Re: [XEN PATCH] docs/misra: document the C dialect and translation toolchain assumptions.

[Roberto Bagnara <roberto.bagnara@xxxxxxxxxxx>]

On 19/06/23 09:54, Jan Beulich wrote:
> On 16.06.2023 17:54, Roberto Bagnara wrote:
> > On 16/06/23 01:26, Stefano Stabellini wrote:
> > > On Thu, 15 Jun 2023, Roberto Bagnara wrote:
> > > > +       static function is used in an inline function with external linkage:
> > > > +          non-documented GCC extension.
> > > I am not sure if I follow about this one. Did you mean "static is used
> > > in an inline function with external linkage" ?
> > An inline function with external linkage can be inlined everywhere.
> > If that calls a static functions, which is not available everywhere,
> > the behavior is not defined.
> I guess I could do with an example where this leads to UB. What I'd expect
> is that it leads to a compilation error.
Here are the two occurrences we have in ARM64 code:

violation for rule MC3R1.R1.1: (required) The program shall contain no 
violations of the standard C syntax and constraints, and shall not exceed the 
implementation's translation limits.
xen/common/spinlock.c:316.29-316.40: Loc #1 [culprit: static function 
`observe_head(spinlock_tickets_t*)' is used in an inline function with external linkage 
(ill-formed for the C99 standard, ISO/IEC 9899:1999: "An ill-formed source detected 
by the parser."
xen/common/spinlock.c:301.26-301.37: Loc #2 [evidence: 
`observe_head(spinlock_tickets_t*)' declared here]
xen/include/xen/spinlock.h:180.1-180.4: Loc #3 [evidence: use 'static' to give 
inline function `_spin_lock_cb(spinlock_t*, void(*)(void*), void*)' internal 
linkage]

violation for rule MC3R1.R1.1: (required) The program shall contain no 
violations of the standard C syntax and constraints, and shall not exceed the 
implementation's translation limits.
xen/common/spinlock.c:324.5-324.12: Loc #1 [culprit: static function `got_lock(union 
lock_debug*)' is used in an inline function with external linkage (ill-formed for the C99 
standard, ISO/IEC 9899:1999: "An ill-formed source detected by the parser."
xen/common/spinlock.c:227.13-227.20: Loc #2 [evidence: `got_lock(union 
lock_debug*)' declared here]
xen/include/xen/spinlock.h:180.1-180.4: Loc #3 [evidence: use 'static' to give 
inline function `_spin_lock_cb(spinlock_t*, void(*)(void*), void*)' internal 
linkage]