From 40e5138fb1e615c927a21d0b3f2e24eca885ede4 Mon Sep 17 00:00:00 2001 From: Thomas Huth Date: Thu, 15 Jul 2021 10:39:28 +0200 Subject: [PATCH 36/39] configure: Fix endianess test with LTO RH-Author: Jon Maloy RH-MergeRequest: 24: v7: Add support for building qemu-kvm with clang and safe-stack RH-Commit: [9/11] c4be415076356fe74efab6f74d7b347064bbdb40 (jmaloy/qemu-kvm-centos-jon) RH-Bugzilla: 1939509 1940132 RH-Acked-by: Danilo Cesar Lemes de Paula RH-Acked-by: Thomas Huth RH-Acked-by: Cornelia Huck If a user is trying to compile QEMU with link-time optimization enabled by running the configure script like this: .../configure --extra-cflags="-flto" then the endianess test is failing since the magic values do not show up in the intermediate object files there. If the host is a big endian machine (like s390x), the QEMU binary is then unusable since the corresponding variable "bigendian" is pre-initialized with "no". To fix this issue, we should rather create a full binary and look for the magic strings there instead. And we really should not continue the build if the endianess check failed, to make it clear right from the start that something went wrong here, thus let's also add some "exit 1" statements here after emitting the error message. Message-Id: <20210715083928.933806-1-thuth@redhat.com> Reviewed-by: Richard Henderson Signed-off-by: Thomas Huth (cherry picked from commit 659eb157a55666bf379f5362238a86d855e262e2) Signed-off-by: Jon Maloy Signed-off-by: Miroslav Rezanina --- configure | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) diff --git a/configure b/configure index 83d8af7fe4..dcd9520bed 100755 --- a/configure +++ b/configure @@ -2323,24 +2323,27 @@ feature_not_found() { # --- # big/little endian test cat > $TMPC << EOF +#include short big_endian[] = { 0x4269, 0x4765, 0x4e64, 0x4961, 0x4e00, 0, }; short little_endian[] = { 0x694c, 0x7454, 0x654c, 0x6e45, 0x6944, 0x6e41, 0, }; -extern int foo(short *, short *); -int main(int argc, char *argv[]) { - return foo(big_endian, little_endian); +int main(int argc, char *argv[]) +{ + return printf("%s %s\n", (char *)big_endian, (char *)little_endian); } EOF -if compile_object ; then - if strings -a $TMPO | grep -q BiGeNdIaN ; then +if compile_prog ; then + if strings -a $TMPE | grep -q BiGeNdIaN ; then bigendian="yes" - elif strings -a $TMPO | grep -q LiTtLeEnDiAn ; then + elif strings -a $TMPE | grep -q LiTtLeEnDiAn ; then bigendian="no" else echo big/little test failed + exit 1 fi else echo big/little test failed + exit 1 fi ########################################## -- 2.27.0