[PATCH] configure: Check whether we can compile the s390-ccw bios with -msoft-float

From: Thomas Huth <thuth@redhat.com>
To: qemu-s390x@nongnu.org, qemu-devel@nongnu.org
Cc: Christian Borntraeger <borntraeger@de.ibm.com>,
	Cornelia Huck <cohuck@redhat.com>
Subject: [PATCH] configure: Check whether we can compile the s390-ccw bios with -msoft-float
Date: Tue, 25 May 2021 16:20:32 +0200	[thread overview]
Message-ID: <20210525142032.156989-1-thuth@redhat.com> (raw)

The -msoft-float switch is not available in older versions of Clang.
Since we rely on the compiler to not generate floating point instructions
unexpectedly, we block those old compilers now via a test in the configure
script. Note that for some weird reasons, the Clang compiler only complains
about the missing soft-float support if no other flags are passed via
"-Wl,..." to the linker. So we have to use "compile_object" instead of
"compile_prog" for this check.

Signed-off-by: Thomas Huth <thuth@redhat.com>
---
 configure | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/configure b/configure
index 676239c697..673419ff31 100755
--- a/configure
+++ b/configure
@@ -5462,7 +5462,7 @@ if test "$cpu" = "s390x" ; then
   write_c_skeleton
   compile_prog "-march=z900" ""
   has_z900=$?
-  if [ $has_z900 = 0 ] || compile_prog "-march=z10" ""; then
+  if [ $has_z900 = 0 ] || compile_object "-march=z10 -msoft-float -Werror"; then
     if [ $has_z900 != 0 ]; then
       echo "WARNING: Your compiler does not support the z900!"
       echo "         The s390-ccw bios will only work with guest CPUs >= z10."
-- 
2.27.0


