Re: [PATCH v3 02/15] cpus: Add const-qualified CPU environment accessors

On 21/8/26 19:07, Richard Henderson wrote:
> On 8/21/26 08:51, Philippe Mathieu-Daudé wrote:
>> No, this now fails distinctly on Ubuntu 24.04:
>>
>> In file included from ../accel/tcg/tcg-runtime.c:26:
>> ../accel/tcg/tcg-runtime.c: In function ‘helper_exit_atomic’:
>> /home/runner/work/qemu/qemu/include/exec/cpu-common.h:100:31: error: 
>> expected expression before ‘typeof’
>>    100 | #define env_cpu(env) _Generic(typeof(*env), \
>>        |                               ^~~~~~
>> ../accel/tcg/tcg-runtime.c:135:26: note: in expansion of macro ‘env_cpu’
>>    135 |     cpu_loop_exit_atomic(env_cpu(env), GETPC());
>>        |                          ^~~~~~~
> 
> Yeah, this of course fails because _Generic wants an expression and 
> typeof() is a type not an expression.
> 
> However, in this case less is more -- just don't dereference env:
> 
> #define env_cpu(env) _Generic(env, \
>              CPUArchState *: \
>                  (CPUState *)((void *)(env) - sizeof(CPUState)), \
>              const CPUArchState *: \
>                  (const CPUState *)((const void *)(env) - 
> sizeof(CPUState)))

Indeed :) The simpler the better. Thanks for the help!
> 
> etc.  It's only top-level qualifiers that are stripped (so const int -> 
> const), but qualified pointers aren't top level (so const int * and int 
> * do not match).
> 
> 
> r~
>