sysdeps/generic/tst-stack-align.h

   1 /* Check stack alignment.  Generic version.
   2    Copyright (C) 2003-2023 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 #include <stdio.h>
  20 #include <stdint.h>
  21
  22 int
  23 __attribute__ ((weak, noclone, noinline))
  24 is_aligned (void *p, int align)
  25 {
  26   return (((uintptr_t) p) & (align - 1)) != 0;
  27 }
  28
  29 #ifndef TEST_STACK_ALIGN_INIT
  30 # define TEST_STACK_ALIGN_INIT() 0
  31 #endif
  32
  33 #define TEST_STACK_ALIGN() \
  34   ({                                                                 \
  35     double _d = 12.0;                                                \
  36     long double _ld = 15.0;                                          \
  37     int _ret = TEST_STACK_ALIGN_INIT ();                             \
  38                                                                      \
  39     printf ("double:  %g %p %zu\n", _d, &_d, __alignof (double));    \
  40     _ret += is_aligned (&_d, __alignof (double));                    \
  41                                                                      \
  42     printf ("ldouble: %Lg %p %zu\n", _ld, &_ld,                      \
  43             __alignof (long double));                                \
  44     _ret += is_aligned (&_ld, __alignof (long double));              \
  45     _ret;                                                            \
  46    })