#! /usr/bin/env bash

# Based on a pmp script from Aspersa (http://code.google.com/p/aspersa/) by Baron Schwartz,
# in turn based on a script by Domas Mituzas at http://poormansprofiler.org

usage()
{
   if [ "${OPT_ERR}" ]; then
      echo "E: ${OPT_ERR}"
   fi
   cat <<-USAGE
Usage: $0 [OPTIONS]
   $0 does two things:
     1) sets a breakpoint and gets a backtrace using GDB
     2) aggregates it
Options:
   -i ITERATIONS  How many traces to gather and aggregate (default 1)
   -l NUMBER      Aggregate only first NUMBER functions (default infinity)
   -p PID         Process ID of the process to trace
   -t FUNCTION    Function to break on (default caml_call_gc)
	USAGE
   exit 1
}


main ()
{
  for o; do
    case "${o}" in
    --help)
           usage;
           ;;
    -p)
       shift; OPT_p="${1}"; shift;
       ;;
    -i)
       shift; OPT_i="${1}"; shift;
       ;;
    -t)
       shift; OPT_t="${1}"; shift;
       ;;
    -l)
       shift; OPT_l="${1}"; shift;
       ;;
    -*)
       OPT_ERR="unknown option ${o}";
       usage
       ;;
    esac
  done
  export OPT_p="${OPT_p:-}";
  export OPT_i="${OPT_i:-1}";
  export OPT_t="${OPT_t:-caml_call_gc}";
  export OPT_l="${OPT_l:--0}";

  if [ ! "${OPT_p}" ] ; then
    OPT_ERR="PID not specified";
    usage
  fi
 
  for i in $(seq 1 $OPT_i); do
    gdb -p "$OPT_p" "/proc/$OPT_p/exe" -batch -n -q -ex 'set interactive off' -ex "b $OPT_t" -ex 'c' -ex 'bt'\
    |awk '/^#[^0]/ {print $4}' |uniq |head -n "$OPT_l" |paste -s -d , ;
  done |sort |uniq -c |sort -n;
}

main $@