Re: [Qemu-devel] [PATCH v4] configure: do CC check before verifying host CPU

[Peter Maydell]

On 1 November 2017 at 19:31, Daniel Henrique Barboza
<address@hidden> wrote:
> When executing 'configure' in a fresh QEMU clone, in a fresh
> OS install running in a ppc64le host, this is the error
> shown:
>
> -----
>
> ../configure --enable-trace-backend=simple --enable-debug
>     --target-list=ppc64-softmmu
>
> ERROR: Unsupported CPU = ppc64le, try --enable-tcg-interpreter
>
> -----
>
> This isn't true, ppc64le host CPU is supported. This happens because,
> in a fresh install, we don't have a C compiler to autodetect
> the $cpu variable to "ppc64".
>
> Since we need a C compiler to properly get the value of $cpu
> in this and other cases, this patch changes the location of the C
> compiler check right after setting the preferred CC.
>
> Signed-off-by: Daniel Henrique Barboza <address@hidden>
> ---
>  configure | 34 +++++++++++++++++-----------------
>  1 file changed, 17 insertions(+), 17 deletions(-)
>
> diff --git a/configure b/configure
> index 285d123dbf..a641bf18b6 100755
> --- a/configure
> +++ b/configure
> @@ -467,6 +467,23 @@ else
>    cc="${CC-${cross_prefix}gcc}"
>  fi
>
> +write_c_skeleton() {
> +    cat > $TMPC <<EOF
> +int main(void) { return 0; }
> +EOF
> +}
> +
> +# check that the C compiler works.
> +write_c_skeleton;
> +if compile_object ; then
> +  : C compiler works ok
> +else
> +    error_exit "\"$cc\" either does not exist or does not work"
> +fi
> +if ! compile_prog ; then
> +    error_exit "\"$cc\" cannot build an executable (is your linker broken?)"
> +fi
> +

I think that currently we try to make "--help" work
even if you don't have a working C compiler. Does this
break that?

thanks
-- PMM