Back in
ccf2d89d39b21bc8c7b497b40be5b82eadb80863 ("configure: try to
disable weak linking on OSX") disabling weak symbols was done to prevent
depending on features when building on a newer macOS but targeting an
older one. Fast-forward to Xcode 11.4 and it turns out Apple have broken
this by depending on weak symbols for critical symbols like FD_SET
leading to compilation errors like the following
ld: weak import of symbol '___darwin_check_fd_set_overflow' not supported because of option: -no_weak_imports for architecture x86_64
Other people/projects have been hit by this issue:
- https://openradar.appspot.com/
FB7647406
- https://github.com/mono/mono/issues/19393
but Apple have kept this behaviour into XCode 12 so we should adapt.
- Introduce the concept of configure only CFLAGS
- Switch to using -Werror=partial-availability with the above
- Stop logging a message about disabling weak linking
The above should avoid finding features the target platform doesn't have
while allowing weak linking. The name CONFIGURE_CFLAGS is used to remain
similar to QEMU's configure. Fingers crossed this approach stays
supported by Apple...
Fixes https://github.com/axboe/fio/issues/1006
Signed-off-by: Sitsofe Wheeler <sitsofe@yahoo.com>
# Default CFLAGS
CFLAGS="-D_GNU_SOURCE -include config-host.h $CFLAGS"
+CONFIGURE_CFLAGS="-Werror-implicit-function-declaration"
BUILD_CFLAGS=""
# Print a helpful header at the top of config.log
}
compile_object() {
- do_cc $CFLAGS -Werror-implicit-function-declaration -c -o $TMPO $TMPC
+ do_cc $CFLAGS $CONFIGURE_CFLAGS -c -o $TMPO $TMPC
}
compile_prog() {
local_cflags="$1"
local_ldflags="$2 $LIBS"
echo "Compiling test case $3" >> config.log
- do_cc $CFLAGS -Werror-implicit-function-declaration $local_cflags -o $TMPE $TMPC $LDFLAGS $local_ldflags
+ do_cc $CFLAGS $CONFIGURE_CFLAGS $local_cflags -o $TMPE $TMPC $LDFLAGS $local_ldflags
}
feature_not_found() {
if test -z "$cpu" && test "$(sysctl -n hw.optional.x86_64)" = "1"; then
cpu="x86_64"
fi
- # Error at compile time linking of weak/partial symbols if possible...
+ # Avoid configure feature detection of features provided by weak symbols
cat > $TMPC <<EOF
int main(void)
{
return 0;
}
EOF
- if compile_prog "" "-Wl,-no_weak_imports" "disable weak symbols"; then
- echo "Disabling weak symbols"
- LDFLAGS="$LDFLAGS -Wl,-no_weak_imports"
+ if compile_prog "" "-Werror=partial-availability" "error on weak symbols"; then
+ CONFIGURE_CFLAGS="$CONFIGURE_CFLAGS -Werror=partial-availability"
fi
;;
SunOS)