Re: [PULL 12/13] configure: Add -Werror to PIE probe

[Mark Cave-Ayland]

On 07/04/2020 16:51, Alex Bennée wrote:

> From: Richard Henderson <address@hidden>
> 
> Without -Werror, the probe may succeed, but then compilation fails
> later when -Werror is added for other reasons.  Shows up on windows,
> where the compiler complains about -fPIC.
> 
> Signed-off-by: Richard Henderson <address@hidden>
> Signed-off-by: Alex Bennée <address@hidden>
> Reviewed-by: Philippe Mathieu-Daudé <address@hidden>
> Tested-by: Philippe Mathieu-Daudé <address@hidden>
> Message-Id: <address@hidden>
> Message-Id: <address@hidden>
> 
> diff --git a/configure b/configure
> index 22870f38672..233c671aaa9 100755
> --- a/configure
> +++ b/configure
> @@ -2119,7 +2119,7 @@ if compile_prog "-Werror -fno-pie" "-no-pie"; then
>  fi
>  
>  if test "$static" = "yes"; then
> -  if test "$pie" != "no" && compile_prog "-fPIE -DPIE" "-static-pie"; then
> +  if test "$pie" != "no" && compile_prog "-Werror -fPIE -DPIE" 
> "-static-pie"; then
>      QEMU_CFLAGS="-fPIE -DPIE $QEMU_CFLAGS"
>      QEMU_LDFLAGS="-static-pie $QEMU_LDFLAGS"
>      pie="yes"
> @@ -2132,7 +2132,7 @@ if test "$static" = "yes"; then
>  elif test "$pie" = "no"; then
>    QEMU_CFLAGS="$CFLAGS_NOPIE $QEMU_CFLAGS"
>    QEMU_LDFLAGS="$LDFLAGS_NOPIE $QEMU_LDFLAGS"
> -elif compile_prog "-fPIE -DPIE" "-pie"; then
> +elif compile_prog "-Werror -fPIE -DPIE" "-pie"; then
>    QEMU_CFLAGS="-fPIE -DPIE $QEMU_CFLAGS"
>    QEMU_LDFLAGS="-pie $QEMU_LDFLAGS"
>    pie="yes"

Note that even with this build fix, the native and cross-compiled Windows 
binaries
crash upon startup unless --disable-pie is explicitly passed to configure (this 
seems
like an unexpected side-effect of d2cd29e307: "configure: Do not force pie=no 
for
non-x86").

Given that users such as Howard and https://bugs.launchpad.net/bugs/1870911 are
starting to notice, would it be best to set this configure option as the 
default for
Windows builds for now?


ATB,

Mark.