Question

Can gcc spit out, given a C file, a list of the all function calls that occur, with filename and line number both for the call itself and for the function’s declaration?

I know gcc somehow retains this information with -g (debuggers rely on it) and that it can dump control flow graphs with -dr (but without filenames or line numbers); but is there a ready-to-use tool that takes gcc output and does what I want?

The reason I want such a tool to use gcc is that this will allow me to use it with the standard build system most gcc-based software comes with (e.g. ./configure && make) even in cases where tools that rely on their own preprocessor and/or parser are a major hassle to fit in. I’m already aware of several such tools, e.g. ctags. So this question is a followup to question 525899.

Answer 1

Try gcc option -fdump-tree-fixupcfg-lineno.

It will ‘pretty print’ parsing AST (with line numbers) in a way that can easily be parsed using relatively simple lexer or any regex engine. Just find all non-keywords preceded by ‘=’ and followed by ‘(‘ – it will be function calls.

All complex expressions will be split into several lines so no two function calls will appear on one line.

Take simple program:

#include <stdio.h> #include <stdlib.h> #include <math.h>  #define PI (3.1415926536)  int main(int argc, char *argv[]) {     double  angle = PI / 2.0;     printf('Sine = %lf, cosine = %lf\n', sin(angle), cos(angle));     return EXIT_SUCCESS; } 

Compile it with -fdump-tree-fixupcfg-lineno and you get something like this:

main (argc, argv) {   double angle;   int D.3381;   double D.3380;   double D.3379;    # BLOCK 2, starting at line 8   # PRED: ENTRY (fallthru)   [test.c : 8] angle = 1.57079632680000003119857865385711193084716796875e+0;   [test.c : 9] D.3379 = [test.c : 9] cos (angle);   [test.c : 9] D.3380 = [test.c : 9] sin (angle);   [test.c : 9] printf (&'Sine = %lf, cosine = %lf\n'[0], D.3380, D.3379);   [test.c : 10] D.3381 = 0;   return D.3381;   # SUCC: EXIT  } 

You won’t get any complex expressions – just assignments and function call and no CPP macros, very easy to parse. Loops and conditionals don’t make it much more difficult.