Re: [PATCH 3/4] tests/unit/test-char: Avoid using g_alloca()

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

On 5/6/25 22:53, Pierrick Bouvier wrote:
> On 6/5/25 12:35 PM, Philippe Mathieu-Daudé wrote:
>> Do not use g_alloca(), simply allocate the CharBackend
>> structure on the stack.
>>
>> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
>> ---
>>   tests/unit/test-char.c | 3 +--
>>   1 file changed, 1 insertion(+), 2 deletions(-)
>>
>> diff --git a/tests/unit/test-char.c b/tests/unit/test-char.c
>> index 60a843b79d9..f30a39f61ff 100644
>> --- a/tests/unit/test-char.c
>> +++ b/tests/unit/test-char.c
>> @@ -993,7 +993,7 @@ static void char_udp_test_internal(Chardev 
>> *reuse_chr, int sock)
>>       struct sockaddr_in other;
>>       SocketIdleData d = { 0, };
>>       Chardev *chr;
>> -    CharBackend *be;
>> +    CharBackend stack_be, *be = &stack_be;
>>       socklen_t alen = sizeof(other);
>>       int ret;
>>       char buf[10];
>> @@ -1009,7 +1009,6 @@ static void char_udp_test_internal(Chardev 
>> *reuse_chr, int sock)
>>           chr = qemu_chr_new("client", tmp, NULL);
>>           g_assert_nonnull(chr);
>> -        be = g_alloca(sizeof(CharBackend));
>>           qemu_chr_fe_init(be, chr, &error_abort);
>>       }
> 
> Would that be more simple to declare the variable, and use &be in the 
> function code?

More context (see reuse_chr ladder):

-- >8 --
@@ -991,45 +991,44 @@ static int make_udp_socket(int *port)
  static void char_udp_test_internal(Chardev *reuse_chr, int sock)
  {
      struct sockaddr_in other;
      SocketIdleData d = { 0, };
      Chardev *chr;
-    CharBackend *be;
+    CharBackend stack_be, *be = &stack_be;
      socklen_t alen = sizeof(other);
      int ret;
      char buf[10];
      char *tmp = NULL;

      if (reuse_chr) {
          chr = reuse_chr;
          be = chr->be;
      } else {
          int port;
          sock = make_udp_socket(&port);
          tmp = g_strdup_printf("udp:127.0.0.1:%d", port);
          chr = qemu_chr_new("client", tmp, NULL);
          g_assert_nonnull(chr);

-        be = g_alloca(sizeof(CharBackend));
          qemu_chr_fe_init(be, chr, &error_abort);
      }
---