[cocci] Space-delimted string literals

* [cocci] Space-delimted string literals
@ 2022-04-01 20:12 Eric Wheeler
  2022-04-02  8:42 ` [cocci] Checking the handling of “space-delimited” string literals by SmPL Markus Elfring
  0 siblings, 1 reply; 4+ messages in thread
From: Eric Wheeler @ 2022-04-01 20:12 UTC (permalink / raw)
  To: cocci

I think this is a known issue, but thought I would share in case it is 
useful.  This function:

	void print_bug(char *s)               
	{                                     
	    printf(__FILE__ ": BUG: %s\n", s);
	}                                     

is not matched by this SmPL:

	@ p @               
	expression list EL; 
	constant C =~ "BUG";
	@@                  
	-printf(C, EL);     
	+BUG(C, EL);        

but without __FILE__ it matches:

	void print_bug(char *s)               
	{                                     
	    printf(": BUG: %s\n", s);
	}                                     

I've tried to do something like this, but it is invalid SmPL:

	@ p @               
	expression list EL; 
	constant FOO, C =~ "BUG";
	@@                  
	-printf(FOO C, EL);     
	+BUG(C, EL);        

and produces this error:
	minus: parse error: 
	  File "cocci/constant-issue", line 5, column 12, charpos = 68
	  around = 'C',
	  whole content = -printf(FOO C, EL);

This isn't a critical issue in my case, only a few replacements, but 
string literal handling in SmPL might benefit other users.

Consider a grammar like this:

	literal := literal | literal literal

Maybe the definition is a but too recursive, but you can see what I'm 
trying to express.  Maybe keep it as a "constant" or perhaps introduce a 
new SmPL metavar type called "literal" or "string".

Considerations if "a" "b" "c" were being matched:

1. Specify A B C metavars and get the string in each as you would expect.
2. Specify just A and get all of them in A
3. Specify A B and A gets the first and B gets the tail as "b" "c".

Just ideas, I'm open to whatever you think is best for the project.

--
Eric Wheeler

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