On 12.06.2023 10:58, Roberto Bagnara wrote: > On 09/06/23 10:46, Jan Beulich wrote: >> On 08.06.2023 13:02, Roberto Bagnara wrote: >>> On 07/06/23 23:53, Stefano Stabellini wrote: >>>> On Wed, 7 Jun 2023, Jan Beulich wrote: >>>>>> + * - `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 >>>>>> + - >>>>> >>>>> Considering that the rule requires uniqueness across the entire code >>>>> base (and hence precludes e.g. two functions having identically named >>>>> local typedefs), I'm a little puzzled this was adopted. I for one >>>>> question that a use like the one mentioned is really at risk of being >>>>> confusing. Instead I think that the need to change at least one of >>>>> the names is at risk of making the code less readable then, even if >>>>> ever so slightly. (All of this said - I don't know if we have any >>>>> violations of this rule.) >>>> >>>> I don't think we have many local typedefs and I think we have only few >>>> violations if I remember right. I'll let Roberto confirm how many. This >>>> rule was considered not a difficult rule (some difficult rules were >>>> found, namely 2.1, 5.5 and 7.4.) >>> >>> There currently are 30 violations for ARM64: >>> >>> - some involve a typedef module_name (in the call it was said this should >>> be renamed module_name_t, which will solve the issue); >>> - most concern repeated typedefs (UINT64 and similar) which are repeated >>> in xen/arch/arm/include/asm/arm64/efibind.h >>> and xen/include/acpi/actypes.h >>> - ret_t and phys_addr_t are also redefined in a couple of places. >>> >>> There are 90 violations for X86_64, for the same reasons, plus >>> >>> - another set of typedefs for basic types (such as u8); >>> - repeated typedefs for things like guest_l1e_t in the same header file: >>> >>> xen/arch/x86/include/asm/guest_pt.h:60.39-60.49: >>> for program `xen/.xen-syms.0', the identifier for typedef `guest_l1e_t' is >>> reused >>> xen/arch/x86/include/asm/guest_pt.h:128.22-128.32: >>> for program `xen/.xen-syms.0', the identifier for typedef `guest_l1e_t' is >>> reused >>> >>> The indicated lines read as follows: >>> >>> typedef struct { guest_intpte_t l1; } guest_l1e_t; >>> typedef l1_pgentry_t guest_l1e_t; >> >> So this is an example where I don't think we can sensibly do away with the >> re-use of the same typedef name: We use it so we can build the same source >> files multiple ways, dealing with different paging modes guests may be in. > > Typedefs being used this way can be deviated with tool configuration. > Here is a list of candidates for that treatment: > > guest_intpte_t > guest_l1e_t > guest_l2e_t > ret_ > > I am not sure about the latter. Please let me know if this is what > you would prefer and possible additions to/removals from the above list.
Well, if deviating such is possible despite their extended use (in certain places), then fine. I was afraid that a deviation with such wide a scope might be hard to justify. Jan
