http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45375
--- Comment #112 from Jan Hubicka <hubicka at gcc dot gnu.org> 2011-09-28
13:33:03 UTC ---
OK, the problem turns out to be configure issue. Configure script greps asm
output and with slim LTO it does not find there what it expects disabling
hidden visibilities. No surprise this leads to a performance disaster. I use
the following hack:
diff -r 06b2977afb85 configure.in
--- a/configure.in Fri Sep 09 23:25:02 2011 -0400
+++ b/configure.in Wed Sep 28 15:30:56 2011 +0200
@@ -3035,7 +3035,7 @@
int foo __attribute__ ((visibility ("hidden"))) = 1;
EOF
ac_cv_visibility_hidden=no
- if ${CC-cc} -Werror -S conftest.c -o conftest.s >/dev/null
2>&1; then
+ if ${CC-cc} -Werror -S -fno-lto conftest.c -o conftest.s
>/dev/null 2>&1; then
if egrep '\.(hidden|private_extern).*foo' conftest.s
>/dev/null; then
ac_cv_visibility_hidden=yes
fi
@@ -3051,7 +3051,7 @@
int foo __attribute__ ((visibility ("default"))) = 1;
EOF
ac_cv_visibility_default=no
- if ${CC-cc} -fvisibility=hidden -Werror -S conftest.c -o
conftest.s >/dev/null 2>&1; then
+ if ${CC-cc} -fvisibility=hidden -Werror -S -fno-lto
conftest.c -o conftest.s >/dev/null 2>&1; then
if ! egrep '\.(hidden|private_extern).*foo' conftest.s
>/dev/null; then
ac_cv_visibility_default=yes
fi
@@ -3070,7 +3070,7 @@
int foo_default = 1;
EOF
ac_cv_visibility_pragma=no
- if ${CC-cc} -Werror -S conftest.c -o conftest.s
>/dev/null 2>&1; then
+ if ${CC-cc} -Werror -S -fno-lto conftest.c -o conftest.s
>/dev/null 2>&1; then
if egrep '\.(hidden|private_extern).*foo_hidden'
conftest.s >/dev/null; then
if ! egrep '\.(hidden|private_extern).*foo_default'
conftest.s > /dev/null; then
ac_cv_visibility_pragma=yes
@@ -3092,7 +3092,7 @@
}
EOF
ac_cv_have_visibility_class_bug=no
- if ! ${CXX-g++} ${CXXFLAGS} ${DSO_PIC_CFLAGS}
${DSO_LDOPTS} -S -o conftest.S conftest.c > /dev/null 2>&1 ; then
+ if ! ${CXX-g++} ${CXXFLAGS} ${DSO_PIC_CFLAGS}
${DSO_LDOPTS} -S -fno-lto -o conftest.S conftest.c > /dev/null 2>&1 ; then
ac_cv_have_visibility_class_bug=yes
else
if test `egrep -c '@PLT|\\$stub' conftest.S` = 0;
then
@@ -3116,7 +3116,7 @@
}
EOF
ac_cv_have_visibility_builtin_bug=no
- if ! ${CC-cc} ${CFLAGS} ${DSO_PIC_CFLAGS} ${DSO_LDOPTS}
-O2 -S -o conftest.S conftest.c > /dev/null 2>&1 ; then
+ if ! ${CC-cc} ${CFLAGS} ${DSO_PIC_CFLAGS} ${DSO_LDOPTS}
-O2 -S -fno-lto -o conftest.S conftest.c > /dev/null 2>&1 ; then
ac_cv_have_visibility_builtin_bug=yes
else
if test `grep -c "@PLT" conftest.S` = 0; then
