Re: [PATCH 1/2] meson: define qemu_isa_flags

[Richard Henderson <richard.henderson@linaro.org>]

On 10/7/24 01:43, Paolo Bonzini wrote:
> Create a separate variable for compiler flags that enable
> specific instruction set extensions, so that they can be used with
> cc.compiles/cc.links.
> 
> Note that -mfpmath=sse is a code generation option but it does not
> enable new instructions, therefore I did not make it part of
> qemu_isa_flags.
> 
> Suggested-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
> Cc: qemu-stable@nongnu.org
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>   meson.build | 24 +++++++++++++++---------
>   1 file changed, 15 insertions(+), 9 deletions(-)
> 
> diff --git a/meson.build b/meson.build
> index 76335bb2a51..bbb0f6d9bcf 100644
> --- a/meson.build
> +++ b/meson.build
> @@ -335,6 +335,10 @@ elif host_os == 'windows'
>     endif
>   endif
>   
> +# Choose instruction set (currently x86-only)
> +
> +qemu_isa_flags = []
> +
>   # __sync_fetch_and_and requires at least -march=i486. Many toolchains
>   # use i686 as default anyway, but for those that don't, an explicit
>   # specification is necessary
> @@ -351,7 +355,7 @@ if host_arch == 'i386' and not cc.links('''
>       sfaa(&val);
>       return val;
>     }''')
> -  qemu_common_flags = ['-march=i486'] + qemu_common_flags
> +  qemu_isa_flags = ['-march=i486']

Use += ?

> -      qemu_common_flags = ['-mcx16'] + qemu_common_flags
> +      qemu_isa_flags = ['-mcx16'] + qemu_isa_flags

Likewise, why verbosely prepend, rather than append with += ?
The same for all others, including

> +qemu_common_flags = qemu_isa_flags + qemu_common_flags


r~