Makefile.in: Regenerate.

	* Makefile.in: Regenerate.
	* Makefile.def (gcc host module) and soft dependency on lto-plugin
	and configure dependency on lto-plugin configure.
	(lto-plugin module): Remove dependency on GCC; add dependency on
	liniberty.

	* doc/invoke.texi: (-flto, -fuse-linker-plugin): Update defaults
	and no longer claim that gold is required for linker plugin.
	* configure: Regenerate.
	* gcc.c (PLUGIN_COND): New macro.
	(LINK_COMMAND_SPEC): Use it.
	(main): Default to plugin enabled with HAVE_LTO_PLUGIN is set.
	* config.in (HAVE_LTO_PLUGIN): New.
	* configure.ac (--with-lto-plugin): New parameter; autodetect
	HAVE_LTO_PLUGIN.

From-SVN: r168593

6 files changed, 97 insertions, 17 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 3624c0d..24a4367 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,17 @@
 2011-01-07  Jan Hubicka  <jh@suse.cz>
 
+	* doc/invoke.texi: (-flto, -fuse-linker-plugin): Update defaults
+	and no longer claim that gold is required for linker plugin.
+	* configure: Regenerate.
+	* gcc.c (PLUGIN_COND): New macro.
+	(LINK_COMMAND_SPEC): Use it.
+	(main): Default to plugin enabled with HAVE_LTO_PLUGIN is set.
+	* config.in (HAVE_LTO_PLUGIN): New.
+	* configure.ac (--with-lto-plugin): New parameter; autodetect
+	HAVE_LTO_PLUGIN.
+
+2011-01-07  Jan Hubicka  <jh@suse.cz>
+
 	PR tree-optimization/46367
 	* ipa-inline.c (cgraph_clone_inlined_nodes): Use original function only
 	when we can update original.
diff --git a/gcc/config.in b/gcc/config.in
index f129f3d..9df41a1 100644
--- a/gcc/config.in
+++ b/gcc/config.in
@@ -1142,6 +1142,10 @@
 #undef HAVE_LDFCN_H
 #endif
 
+/* Define if your linker supports plugin. */
+#ifndef USED_FOR_TARGET
+#undef HAVE_LTO_PLUGIN
+#endif
 
 /* Define if your linker supports --as-needed and --no-as-needed options. */
 #ifndef USED_FOR_TARGET
diff --git a/gcc/configure b/gcc/configure
index d1a68a8..46c5285 100755
--- a/gcc/configure
+++ b/gcc/configure
@@ -23093,6 +23093,29 @@ $as_echo "#define HAVE_LD_DEMANGLE 1" >>confdefs.h
 $as_echo "$gcc_cv_ld_demangle" >&6; }
 fi
 
+if test -f ../lto-plugin/Makefile ; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking linker plugin support" >&5
+$as_echo_n "checking linker plugin support... " >&6; }
+  gcc_cv_lto_plugin=no
+  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
+    fi
+  # Check if the linker supports --plugin-opt option
+  elif $ORIGINAL_PLUGIN_LD_FOR_TARGET --help 2>/dev/null | grep plugin-opt > /dev/null; then
+    gcc_cv_lto_plugin=yes
+  fi
+  if test x"$gcc_cv_lto_plugin" = xyes; then
+
+$as_echo "#define HAVE_LTO_PLUGIN 1" >>confdefs.h
+
+  fi
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $gcc_cv_lto_plugin" >&5
+$as_echo "$gcc_cv_lto_plugin" >&6; }
+fi
+
 case "$target" in
   # All TARGET_ABI_OSF targets.
   alpha*-*-osf* | alpha*-*-linux* | alpha*-*-*bsd*)
diff --git a/gcc/configure.ac b/gcc/configure.ac
index 4e7ace4..776c71f 100644
--- a/gcc/configure.ac
+++ b/gcc/configure.ac
@@ -3149,6 +3149,26 @@ if test x"$demangler_in_ld" = xyes; then
   AC_MSG_RESULT($gcc_cv_ld_demangle)
 fi
 
+AC_MSG_CHECKING(linker plugin support)
+gcc_cv_lto_plugin=no
+if test -f ../lto-plugin/Makefile ; 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
+    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_MSG_RESULT($gcc_cv_lto_plugin)
+
 case "$target" in
   # All TARGET_ABI_OSF targets.
   alpha*-*-osf* | alpha*-*-linux* | alpha*-*-*bsd*)
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 8d67e96..800c592 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -7587,23 +7587,21 @@ types in separate translation units to be linked together (undefined
 behavior according to ISO C99 6.2.7), a non-fatal diagnostic may be
 issued.  The behavior is still undefined at runtime.
 
-If object files containing GIMPLE bytecode are stored in a library
-archive, say @file{libfoo.a}, it is possible to extract and use them
-in an LTO link if you are using @command{gold} as the linker (which,
-in turn requires GCC to be configured with @option{--enable-gold}).
-To enable this feature, use the flag @option{-fuse-linker-plugin} at
-link-time:
+If object files containing GIMPLE bytecode are stored in a library archive, say
+@file{libfoo.a}, it is possible to extract and use them in an LTO link if you
+are using a linker with linker plugin support.  To enable this feature, use
+the flag @option{-fuse-linker-plugin} at link-time:
 
 @smallexample
 gcc -o myprog -O2 -flto -fuse-linker-plugin a.o b.o -lfoo
 @end smallexample
 
-With the linker plugin enabled, @command{gold} will extract the needed
+With the linker plugin enabled, the linker will extract the needed
 GIMPLE files from @file{libfoo.a} and pass them on to the running GCC
 to make them part of the aggregated GIMPLE image to be optimized.
 
-If you are not using @command{gold} and/or do not specify
-@option{-fuse-linker-plugin} then the objects inside @file{libfoo.a}
+If you are not using a linker with linker plugin support and/or do not 
+enable linker plugin then the objects inside @file{libfoo.a}
 will be extracted and linked as usual, but they will not participate
 in the LTO optimization process.
 
@@ -7667,13 +7665,20 @@ files in LTO mode (via @option{-flto}).
 Disabled by default.
 
 @item -fuse-linker-plugin
-Enables the extraction of objects with GIMPLE bytecode information
-from library archives.  This option relies on features available only
-in @command{gold}, so to use this you must configure GCC with
-@option{--enable-gold}.  See @option{-flto} for a description on the
-effect of this flag and how to use it.
-
-Disabled by default.
+Enables the use of linker plugin during link time optimization.  This option
+relies on the linker plugin support in linker that is available in @code{gold}
+or in GNU ld 2.21.51 or newer..
+
+This option enables the extraction of object files with GIMPLE bytecode out of
+library archives. This improves the quality of optimization by exposing more
+code the the link time optimizer.  This information specify what symbols 
+can be accessed externally (by non-LTO object or during dynamic linking).
+Resulting code quality improvements on binaries (and shared libaries that do
+use hidden visibility) is similar to @code{-fwhole-program}.  See
+@option{-flto} for a description on the effect of this flag and how to use it.
+
+Enabled by default when LTO support in GCC is enabled and GCC was compiled
+with linker supporting plugins (GNU ld or @code{gold}).
 
 @item -fcprop-registers
 @opindex fcprop-registers
diff --git a/gcc/gcc.c b/gcc/gcc.c
index 2aebcef..9532d7e 100644
--- a/gcc/gcc.c
+++ b/gcc/gcc.c
@@ -621,6 +621,13 @@ proper position among the other output files.  */
 # endif
 #endif
 
+/* Conditional to test whether plugin is used or not.  */
+#ifdef HAVE_LTO_PLUGIN
+#define PLUGIN_COND "!fno-use-linker-plugin"
+#else
+#define PLUGIN_COND "fuse-linker-plugin"
+#endif
+
 
 /* -u* was put back because both BSD and SysV seem to support it.  */
 /* %{static:} simply prevents an error message if the target machine
@@ -634,7 +641,7 @@ proper position among the other output files.  */
 #define LINK_COMMAND_SPEC "\
 %{!fsyntax-only:%{!c:%{!M:%{!MM:%{!E:%{!S:\
     %(linker) \
-    %{fuse-linker-plugin: \
+    %{"PLUGIN_COND": \
     -plugin %(linker_plugin_file) \
     -plugin-opt=%(lto_wrapper) \
     -plugin-opt=-fresolution=%u.res \
@@ -6779,7 +6786,11 @@ 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
+      const char *fno_use_linker_plugin = "fno-use-linker-plugin";
+#else
       const char *fuse_linker_plugin = "fuse-linker-plugin";
+#endif
 
       /* We'll use ld if we can't find collect2.  */
       if (! strcmp (linker_name_spec, "collect2"))
@@ -6789,8 +6800,13 @@ warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n\n"
 	    linker_name_spec = "ld";
 	}
 
+#ifdef HAVE_LTO_PLUGIN
+      if (!switch_matches (fno_use_linker_plugin,
+			   fno_use_linker_plugin + strlen (fno_use_linker_plugin), 0))
+#else
       if (switch_matches (fuse_linker_plugin,
 			  fuse_linker_plugin + strlen (fuse_linker_plugin), 0))
+#endif
 	{
 	  linker_plugin_file_spec = find_a_file (&exec_prefixes,
 						 LTOPLUGINSONAME, R_OK,