configure: Fix endianess test with LTO

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 <richard.henderson@linaro.org>
Signed-off-by: Thomas Huth <thuth@redhat.com>
This commit is contained in:
Thomas Huth 2021-07-15 10:39:28 +02:00
parent 8619b5ddb5
commit 659eb157a5

15
configure vendored
View File

@ -2365,24 +2365,27 @@ feature_not_found() {
# --- # ---
# big/little endian test # big/little endian test
cat > $TMPC << EOF cat > $TMPC << EOF
#include <stdio.h>
short big_endian[] = { 0x4269, 0x4765, 0x4e64, 0x4961, 0x4e00, 0, }; short big_endian[] = { 0x4269, 0x4765, 0x4e64, 0x4961, 0x4e00, 0, };
short little_endian[] = { 0x694c, 0x7454, 0x654c, 0x6e45, 0x6944, 0x6e41, 0, }; short little_endian[] = { 0x694c, 0x7454, 0x654c, 0x6e45, 0x6944, 0x6e41, 0, };
extern int foo(short *, short *); int main(int argc, char *argv[])
int main(int argc, char *argv[]) { {
return foo(big_endian, little_endian); return printf("%s %s\n", (char *)big_endian, (char *)little_endian);
} }
EOF EOF
if compile_object ; then if compile_prog ; then
if strings -a $TMPO | grep -q BiGeNdIaN ; then if strings -a $TMPE | grep -q BiGeNdIaN ; then
bigendian="yes" bigendian="yes"
elif strings -a $TMPO | grep -q LiTtLeEnDiAn ; then elif strings -a $TMPE | grep -q LiTtLeEnDiAn ; then
bigendian="no" bigendian="no"
else else
echo big/little test failed echo big/little test failed
exit 1
fi fi
else else
echo big/little test failed echo big/little test failed
exit 1
fi fi
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