1  /* Test program to trigger mcount overflow in profiling collection.
       2     Copyright (C) 2017-2023 Free Software Foundation, Inc.
       3     This file is part of the GNU C Library.
       4  
       5     The GNU C Library is free software; you can redistribute it and/or
       6     modify it under the terms of the GNU Lesser General Public
       7     License as published by the Free Software Foundation; either
       8     version 2.1 of the License, or (at your option) any later version.
       9  
      10     The GNU C Library is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      13     Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public
      16     License along with the GNU C Library; if not, see
      17     <https://www.gnu.org/licenses/>.  */
      18  
      19  /* Program with sufficiently complex, yet pointless, call graph
      20     that it will trigger an mcount overflow, when you set the
      21     minarcs/maxarcs tunables to very low values. */
      22  
      23  #define PREVENT_TAIL_CALL asm volatile ("")
      24  
      25  /* Calls REP(n) macro 16 times, for n=0..15.
      26   * You need to define REP(n) before using this.
      27   */
      28  #define REPS \
      29    REP(0) REP(1) REP(2) REP(3) REP(4) REP(5) REP(6) REP(7) \
      30    REP(8) REP(9) REP(10) REP(11) REP(12) REP(13) REP(14) REP(15)
      31  
      32  /* Defines 16 leaf functions named f1_0 to f1_15 */
      33  #define REP(n) \
      34    __attribute__ ((noinline, noclone, weak)) void f1_##n (void) {};
      35  REPS
      36  #undef REP
      37  
      38  /* Calls all 16 leaf functions f1_* in succession */
      39  __attribute__ ((noinline, noclone, weak)) void
      40  f2 (void)
      41  {
      42  # define REP(n) f1_##n();
      43    REPS
      44  # undef REP
      45    PREVENT_TAIL_CALL;
      46  }
      47  
      48  /* Defines 16 functions named f2_0 to f2_15, which all just call f2 */
      49  #define REP(n) \
      50    __attribute__ ((noinline, noclone, weak)) void \
      51    f2_##n (void) { f2(); PREVENT_TAIL_CALL; };
      52  REPS
      53  #undef REP
      54  
      55  __attribute__ ((noinline, noclone, weak)) void
      56  f3 (int count)
      57  {
      58    for (int i = 0; i < count; ++i)
      59      {
      60        /* Calls f1_0(), f2_0(), f1_1(), f2_1(), f3_0(), etc */
      61  #     define REP(n) f1_##n(); f2_##n();
      62        REPS
      63  #     undef REP
      64      }
      65  }
      66  
      67  int
      68  main (void)
      69  {
      70    f3 (1000);
      71    return 0;
      72  }