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Diffstat (limited to 'gmon/tst-mcount-overflow.c')
-rw-r--r-- | gmon/tst-mcount-overflow.c | 72 |
1 files changed, 72 insertions, 0 deletions
diff --git a/gmon/tst-mcount-overflow.c b/gmon/tst-mcount-overflow.c new file mode 100644 index 0000000000..06cc93ef87 --- /dev/null +++ b/gmon/tst-mcount-overflow.c @@ -0,0 +1,72 @@ +/* Test program to trigger mcount overflow in profiling collection. + Copyright (C) 2017-2023 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <https://www.gnu.org/licenses/>. */ + +/* Program with sufficiently complex, yet pointless, call graph + that it will trigger an mcount overflow, when you set the + minarcs/maxarcs tunables to very low values. */ + +#define PREVENT_TAIL_CALL asm volatile ("") + +/* Calls REP(n) macro 16 times, for n=0..15. + * You need to define REP(n) before using this. + */ +#define REPS \ + REP(0) REP(1) REP(2) REP(3) REP(4) REP(5) REP(6) REP(7) \ + REP(8) REP(9) REP(10) REP(11) REP(12) REP(13) REP(14) REP(15) + +/* Defines 16 leaf functions named f1_0 to f1_15 */ +#define REP(n) \ + __attribute__ ((noinline, noclone, weak)) void f1_##n (void) {}; +REPS +#undef REP + +/* Calls all 16 leaf functions f1_* in succession */ +__attribute__ ((noinline, noclone, weak)) void +f2 (void) +{ +# define REP(n) f1_##n(); + REPS +# undef REP + PREVENT_TAIL_CALL; +} + +/* Defines 16 functions named f2_0 to f2_15, which all just call f2 */ +#define REP(n) \ + __attribute__ ((noinline, noclone, weak)) void \ + f2_##n (void) { f2(); PREVENT_TAIL_CALL; }; +REPS +#undef REP + +__attribute__ ((noinline, noclone, weak)) void +f3 (int count) +{ + for (int i = 0; i < count; ++i) + { + /* Calls f1_0(), f2_0(), f1_1(), f2_1(), f3_0(), etc */ +# define REP(n) f1_##n(); f2_##n(); + REPS +# undef REP + } +} + +int +main (void) +{ + f3 (1000); + return 0; +} |