tests/test-calloc-gnu.c

   1 /* Test of calloc function.
   2    Copyright (C) 2010-2024 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation, either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 #include <config.h>
  18
  19 /* Specification.  */
  20 #include <stdlib.h>
  21
  22 #include <errno.h>
  23 #include <stdint.h>
  24
  25 #include "macros.h"
  26
  27 /* Return N.
  28    Usual compilers are not able to infer something about the return value.  */
  29 static size_t
  30 identity (size_t n)
  31 {
  32   unsigned int x = rand ();
  33   unsigned int y = x * x * x * x;
  34   x++; y |= x * x * x * x;
  35   x++; y |= x * x * x * x;
  36   x++; y |= x * x * x * x;
  37   y = y >> 1;
  38   y &= -y;
  39   y -= 8;
  40   /* At this point Y is zero but GCC doesn't infer this.  */
  41   return n + y;
  42 }
  43
  44 int
  45 main ()
  46 {
  47   /* Check that calloc (0, 0) is not a NULL pointer.  */
  48   {
  49     void * volatile p = calloc (0, 0);
  50     ASSERT (p != NULL);
  51     free (p);
  52   }
  53
  54   /* Check that calloc fails when requested to allocate a block of memory
  55      larger than PTRDIFF_MAX or SIZE_MAX bytes.
  56      Use 'identity' to avoid a compiler warning from GCC 7.
  57      'volatile' is needed to defeat an incorrect optimization by clang 10,
  58      see <https://bugs.llvm.org/show_bug.cgi?id=46055>.  */
  59   {
  60     for (size_t n = 2; n != 0; n <<= 1)
  61       {
  62         void *volatile p = calloc (PTRDIFF_MAX / n + 1, identity (n));
  63         ASSERT (p == NULL);
  64         ASSERT (errno == ENOMEM);
  65
  66         p = calloc (SIZE_MAX / n + 1, identity (n));
  67         ASSERT (p == NULL);
  68         ASSERT (errno == ENOMEM);
  69       }
  70   }
  71
  72   return test_exit_status;
  73 }