Re: [PATCH v3 3/3] qapi: Generate enum count as definition

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Philippe Mathieu-Daudé (philmd@linaro.org) wrote:
> QAPI's gen_enum() generates QAPI enum values and the
> number of this values (as foo__MAX).
> The number of entries in an enum type is not part of
> the enumerated values, but we generate it as such.
> See for example:
> 
>   typedef enum OnOffAuto {
>       ON_OFF_AUTO_AUTO,
>       ON_OFF_AUTO_ON,
>       ON_OFF_AUTO_OFF,
>       ON_OFF_AUTO__MAX,        <---------
>   } OnOffAuto;
> 
> Instead of declaring the enum count as the last enumerated
> value, #define it, so it is not part of the enum.
> The previous example becomes:
> 
>   typedef enum OnOffAuto {
>       ON_OFF_AUTO_AUTO,
>       ON_OFF_AUTO_ON,
>       ON_OFF_AUTO_OFF,
>   #define ON_OFF_AUTO__MAX 3   <---------
>   } OnOffAuto;
> 
> When iterating over a QAPISchemaEnumType, all possible
> values are covered. The 'default' switch case generated in
> gen_visit_object_members() is now unreachable, remove it.
> 
> Since Clang enables the -Wswitch warning by default [*],
> remove all pointless foo__MAX cases in switch statement,
> in order to avoid:
> 
>  audio/audio.c:2231:10: error: case value not in enumerated type 'AudioFormat' (aka 'enum AudioFormat') [-Wswitch]
>     case AUDIO_FORMAT__MAX:
>          ^
>  ui/input.c:233:14: error: case value not in enumerated type 'KeyValueKind' (aka 'enum KeyValueKind') [-Wswitch]
>         case KEY_VALUE_KIND__MAX:
>              ^
>  ...
> 
> [*] https://clang.llvm.org/docs/DiagnosticsReference.html#wswitch
> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
> Reviewed-by: Juan Quintela <quintela@redhat.com>
> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> ---
>  docs/devel/qapi-code-gen.rst |  4 ++--
>  scripts/qapi/types.py        | 11 +++++++----
>  scripts/qapi/visit.py        |  2 --
>  audio/audio_template.h       |  3 ---
>  audio/audio.c                |  6 ------
>  migration/migration.c        |  2 --
>  replay/replay-input.c        | 12 ------------
>  softmmu/tpm-hmp-cmds.c       |  2 --
>  ui/input-linux.c             |  4 ----
>  ui/input.c                   |  6 ------
>  10 files changed, 9 insertions(+), 43 deletions(-)
> 
> diff --git a/docs/devel/qapi-code-gen.rst b/docs/devel/qapi-code-gen.rst
> index d684c7c24d..45b0da448d 100644
> --- a/docs/devel/qapi-code-gen.rst
> +++ b/docs/devel/qapi-code-gen.rst
> @@ -227,7 +227,7 @@ optional 'prefix' member overrides PREFIX.
>  
>  The generated C enumeration constants have values 0, 1, ..., N-1 (in
>  QAPI schema order), where N is the number of values.  There is an
> -additional enumeration constant PREFIX__MAX with value N.
> +additional definition constant PREFIX__MAX with value N.
>  
>  Do not use string or an integer type when an enumeration type can do
>  the job satisfactorily.
> @@ -1825,7 +1825,7 @@ Example::
>  
>      typedef enum example_QAPIEvent {
>          EXAMPLE_QAPI_EVENT_MY_EVENT,
> -        EXAMPLE_QAPI_EVENT__MAX,
> +    #define EXAMPLE_QAPI_EVENT__MAX 1
>      } example_QAPIEvent;
>  
>      #define example_QAPIEvent_str(val) \
> diff --git a/scripts/qapi/types.py b/scripts/qapi/types.py
> index 7a7be7315f..6459a6f925 100644
> --- a/scripts/qapi/types.py
> +++ b/scripts/qapi/types.py
> @@ -88,16 +88,13 @@ def gen_enum(name: str,
>               members: List[QAPISchemaEnumMember],
>               prefix: Optional[str] = None) -> str:
>      assert members
> -    # append automatically generated _MAX value
> -    enum_members = members + [QAPISchemaEnumMember('_MAX', None)]
> -
>      ret = mcgen('''
>  
>  typedef enum %(c_name)s {
>  ''',
>                  c_name=c_name(name))
>  
> -    for memb in enum_members:
> +    for memb in members:
>          ret += memb.ifcond.gen_if()
>          ret += mcgen('''
>      %(c_enum)s,
> @@ -105,6 +102,12 @@ def gen_enum(name: str,
>                       c_enum=c_enum_const(name, memb.name, prefix))
>          ret += memb.ifcond.gen_endif()
>  
> +    ret += mcgen('''
> +#define %(c_name)s %(c_length)s
> +''',
> +                 c_name=c_enum_const(name, '_MAX', prefix),
> +                 c_length=len(members))
> +
>      ret += mcgen('''
>  } %(c_name)s;
>  ''',
> diff --git a/scripts/qapi/visit.py b/scripts/qapi/visit.py
> index 26a584ee4c..f66a31a963 100644
> --- a/scripts/qapi/visit.py
> +++ b/scripts/qapi/visit.py
> @@ -159,8 +159,6 @@ def gen_visit_object_members(name: str,
>  
>              ret += var.ifcond.gen_endif()
>          ret += mcgen('''
> -    default:
> -        abort();
>      }
>  ''')
>  
> diff --git a/audio/audio_template.h b/audio/audio_template.h
> index e42326c20d..d545c03afb 100644
> --- a/audio/audio_template.h
> +++ b/audio/audio_template.h
> @@ -376,9 +376,6 @@ AudiodevPerDirectionOptions *glue(audio_get_pdo_, TYPE)(Audiodev *dev)
>  #endif
>      case AUDIODEV_DRIVER_WAV:
>          return dev->u.wav.TYPE;
> -
> -    case AUDIODEV_DRIVER__MAX:
> -        break;
>      }
>      abort();
>  }
> diff --git a/audio/audio.c b/audio/audio.c
> index 70b096713c..ea372288eb 100644
> --- a/audio/audio.c
> +++ b/audio/audio.c
> @@ -2071,9 +2071,6 @@ void audio_create_pdos(Audiodev *dev)
>          CASE(SPICE, spice, );
>  #endif
>          CASE(WAV, wav, );
> -
> -    case AUDIODEV_DRIVER__MAX:
> -        abort();
>      };
>  }
>  
> @@ -2219,9 +2216,6 @@ int audioformat_bytes_per_sample(AudioFormat fmt)
>      case AUDIO_FORMAT_S32:
>      case AUDIO_FORMAT_F32:
>          return 4;
> -
> -    case AUDIO_FORMAT__MAX:
> -        ;
>      }
>      abort();
>  }
> diff --git a/migration/migration.c b/migration/migration.c
> index ae2025d9d8..bdadab3b5e 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -2220,8 +2220,6 @@ bool migration_is_idle(void)
>      case MIGRATION_STATUS_DEVICE:
>      case MIGRATION_STATUS_WAIT_UNPLUG:
>          return false;
> -    case MIGRATION_STATUS__MAX:
> -        g_assert_not_reached();

Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

>      }
>  
>      return false;
> diff --git a/replay/replay-input.c b/replay/replay-input.c
> index 1147e3d34e..c6de8e33ac 100644
> --- a/replay/replay-input.c
> +++ b/replay/replay-input.c
> @@ -38,9 +38,6 @@ void replay_save_input_event(InputEvent *evt)
>              replay_put_dword(key->key->u.qcode.data);
>              replay_put_byte(key->down);
>              break;
> -        case KEY_VALUE_KIND__MAX:
> -            /* keep gcc happy */
> -            break;
>          }
>          break;
>      case INPUT_EVENT_KIND_BTN:
> @@ -58,9 +55,6 @@ void replay_save_input_event(InputEvent *evt)
>          replay_put_dword(move->axis);
>          replay_put_qword(move->value);
>          break;
> -    case INPUT_EVENT_KIND__MAX:
> -        /* keep gcc happy */
> -        break;
>      }
>  }
>  
> @@ -89,9 +83,6 @@ InputEvent *replay_read_input_event(void)
>              evt.u.key.data->key->u.qcode.data = (QKeyCode)replay_get_dword();
>              evt.u.key.data->down = replay_get_byte();
>              break;
> -        case KEY_VALUE_KIND__MAX:
> -            /* keep gcc happy */
> -            break;
>          }
>          break;
>      case INPUT_EVENT_KIND_BTN:
> @@ -109,9 +100,6 @@ InputEvent *replay_read_input_event(void)
>          evt.u.abs.data->axis = (InputAxis)replay_get_dword();
>          evt.u.abs.data->value = replay_get_qword();
>          break;
> -    case INPUT_EVENT_KIND__MAX:
> -        /* keep gcc happy */
> -        break;
>      }
>  
>      return QAPI_CLONE(InputEvent, &evt);
> diff --git a/softmmu/tpm-hmp-cmds.c b/softmmu/tpm-hmp-cmds.c
> index 9ed6ad6c4d..5a354cf6ac 100644
> --- a/softmmu/tpm-hmp-cmds.c
> +++ b/softmmu/tpm-hmp-cmds.c
> @@ -52,8 +52,6 @@ void hmp_info_tpm(Monitor *mon, const QDict *qdict)
>              teo = ti->options->u.emulator.data;
>              monitor_printf(mon, ",chardev=%s", teo->chardev);
>              break;
> -        case TPM_TYPE__MAX:
> -            break;
>          }
>          monitor_printf(mon, "\n");
>          c++;
> diff --git a/ui/input-linux.c b/ui/input-linux.c
> index e572a2e905..a6e7574422 100644
> --- a/ui/input-linux.c
> +++ b/ui/input-linux.c
> @@ -120,10 +120,6 @@ static bool input_linux_check_toggle(InputLinux *il)
>          return (il->keydown[KEY_LEFTCTRL] ||
>                  il->keydown[KEY_RIGHTCTRL]) &&
>              il->keydown[KEY_SCROLLLOCK];
> -
> -    case GRAB_TOGGLE_KEYS__MAX:
> -        /* avoid gcc error */
> -        break;
>      }
>      return false;
>  }
> diff --git a/ui/input.c b/ui/input.c
> index f2d1e7a3a7..ca8f49a403 100644
> --- a/ui/input.c
> +++ b/ui/input.c
> @@ -230,9 +230,6 @@ static void qemu_input_event_trace(QemuConsole *src, InputEvent *evt)
>              name = QKeyCode_str(key->key->u.qcode.data);
>              trace_input_event_key_qcode(idx, name, key->down);
>              break;
> -        case KEY_VALUE_KIND__MAX:
> -            /* keep gcc happy */
> -            break;
>          }
>          break;
>      case INPUT_EVENT_KIND_BTN:
> @@ -250,9 +247,6 @@ static void qemu_input_event_trace(QemuConsole *src, InputEvent *evt)
>          name = InputAxis_str(move->axis);
>          trace_input_event_abs(idx, name, move->value);
>          break;
> -    case INPUT_EVENT_KIND__MAX:
> -        /* keep gcc happy */
> -        break;
>      }
>  }
>  
> -- 
> 2.38.1
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK