PATCH: Enable multi-arch by default if possible

["H.J. Lu" <hongjiu dot lu at intel dot com>]

Hi,

This patch enables multi-arch by default if the assembler supports
gnu_indirect_function symbol type and the architecture supports it.

Tested on Linux/ia32, Linux/Intel64 and Linux/ia64 with the Linux
binutils 2.20.51.0.4.


H.J.
---
2009-12-17  H.J. Lu  <hongjiu.lu@intel.com>

	* configure.in: Enable multi-arch by default if the assembler
	supports gnu_indirect_function symbol type and the architecture
	supports it.
	* configure: Regenerated.

diff --git a/configure b/configure
index ce76653..49ac30d 100755
--- a/configure
+++ b/configure
@@ -724,12 +724,12 @@ INSTALL_PROGRAM
 sysdeps_add_ons
 sysnames
 submachine
+multi_arch
 base_machine
 add_on_subdirs
 add_ons
 libc_cv_nss_crypt
 experimental_malloc
-multi_arch
 all_warnings
 force_install
 bindnow
@@ -3801,18 +3801,13 @@ fi
 if test "${enable_multi_arch+set}" = set; then
   enableval=$enable_multi_arch; multi_arch=$enableval
 else
-  multi_arch=no
+  multi_arch=default
 fi
 
-if test x"$multi_arch" = xyes; then
-  cat >>confdefs.h <<\_ACEOF
-#define USE_MULTIARCH 1
-_ACEOF
-
+if test x"$multi_arch" != xno; then
   multi_arch_d=/multiarch
 fi
 
-
 # Check whether --enable-experimental-malloc was given.
 if test "${enable_experimental_malloc+set}" = set; then
   enableval=$enable_experimental_malloc; experimental_malloc=$enableval
@@ -4359,6 +4354,44 @@ for b in $base ''; do
   done
 done
 
+# If the assembler supports gnu_indirect_function symbol type and the
+# architecture supports multi-arch, we enable multi-arch by default.
+if test "$multi_arch" = default; then
+{ $as_echo "$as_me:$LINENO: checking for assembler gnu_indirect_function symbol type support" >&5
+$as_echo_n "checking for assembler gnu_indirect_function symbol type support... " >&6; }
+if test "${libc_cv_asm_gnu_indirect_function+set}" = set; then
+  $as_echo_n "(cached) " >&6
+else
+  cat > conftest.s <<EOF
+.type foo,%gnu_indirect_function
+EOF
+if ${CC-cc} -c $ASFLAGS conftest.s 1>&5 2>&5;
+then
+  libc_cv_asm_gnu_indirect_function=yes
+else
+  libc_cv_asm_gnu_indirect_function=no
+fi
+rm -f conftest*
+fi
+{ $as_echo "$as_me:$LINENO: result: $libc_cv_asm_gnu_indirect_function" >&5
+$as_echo "$libc_cv_asm_gnu_indirect_function" >&6; }
+  multi_arch=no
+  if test "$libc_cv_asm_gnu_indirect_function" = yes; then
+    case $sysnames_add_ons$sysnames in
+    *"$multi_arch_d"*)
+       multi_arch=yes
+      ;;
+    esac
+  fi
+fi
+if test x"$multi_arch" = xyes; then
+  cat >>confdefs.h <<\_ACEOF
+#define USE_MULTIARCH 1
+_ACEOF
+
+fi
+
+
 if test -z "$os_used" && test "$os" != none; then
   { { $as_echo "$as_me:$LINENO: error: Operating system $os is not supported." >&5
 $as_echo "$as_me: error: Operating system $os is not supported." >&2;}
diff --git a/configure.in b/configure.in
index 182c683..8e50602 100644
--- a/configure.in
+++ b/configure.in
@@ -272,12 +272,10 @@ AC_ARG_ENABLE([multi-arch],
 	      AC_HELP_STRING([--enable-multi-arch],
 			     [enable single DSO with optimizations for multiple architectures]),
 	      [multi_arch=$enableval],
-	      [multi_arch=no])
-if test x"$multi_arch" = xyes; then
-  AC_DEFINE(USE_MULTIARCH)
+	      [multi_arch=default])
+if test x"$multi_arch" != xno; then
   multi_arch_d=/multiarch
 fi
-AC_SUBST(multi_arch)
 
 AC_ARG_ENABLE([experimental-malloc],
 	      AC_HELP_STRING([--enable-experimental-malloc],
@@ -722,6 +720,35 @@ for b in $base ''; do
   done
 done
 
+# If the assembler supports gnu_indirect_function symbol type and the
+# architecture supports multi-arch, we enable multi-arch by default.
+if test "$multi_arch" = default; then
+AC_CACHE_CHECK([for assembler gnu_indirect_function symbol type support],
+               libc_cv_asm_gnu_indirect_function, [dnl
+cat > conftest.s <<EOF
+.type foo,%gnu_indirect_function
+EOF
+if ${CC-cc} -c $ASFLAGS conftest.s 1>&AS_MESSAGE_LOG_FD 2>&AS_MESSAGE_LOG_FD;
+then
+  libc_cv_asm_gnu_indirect_function=yes
+else
+  libc_cv_asm_gnu_indirect_function=no
+fi
+rm -f conftest*])
+  multi_arch=no
+  if test "$libc_cv_asm_gnu_indirect_function" = yes; then
+    case $sysnames_add_ons$sysnames in
+    *"$multi_arch_d"*)
+       multi_arch=yes
+      ;;
+    esac
+  fi
+fi
+if test x"$multi_arch" = xyes; then
+  AC_DEFINE(USE_MULTIARCH)
+fi
+AC_SUBST(multi_arch)
+
 if test -z "$os_used" && test "$os" != none; then
   AC_MSG_ERROR(Operating system $os is not supported.)
 fi