Dead Code

Dead Code

[Joel Sherrill]

Hi

I think Coverity spotted a case where an || should be an &&
in libc/string/strsignal.c. What does everyone else think?

  74#if defined(SIGRTMIN) && defined(SIGRTMAX)
    	cond_at_most: Condition signal >= 27, taking false branch. Now the value of signal is at most 26.
    	at_most: At condition signal <= 31, the value of signal must be at most 26.
    	dead_error_condition: The condition signal <= 31 must be true.
  75  if ((signal >= SIGRTMIN) || (signal <= SIGRTMAX)) {
  76    siprintf (buffer, "Real-time signal %d", signal - SIGRTMIN);
  77    return buffer;
  78  }
  79#endif
  80
    	
CID 175333 (#1 of 1): Logically dead code (DEADCODE)
dead_error_line: Execution cannot reach this statement: switch (signal) {

   case 1:....

--joel

Re: Dead Code

[Craig Howland]

On 03/15/2017 11:48 AM, Joel Sherrill wrote:
> Hi
>
> I think Coverity spotted a case where an || should be an &&
> in libc/string/strsignal.c. What does everyone else think?
>
>  74#if defined(SIGRTMIN) && defined(SIGRTMAX)
>        cond_at_most: Condition signal >= 27, taking false branch. Now the 
> value of signal is at most 26.
>        at_most: At condition signal <= 31, the value of signal must be at most 
> 26.
>        dead_error_condition: The condition signal <= 31 must be true.
>  75  if ((signal >= SIGRTMIN) || (signal <= SIGRTMAX)) {
>  76    siprintf (buffer, "Real-time signal %d", signal - SIGRTMIN);
>  77    return buffer;
>  78  }
>  79#endif
>  80
>
> CID 175333 (#1 of 1): Logically dead code (DEADCODE)
> dead_error_line: Execution cannot reach this statement: switch (signal) {
>
>   case 1:....
>
> --joel
I agree.  (Very easy to test, for that matter.)
Craig

Re: Dead Code

[Joel Sherrill]

On 3/15/2017 11:51 AM, Craig Howland wrote:
> On 03/15/2017 11:48 AM, Joel Sherrill wrote:
>> Hi
>>
>> I think Coverity spotted a case where an || should be an &&
>> in libc/string/strsignal.c. What does everyone else think?
>>
>>  74#if defined(SIGRTMIN) && defined(SIGRTMAX)
>>        cond_at_most: Condition signal >= 27, taking false branch. Now the
>> value of signal is at most 26.
>>        at_most: At condition signal <= 31, the value of signal must be at most
>> 26.
>>        dead_error_condition: The condition signal <= 31 must be true.
>>  75  if ((signal >= SIGRTMIN) || (signal <= SIGRTMAX)) {
>>  76    siprintf (buffer, "Real-time signal %d", signal - SIGRTMIN);
>>  77    return buffer;
>>  78  }
>>  79#endif
>>  80
>>
>> CID 175333 (#1 of 1): Logically dead code (DEADCODE)
>> dead_error_line: Execution cannot reach this statement: switch (signal) {
>>
>>   case 1:....
>>
>> --joel
> I agree.  (Very easy to test, for that matter.)

I was thinking the same thing about a test and was
writing one while waiting for some feedback. Based
on this output, it is definitely broken!!

=== Normal Signals

signal=SIGHUP => Real-time signal -26
signal=SIGINT => Real-time signal -25
signal=SIGQUIT => Real-time signal -24
signal=SIGILL => Real-time signal -23

It also looks like I wrote this code so I should
take my lashings with a wet noodle. :)

Patch coming shortly.

Thanks for the review. I hope you will join in
and take a look at some of them.

--joel

> Craig
>