Patchwork configure: use -Wwombat to test whether gcc recognizes -Wno-wombat

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Submitter Peter Maydell
Date Oct. 27, 2012, 9:19 p.m.
Message ID <1351372747-15992-1-git-send-email-peter.maydell@linaro.org>
Download mbox | patch
Permalink /patch/194634/
State New
Headers show

Comments

Peter Maydell - Oct. 27, 2012, 9:19 p.m.
gcc will silently accept unrecognized -Wno-wombat warning suppression
options (it only mentions them if it has to print a compiler warning
for some other reason). Since we already run a check for whether gcc
recognizes the warning options we use, we can easily make this use
the positive sense of the option when checking for support for the
suppression option. This doesn't have any effect except that it avoids
gcc emitting extra messages about unrecognized command line options
when it is printing other warning messages.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 configure | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
Stefan Weil - Oct. 27, 2012, 9:32 p.m.
Am 27.10.2012 23:19, schrieb Peter Maydell:
> gcc will silently accept unrecognized -Wno-wombat warning suppression
> options (it only mentions them if it has to print a compiler warning
> for some other reason). Since we already run a check for whether gcc
> recognizes the warning options we use, we can easily make this use
> the positive sense of the option when checking for support for the
> suppression option. This doesn't have any effect except that it avoids
> gcc emitting extra messages about unrecognized command line options
> when it is printing other warning messages.
>
> Signed-off-by: Peter Maydell<peter.maydell@linaro.org>
> ---
>   configure | 6 +++++-
>   1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/configure b/configure
> index 37f712d..4c2ba06 100755
> --- a/configure
> +++ b/configure
> @@ -1169,7 +1169,11 @@ cat>  $TMPC<<  EOF
>   int main(void) { return 0; }
>   EOF
>   for flag in $gcc_flags; do
> -    if compile_prog "-Werror $flag" "" ; then
> +    # Use the positive sense of the flag when testing for -Wno-wombat
> +    # support (gcc will happily accept the -Wno- form of unknown
> +    # warning options).
> +    optflag="$(echo $flag | sed -e 's/^-Wno-/-W/')"
> +    if compile_prog "-Werror $optflag" "" ; then
>   	QEMU_CFLAGS="$QEMU_CFLAGS $flag"
>       fi
>   done

Yes, that's really a very simple and working solution.

Reviewed-by: Stefan Weil <sw@weilnetz.de>
Igor Mitsyanko - Oct. 28, 2012, 3:03 p.m.
On 10/28/2012 1:19 AM, Peter Maydell wrote:
> gcc will silently accept unrecognized -Wno-wombat warning suppression
> options (it only mentions them if it has to print a compiler warning
> for some other reason). Since we already run a check for whether gcc
> recognizes the warning options we use, we can easily make this use
> the positive sense of the option when checking for support for the
> suppression option. This doesn't have any effect except that it avoids
> gcc emitting extra messages about unrecognized command line options
> when it is printing other warning messages.
>
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
>   configure | 6 +++++-
>   1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/configure b/configure
> index 37f712d..4c2ba06 100755
> --- a/configure
> +++ b/configure
> @@ -1169,7 +1169,11 @@ cat > $TMPC << EOF
>   int main(void) { return 0; }
>   EOF
>   for flag in $gcc_flags; do
> -    if compile_prog "-Werror $flag" "" ; then
> +    # Use the positive sense of the flag when testing for -Wno-wombat
> +    # support (gcc will happily accept the -Wno- form of unknown
> +    # warning options).
> +    optflag="$(echo $flag | sed -e 's/^-Wno-/-W/')"
> +    if compile_prog "-Werror $optflag" "" ; then
>   	QEMU_CFLAGS="$QEMU_CFLAGS $flag"
>       fi
>   done
>

Reviewed-by: Igor Mitsyanko <i.mitsyanko@samsung.com>
Blue Swirl - Oct. 30, 2012, 9:09 p.m.
Thanks, applied.

On Sat, Oct 27, 2012 at 9:19 PM, Peter Maydell <peter.maydell@linaro.org> wrote:
> gcc will silently accept unrecognized -Wno-wombat warning suppression
> options (it only mentions them if it has to print a compiler warning
> for some other reason). Since we already run a check for whether gcc
> recognizes the warning options we use, we can easily make this use
> the positive sense of the option when checking for support for the
> suppression option. This doesn't have any effect except that it avoids
> gcc emitting extra messages about unrecognized command line options
> when it is printing other warning messages.
>
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
>  configure | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/configure b/configure
> index 37f712d..4c2ba06 100755
> --- a/configure
> +++ b/configure
> @@ -1169,7 +1169,11 @@ cat > $TMPC << EOF
>  int main(void) { return 0; }
>  EOF
>  for flag in $gcc_flags; do
> -    if compile_prog "-Werror $flag" "" ; then
> +    # Use the positive sense of the flag when testing for -Wno-wombat
> +    # support (gcc will happily accept the -Wno- form of unknown
> +    # warning options).
> +    optflag="$(echo $flag | sed -e 's/^-Wno-/-W/')"
> +    if compile_prog "-Werror $optflag" "" ; then
>         QEMU_CFLAGS="$QEMU_CFLAGS $flag"
>      fi
>  done
> --
> 1.7.11.4
>

Patch

diff --git a/configure b/configure
index 37f712d..4c2ba06 100755
--- a/configure
+++ b/configure
@@ -1169,7 +1169,11 @@  cat > $TMPC << EOF
 int main(void) { return 0; }
 EOF
 for flag in $gcc_flags; do
-    if compile_prog "-Werror $flag" "" ; then
+    # Use the positive sense of the flag when testing for -Wno-wombat
+    # support (gcc will happily accept the -Wno- form of unknown
+    # warning options).
+    optflag="$(echo $flag | sed -e 's/^-Wno-/-W/')"
+    if compile_prog "-Werror $optflag" "" ; then
 	QEMU_CFLAGS="$QEMU_CFLAGS $flag"
     fi
 done