Tool to Trace Local Function Calls in Linux

Tool to trace local function calls in Linux

Assuming you only want to be notified for specific functions, you can do it like this:

compile with debug informations (as you already have symbol informations, you probably also have enough debugs in)

given

#include <iostream>

int fac(int n) {
    if(n == 0)
        return 1;
    return n * fac(n-1);
}

int main()
{
    for(int i=0;i<4;i++)
        std::cout << fac(i) << std::endl;
}

Use gdb to trace:

[js@HOST2 cpp]$ g++ -g3 test.cpp
[js@HOST2 cpp]$ gdb ./a.out
(gdb) b fac
Breakpoint 1 at 0x804866a: file test.cpp, line 4.
(gdb) commands 1
Type commands for when breakpoint 1 is hit, one per line.
End with a line saying just "end".
>silent
>bt 1
>c
>end
(gdb) run
Starting program: /home/js/cpp/a.out
#0  fac (n=0) at test.cpp:4
1
#0  fac (n=1) at test.cpp:4
#0  fac (n=0) at test.cpp:4
1
#0  fac (n=2) at test.cpp:4
#0  fac (n=1) at test.cpp:4
#0  fac (n=0) at test.cpp:4
2
#0  fac (n=3) at test.cpp:4
#0  fac (n=2) at test.cpp:4
#0  fac (n=1) at test.cpp:4
#0  fac (n=0) at test.cpp:4
6

Program exited normally.
(gdb)

Here is what i do to collect all function's addresses:

tmp=$(mktemp)
readelf -s ./a.out | gawk '
{ 
  if($4 == "FUNC" && $2 != 0) { 
    print "# code for " $NF; 
    print "b *0x" $2; 
    print "commands"; 
    print "silent"; 
    print "bt 1"; 
    print "c"; 
    print "end"; 
    print ""; 
  } 
}' > $tmp; 
gdb --command=$tmp ./a.out; 
rm -f $tmp

Note that instead of just printing the current frame(bt 1), you can do anything you like, printing the value of some global, executing some shell command or mailing something if it hits the fatal_bomb_exploded function :) Sadly, gcc outputs some "Current Language changed" messages in between. But that's easily grepped out. No big deal.

tracing program function calls

Yes, profiling is the only way to do this.

All you will get is the function address, which you can map again to its name by dladdr() API.

All the best!!!!

linux tool to show c function call from source

GNU cflow is your good friend.
https://www.gnu.org/software/cflow/manual/cflow.html

List of all function calls made in an application

How can we list all the functions being called in an application

For any realistically sized application, this list will have thousands of entries, which will probably make it useless.

You can find out all functions defined (but not necessarily called) in an application with the nm command, e.g.

nm /path/to/a.out | egrep ' [TW] '

You can also use GDB to set a breakpoint on each function:

(gdb) set logging on     # collect trace in gdb.txt
(gdb) set confirm off    # you wouldn't want to confirm every one of them
(gdb) rbreak .           # set a breakpoint on each function

Once you continue, you'll hit a breakpoint for each function called. Use the disable and continue commands to move forward. I don't believe there is an easy way to automate that, unless you want to use Python scripting.

Already mentioned gprof is another good option.

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