[RS6000] .gnu.attributes Tag_GNU_Power_ABI_FP

Extend this attribute to cover long double ABIs, for 64-bit too.

This patch also corrects an error that crept in to code setting
rs6000_passes_float.  See the added comment.  Passing IEEE128 values
in vsx regs ought to set both Tag_GNU_Power_ABI_FP and
Tag_GNU_Power_ABI_Vector.  Also adds a new option, default on, that
disables output of .gnu_attribute assembly directives.

	* config/rs6000/sysv4.opt (mgnu-attribute): New option.
	* doc/invoke.texi: Document it.
	* config/rs6000/rs6000.c (HAVE_LD_PPC_GNU_ATTR_LONG_DOUBLE): Define.
	(rs6000_passes_float): Comment.
	(rs6000_passes_long_double): New static var.
	(call_ABI_of_interest): Return false unless rs6000_gnu_attr is set.
	(init_cumulative_args): Set up to emit fp .gnu_attribute for
	ELF 64-bit ABIs as well as 32-bit ELF.  Correct rs6000_passes_float
	to include fp values returned in vectors.
	Set rs6000_passes_long_double.
	(rs6000_function_arg_advance_1): Likewise for function args.
	(rs6000_elf_file_end): Emit fp .gnu_attribute for ELF 64-bit ABIs,
	and SPE.  Emit long double tag value too.
	(rs6000_opt_vars): Add gnu-attr.
	* configure.ac (HAVE_LD_PPC_GNU_ATTR_LONG_DOUBLE): New ppc32 test.
	* configure: Regenerate.
	* config.in: Regenerate.

From-SVN: r240601

1 files changed, 45 insertions, 0 deletions

diff --git a/gcc/configure.ac b/gcc/configure.ac
index 534f22e47de..a702f176974 100644
--- a/gcc/configure.ac
+++ b/gcc/configure.ac
@@ -5322,6 +5322,51 @@ if test "x$gcc_cv_ld_clearcap" = xyes; then
 fi
 AC_MSG_RESULT($gcc_cv_ld_clearcap)
 
+case "$target" in
+  powerpc*-*-*)
+    case "$target" in
+      *le-*-linux*)
+	emul_name="-melf32lppc"
+	;;
+      *)
+	emul_name="-melf32ppc"
+	;;
+    esac
+    AC_CACHE_CHECK(linker .gnu.attributes long double support,
+    gcc_cv_ld_ppc_attr,
+    [gcc_cv_ld_ppc_attr=no
+    if test x"$ld_is_gold" = xyes; then
+      gcc_cv_ld_ppc_attr=yes
+    elif test $in_tree_ld = yes ; then
+      if test "$gcc_cv_gld_major_version" -eq 2 \
+		-a "$gcc_cv_gld_minor_version" -ge 28 \
+		-o "$gcc_cv_gld_major_version" -gt 2; then
+        gcc_cv_ld_ppc_attr=yes
+      fi
+    elif test x$gcc_cv_as != x -a x$gcc_cv_ld != x ; then
+      # check that merging the long double .gnu_attribute doesn't warn
+      cat > conftest1.s <<EOF
+	.gnu_attribute 4,1
+EOF
+      cat > conftest2.s <<EOF
+	.gnu_attribute 4,9
+EOF
+      if $gcc_cv_as -a32 -o conftest1.o conftest1.s > /dev/null 2>&1 \
+         && $gcc_cv_as -a32 -o conftest2.o conftest2.s > /dev/null 2>&1 \
+         && $gcc_cv_ld $emul_name -r -o conftest.o conftest1.o conftest2.o > /dev/null 2> conftest.err \
+	 && test ! -s conftest.err; then
+        gcc_cv_ld_ppc_attr=yes
+      fi
+      rm -f conftest.err conftest.o conftest1.o conftest2.o conftest1.s conftest2.s
+    fi
+    ])
+    if test x$gcc_cv_ld_ppc_attr = xyes; then
+      AC_DEFINE(HAVE_LD_PPC_GNU_ATTR_LONG_DOUBLE, 1,
+    [Define if your PowerPC linker has .gnu.attributes long double support.])
+    fi
+    ;;
+esac
+
 case "$target:$tm_file" in
   powerpc64-*-freebsd* | powerpc64*-*-linux* | powerpc*-*-linux*rs6000/biarch64.h*)
   case "$target" in