Re: [PATCH 5/5] s390x/tcg: fix format-truncation warning

[Thomas Huth <thuth@redhat.com>]

On 28/03/2022 12.22, Marc-André Lureau wrote:
> Hi
> 
> On Mon, Mar 28, 2022 at 12:59 PM Thomas Huth <thuth@redhat.com> wrote:
>>
>> On 28/03/2022 10.47, marcandre.lureau@redhat.com wrote:
>>> From: Marc-André Lureau <marcandre.lureau@redhat.com>
>>>
>>> ../target/s390x/tcg/translate.c: In function ‘s390x_translate_init’:
>>> ../target/s390x/tcg/translate.c:224:64: error: ‘%d’ directive output may be truncated writing between 1 and 11 bytes into a region of size 3 [-Werror=format-truncation=]
>>>     224 |         snprintf(cpu_reg_names[i], sizeof(cpu_reg_names[0]), "r%d", i);
>>>         |                                                                ^~
>>>
>>> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
>>> ---
>>>    target/s390x/tcg/translate.c | 4 ++--
>>>    1 file changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/target/s390x/tcg/translate.c b/target/s390x/tcg/translate.c
>>> index 5acfc0ff9b4e..a082342a0424 100644
>>> --- a/target/s390x/tcg/translate.c
>>> +++ b/target/s390x/tcg/translate.c
>>> @@ -199,7 +199,7 @@ static TCGv_i64 regs[16];
>>>
>>>    void s390x_translate_init(void)
>>>    {
>>> -    int i;
>>> +    size_t i;
>>>
>>>        psw_addr = tcg_global_mem_new_i64(cpu_env,
>>>                                          offsetof(CPUS390XState, psw.addr),
>>> @@ -221,7 +221,7 @@ void s390x_translate_init(void)
>>>                                       "cc_vr");
>>>
>>>        for (i = 0; i < 16; i++) {
>>> -        snprintf(cpu_reg_names[i], sizeof(cpu_reg_names[0]), "r%d", i);
>>> +        snprintf(cpu_reg_names[i], sizeof(cpu_reg_names[0]), "r%zu", i);
>>
>> The compiler is *really* too stupid to see that i is in the range between 0
>> and 16 here??? ... that rather sounds like a compiler bug to me than
>> something that we should work-around in the QEMU source code. Considering
>> that you're using a x.0 release of GCC, please file a bug against GCC
>> instead. If they refuse to fix it for GCC 12.1 or later, we can revisit this
>> patch, but currently, I really think this should be fixed in GCC instead.
>>
> 
> I opened: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105080

Thanks! Looks like it will be fixed in the final release of GCC 12, so I 
think we can definitely drop this QEMU patch here.

  Thomas