Re: [Qemu-devel] [PATCH for-2.0] configure: use do_cc when checking for -fstack-protector support

[Alexey Kardashevskiy]

On 04/09/2014 09:04 PM, Peter Maydell wrote:
> MacOSX clang silently swallows unrecognized -f options when doing a link
> with '-framework' also on the command line, so to detect support for
> the various -fstack-protector options we must do a plain .c to .o compile,
> not a complete compile-and-link.
> 
> Signed-off-by: Peter Maydell <address@hidden>
> ---
> This should be a pretty safe change and it prevents clang/MacOSX
> builds from spewing a warning on every C file compilation, so I'd
> like to get it into 2.0.
> 
>  configure | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/configure b/configure
> index eb0e7bb..c85475f 100755
> --- a/configure
> +++ b/configure
> @@ -1448,7 +1448,7 @@ done
>  if test "$stack_protector" != "no" ; then
>    gcc_flags="-fstack-protector-strong -fstack-protector-all"
>    for flag in $gcc_flags; do
> -    if compile_prog "-Werror $flag" "" ; then
> +    if do_cc $QEMU_CFLAGS -Werror $flag -c -o $TMPO $TMPC ; then
>        QEMU_CFLAGS="$QEMU_CFLAGS $flag"
>        LIBTOOLFLAGS="$LIBTOOLFLAGS -Wc,$flag"
>        break
> 

My cross environment fails after this patch on "-fstack-protector-all".
Without the patch, gcc for test program gets additional "-m64 -g
-L/home/alexey/crosslib/qemu-build-lib-fc19/usr/lib64" (the last one is
mine, passed via --extra-ldflags=), fails with an error (below). With the
patch, the configure script thinks everything is fine and fails on "ERROR:
zlib check failed".

Why is this happening? Thanks.



powerpc64-linux-gcc -m64 -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64
-D_LARGEFILE_SOURCE -Wstrict-prototypes -Wredundant-decls -Wall -Wundef
-Wwrite-strings -Wmissing-prototypes -fno-strict-aliasing -fno-common
--sysroot=/home/alexey/crosslib/qemu-build-lib-fc19/ -isystem
/home/alexey/crosslib/qemu-build-lib-fc19/usr/include -D__EXCEPTIONS
-D__LONG_DOUBLE_128__ -D__NO_INLINE__ -Wno-redundant-decls
-Wno-missing-prototypes -Wmissing-include-dirs -Wno-system-headers
-Wendif-labels -Wmissing-include-dirs -Wempty-body -Wnested-externs
-Wformat-security -Wformat-y2k -Winit-self -Wignored-qualifiers
-Wold-style-declaration -Wold-style-definition -Wtype-limits -Werror
-fstack-protector-strong -o /tmp/qemu-conf-24556-2284-15038.exe
/tmp/qemu-conf-31026-2284-18135.c -m64 -g
-L/home/alexey/crosslib/qemu-build-lib-fc19/usr/lib64
powerpc64-linux-gcc: error: unrecognized command line option
'-fstack-protector-strong'
powerpc64-linux-gcc -m64 -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64
-D_LARGEFILE_SOURCE -Wstrict-prototypes -Wredundant-decls -Wall -Wundef
-Wwrite-strings -Wmissing-prototypes -fno-strict-aliasing -fno-common
--sysroot=/home/alexey/crosslib/qemu-build-lib-fc19/ -isystem
/home/alexey/crosslib/qemu-build-lib-fc19/usr/include -D__EXCEPTIONS
-D__LONG_DOUBLE_128__ -D__NO_INLINE__ -Wno-redundant-decls
-Wno-missing-prototypes -Wmissing-include-dirs -Wno-system-headers
-Wendif-labels -Wmissing-include-dirs -Wempty-body -Wnested-externs
-Wformat-security -Wformat-y2k -Winit-self -Wignored-qualifiers
-Wold-style-declaration -Wold-style-definition -Wtype-limits -Werror
-fstack-protector-all -o /tmp/qemu-conf-24556-2284-15038.exe
/tmp/qemu-conf-31026-2284-18135.c -m64 -g
-L/home/alexey/crosslib/qemu-build-lib-fc19/usr/lib64
/home/system/opt/cross/gcc-4.8.0-nolibc/powerpc64-linux/bin/../lib/gcc/powerpc64-linux/4.8.0/../../../../powerpc64-linux/bin/ld:
cannot find -lssp_nonshared
/home/system/opt/cross/gcc-4.8.0-nolibc/powerpc64-linux/bin/../lib/gcc/powerpc64-linux/4.8.0/../../../../powerpc64-linux/bin/ld:
cannot find -lssp
collect2: error: ld returned 1 exit status




-- 
Alexey