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Perl script to find where functions is called in c

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# 1  
Old 12-27-2010
Perl script to find where functions is called in c
Hello,

I need to write a perl script to find where functions is called in c files..

The script should scan the file and find out the function names and then search to see where they are called...

Lets for now assume all functions are internal.

I don't know where to start Smilie

---------- Post updated at 06:10 AM ---------- Previous update was at 05:25 AM ----------

okay.. I managed to do it using this:
Code:
open FILE, "<test.h" or die $!;


while(<FILE>){
if(/static void ([^ \n\(]+)/)
{

print "function: $1\n";

$str=$1;
open FILE2, "<test.c" or die $!;
while(<FILE2>){
        if(!$sw && /(.+)\(.*\)/){
                $func_name=$1;
                $func_start=$.;
                $sw=1;
                next;
        }
        $c++ if $sw && /\{/;
        $c-- if $sw && /\}/; 
        if(/$str/){
                $print=1;
        }
        if($sw && $c==0){
                if($print){
                        
                        print "Caller function: $func_name\n";
                        $print=0;
                }
                $sw=0;
        }
}
close FILE2;


print "\n";
}
}

Now the problem is, I do not want to print the result, I want to write it in a certain part of the file.. for example, the h file has the format:
Code:
/* Function -------------------------------------------- 
* function name: function1
* caller: 
*
------------------------------------------------------------*/
static void function1(..);

I want the result to be written infront of the "caller: " field.
# 2  
Old 12-27-2010
Well, I use cscope, which is free. You need a state engine to parse C states, but you are only interested in locating calls and subroutines. You have to handle every C meta-character and expression correctly, so you know when you are in comments and quotations. Just assign the states numbers in an int or enum as you discover them. Beware advanced things like "XXX"\n"YYY" ( = "XXXYYY"), and \ at end of line! When you find a variable name, you need to decide if it is a call or a subroutine declaration or a non-subroutine declaration like int i. You have to worry about type names in typedefs and #defines, possibly in includes, so you must preprocess with cpp or cc -E and process the structured comments in that output that show where include file lines are. So easy, almost like writing a compiler!
# 3  
Old 01-13-2011
okay, I solved this but faced another problem..
It works great if the function declaration is on a single line:
Code:
void function1(arg1, arg2)

but doesn't work if its multiline:
Code:
void function1(arg1, 
                                    arg2, arg3)

# 4  
Old 01-13-2011
You could something like this:

Code:
# cat input
void function1(arg1, 
   arg33,
   arg2,arg3)

Code:
#!/usr/bin/perl

open FILE, "<".shift or die $!;

while (<FILE>) {
   chomp;
   if(/void ([^ \(])+/ || $f)
     {
     $f=1;
     $cF.=$_ ;
     last if ( /\)\s*$/ );
     }
   }

print "cF:".$cF."\n";

# 5  
Old 01-13-2011
I usually deal with such parsing tasks with a little state machine that normlizes the C into one string block with all white space down to one or zero spaces as allowed. The state machine parses bytes until the end of declaration, knowing when it is in comments and in quotes, and the depth of any (){}[] has cancelled down to 0. The block might get very big, so it might be good to abstract out whatever is in {}, as you must reparse inside {} to see what is declared there. The code needs to be preprocessed so macros are expanded, and the parser needs to keep track of the files and line numbers it is in via include: # line_number "file_name"
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