
+      # GNU ld --version looks like this:
+      #
+      # GNU ld (GNU Binutils) 2.21.51.20110225
+      ld_vers=`echo $ld_ver | sed -n \
+	  -e 's,^.*[	 ]\([0-9][0-9]*\.[0-9][0-9]*.*\)$,\1,p'`
+    fi
     ld_date=`echo $ld_ver | sed -n 's,^.*\([2-9][0-9][0-9][0-9]\)[-]*\([01][0-9]\)[-]*\([0-3][0-9]\).*$,\1\2\3,p'`
     ld_vers_major=`expr "$ld_vers" : '\([0-9]*\)'`
     ld_vers_minor=`expr "$ld_vers" : '[0-9]*\.\([0-9]*\)'`
@@ -21762,7 +21777,9 @@ else
   fi
 else
   gcc_cv_ld_hidden=yes
-  if echo "$ld_ver" | grep GNU > /dev/null; then
+  if test x"$ld_is_gold" = xyes; then
+    :
+  elif echo "$ld_ver" | grep GNU > /dev/null; then
     if test 0"$ld_date" -lt 20020404; then
       if test -n "$ld_date"; then
 	# If there was date string, but was earlier than 2002-04-04, fail
@@ -23115,24 +23132,30 @@ fi
 
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking linker plugin support" >&5
 $as_echo_n "checking linker plugin support... " >&6; }
-gcc_cv_lto_plugin=no
+gcc_cv_lto_plugin=0
 if test -f liblto_plugin.la; then
   if test $in_tree_ld = yes -a x"$ORIGINAL_PLUGIN_LD_FOR_TARGET=" = x"$gcc_cv_ld"; then
-    if test x"$ld_is_gold" = xyes; then
-      gcc_cv_lto_plugin=yes
-    elif test "$gcc_cv_gld_major_version" -eq 2 -a "$gcc_cv_gld_minor_version" -ge 21 -o "$gcc_cv_gld_major_version" -gt 2; then \
-      gcc_cv_lto_plugin=yes
+    if test "$gcc_cv_gld_major_version" -eq 2 -a "$gcc_cv_gld_minor_version" -ge 21 -o "$gcc_cv_gld_major_version" -gt 2; then
+      gcc_cv_lto_plugin=2
+    elif test "$ld_is_gold" = yes -a "$gcc_cv_gld_major_version" -eq 2 -a "$gcc_cv_gld_minor_version" -eq 20; then
+      gcc_cv_lto_plugin=1
+
+    fi
+  elif echo "$ld_ver" | grep GNU > /dev/null; then
+    # Require GNU ld or gold 2.21+ for plugin support by default.
+    if test "$ld_vers_major" -eq 2 -a "$ld_vers_minor" -ge 21; then
+      gcc_cv_lto_plugin=2
+    # Allow -fuse-linker-plugin to enable plugin support in GNU gold 2.20.
+    elif test "$ld_is_gold" = yes -a "$ld_vers_major" -eq 2 -a "$ld_vers_minor" -eq 20; then
+      gcc_cv_lto_plugin=1
     fi
-  # Check if the linker supports --plugin-opt option
-  elif $ORIGINAL_PLUGIN_LD_FOR_TARGET --help 2>/dev/null | grep plugin-opt > /dev/null; then
-    gcc_cv_lto_plugin=yes
   fi
 fi
-if test x"$gcc_cv_lto_plugin" = xyes; then
 
-$as_echo "#define HAVE_LTO_PLUGIN 1" >>confdefs.h
+cat >>confdefs.h <<_ACEOF
+#define HAVE_LTO_PLUGIN $gcc_cv_lto_plugin
+_ACEOF
 
-fi
 { $as_echo "$as_me:${as_lineno-$LINENO}: result: $gcc_cv_lto_plugin" >&5
 $as_echo "$gcc_cv_lto_plugin" >&6; }
 

gcc/configure.ac

@@ -1967,7 +1967,8 @@ case "$ORIGINAL_LD_FOR_TARGET" in
 esac 
 
 AC_MSG_CHECKING(what linker to use)
-if test "$gcc_cv_ld" = ../ld/ld-new$build_exeext; then
+if test "$gcc_cv_ld" = ../ld/ld-new$build_exeext \
+   || test "$gcc_cv_ld" = ../gold/ld-new$build_exeext; then
 	# Single tree build which includes ld.  We want to prefer it
 	# over whatever linker top-level may have detected, since
 	# we'll use what we're building after installation anyway.
@@ -1978,6 +1979,8 @@ if test "$gcc_cv_ld" = ../ld/ld-new$build_exeext; then
 	    || grep 'EMUL = .*linux' ../ld/Makefile \
 	    || grep 'EMUL = .*lynx' ../ld/Makefile) > /dev/null; then
 	  in_tree_ld_is_elf=yes
+	elif test "$ld_is_gold" = yes; then
+	  in_tree_ld_is_elf=yes
 	fi
 	for f in $gcc_cv_ld_bfd_srcdir/configure $gcc_cv_ld_gld_srcdir/configure $gcc_cv_ld_gld_srcdir/configure.in $gcc_cv_ld_gld_srcdir/Makefile.in
 	do
@@ -2192,11 +2195,23 @@ fi
 changequote(,)dnl
 if test $in_tree_ld != yes ; then
   ld_ver=`$gcc_cv_ld --version 2>/dev/null | sed 1q`
-  if test x"$ld_is_gold" = xyes; then
-    gcc_cv_ld_hidden=yes
-  elif echo "$ld_ver" | grep GNU > /dev/null; then
-    ld_vers=`echo $ld_ver | sed -n \
-	-e 's,^.*[	 ]\([0-9][0-9]*\.[0-9][0-9]*.*\)$,\1,p'`
+  if echo "$ld_ver" | grep GNU > /dev/null; then
+    if test x"$ld_is_gold" = xyes; then
+      # GNU gold --version looks like this:
+      #
+      # GNU gold (GNU Binutils 2.21.51.20110225) 1.11
+      #
+      # We extract the binutils version which is more familiar and specific
+      # than the gold version.
+      ld_vers=`echo $ld_ver | sed -n \
+	  -e 's,^[^)]*[	 ]\([0-9][0-9]*\.[0-9][0-9]*[^)]*\)) .*$,\1,p'`
+    else
+      # GNU ld --version looks like this:
+      #
+      # GNU ld (GNU Binutils) 2.21.51.20110225
+      ld_vers=`echo $ld_ver | sed -n \
+	  -e 's,^.*[	 ]\([0-9][0-9]*\.[0-9][0-9]*.*\)$,\1,p'`
+    fi
     ld_date=`echo $ld_ver | sed -n 's,^.*\([2-9][0-9][0-9][0-9]\)[-]*\([01][0-9]\)[-]*\([0-3][0-9]\).*$,\1\2\3,p'`
     ld_vers_major=`expr "$ld_vers" : '\([0-9]*\)'`
     ld_vers_minor=`expr "$ld_vers" : '[0-9]*\.\([0-9]*\)'`
@@ -2235,7 +2250,9 @@ AC_CACHE_CHECK(linker for .hidden support, gcc_cv_ld_hidden,
   fi
 else
   gcc_cv_ld_hidden=yes
-  if echo "$ld_ver" | grep GNU > /dev/null; then
+  if test x"$ld_is_gold" = xyes; then
+    :
+  elif echo "$ld_ver" | grep GNU > /dev/null; then
     if test 0"$ld_date" -lt 20020404; then
       if test -n "$ld_date"; then
 	# If there was date string, but was earlier than 2002-04-04, fail
@@ -3173,23 +3190,27 @@ if test x"$demangler_in_ld" = xyes; then
 fi
 
 AC_MSG_CHECKING(linker plugin support)
-gcc_cv_lto_plugin=no
+gcc_cv_lto_plugin=0
 if test -f liblto_plugin.la; then
   if test $in_tree_ld = yes -a x"$ORIGINAL_PLUGIN_LD_FOR_TARGET=" = x"$gcc_cv_ld"; then
-    if test x"$ld_is_gold" = xyes; then
-      gcc_cv_lto_plugin=yes
-    elif test "$gcc_cv_gld_major_version" -eq 2 -a "$gcc_cv_gld_minor_version" -ge 21 -o "$gcc_cv_gld_major_version" -gt 2; then \
-      gcc_cv_lto_plugin=yes
+    if test "$gcc_cv_gld_major_version" -eq 2 -a "$gcc_cv_gld_minor_version" -ge 21 -o "$gcc_cv_gld_major_version" -gt 2; then
+      gcc_cv_lto_plugin=2
+    elif test "$ld_is_gold" = yes -a "$gcc_cv_gld_major_version" -eq 2 -a "$gcc_cv_gld_minor_version" -eq 20; then
+      gcc_cv_lto_plugin=1
+
+    fi
+  elif echo "$ld_ver" | grep GNU > /dev/null; then
+    # Require GNU ld or gold 2.21+ for plugin support by default.
+    if test "$ld_vers_major" -eq 2 -a "$ld_vers_minor" -ge 21; then
+      gcc_cv_lto_plugin=2
+    # Allow -fuse-linker-plugin to enable plugin support in GNU gold 2.20.
+    elif test "$ld_is_gold" = yes -a "$ld_vers_major" -eq 2 -a "$ld_vers_minor" -eq 20; then
+      gcc_cv_lto_plugin=1
     fi
-  # Check if the linker supports --plugin-opt option
-  elif $ORIGINAL_PLUGIN_LD_FOR_TARGET --help 2>/dev/null | grep plugin-opt > /dev/null; then
-    gcc_cv_lto_plugin=yes
   fi
 fi
-if test x"$gcc_cv_lto_plugin" = xyes; then
-  AC_DEFINE(HAVE_LTO_PLUGIN, 1,
-[Define if your linker supports plugin.])
-fi
+AC_DEFINE_UNQUOTED(HAVE_LTO_PLUGIN, $gcc_cv_lto_plugin,
+  [Define to the level of your linker's plugin support.])
 AC_MSG_RESULT($gcc_cv_lto_plugin)
 
 case "$target" in

gcc/gcc.c

@@ -621,19 +621,37 @@ proper position among the other output files.  */
 # endif
 #endif
 
-/* Conditional to test whether plugin is used or not.
+/* Conditional to test whether the LTO plugin is used or not.
    FIXME: For slim LTO we will need to enable plugin unconditionally.  This
    still cause problems with PLUGIN_LD != LD and when plugin is built but
    not useable.  For GCC 4.6 we don't support slim LTO and thus we can enable
    plugin only when LTO is enabled.  We still honor explicit
-   -fuse-linker-plugin.  */
-#ifdef HAVE_LTO_PLUGIN
+   -fuse-linker-plugin if the linker used understands -plugin.  */
+
+/* The linker has some plugin support.  */
+#if HAVE_LTO_PLUGIN > 0
+/* The linker used has full plugin support, use LTO plugin by default.  */
+#if HAVE_LTO_PLUGIN == 2
 #define PLUGIN_COND "!fno-use-linker-plugin:%{flto|flto=*|fuse-linker-plugin"
 #define PLUGIN_COND_CLOSE "}"
 #else
+/* The linker used has limited plugin support, use LTO plugin with explicit
+   -fuse-linker-plugin.  */
 #define PLUGIN_COND "fuse-linker-plugin"
 #define PLUGIN_COND_CLOSE ""
 #endif
+#define LINK_PLUGIN_SPEC \
+    "%{"PLUGIN_COND": \
+    -plugin %(linker_plugin_file) \
+    -plugin-opt=%(lto_wrapper) \
+    -plugin-opt=-fresolution=%u.res \
+    %{!nostdlib:%{!nodefaultlibs:%:pass-through-libs(%(link_gcc_c_sequence))}} \
+    }"PLUGIN_COND_CLOSE
+#else
+/* The linker used doesn't support -plugin, reject -fuse-linker-plugin.  */
+#define LINK_PLUGIN_SPEC "%{fuse-linker-plugin:\
+    %e-fuse-linker-plugin is not supported in this configuration}"
+#endif
 
 
 /* -u* was put back because both BSD and SysV seem to support it.  */
@@ -648,14 +666,9 @@ proper position among the other output files.  */
 #ifndef LINK_COMMAND_SPEC
 #define LINK_COMMAND_SPEC "\
 %{!fsyntax-only:%{!c:%{!M:%{!MM:%{!E:%{!S:\
-    %(linker) \
-    %{"PLUGIN_COND": \
-    -plugin %(linker_plugin_file) \
-    -plugin-opt=%(lto_wrapper) \
-    -plugin-opt=-fresolution=%u.res \
-    %{!nostdlib:%{!nodefaultlibs:%:pass-through-libs(%(link_gcc_c_sequence))}} \
-    }"PLUGIN_COND_CLOSE" \
-    %{flto|flto=*:%<fcompare-debug*} \
+    %(linker) " \
+    LINK_PLUGIN_SPEC \
+    "%{flto|flto=*:%<fcompare-debug*} \
     %{flto} %{flto=*} %l " LINK_PIE_SPEC \
    "%X %{o*} %{e*} %{N} %{n} %{r}\
     %{s} %{t} %{u*} %{z} %{Z} %{!nostdlib:%{!nostartfiles:%S}}\
@@ -6815,11 +6828,13 @@ warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n\n"
   if (num_linker_inputs > 0 && !seen_error () && print_subprocess_help < 2)
     {
       int tmp = execution_count;
-#ifdef HAVE_LTO_PLUGIN
+#if HAVE_LTO_PLUGIN > 0
+#if HAVE_LTO_PLUGIN == 2
       const char *fno_use_linker_plugin = "fno-use-linker-plugin";
 #else
       const char *fuse_linker_plugin = "fuse-linker-plugin";
 #endif
+#endif
 
       /* We'll use ld if we can't find collect2.  */
       if (! strcmp (linker_name_spec, "collect2"))
@@ -6829,7 +6844,8 @@ warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n\n"
 	    linker_name_spec = "ld";
 	}
 
-#ifdef HAVE_LTO_PLUGIN
+#if HAVE_LTO_PLUGIN > 0
+#if HAVE_LTO_PLUGIN == 2
       if (!switch_matches (fno_use_linker_plugin,
 			   fno_use_linker_plugin + strlen (fno_use_linker_plugin), 0))
 #else
@@ -6843,6 +6859,7 @@ warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n\n"
 	  if (!linker_plugin_file_spec)
 	    fatal_error ("-fuse-linker-plugin, but " LTOPLUGINSONAME " not found");
 	}
+#endif
       lto_gcc_spec = argv[0];
 
       /* Rebuild the COMPILER_PATH and LIBRARY_PATH environment variables