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

[Peter Maydell]

On 10 April 2014 17:31, Michael S. Tsirkin <address@hidden> wrote:
> On Wed, Apr 09, 2014 at 12:04:47PM +0100, 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>
>
> Hmm it worries me a bit that we aren't passing it to linker:
> might break some builds in case compiler has a working
> protector but linker doesn't.

Given we both compile and link (in configure) with the
same $compiler binary, this seems vanishingly unlikely.

> configure: check -c each time we run compiler
>
> Some warnings/errors only surface if you run compiler
> without a linker. Run both on each test.
>
> Signed-off-by: Michael S. Tsirkin <address@hidden>
>
>
> diff --git a/configure b/configure
> index eb0e7bb..8adc72b 100755
> --- a/configure
> +++ b/configure
> @@ -102,6 +102,7 @@ compile_object() {
>  compile_prog() {
>    local_cflags="$1"
>    local_ldflags="$2"
> +  do_cc $QEMU_CFLAGS -c $local_cflags -o $TMPO $TMPC
>    do_cc $QEMU_CFLAGS $local_cflags -o $TMPE $TMPC $LDFLAGS $local_ldflags
>  }
>

That's a lot of extra compiles and configure isn't
exactly a speed demon as it is...

thanks
-- PMM