Re: [Qemu-devel] [PATCH 10/10] linux-user: remove unused variables

[Richard Henderson <rth@twiddle.net>]

On 06/15/2011 01:35 AM, Alexander Graf wrote:
>> -                abi_ulong arg5 = 0, arg6 = 0, arg7 = 0, arg8 = 0;
>> +                abi_ulong arg5 = 0, arg6 = 0;
>>
>>                 nb_args = mips_syscall_args[syscall_num];
>>                 sp_reg = env->active_tc.gpr[29];
>>                 switch (nb_args) {
>>                 /* these arguments are taken from the stack */
>>                 /* FIXME - what to do if get_user() fails? */
>> -                case 8: get_user_ual(arg8, sp_reg + 28);
>> -                case 7: get_user_ual(arg7, sp_reg + 24);
>> +                case 8: /* get_user_ual(arg8, sp_reg + 28); */
>> +                case 7: /* get_user_ual(arg7, sp_reg + 24); */
> 
> I'd prefer to see these and the respective variable definitions #if
> 0'd with a comment, stating that they're currently unused.

I'd prefer not to see if 0 code.  Better, I think, to mark the
variables as __attribute__((unused)) with that same comment.

>> @@ -7058,18 +7056,14 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
>>     case TARGET_NR_osf_sigprocmask:
>>         {
>>             abi_ulong mask;
>> -            int how = arg1;
>>             sigset_t set, oldset;
>>
>>             switch(arg1) {
>>             case TARGET_SIG_BLOCK:
>> -                how = SIG_BLOCK;
>>                 break;
>>             case TARGET_SIG_UNBLOCK:
>> -                how = SIG_UNBLOCK;
>>                 break;
>>             case TARGET_SIG_SETMASK:
>> -                how = SIG_SETMASK;
> 
> why go through the effort of setting "how" and then not using it? I'm
> pretty sure this is a bug as well. A few lines down is the following
> code:
> 
>    sigprocmask(arg1, &set, &oldset);
> 
> which in TARGET_NR_sigprocmask would be:
> 
>   ret = get_errno(sigprocmask(how, &set, &oldset));
> 
> So we end up sending guest masks to the host. Richard, this is Alpha
> specific code. Mind to double-check?

I remember fixing this before.  Perhaps it was in a patch tree that 
never got pulled...


r~