Re: [PATCH] xen: address violation of MISRA C Rule 11.1

[Jan Beulich <jbeulich@suse.com>]

On 11.12.2024 12:02, Alessandro Zucchelli wrote:
> Rule 11.1 states as following: "Conversions shall not be performed
> between a pointer to a function and any other type".
> 
> Functions "__machine_restart" and "__machine_halt" in "x86/shutdown.c"
> and "halt_this_cpu" in "arm/shutdown.c" are defined as noreturn
> functions and subsequently passed as parameters to function calls.
> This violates the rule in Clang, where the "noreturn" attribute is
> considered part of the function"s type.

I'm unaware of build issues with Clang, hence can you clarify how Clang's
view comes into play here? In principle various attributes ought to be
part of a function's type; iirc that's also the case for gcc. Yet how
that matters to Eclair is still entirely unclear to me.

> By removing the "noreturn"
> attribbute and replacing it with uses of the ASSERT_UNREACHABLE macro,
> these violations are addressed.

Papered over, I'd say. What about release builds, for example?

Deleting the attribute also has a clear downside documentation-wise. If
we really mean to remove them from what the compiler gets to see, I think
we ought to still retain them in commented-out shape.

Jan