Re: [cocci] match arbitrary argument position

[Jakob Koschel <jkl820.git@gmail.com>]

> On 16. Aug 2022, at 23:07, Julia Lawall <Julia.Lawall@inria.fr> wrote:
> 
>>>> Based on that I was wondering if there is a way to say: match if the expression is
>>>> within an expression list. So if I for instance have something like this:
>>>> 
>>>> @main@
>>>> type T;
>>>> parameter list P;
>>>> expression list E;
>>>> expression E1;
>>>> identifier func, func_call;
>>>> @@
>>>> 
>>>> T func(P@E) {
>>>>   ...
>>>>   func_call(E1 in E)
>>>>   ...
>>>> }
>>>> 
>>>> (above is not valid syntax of course)
>>>> 
>>>> Ideally I would like to make and get the parameters of 'func' that are used in any position
>>>> as arguments in 'func_call' if that makes sense?
>> 
>> Do you have any idea regarding the expression lists?
>> 
>> looking at the following code snippet:
>> 
>> test.c:
>> 
>>   int func1(int argc, char *argv) {
>>      func2(argc, argv);
>> 
>>      func3(argc, argv);
>> 
>>      func3(argv);
>>   }
>> 
>> what works is (only matches the first func3 call):
>> 
>>   @main4@
>>   expression list Es;
>>   @@
>> 
>>   func2(Es)
>> 
>>   @main5@
>>   expression list main4.Es;
>>   identifier func;
>>   @@
>> 
>>     func(Es);
>>   + // add comment
>> 
>> 
>> what doesn't work (matching on the expression list from the parameter list):
>> 
>>   @main4@
>>   expression list Es;
>>   @@
>> 
>>   int func1(Ps@Es) {
>>   ...
>>   }
>> 
>>   @main5@
>>   expression list main4.Es;
> 
> Could you try
> 
> expression list main4.Ps;
> 
> It may transform the parameters into a list of expressions.

I just tried:

@main4@
parameter list Ps;
@@

int func1(Ps) {
...
}

@main5@
expression list main4.Ps;
identifier func;
@@

  func(Es);
+ // add comment

but that throws:

meta: semantic error: incompatible inheritance declaration Ps
  File "test.cocci", line 45, column 24, charpos = 539
  around = ';',
  whole content = expression list main4.Ps;

> 
> julia
> 
>>   identifier func;
>>   @@
>> 
>>     func(Es);
>>   + // add comment
>> 
>> 
>> Ideally I would like to 'find' all parameters used in a function call,
>> I also tried this:
>> 
>>   @main4@
>>   parameter P;
>>   expression E;
>>   @@
>> 
>>   int func1(..., P@E, ...) {
>>   ...
>>   }
>> 
>>   @main5@
>>   expression main4.E;
>>   identifier func;
>>   @@
>> 
>>     func(..., E, ...);
>>   + // add comment
>> 
>> 
>> But it throws: 'rule starting on line 41 contains unattached metavariables: main4.E'.
>> 
>> Any idea, why e.g. the second one doesn't work? If I print it with python the expression list
>> looks the same as for the first one.
>> Also in the end this boils down to: is it possible to match to any of the expression list elements?
>> 
>> Thanks,
>> Jakob
>> 
>>>> 
>>>> 
>>>> Any help is very much appreciated!
>>>> 
>>>> Thanks,
>>>> Jakob