After considerable discussion in this thread
Unreviewed build, lto patch
http://gcc.gnu.org/ml/gcc-patches/2011-02/msg00868.html
Richard's recommendation was to only use the lto-plugin with known-good
linkers supporting -plugin, i.e. GNU ld or gold >= 2.21.
I'm extracting the binutils version number from gold --version since
it's more familiar than the separate gold version number and provides a
higher resolution than the gold version number that only changes once
per binutils release.
Here's the reworked patch that implements this suggestion. I couldn't
check with gold yet since it doesn't work on Solaris so far, but
i386-pc-solaris2.11 bootstraps with Sun ld and GNU ld 2.21 work as
expected, i.e. the failure described in PR lto/46944 is gone.
Ok for mainline?
Rainer
2011-02-05 Rainer Orth <r...@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): Require gld or gold 2.21.
* configure: Regenerate.
* gcc.c [HAVE_LTO_PLUGIN] (PLUGIN_COND, PLUGIN_COND_CLOSE): Remove.
(LINK_PLUGIN_SPEC): Define.
Extract from LINK_COMMAND_SPEC, integrate PLUGIN_COND,
PLUGIN_COND_CLOSE.
[!HAVE_LTO_PLUGIN] (LINK_PLUGIN_SPEC): Define, reject
-fuse-linker-plugin.
(LINK_COMMAND_SPEC): Use it.
diff -r bbab4a602b6f gcc/configure.ac
--- a/gcc/configure.ac Sat Feb 26 09:27:25 2011 +0100
+++ b/gcc/configure.ac Sat Mar 05 09:36:08 2011 +0100
@@ -1967,7 +1967,8 @@
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 @@
|| 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 @@
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 @@
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
@@ -3176,14 +3193,14 @@
gcc_cv_lto_plugin=no
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 "$gcc_cv_gld_major_version" -gt 2; then \
+ if test "$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=yes
fi
- # Check if the linker supports --plugin-opt option
- elif $ORIGINAL_PLUGIN_LD_FOR_TARGET --help 2>/dev/null | grep plugin-opt >
/dev/null; then
- gcc_cv_lto_plugin=yes
+ elif echo "$ld_ver" | grep GNU > /dev/null; then
+ # Require GNU ld or gold 2.21 for plugin support.
+ if test "$ld_vers_major" -eq 2 -a "$ld_vers_minor" -ge 21; then
+ gcc_cv_lto_plugin=yes
+ fi
fi
fi
if test x"$gcc_cv_lto_plugin" = xyes; then
diff -r bbab4a602b6f gcc/gcc.c
--- a/gcc/gcc.c Sat Feb 26 09:27:25 2011 +0100
+++ b/gcc/gcc.c Sat Mar 05 09:36:08 2011 +0100
@@ -623,16 +623,20 @@
/* Conditional to test whether 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
+ still causes 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. */
+ plugin only when LTO is enabled. */
#ifdef HAVE_LTO_PLUGIN
-#define PLUGIN_COND "!fno-use-linker-plugin:%{flto|flto=*|fuse-linker-plugin"
-#define PLUGIN_COND_CLOSE "}"
+#define LINK_PLUGIN_SPEC \
+ "%{!fno-use-linker-plugin:%{flto|flto=*|fuse-linker-plugin: \
+ -plugin %(linker_plugin_file) \
+ -plugin-opt=%(lto_wrapper) \
+ -plugin-opt=-fresolution=%u.res \
+ %{!nostdlib:%{!nodefaultlibs:%:pass-through-libs(%(link_gcc_c_sequence))}}
\
+ }}"
#else
-#define PLUGIN_COND "fuse-linker-plugin"
-#define PLUGIN_COND_CLOSE ""
+#define LINK_PLUGIN_SPEC "%{fuse-linker-plugin:\
+ %e-fuse-linker-plugin is not supported in this configuration}"
#endif
@@ -648,14 +652,9 @@
#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}}\
--
-----------------------------------------------------------------------------
Rainer Orth, Center for Biotechnology, Bielefeld University
