On 8/19/25 16:25, Jan Beulich wrote:
> On 19.08.2025 15:12, Dmytro Prokopchuk1 wrote:
>> MISRA C Rule 2.1 states: "A project shall not contain unreachable code."
>>
>> The function 'PrintErrMesg()' is implemented to never return control to
>> its caller. At the end of its execution, it calls 'blexit()', which, in
>> turn, invokes '__builtin_unreachable()'. This makes the 'return false;'
>> statement in 'read_file()' function unreachable.
>
> I'm disappointed. In earlier review comments I pointed out that there are
> two. Yet you say "the", without further disambiguation.
>
>> --- a/automation/eclair_analysis/ECLAIR/deviations.ecl
>> +++ b/automation/eclair_analysis/ECLAIR/deviations.ecl
>> @@ -41,6 +41,10 @@ not executable, and therefore it is safe for them to be
>> unreachable."
>>
>> -call_properties+={"name(__builtin_unreachable)&&stmt(begin(any_exp(macro(name(ASSERT_UNREACHABLE)))))",
>> {"noreturn(false)"}}
>> -doc_end
>>
>> +-doc_begin="Unreachability caused by the call to the 'PrintErrMesg()'
>> function is deliberate, as it terminates execution, ensuring no control flow
>> continues past this point."
>> +-config=MC3A2.R2.1,reports+={deliberate, "any_area(^.*PrintErrMesg.*$ &&
>> any_loc(file(^xen/common/efi/boot\\.c$)))"}
>> +-doc_end
>
> I don't understand the description here, nor ...
>
>> --- a/docs/misra/deviations.rst
>> +++ b/docs/misra/deviations.rst
>> @@ -97,6 +97,13 @@ Deviations related to MISRA C:2012 Rules:
>> Xen expects developers to ensure code remains safe and reliable in
>> builds,
>> even when debug-only assertions like `ASSERT_UNREACHABLE() are
>> removed.
>>
>> + * - R2.1
>> + - Function `PrintErrMesg()` terminates execution (at the end it calls
>> + `blexit()`, which, in turn, invokes `__builtin_unreachable()`),
>> ensuring
>> + no code beyond this point is ever reached. This guarantees that
>> execution
>> + won't incorrectly proceed or introduce unwanted behavior.
>> + - Tagged as `deliberate` for ECLAIR.
>
> .. the text here. PrintErrMesg() is noreturn. Why would anything need saying
> about
> it? Isn't the problem here solely with the tail of read_file(), while other
> uses
> of PrintErrMesg() are okay?
>
> Jan
I'm a little bit confused.
As I understood you proposed to insert the SAF comment before the
'return' statement (with proper justification).
And current Eclair configuration & descriptions are not good at all.
Am I right?
Dmytro.
