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authorRoland McGrath <roland@hack.frob.com>2011-06-11 05:14:37 -0700
committerRoland McGrath <roland@hack.frob.com>2011-07-14 20:50:18 -0700
commitfd5e21c75d8e9221d766f4bc922a237265514ec2 (patch)
tree71751682113629df33d174e174e077666366e1e3 /configure.in
parent5c55070081c27168d27145afdf6a92cd56c9abb3 (diff)
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Default to --with-default-link=yes if configure check finds good -shared layout.
Diffstat (limited to 'configure.in')
-rw-r--r--configure.in58
1 files changed, 55 insertions, 3 deletions
diff --git a/configure.in b/configure.in
index a28cd70..65ace27 100644
--- a/configure.in
+++ b/configure.in
@@ -117,10 +117,9 @@ AC_ARG_WITH([headers],
AC_SUBST(use_default_link)
AC_ARG_WITH([default-link],
AC_HELP_STRING([--with-default-link],
- [do not use explicit linker scripts
- @<:@default=no@:>@]),
+ [do not use explicit linker scripts]),
[use_default_link=$withval],
- [use_default_link=no])
+ [use_default_link=default])
AC_ARG_ENABLE([sanity-checks],
AC_HELP_STRING([--disable-sanity-checks],
@@ -1801,6 +1800,59 @@ EOF
fi
rm -f conftest*])
AC_SUBST(libc_cv_hashstyle)
+
+ # The linker's default -shared behavior is good enough if it
+ # does these things that our custom linker scripts ensure that
+ # all allocated NOTE sections come first.
+ if test "$use_default_link" = default; then
+ AC_CACHE_CHECK([for sufficient default -shared layout],
+ libc_cv_use_default_link, [dnl
+ libc_cv_use_default_link=no
+ cat > conftest.s <<\EOF
+ .section .note.a,"a",%note
+ .balign 4
+ .long 4,4,9
+ .string "GNU"
+ .string "foo"
+ .section .note.b,"a",%note
+ .balign 4
+ .long 4,4,9
+ .string "GNU"
+ .string "bar"
+EOF
+ if AC_TRY_COMMAND([dnl
+ ${CC-cc} $ASFLAGS -shared -o conftest.so conftest.s 1>&AS_MESSAGE_LOG_FD]) &&
+ ac_try=`$READELF -S conftest.so | sed -n \
+ ['${x;p;}
+ s/^ *\[ *[1-9][0-9]*\] *\([^ ][^ ]*\) *\([^ ][^ ]*\) .*$/\2 \1/
+ t a
+ b
+ : a
+ H']`
+ then
+ libc_seen_a=no libc_seen_b=no
+ set -- $ac_try
+ while test $# -ge 2 -a "$1" = NOTE; do
+ case "$2" in
+ .note.a) libc_seen_a=yes ;;
+ .note.b) libc_seen_b=yes ;;
+ esac
+ shift 2
+ done
+ case "$libc_seen_a$libc_seen_b" in
+ yesyes)
+ libc_cv_use_default_link=yes
+ ;;
+ *)
+ echo >&AS_MESSAGE_LOG_FD "\
+$libc_seen_a$libc_seen_b from:
+$ac_try"
+ ;;
+ esac
+ fi
+ rm -f conftest*])
+ use_default_link=$libc_cv_use_default_link
+ fi
fi
AC_CACHE_CHECK(linker output format, libc_cv_output_format, [dnl