| Message ID | 20240213223334.3693410-2-stefano.stabellini@amd.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2,1/3] docs/misra/rules.rst: add rule 16.6 and 20.12 | expand |
On 13.02.2024 23:33, Stefano Stabellini wrote: > Signed-off-by: Stefano Stabellini <stefano.stabellini@amd.com> > --- > docs/misra/rules.rst | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/docs/misra/rules.rst b/docs/misra/rules.rst > index c185366966..931158b354 100644 > --- a/docs/misra/rules.rst > +++ b/docs/misra/rules.rst > @@ -181,6 +181,12 @@ maintainers if you want to suggest a change. > headers (xen/include/public/) are allowed to retain longer > identifiers for backward compatibility. > > + * - `Rule 5.5 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_05_05.c>`_ > + - Required > + - Identifiers shall be distinct from macro names > + - Clashes between function-like macros and non-callable entities > + are allowed. The pattern #define x x is also allowed. Just for me to know what exactly is covered (hence also a question to Roberto as to [to be] implemented Eclair behavior): Even when the above would be sufficient (and imo better) people frequently write #define a(x, y) b(x, y) which, transformed to the specific case here, would then be #define a(x, y) a(x, y) I'd assume such ought to also be covered, but that's not clear from the spelling above. Jan
On 14/02/24 09:28, Jan Beulich wrote: > On 13.02.2024 23:33, Stefano Stabellini wrote: >> Signed-off-by: Stefano Stabellini <stefano.stabellini@amd.com> >> --- >> docs/misra/rules.rst | 6 ++++++ >> 1 file changed, 6 insertions(+) >> >> diff --git a/docs/misra/rules.rst b/docs/misra/rules.rst >> index c185366966..931158b354 100644 >> --- a/docs/misra/rules.rst >> +++ b/docs/misra/rules.rst >> @@ -181,6 +181,12 @@ maintainers if you want to suggest a change. >> headers (xen/include/public/) are allowed to retain longer >> identifiers for backward compatibility. >> >> + * - `Rule 5.5 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_05_05.c>`_ >> + - Required >> + - Identifiers shall be distinct from macro names >> + - Clashes between function-like macros and non-callable entities >> + are allowed. The pattern #define x x is also allowed. > > Just for me to know what exactly is covered (hence also a question > to Roberto as to [to be] implemented Eclair behavior): Even when > the above would be sufficient (and imo better) people frequently > write > > #define a(x, y) b(x, y) > > which, transformed to the specific case here, would then be > > #define a(x, y) a(x, y) > > I'd assume such ought to also be covered, but that's not clear > from the spelling above. I list what happens in some different situations, then we can find the right words for the documentation and/or refine the configuration: If you #define x x and then use `x' as identifier, the resulting violation is deviated (allowed pattern). If you #define a(x, y) a(x, y) and then use `a' as identifier for a non-callable entity, the resulting violation is deviated (no clash with non-callable entities). If you use identifier `a' for a callable entity, the resulting violation is reported: the allowed pattern covers only macros expanding to their own name, in this case the macro name is considered to be `a' only, not a(x, y). If you #define a(x, y) b(x, y) and then use `a' as identifier for a non-callable entity, the resulting violation is deviated (no clash with non-callable entities). If you use `a' as identifier for a callable entity, this is not a violation because after the preprocessing phase, identifier `a' no longer exists. As far as I know, this is what was agreed upon in one of the recent MISRA meetings.
On 14.02.2024 12:27, Federico Serafini wrote: > On 14/02/24 09:28, Jan Beulich wrote: >> On 13.02.2024 23:33, Stefano Stabellini wrote: >>> Signed-off-by: Stefano Stabellini <stefano.stabellini@amd.com> >>> --- >>> docs/misra/rules.rst | 6 ++++++ >>> 1 file changed, 6 insertions(+) >>> >>> diff --git a/docs/misra/rules.rst b/docs/misra/rules.rst >>> index c185366966..931158b354 100644 >>> --- a/docs/misra/rules.rst >>> +++ b/docs/misra/rules.rst >>> @@ -181,6 +181,12 @@ maintainers if you want to suggest a change. >>> headers (xen/include/public/) are allowed to retain longer >>> identifiers for backward compatibility. >>> >>> + * - `Rule 5.5 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_05_05.c>`_ >>> + - Required >>> + - Identifiers shall be distinct from macro names >>> + - Clashes between function-like macros and non-callable entities >>> + are allowed. The pattern #define x x is also allowed. >> >> Just for me to know what exactly is covered (hence also a question >> to Roberto as to [to be] implemented Eclair behavior): Even when >> the above would be sufficient (and imo better) people frequently >> write >> >> #define a(x, y) b(x, y) >> >> which, transformed to the specific case here, would then be >> >> #define a(x, y) a(x, y) >> >> I'd assume such ought to also be covered, but that's not clear >> from the spelling above. > > I list what happens in some different situations, > then we can find the right words for the documentation and/or > refine the configuration: > > If you > #define x x > and then use `x' as identifier, > the resulting violation is deviated (allowed pattern). > > If you > #define a(x, y) a(x, y) > and then use `a' as identifier for a non-callable entity, > the resulting violation is deviated (no clash with non-callable > entities). > If you use identifier `a' for a callable entity, the resulting violation > is reported: the allowed pattern covers only macros expanding to their > own name, in this case the macro name is considered to be > `a' only, not a(x, y). > > If you > #define a(x, y) b(x, y) > and then use `a' as identifier for a non-callable entity, > the resulting violation is deviated (no clash with non-callable > entities). I'm afraid I don't see what violation there is in this case, to deviate. As a result I'm also not sure I correctly understand the rest of your reply. > If you use `a' as identifier for a callable entity, > this is not a violation because after the preprocessing phase, > identifier `a' no longer exists. > > As far as I know, this is what was agreed upon in one of the recent > MISRA meetings. That was my fear (of being what I'd call a wrong [insufficient] interpretation of what was meant). Jan
On 14/02/24 14:15, Jan Beulich wrote: > On 14.02.2024 12:27, Federico Serafini wrote: >> On 14/02/24 09:28, Jan Beulich wrote: >>> On 13.02.2024 23:33, Stefano Stabellini wrote: >>>> Signed-off-by: Stefano Stabellini <stefano.stabellini@amd.com> >>>> --- >>>> docs/misra/rules.rst | 6 ++++++ >>>> 1 file changed, 6 insertions(+) >>>> >>>> diff --git a/docs/misra/rules.rst b/docs/misra/rules.rst >>>> index c185366966..931158b354 100644 >>>> --- a/docs/misra/rules.rst >>>> +++ b/docs/misra/rules.rst >>>> @@ -181,6 +181,12 @@ maintainers if you want to suggest a change. >>>> headers (xen/include/public/) are allowed to retain longer >>>> identifiers for backward compatibility. >>>> >>>> + * - `Rule 5.5 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_05_05.c>`_ >>>> + - Required >>>> + - Identifiers shall be distinct from macro names >>>> + - Clashes between function-like macros and non-callable entities >>>> + are allowed. The pattern #define x x is also allowed. >>> >>> Just for me to know what exactly is covered (hence also a question >>> to Roberto as to [to be] implemented Eclair behavior): Even when >>> the above would be sufficient (and imo better) people frequently >>> write >>> >>> #define a(x, y) b(x, y) >>> >>> which, transformed to the specific case here, would then be >>> >>> #define a(x, y) a(x, y) >>> >>> I'd assume such ought to also be covered, but that's not clear >>> from the spelling above. >> >> I list what happens in some different situations, >> then we can find the right words for the documentation and/or >> refine the configuration: >> >> If you >> #define x x >> and then use `x' as identifier, >> the resulting violation is deviated (allowed pattern). >> >> If you >> #define a(x, y) a(x, y) >> and then use `a' as identifier for a non-callable entity, >> the resulting violation is deviated (no clash with non-callable >> entities). >> If you use identifier `a' for a callable entity, the resulting violation >> is reported: the allowed pattern covers only macros expanding to their >> own name, in this case the macro name is considered to be >> `a' only, not a(x, y). >> >> If you >> #define a(x, y) b(x, y) >> and then use `a' as identifier for a non-callable entity, >> the resulting violation is deviated (no clash with non-callable >> entities). > > I'm afraid I don't see what violation there is in this case, to > deviate. As a result I'm also not sure I correctly understand the > rest of your reply. #define a(x, y) b(x, y) int a; // Violation of Rule 5.5. The macro name `a' that exist before the preprocessing phase, still exists after the preprocessing phase as identifier for the integer variable and this is a violation. >> If you use `a' as identifier for a callable entity, >> this is not a violation because after the preprocessing phase, >> identifier `a' no longer exists. I correct myself: if you use `a' as identifier for a *function*, it is not a violation because after the preprocessing phase the identifier `a' no longer exists, for example: #define a(x, y) b(x, y) void a(int x, int y); // Ok.
On Wed, 14 Feb 2024, Federico Serafini wrote: > On 14/02/24 14:15, Jan Beulich wrote: > > On 14.02.2024 12:27, Federico Serafini wrote: > > > On 14/02/24 09:28, Jan Beulich wrote: > > > > On 13.02.2024 23:33, Stefano Stabellini wrote: > > > > > Signed-off-by: Stefano Stabellini <stefano.stabellini@amd.com> > > > > > --- > > > > > docs/misra/rules.rst | 6 ++++++ > > > > > 1 file changed, 6 insertions(+) > > > > > > > > > > diff --git a/docs/misra/rules.rst b/docs/misra/rules.rst > > > > > index c185366966..931158b354 100644 > > > > > --- a/docs/misra/rules.rst > > > > > +++ b/docs/misra/rules.rst > > > > > @@ -181,6 +181,12 @@ maintainers if you want to suggest a change. > > > > > headers (xen/include/public/) are allowed to retain longer > > > > > identifiers for backward compatibility. > > > > > + * - `Rule 5.5 > > > > > <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_05_05.c>`_ > > > > > + - Required > > > > > + - Identifiers shall be distinct from macro names > > > > > + - Clashes between function-like macros and non-callable entities > > > > > + are allowed. The pattern #define x x is also allowed. > > > > > > > > Just for me to know what exactly is covered (hence also a question > > > > to Roberto as to [to be] implemented Eclair behavior): Even when > > > > the above would be sufficient (and imo better) people frequently > > > > write > > > > > > > > #define a(x, y) b(x, y) > > > > > > > > which, transformed to the specific case here, would then be > > > > > > > > #define a(x, y) a(x, y) > > > > > > > > I'd assume such ought to also be covered, but that's not clear > > > > from the spelling above. > > > > > > I list what happens in some different situations, > > > then we can find the right words for the documentation and/or > > > refine the configuration: > > > > > > If you > > > #define x x > > > and then use `x' as identifier, > > > the resulting violation is deviated (allowed pattern). > > > > > > If you > > > #define a(x, y) a(x, y) > > > and then use `a' as identifier for a non-callable entity, > > > the resulting violation is deviated (no clash with non-callable > > > entities). > > > If you use identifier `a' for a callable entity, the resulting violation > > > is reported: the allowed pattern covers only macros expanding to their > > > own name, in this case the macro name is considered to be > > > `a' only, not a(x, y). > > > > > > If you > > > #define a(x, y) b(x, y) > > > and then use `a' as identifier for a non-callable entity, > > > the resulting violation is deviated (no clash with non-callable > > > entities). > > > > I'm afraid I don't see what violation there is in this case, to > > deviate. As a result I'm also not sure I correctly understand the > > rest of your reply. > > #define a(x, y) b(x, y) > > int a; // Violation of Rule 5.5. > > The macro name `a' that exist before the preprocessing phase, > still exists after the preprocessing phase as identifier for the integer > variable and this is a violation. > > > > If you use `a' as identifier for a callable entity, > > > this is not a violation because after the preprocessing phase, > > > identifier `a' no longer exists. > I correct myself: > if you use `a' as identifier for a *function*, > it is not a violation because after the preprocessing phase > the identifier `a' no longer exists, for example: > > #define a(x, y) b(x, y) > > void a(int x, int y); // Ok. Federico, do you have a better wording suggestion for this rule? Jan, any further requests here? What would you like to see as next step?
On 01.03.2024 00:28, Stefano Stabellini wrote: > On Wed, 14 Feb 2024, Federico Serafini wrote: >> On 14/02/24 14:15, Jan Beulich wrote: >>> On 14.02.2024 12:27, Federico Serafini wrote: >>>> On 14/02/24 09:28, Jan Beulich wrote: >>>>> On 13.02.2024 23:33, Stefano Stabellini wrote: >>>>>> Signed-off-by: Stefano Stabellini <stefano.stabellini@amd.com> >>>>>> --- >>>>>> docs/misra/rules.rst | 6 ++++++ >>>>>> 1 file changed, 6 insertions(+) >>>>>> >>>>>> diff --git a/docs/misra/rules.rst b/docs/misra/rules.rst >>>>>> index c185366966..931158b354 100644 >>>>>> --- a/docs/misra/rules.rst >>>>>> +++ b/docs/misra/rules.rst >>>>>> @@ -181,6 +181,12 @@ maintainers if you want to suggest a change. >>>>>> headers (xen/include/public/) are allowed to retain longer >>>>>> identifiers for backward compatibility. >>>>>> + * - `Rule 5.5 >>>>>> <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_05_05.c>`_ >>>>>> + - Required >>>>>> + - Identifiers shall be distinct from macro names >>>>>> + - Clashes between function-like macros and non-callable entities >>>>>> + are allowed. The pattern #define x x is also allowed. >>>>> >>>>> Just for me to know what exactly is covered (hence also a question >>>>> to Roberto as to [to be] implemented Eclair behavior): Even when >>>>> the above would be sufficient (and imo better) people frequently >>>>> write >>>>> >>>>> #define a(x, y) b(x, y) >>>>> >>>>> which, transformed to the specific case here, would then be >>>>> >>>>> #define a(x, y) a(x, y) >>>>> >>>>> I'd assume such ought to also be covered, but that's not clear >>>>> from the spelling above. >>>> >>>> I list what happens in some different situations, >>>> then we can find the right words for the documentation and/or >>>> refine the configuration: >>>> >>>> If you >>>> #define x x >>>> and then use `x' as identifier, >>>> the resulting violation is deviated (allowed pattern). >>>> >>>> If you >>>> #define a(x, y) a(x, y) >>>> and then use `a' as identifier for a non-callable entity, >>>> the resulting violation is deviated (no clash with non-callable >>>> entities). >>>> If you use identifier `a' for a callable entity, the resulting violation >>>> is reported: the allowed pattern covers only macros expanding to their >>>> own name, in this case the macro name is considered to be >>>> `a' only, not a(x, y). >>>> >>>> If you >>>> #define a(x, y) b(x, y) >>>> and then use `a' as identifier for a non-callable entity, >>>> the resulting violation is deviated (no clash with non-callable >>>> entities). >>> >>> I'm afraid I don't see what violation there is in this case, to >>> deviate. As a result I'm also not sure I correctly understand the >>> rest of your reply. >> >> #define a(x, y) b(x, y) >> >> int a; // Violation of Rule 5.5. >> >> The macro name `a' that exist before the preprocessing phase, >> still exists after the preprocessing phase as identifier for the integer >> variable and this is a violation. >> >>>> If you use `a' as identifier for a callable entity, >>>> this is not a violation because after the preprocessing phase, >>>> identifier `a' no longer exists. >> I correct myself: >> if you use `a' as identifier for a *function*, >> it is not a violation because after the preprocessing phase >> the identifier `a' no longer exists, for example: >> >> #define a(x, y) b(x, y) >> >> void a(int x, int y); // Ok. > > Federico, do you have a better wording suggestion for this rule? > > Jan, any further requests here? What would you like to see as next step? A more concise wording proposal would probably help. Jan
On 01/03/24 09:06, Jan Beulich wrote: > On 01.03.2024 00:28, Stefano Stabellini wrote: >> On Wed, 14 Feb 2024, Federico Serafini wrote: >>> On 14/02/24 14:15, Jan Beulich wrote: >>>> On 14.02.2024 12:27, Federico Serafini wrote: >>>>> On 14/02/24 09:28, Jan Beulich wrote: >>>>>> On 13.02.2024 23:33, Stefano Stabellini wrote: >>>>>>> Signed-off-by: Stefano Stabellini <stefano.stabellini@amd.com> >>>>>>> --- >>>>>>> docs/misra/rules.rst | 6 ++++++ >>>>>>> 1 file changed, 6 insertions(+) >>>>>>> >>>>>>> diff --git a/docs/misra/rules.rst b/docs/misra/rules.rst >>>>>>> index c185366966..931158b354 100644 >>>>>>> --- a/docs/misra/rules.rst >>>>>>> +++ b/docs/misra/rules.rst >>>>>>> @@ -181,6 +181,12 @@ maintainers if you want to suggest a change. >>>>>>> headers (xen/include/public/) are allowed to retain longer >>>>>>> identifiers for backward compatibility. >>>>>>> + * - `Rule 5.5 >>>>>>> <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_05_05.c>`_ >>>>>>> + - Required >>>>>>> + - Identifiers shall be distinct from macro names >>>>>>> + - Clashes between function-like macros and non-callable entities >>>>>>> + are allowed. The pattern #define x x is also allowed. >>>>>> >>>>>> Just for me to know what exactly is covered (hence also a question >>>>>> to Roberto as to [to be] implemented Eclair behavior): Even when >>>>>> the above would be sufficient (and imo better) people frequently >>>>>> write >>>>>> >>>>>> #define a(x, y) b(x, y) >>>>>> >>>>>> which, transformed to the specific case here, would then be >>>>>> >>>>>> #define a(x, y) a(x, y) >>>>>> >>>>>> I'd assume such ought to also be covered, but that's not clear >>>>>> from the spelling above. >>>>> >>>>> I list what happens in some different situations, >>>>> then we can find the right words for the documentation and/or >>>>> refine the configuration: >>>>> >>>>> If you >>>>> #define x x >>>>> and then use `x' as identifier, >>>>> the resulting violation is deviated (allowed pattern). >>>>> >>>>> If you >>>>> #define a(x, y) a(x, y) >>>>> and then use `a' as identifier for a non-callable entity, >>>>> the resulting violation is deviated (no clash with non-callable >>>>> entities). >>>>> If you use identifier `a' for a callable entity, the resulting violation >>>>> is reported: the allowed pattern covers only macros expanding to their >>>>> own name, in this case the macro name is considered to be >>>>> `a' only, not a(x, y). >>>>> >>>>> If you >>>>> #define a(x, y) b(x, y) >>>>> and then use `a' as identifier for a non-callable entity, >>>>> the resulting violation is deviated (no clash with non-callable >>>>> entities). >>>> >>>> I'm afraid I don't see what violation there is in this case, to >>>> deviate. As a result I'm also not sure I correctly understand the >>>> rest of your reply. >>> >>> #define a(x, y) b(x, y) >>> >>> int a; // Violation of Rule 5.5. >>> >>> The macro name `a' that exist before the preprocessing phase, >>> still exists after the preprocessing phase as identifier for the integer >>> variable and this is a violation. >>> >>>>> If you use `a' as identifier for a callable entity, >>>>> this is not a violation because after the preprocessing phase, >>>>> identifier `a' no longer exists. >>> I correct myself: >>> if you use `a' as identifier for a *function*, >>> it is not a violation because after the preprocessing phase >>> the identifier `a' no longer exists, for example: >>> >>> #define a(x, y) b(x, y) >>> >>> void a(int x, int y); // Ok. >> >> Federico, do you have a better wording suggestion for this rule? >> >> Jan, any further requests here? What would you like to see as next step? > > A more concise wording proposal would probably help. What do you think about: diff --git a/docs/misra/rules.rst b/docs/misra/rules.rst index 1e134ccebc..a975b9a85f 100644 --- a/docs/misra/rules.rst +++ b/docs/misra/rules.rst @@ -181,6 +181,13 @@ maintainers if you want to suggest a change. headers (xen/include/public/) are allowed to retain longer identifiers for backward compatibility. + * - `Rule 5.5 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_05_05.c>`_ + - Required + - Identifiers shall be distinct from macro names + - Macros expanding to their own name are allowed (e.g., #define x x). + Clashes between names of function-like macros and identifiers of + non-callable entities are allowed. + * - `Rule 5.6 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_05_06.c>`_ - Required - A typedef name shall be a unique identifier
On 04.03.2024 14:31, Federico Serafini wrote: > On 01/03/24 09:06, Jan Beulich wrote: >> On 01.03.2024 00:28, Stefano Stabellini wrote: >>> On Wed, 14 Feb 2024, Federico Serafini wrote: >>>> On 14/02/24 14:15, Jan Beulich wrote: >>>>> On 14.02.2024 12:27, Federico Serafini wrote: >>>>>> On 14/02/24 09:28, Jan Beulich wrote: >>>>>>> On 13.02.2024 23:33, Stefano Stabellini wrote: >>>>>>>> Signed-off-by: Stefano Stabellini <stefano.stabellini@amd.com> >>>>>>>> --- >>>>>>>> docs/misra/rules.rst | 6 ++++++ >>>>>>>> 1 file changed, 6 insertions(+) >>>>>>>> >>>>>>>> diff --git a/docs/misra/rules.rst b/docs/misra/rules.rst >>>>>>>> index c185366966..931158b354 100644 >>>>>>>> --- a/docs/misra/rules.rst >>>>>>>> +++ b/docs/misra/rules.rst >>>>>>>> @@ -181,6 +181,12 @@ maintainers if you want to suggest a change. >>>>>>>> headers (xen/include/public/) are allowed to retain longer >>>>>>>> identifiers for backward compatibility. >>>>>>>> + * - `Rule 5.5 >>>>>>>> <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_05_05.c>`_ >>>>>>>> + - Required >>>>>>>> + - Identifiers shall be distinct from macro names >>>>>>>> + - Clashes between function-like macros and non-callable entities >>>>>>>> + are allowed. The pattern #define x x is also allowed. >>>>>>> >>>>>>> Just for me to know what exactly is covered (hence also a question >>>>>>> to Roberto as to [to be] implemented Eclair behavior): Even when >>>>>>> the above would be sufficient (and imo better) people frequently >>>>>>> write >>>>>>> >>>>>>> #define a(x, y) b(x, y) >>>>>>> >>>>>>> which, transformed to the specific case here, would then be >>>>>>> >>>>>>> #define a(x, y) a(x, y) >>>>>>> >>>>>>> I'd assume such ought to also be covered, but that's not clear >>>>>>> from the spelling above. >>>>>> >>>>>> I list what happens in some different situations, >>>>>> then we can find the right words for the documentation and/or >>>>>> refine the configuration: >>>>>> >>>>>> If you >>>>>> #define x x >>>>>> and then use `x' as identifier, >>>>>> the resulting violation is deviated (allowed pattern). >>>>>> >>>>>> If you >>>>>> #define a(x, y) a(x, y) >>>>>> and then use `a' as identifier for a non-callable entity, >>>>>> the resulting violation is deviated (no clash with non-callable >>>>>> entities). >>>>>> If you use identifier `a' for a callable entity, the resulting violation >>>>>> is reported: the allowed pattern covers only macros expanding to their >>>>>> own name, in this case the macro name is considered to be >>>>>> `a' only, not a(x, y). >>>>>> >>>>>> If you >>>>>> #define a(x, y) b(x, y) >>>>>> and then use `a' as identifier for a non-callable entity, >>>>>> the resulting violation is deviated (no clash with non-callable >>>>>> entities). >>>>> >>>>> I'm afraid I don't see what violation there is in this case, to >>>>> deviate. As a result I'm also not sure I correctly understand the >>>>> rest of your reply. >>>> >>>> #define a(x, y) b(x, y) >>>> >>>> int a; // Violation of Rule 5.5. >>>> >>>> The macro name `a' that exist before the preprocessing phase, >>>> still exists after the preprocessing phase as identifier for the integer >>>> variable and this is a violation. >>>> >>>>>> If you use `a' as identifier for a callable entity, >>>>>> this is not a violation because after the preprocessing phase, >>>>>> identifier `a' no longer exists. >>>> I correct myself: >>>> if you use `a' as identifier for a *function*, >>>> it is not a violation because after the preprocessing phase >>>> the identifier `a' no longer exists, for example: >>>> >>>> #define a(x, y) b(x, y) >>>> >>>> void a(int x, int y); // Ok. >>> >>> Federico, do you have a better wording suggestion for this rule? >>> >>> Jan, any further requests here? What would you like to see as next step? >> >> A more concise wording proposal would probably help. > > What do you think about: > > diff --git a/docs/misra/rules.rst b/docs/misra/rules.rst > index 1e134ccebc..a975b9a85f 100644 > --- a/docs/misra/rules.rst > +++ b/docs/misra/rules.rst > @@ -181,6 +181,13 @@ maintainers if you want to suggest a change. > headers (xen/include/public/) are allowed to retain longer > identifiers for backward compatibility. > > + * - `Rule 5.5 > <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_05_05.c>`_ > + - Required > + - Identifiers shall be distinct from macro names > + - Macros expanding to their own name are allowed (e.g., #define x x). > + Clashes between names of function-like macros and identifiers of > + non-callable entities are allowed. Imo that still leaves open e.g. the #define a(x, y) a(x, y) case: Permitted ("own name") or not permitted ("a" pretty clearly is expected to be a callable entity here, besides being a function-like macro)? Jan
On 04/03/24 15:17, Jan Beulich wrote: > On 04.03.2024 14:31, Federico Serafini wrote: >> On 01/03/24 09:06, Jan Beulich wrote: >>> On 01.03.2024 00:28, Stefano Stabellini wrote: >>>> On Wed, 14 Feb 2024, Federico Serafini wrote: >>>>> On 14/02/24 14:15, Jan Beulich wrote: >>>>>> On 14.02.2024 12:27, Federico Serafini wrote: >>>>>>> On 14/02/24 09:28, Jan Beulich wrote: >>>>>>>> On 13.02.2024 23:33, Stefano Stabellini wrote: >>>>>>>>> Signed-off-by: Stefano Stabellini <stefano.stabellini@amd.com> >>>>>>>>> --- >>>>>>>>> docs/misra/rules.rst | 6 ++++++ >>>>>>>>> 1 file changed, 6 insertions(+) >>>>>>>>> >>>>>>>>> diff --git a/docs/misra/rules.rst b/docs/misra/rules.rst >>>>>>>>> index c185366966..931158b354 100644 >>>>>>>>> --- a/docs/misra/rules.rst >>>>>>>>> +++ b/docs/misra/rules.rst >>>>>>>>> @@ -181,6 +181,12 @@ maintainers if you want to suggest a change. >>>>>>>>> headers (xen/include/public/) are allowed to retain longer >>>>>>>>> identifiers for backward compatibility. >>>>>>>>> + * - `Rule 5.5 >>>>>>>>> <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_05_05.c>`_ >>>>>>>>> + - Required >>>>>>>>> + - Identifiers shall be distinct from macro names >>>>>>>>> + - Clashes between function-like macros and non-callable entities >>>>>>>>> + are allowed. The pattern #define x x is also allowed. >>>>>>>> >>>>>>>> Just for me to know what exactly is covered (hence also a question >>>>>>>> to Roberto as to [to be] implemented Eclair behavior): Even when >>>>>>>> the above would be sufficient (and imo better) people frequently >>>>>>>> write >>>>>>>> >>>>>>>> #define a(x, y) b(x, y) >>>>>>>> >>>>>>>> which, transformed to the specific case here, would then be >>>>>>>> >>>>>>>> #define a(x, y) a(x, y) >>>>>>>> >>>>>>>> I'd assume such ought to also be covered, but that's not clear >>>>>>>> from the spelling above. >>>>>>> >>>>>>> I list what happens in some different situations, >>>>>>> then we can find the right words for the documentation and/or >>>>>>> refine the configuration: >>>>>>> >>>>>>> If you >>>>>>> #define x x >>>>>>> and then use `x' as identifier, >>>>>>> the resulting violation is deviated (allowed pattern). >>>>>>> >>>>>>> If you >>>>>>> #define a(x, y) a(x, y) >>>>>>> and then use `a' as identifier for a non-callable entity, >>>>>>> the resulting violation is deviated (no clash with non-callable >>>>>>> entities). >>>>>>> If you use identifier `a' for a callable entity, the resulting violation >>>>>>> is reported: the allowed pattern covers only macros expanding to their >>>>>>> own name, in this case the macro name is considered to be >>>>>>> `a' only, not a(x, y). >>>>>>> >>>>>>> If you >>>>>>> #define a(x, y) b(x, y) >>>>>>> and then use `a' as identifier for a non-callable entity, >>>>>>> the resulting violation is deviated (no clash with non-callable >>>>>>> entities). >>>>>> >>>>>> I'm afraid I don't see what violation there is in this case, to >>>>>> deviate. As a result I'm also not sure I correctly understand the >>>>>> rest of your reply. >>>>> >>>>> #define a(x, y) b(x, y) >>>>> >>>>> int a; // Violation of Rule 5.5. >>>>> >>>>> The macro name `a' that exist before the preprocessing phase, >>>>> still exists after the preprocessing phase as identifier for the integer >>>>> variable and this is a violation. >>>>> >>>>>>> If you use `a' as identifier for a callable entity, >>>>>>> this is not a violation because after the preprocessing phase, >>>>>>> identifier `a' no longer exists. >>>>> I correct myself: >>>>> if you use `a' as identifier for a *function*, >>>>> it is not a violation because after the preprocessing phase >>>>> the identifier `a' no longer exists, for example: >>>>> >>>>> #define a(x, y) b(x, y) >>>>> >>>>> void a(int x, int y); // Ok. >>>> >>>> Federico, do you have a better wording suggestion for this rule? >>>> >>>> Jan, any further requests here? What would you like to see as next step? >>> >>> A more concise wording proposal would probably help. >> >> What do you think about: >> >> diff --git a/docs/misra/rules.rst b/docs/misra/rules.rst >> index 1e134ccebc..a975b9a85f 100644 >> --- a/docs/misra/rules.rst >> +++ b/docs/misra/rules.rst >> @@ -181,6 +181,13 @@ maintainers if you want to suggest a change. >> headers (xen/include/public/) are allowed to retain longer >> identifiers for backward compatibility. >> >> + * - `Rule 5.5 >> <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_05_05.c>`_ >> + - Required >> + - Identifiers shall be distinct from macro names >> + - Macros expanding to their own name are allowed (e.g., #define x x). >> + Clashes between names of function-like macros and identifiers of >> + non-callable entities are allowed. > > Imo that still leaves open e.g. the > > #define a(x, y) a(x, y) > > case: Permitted ("own name") or not permitted ("a" pretty clearly is expected > to be a callable entity here, besides being a function-like macro)? I would not consider your example as a macro that expands to its own name, the macro name is considered to be `a' only. Rather, you example can be used to trigger the "callable-noncallable" part of the deviation, for example: #define a(x, y) a(x, y) void a(int x, int y); /* Not permitted (callable entity 'a'). */ void foo(int a); /* Permitted (non-callable entity `a'). */
On 04.03.2024 16:39, Federico Serafini wrote: > On 04/03/24 15:17, Jan Beulich wrote: >> On 04.03.2024 14:31, Federico Serafini wrote: >>> On 01/03/24 09:06, Jan Beulich wrote: >>>> On 01.03.2024 00:28, Stefano Stabellini wrote: >>>>> On Wed, 14 Feb 2024, Federico Serafini wrote: >>>>>> On 14/02/24 14:15, Jan Beulich wrote: >>>>>>> On 14.02.2024 12:27, Federico Serafini wrote: >>>>>>>> On 14/02/24 09:28, Jan Beulich wrote: >>>>>>>>> On 13.02.2024 23:33, Stefano Stabellini wrote: >>>>>>>>>> Signed-off-by: Stefano Stabellini <stefano.stabellini@amd.com> >>>>>>>>>> --- >>>>>>>>>> docs/misra/rules.rst | 6 ++++++ >>>>>>>>>> 1 file changed, 6 insertions(+) >>>>>>>>>> >>>>>>>>>> diff --git a/docs/misra/rules.rst b/docs/misra/rules.rst >>>>>>>>>> index c185366966..931158b354 100644 >>>>>>>>>> --- a/docs/misra/rules.rst >>>>>>>>>> +++ b/docs/misra/rules.rst >>>>>>>>>> @@ -181,6 +181,12 @@ maintainers if you want to suggest a change. >>>>>>>>>> headers (xen/include/public/) are allowed to retain longer >>>>>>>>>> identifiers for backward compatibility. >>>>>>>>>> + * - `Rule 5.5 >>>>>>>>>> <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_05_05.c>`_ >>>>>>>>>> + - Required >>>>>>>>>> + - Identifiers shall be distinct from macro names >>>>>>>>>> + - Clashes between function-like macros and non-callable entities >>>>>>>>>> + are allowed. The pattern #define x x is also allowed. >>>>>>>>> >>>>>>>>> Just for me to know what exactly is covered (hence also a question >>>>>>>>> to Roberto as to [to be] implemented Eclair behavior): Even when >>>>>>>>> the above would be sufficient (and imo better) people frequently >>>>>>>>> write >>>>>>>>> >>>>>>>>> #define a(x, y) b(x, y) >>>>>>>>> >>>>>>>>> which, transformed to the specific case here, would then be >>>>>>>>> >>>>>>>>> #define a(x, y) a(x, y) >>>>>>>>> >>>>>>>>> I'd assume such ought to also be covered, but that's not clear >>>>>>>>> from the spelling above. >>>>>>>> >>>>>>>> I list what happens in some different situations, >>>>>>>> then we can find the right words for the documentation and/or >>>>>>>> refine the configuration: >>>>>>>> >>>>>>>> If you >>>>>>>> #define x x >>>>>>>> and then use `x' as identifier, >>>>>>>> the resulting violation is deviated (allowed pattern). >>>>>>>> >>>>>>>> If you >>>>>>>> #define a(x, y) a(x, y) >>>>>>>> and then use `a' as identifier for a non-callable entity, >>>>>>>> the resulting violation is deviated (no clash with non-callable >>>>>>>> entities). >>>>>>>> If you use identifier `a' for a callable entity, the resulting violation >>>>>>>> is reported: the allowed pattern covers only macros expanding to their >>>>>>>> own name, in this case the macro name is considered to be >>>>>>>> `a' only, not a(x, y). >>>>>>>> >>>>>>>> If you >>>>>>>> #define a(x, y) b(x, y) >>>>>>>> and then use `a' as identifier for a non-callable entity, >>>>>>>> the resulting violation is deviated (no clash with non-callable >>>>>>>> entities). >>>>>>> >>>>>>> I'm afraid I don't see what violation there is in this case, to >>>>>>> deviate. As a result I'm also not sure I correctly understand the >>>>>>> rest of your reply. >>>>>> >>>>>> #define a(x, y) b(x, y) >>>>>> >>>>>> int a; // Violation of Rule 5.5. >>>>>> >>>>>> The macro name `a' that exist before the preprocessing phase, >>>>>> still exists after the preprocessing phase as identifier for the integer >>>>>> variable and this is a violation. >>>>>> >>>>>>>> If you use `a' as identifier for a callable entity, >>>>>>>> this is not a violation because after the preprocessing phase, >>>>>>>> identifier `a' no longer exists. >>>>>> I correct myself: >>>>>> if you use `a' as identifier for a *function*, >>>>>> it is not a violation because after the preprocessing phase >>>>>> the identifier `a' no longer exists, for example: >>>>>> >>>>>> #define a(x, y) b(x, y) >>>>>> >>>>>> void a(int x, int y); // Ok. >>>>> >>>>> Federico, do you have a better wording suggestion for this rule? >>>>> >>>>> Jan, any further requests here? What would you like to see as next step? >>>> >>>> A more concise wording proposal would probably help. >>> >>> What do you think about: >>> >>> diff --git a/docs/misra/rules.rst b/docs/misra/rules.rst >>> index 1e134ccebc..a975b9a85f 100644 >>> --- a/docs/misra/rules.rst >>> +++ b/docs/misra/rules.rst >>> @@ -181,6 +181,13 @@ maintainers if you want to suggest a change. >>> headers (xen/include/public/) are allowed to retain longer >>> identifiers for backward compatibility. >>> >>> + * - `Rule 5.5 >>> <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_05_05.c>`_ >>> + - Required >>> + - Identifiers shall be distinct from macro names >>> + - Macros expanding to their own name are allowed (e.g., #define x x). >>> + Clashes between names of function-like macros and identifiers of >>> + non-callable entities are allowed. >> >> Imo that still leaves open e.g. the >> >> #define a(x, y) a(x, y) >> >> case: Permitted ("own name") or not permitted ("a" pretty clearly is expected >> to be a callable entity here, besides being a function-like macro)? > > I would not consider your example as a macro that expands to its own > name, the macro name is considered to be `a' only. That's what I was assuming, and hence my asking back. I think the above ought to be permitted just like "#define x x", and hence the suggested text would need expanding, to ... > Rather, you example can be used to trigger the "callable-noncallable" > part of the deviation, for example: > > #define a(x, y) a(x, y) > > void a(int x, int y); /* Not permitted (callable entity 'a'). */ ... prevent this ("not permitted") from happening. I'm pretty sure you've already found instances of this pattern in our code base. Jan > void foo(int a); /* Permitted (non-callable entity `a'). */ >
On Mon, 4 Mar 2024, Jan Beulich wrote: > On 04.03.2024 16:39, Federico Serafini wrote: > > On 04/03/24 15:17, Jan Beulich wrote: > >> On 04.03.2024 14:31, Federico Serafini wrote: > >>> On 01/03/24 09:06, Jan Beulich wrote: > >>>> On 01.03.2024 00:28, Stefano Stabellini wrote: > >>>>> On Wed, 14 Feb 2024, Federico Serafini wrote: > >>>>>> On 14/02/24 14:15, Jan Beulich wrote: > >>>>>>> On 14.02.2024 12:27, Federico Serafini wrote: > >>>>>>>> On 14/02/24 09:28, Jan Beulich wrote: > >>>>>>>>> On 13.02.2024 23:33, Stefano Stabellini wrote: > >>>>>>>>>> Signed-off-by: Stefano Stabellini <stefano.stabellini@amd.com> > >>>>>>>>>> --- > >>>>>>>>>> docs/misra/rules.rst | 6 ++++++ > >>>>>>>>>> 1 file changed, 6 insertions(+) > >>>>>>>>>> > >>>>>>>>>> diff --git a/docs/misra/rules.rst b/docs/misra/rules.rst > >>>>>>>>>> index c185366966..931158b354 100644 > >>>>>>>>>> --- a/docs/misra/rules.rst > >>>>>>>>>> +++ b/docs/misra/rules.rst > >>>>>>>>>> @@ -181,6 +181,12 @@ maintainers if you want to suggest a change. > >>>>>>>>>> headers (xen/include/public/) are allowed to retain longer > >>>>>>>>>> identifiers for backward compatibility. > >>>>>>>>>> + * - `Rule 5.5 > >>>>>>>>>> <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_05_05.c>`_ > >>>>>>>>>> + - Required > >>>>>>>>>> + - Identifiers shall be distinct from macro names > >>>>>>>>>> + - Clashes between function-like macros and non-callable entities > >>>>>>>>>> + are allowed. The pattern #define x x is also allowed. > >>>>>>>>> > >>>>>>>>> Just for me to know what exactly is covered (hence also a question > >>>>>>>>> to Roberto as to [to be] implemented Eclair behavior): Even when > >>>>>>>>> the above would be sufficient (and imo better) people frequently > >>>>>>>>> write > >>>>>>>>> > >>>>>>>>> #define a(x, y) b(x, y) > >>>>>>>>> > >>>>>>>>> which, transformed to the specific case here, would then be > >>>>>>>>> > >>>>>>>>> #define a(x, y) a(x, y) > >>>>>>>>> > >>>>>>>>> I'd assume such ought to also be covered, but that's not clear > >>>>>>>>> from the spelling above. > >>>>>>>> > >>>>>>>> I list what happens in some different situations, > >>>>>>>> then we can find the right words for the documentation and/or > >>>>>>>> refine the configuration: > >>>>>>>> > >>>>>>>> If you > >>>>>>>> #define x x > >>>>>>>> and then use `x' as identifier, > >>>>>>>> the resulting violation is deviated (allowed pattern). > >>>>>>>> > >>>>>>>> If you > >>>>>>>> #define a(x, y) a(x, y) > >>>>>>>> and then use `a' as identifier for a non-callable entity, > >>>>>>>> the resulting violation is deviated (no clash with non-callable > >>>>>>>> entities). > >>>>>>>> If you use identifier `a' for a callable entity, the resulting violation > >>>>>>>> is reported: the allowed pattern covers only macros expanding to their > >>>>>>>> own name, in this case the macro name is considered to be > >>>>>>>> `a' only, not a(x, y). > >>>>>>>> > >>>>>>>> If you > >>>>>>>> #define a(x, y) b(x, y) > >>>>>>>> and then use `a' as identifier for a non-callable entity, > >>>>>>>> the resulting violation is deviated (no clash with non-callable > >>>>>>>> entities). > >>>>>>> > >>>>>>> I'm afraid I don't see what violation there is in this case, to > >>>>>>> deviate. As a result I'm also not sure I correctly understand the > >>>>>>> rest of your reply. > >>>>>> > >>>>>> #define a(x, y) b(x, y) > >>>>>> > >>>>>> int a; // Violation of Rule 5.5. > >>>>>> > >>>>>> The macro name `a' that exist before the preprocessing phase, > >>>>>> still exists after the preprocessing phase as identifier for the integer > >>>>>> variable and this is a violation. > >>>>>> > >>>>>>>> If you use `a' as identifier for a callable entity, > >>>>>>>> this is not a violation because after the preprocessing phase, > >>>>>>>> identifier `a' no longer exists. > >>>>>> I correct myself: > >>>>>> if you use `a' as identifier for a *function*, > >>>>>> it is not a violation because after the preprocessing phase > >>>>>> the identifier `a' no longer exists, for example: > >>>>>> > >>>>>> #define a(x, y) b(x, y) > >>>>>> > >>>>>> void a(int x, int y); // Ok. > >>>>> > >>>>> Federico, do you have a better wording suggestion for this rule? > >>>>> > >>>>> Jan, any further requests here? What would you like to see as next step? > >>>> > >>>> A more concise wording proposal would probably help. > >>> > >>> What do you think about: > >>> > >>> diff --git a/docs/misra/rules.rst b/docs/misra/rules.rst > >>> index 1e134ccebc..a975b9a85f 100644 > >>> --- a/docs/misra/rules.rst > >>> +++ b/docs/misra/rules.rst > >>> @@ -181,6 +181,13 @@ maintainers if you want to suggest a change. > >>> headers (xen/include/public/) are allowed to retain longer > >>> identifiers for backward compatibility. > >>> > >>> + * - `Rule 5.5 > >>> <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_05_05.c>`_ > >>> + - Required > >>> + - Identifiers shall be distinct from macro names > >>> + - Macros expanding to their own name are allowed (e.g., #define x x). > >>> + Clashes between names of function-like macros and identifiers of > >>> + non-callable entities are allowed. > >> > >> Imo that still leaves open e.g. the > >> > >> #define a(x, y) a(x, y) > >> > >> case: Permitted ("own name") or not permitted ("a" pretty clearly is expected > >> to be a callable entity here, besides being a function-like macro)? > > > > I would not consider your example as a macro that expands to its own > > name, the macro name is considered to be `a' only. > > That's what I was assuming, and hence my asking back. I think the > above ought to be permitted just like "#define x x", and hence the > suggested text would need expanding, to ... > > > Rather, you example can be used to trigger the "callable-noncallable" > > part of the deviation, for example: > > > > #define a(x, y) a(x, y) > > > > void a(int x, int y); /* Not permitted (callable entity 'a'). */ > > ... prevent this ("not permitted") from happening. I'm pretty sure > you've already found instances of this pattern in our code base. Sorry Jan, purely asking as a clarification because I couldn't understand what you wrote. You are asking for a clarification in the wording so that the following is explicitly allowed, right? #define a(x, y) a(x, y) void a(int x, int y);
On 05.03.2024 02:49, Stefano Stabellini wrote: > On Mon, 4 Mar 2024, Jan Beulich wrote: >> On 04.03.2024 16:39, Federico Serafini wrote: >>> On 04/03/24 15:17, Jan Beulich wrote: >>>> On 04.03.2024 14:31, Federico Serafini wrote: >>>>> On 01/03/24 09:06, Jan Beulich wrote: >>>>>> On 01.03.2024 00:28, Stefano Stabellini wrote: >>>>>>> On Wed, 14 Feb 2024, Federico Serafini wrote: >>>>>>>> On 14/02/24 14:15, Jan Beulich wrote: >>>>>>>>> On 14.02.2024 12:27, Federico Serafini wrote: >>>>>>>>>> On 14/02/24 09:28, Jan Beulich wrote: >>>>>>>>>>> On 13.02.2024 23:33, Stefano Stabellini wrote: >>>>>>>>>>>> Signed-off-by: Stefano Stabellini <stefano.stabellini@amd.com> >>>>>>>>>>>> --- >>>>>>>>>>>> docs/misra/rules.rst | 6 ++++++ >>>>>>>>>>>> 1 file changed, 6 insertions(+) >>>>>>>>>>>> >>>>>>>>>>>> diff --git a/docs/misra/rules.rst b/docs/misra/rules.rst >>>>>>>>>>>> index c185366966..931158b354 100644 >>>>>>>>>>>> --- a/docs/misra/rules.rst >>>>>>>>>>>> +++ b/docs/misra/rules.rst >>>>>>>>>>>> @@ -181,6 +181,12 @@ maintainers if you want to suggest a change. >>>>>>>>>>>> headers (xen/include/public/) are allowed to retain longer >>>>>>>>>>>> identifiers for backward compatibility. >>>>>>>>>>>> + * - `Rule 5.5 >>>>>>>>>>>> <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_05_05.c>`_ >>>>>>>>>>>> + - Required >>>>>>>>>>>> + - Identifiers shall be distinct from macro names >>>>>>>>>>>> + - Clashes between function-like macros and non-callable entities >>>>>>>>>>>> + are allowed. The pattern #define x x is also allowed. >>>>>>>>>>> >>>>>>>>>>> Just for me to know what exactly is covered (hence also a question >>>>>>>>>>> to Roberto as to [to be] implemented Eclair behavior): Even when >>>>>>>>>>> the above would be sufficient (and imo better) people frequently >>>>>>>>>>> write >>>>>>>>>>> >>>>>>>>>>> #define a(x, y) b(x, y) >>>>>>>>>>> >>>>>>>>>>> which, transformed to the specific case here, would then be >>>>>>>>>>> >>>>>>>>>>> #define a(x, y) a(x, y) >>>>>>>>>>> >>>>>>>>>>> I'd assume such ought to also be covered, but that's not clear >>>>>>>>>>> from the spelling above. >>>>>>>>>> >>>>>>>>>> I list what happens in some different situations, >>>>>>>>>> then we can find the right words for the documentation and/or >>>>>>>>>> refine the configuration: >>>>>>>>>> >>>>>>>>>> If you >>>>>>>>>> #define x x >>>>>>>>>> and then use `x' as identifier, >>>>>>>>>> the resulting violation is deviated (allowed pattern). >>>>>>>>>> >>>>>>>>>> If you >>>>>>>>>> #define a(x, y) a(x, y) >>>>>>>>>> and then use `a' as identifier for a non-callable entity, >>>>>>>>>> the resulting violation is deviated (no clash with non-callable >>>>>>>>>> entities). >>>>>>>>>> If you use identifier `a' for a callable entity, the resulting violation >>>>>>>>>> is reported: the allowed pattern covers only macros expanding to their >>>>>>>>>> own name, in this case the macro name is considered to be >>>>>>>>>> `a' only, not a(x, y). >>>>>>>>>> >>>>>>>>>> If you >>>>>>>>>> #define a(x, y) b(x, y) >>>>>>>>>> and then use `a' as identifier for a non-callable entity, >>>>>>>>>> the resulting violation is deviated (no clash with non-callable >>>>>>>>>> entities). >>>>>>>>> >>>>>>>>> I'm afraid I don't see what violation there is in this case, to >>>>>>>>> deviate. As a result I'm also not sure I correctly understand the >>>>>>>>> rest of your reply. >>>>>>>> >>>>>>>> #define a(x, y) b(x, y) >>>>>>>> >>>>>>>> int a; // Violation of Rule 5.5. >>>>>>>> >>>>>>>> The macro name `a' that exist before the preprocessing phase, >>>>>>>> still exists after the preprocessing phase as identifier for the integer >>>>>>>> variable and this is a violation. >>>>>>>> >>>>>>>>>> If you use `a' as identifier for a callable entity, >>>>>>>>>> this is not a violation because after the preprocessing phase, >>>>>>>>>> identifier `a' no longer exists. >>>>>>>> I correct myself: >>>>>>>> if you use `a' as identifier for a *function*, >>>>>>>> it is not a violation because after the preprocessing phase >>>>>>>> the identifier `a' no longer exists, for example: >>>>>>>> >>>>>>>> #define a(x, y) b(x, y) >>>>>>>> >>>>>>>> void a(int x, int y); // Ok. >>>>>>> >>>>>>> Federico, do you have a better wording suggestion for this rule? >>>>>>> >>>>>>> Jan, any further requests here? What would you like to see as next step? >>>>>> >>>>>> A more concise wording proposal would probably help. >>>>> >>>>> What do you think about: >>>>> >>>>> diff --git a/docs/misra/rules.rst b/docs/misra/rules.rst >>>>> index 1e134ccebc..a975b9a85f 100644 >>>>> --- a/docs/misra/rules.rst >>>>> +++ b/docs/misra/rules.rst >>>>> @@ -181,6 +181,13 @@ maintainers if you want to suggest a change. >>>>> headers (xen/include/public/) are allowed to retain longer >>>>> identifiers for backward compatibility. >>>>> >>>>> + * - `Rule 5.5 >>>>> <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_05_05.c>`_ >>>>> + - Required >>>>> + - Identifiers shall be distinct from macro names >>>>> + - Macros expanding to their own name are allowed (e.g., #define x x). >>>>> + Clashes between names of function-like macros and identifiers of >>>>> + non-callable entities are allowed. >>>> >>>> Imo that still leaves open e.g. the >>>> >>>> #define a(x, y) a(x, y) >>>> >>>> case: Permitted ("own name") or not permitted ("a" pretty clearly is expected >>>> to be a callable entity here, besides being a function-like macro)? >>> >>> I would not consider your example as a macro that expands to its own >>> name, the macro name is considered to be `a' only. >> >> That's what I was assuming, and hence my asking back. I think the >> above ought to be permitted just like "#define x x", and hence the >> suggested text would need expanding, to ... >> >>> Rather, you example can be used to trigger the "callable-noncallable" >>> part of the deviation, for example: >>> >>> #define a(x, y) a(x, y) >>> >>> void a(int x, int y); /* Not permitted (callable entity 'a'). */ >> >> ... prevent this ("not permitted") from happening. I'm pretty sure >> you've already found instances of this pattern in our code base. > > Sorry Jan, purely asking as a clarification because I couldn't > understand what you wrote. > > You are asking for a clarification in the wording so that the following > is explicitly allowed, right? > > #define a(x, y) a(x, y) > void a(int x, int y); Yes. (Or, less desirable, unambiguously disallowed.) Jan
On 04.03.2024 17:36, Jan Beulich wrote: > On 04.03.2024 16:39, Federico Serafini wrote: >> On 04/03/24 15:17, Jan Beulich wrote: >>> On 04.03.2024 14:31, Federico Serafini wrote: >>>> On 01/03/24 09:06, Jan Beulich wrote: >>>>> On 01.03.2024 00:28, Stefano Stabellini wrote: >>>>>> On Wed, 14 Feb 2024, Federico Serafini wrote: >>>>>>> On 14/02/24 14:15, Jan Beulich wrote: >>>>>>>> On 14.02.2024 12:27, Federico Serafini wrote: >>>>>>>>> On 14/02/24 09:28, Jan Beulich wrote: >>>>>>>>>> On 13.02.2024 23:33, Stefano Stabellini wrote: >>>>>>>>>>> Signed-off-by: Stefano Stabellini <stefano.stabellini@amd.com> >>>>>>>>>>> --- >>>>>>>>>>> docs/misra/rules.rst | 6 ++++++ >>>>>>>>>>> 1 file changed, 6 insertions(+) >>>>>>>>>>> >>>>>>>>>>> diff --git a/docs/misra/rules.rst b/docs/misra/rules.rst >>>>>>>>>>> index c185366966..931158b354 100644 >>>>>>>>>>> --- a/docs/misra/rules.rst >>>>>>>>>>> +++ b/docs/misra/rules.rst >>>>>>>>>>> @@ -181,6 +181,12 @@ maintainers if you want to suggest a change. >>>>>>>>>>> headers (xen/include/public/) are allowed to retain longer >>>>>>>>>>> identifiers for backward compatibility. >>>>>>>>>>> + * - `Rule 5.5 >>>>>>>>>>> <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_05_05.c>`_ >>>>>>>>>>> + - Required >>>>>>>>>>> + - Identifiers shall be distinct from macro names >>>>>>>>>>> + - Clashes between function-like macros and non-callable entities >>>>>>>>>>> + are allowed. The pattern #define x x is also allowed. >>>>>>>>>> >>>>>>>>>> Just for me to know what exactly is covered (hence also a question >>>>>>>>>> to Roberto as to [to be] implemented Eclair behavior): Even when >>>>>>>>>> the above would be sufficient (and imo better) people frequently >>>>>>>>>> write >>>>>>>>>> >>>>>>>>>> #define a(x, y) b(x, y) >>>>>>>>>> >>>>>>>>>> which, transformed to the specific case here, would then be >>>>>>>>>> >>>>>>>>>> #define a(x, y) a(x, y) >>>>>>>>>> >>>>>>>>>> I'd assume such ought to also be covered, but that's not clear >>>>>>>>>> from the spelling above. >>>>>>>>> >>>>>>>>> I list what happens in some different situations, >>>>>>>>> then we can find the right words for the documentation and/or >>>>>>>>> refine the configuration: >>>>>>>>> >>>>>>>>> If you >>>>>>>>> #define x x >>>>>>>>> and then use `x' as identifier, >>>>>>>>> the resulting violation is deviated (allowed pattern). >>>>>>>>> >>>>>>>>> If you >>>>>>>>> #define a(x, y) a(x, y) >>>>>>>>> and then use `a' as identifier for a non-callable entity, >>>>>>>>> the resulting violation is deviated (no clash with non-callable >>>>>>>>> entities). >>>>>>>>> If you use identifier `a' for a callable entity, the resulting violation >>>>>>>>> is reported: the allowed pattern covers only macros expanding to their >>>>>>>>> own name, in this case the macro name is considered to be >>>>>>>>> `a' only, not a(x, y). >>>>>>>>> >>>>>>>>> If you >>>>>>>>> #define a(x, y) b(x, y) >>>>>>>>> and then use `a' as identifier for a non-callable entity, >>>>>>>>> the resulting violation is deviated (no clash with non-callable >>>>>>>>> entities). >>>>>>>> >>>>>>>> I'm afraid I don't see what violation there is in this case, to >>>>>>>> deviate. As a result I'm also not sure I correctly understand the >>>>>>>> rest of your reply. >>>>>>> >>>>>>> #define a(x, y) b(x, y) >>>>>>> >>>>>>> int a; // Violation of Rule 5.5. >>>>>>> >>>>>>> The macro name `a' that exist before the preprocessing phase, >>>>>>> still exists after the preprocessing phase as identifier for the integer >>>>>>> variable and this is a violation. >>>>>>> >>>>>>>>> If you use `a' as identifier for a callable entity, >>>>>>>>> this is not a violation because after the preprocessing phase, >>>>>>>>> identifier `a' no longer exists. >>>>>>> I correct myself: >>>>>>> if you use `a' as identifier for a *function*, >>>>>>> it is not a violation because after the preprocessing phase >>>>>>> the identifier `a' no longer exists, for example: >>>>>>> >>>>>>> #define a(x, y) b(x, y) >>>>>>> >>>>>>> void a(int x, int y); // Ok. >>>>>> >>>>>> Federico, do you have a better wording suggestion for this rule? >>>>>> >>>>>> Jan, any further requests here? What would you like to see as next step? >>>>> >>>>> A more concise wording proposal would probably help. >>>> >>>> What do you think about: >>>> >>>> diff --git a/docs/misra/rules.rst b/docs/misra/rules.rst >>>> index 1e134ccebc..a975b9a85f 100644 >>>> --- a/docs/misra/rules.rst >>>> +++ b/docs/misra/rules.rst >>>> @@ -181,6 +181,13 @@ maintainers if you want to suggest a change. >>>> headers (xen/include/public/) are allowed to retain longer >>>> identifiers for backward compatibility. >>>> >>>> + * - `Rule 5.5 >>>> <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_05_05.c>`_ >>>> + - Required >>>> + - Identifiers shall be distinct from macro names >>>> + - Macros expanding to their own name are allowed (e.g., #define x x). >>>> + Clashes between names of function-like macros and identifiers of >>>> + non-callable entities are allowed. >>> >>> Imo that still leaves open e.g. the >>> >>> #define a(x, y) a(x, y) >>> >>> case: Permitted ("own name") or not permitted ("a" pretty clearly is expected >>> to be a callable entity here, besides being a function-like macro)? >> >> I would not consider your example as a macro that expands to its own >> name, the macro name is considered to be `a' only. > > That's what I was assuming, and hence my asking back. I think the > above ought to be permitted just like "#define x x", and hence the > suggested text would need expanding, to ... > >> Rather, you example can be used to trigger the "callable-noncallable" >> part of the deviation, for example: >> >> #define a(x, y) a(x, y) >> >> void a(int x, int y); /* Not permitted (callable entity 'a'). */ > > ... prevent this ("not permitted") from happening. I'm pretty sure > you've already found instances of this pattern in our code base. And btw, see https://lists.xen.org/archives/html/xen-devel/2024-03/msg00159.html for yet another slightly different pattern that I'd rather not see becoming "forbidden". Jan
diff --git a/docs/misra/rules.rst b/docs/misra/rules.rst index c185366966..931158b354 100644 --- a/docs/misra/rules.rst +++ b/docs/misra/rules.rst @@ -181,6 +181,12 @@ maintainers if you want to suggest a change. headers (xen/include/public/) are allowed to retain longer identifiers for backward compatibility. + * - `Rule 5.5 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_05_05.c>`_ + - Required + - Identifiers shall be distinct from macro names + - Clashes between function-like macros and non-callable entities + are allowed. The pattern #define x x is also allowed. + * - `Rule 5.6 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_05_06.c>`_ - Required - A typedef name shall be a unique identifier
Signed-off-by: Stefano Stabellini <stefano.stabellini@amd.com> --- docs/misra/rules.rst | 6 ++++++ 1 file changed, 6 insertions(+)