1  typedef __SIZE_TYPE__ size_t;
       2  #define NULL ((void *)0)
       3  
       4  /* Concatenating a pair of strings.  */
       5  
       6  /* Correct but poor implementation with repeated __builtin_strlen calls.  */
       7  
       8  char *
       9  alloc_dup_of_concatenated_pair_1_correct (const char *x, const char *y)
      10  {
      11    size_t sz = __builtin_strlen (x) + __builtin_strlen (y) + 1;
      12    char *result = __builtin_malloc (sz);
      13    if (!result)
      14      return NULL;
      15    __builtin_memcpy (result, x, __builtin_strlen (x));
      16    __builtin_memcpy (result + __builtin_strlen (x), y, __builtin_strlen (y));
      17    result[__builtin_strlen(x) + __builtin_strlen (y)] = '\0';
      18    return result;
      19  }
      20  
      21  /* Incorrect version: forgetting to add space for terminator.  */
      22  
      23  char *
      24  alloc_dup_of_concatenated_pair_1_incorrect (const char *x, const char *y)
      25  {
      26    /* Forgetting to add space for the terminator here.  */
      27    size_t sz = __builtin_strlen (x) + __builtin_strlen (y);
      28    char *result = __builtin_malloc (sz);
      29    if (!result)
      30      return NULL;
      31    __builtin_memcpy (result, x, __builtin_strlen (x));
      32    __builtin_memcpy (result + __builtin_strlen (x), y, __builtin_strlen (y));
      33    result[__builtin_strlen(x) + __builtin_strlen (y)] = '\0'; /* { dg-warning "heap-based buffer overflow" "PR analyzer/105899" { xfail *-*-* } } */
      34    return result;
      35  }
      36  
      37  /* As above, but only calling __builtin_strlen once on each input.  */
      38  
      39  char *
      40  alloc_dup_of_concatenated_pair_2_correct (const char *x, const char *y)
      41  {
      42    size_t len_x = __builtin_strlen (x);
      43    size_t len_y = __builtin_strlen (y);
      44    size_t sz = len_x + len_y + 1;
      45    char *result = __builtin_malloc (sz);
      46    if (!result)
      47      return NULL;
      48    __builtin_memcpy (result, x, len_x);
      49    __builtin_memcpy (result + len_x, y, len_y);
      50    result[len_x + len_y] = '\0';
      51    return result;
      52  }
      53  
      54  char *
      55  alloc_dup_of_concatenated_pair_2_incorrect (const char *x, const char *y)
      56  {
      57    size_t len_x = __builtin_strlen (x);
      58    size_t len_y = __builtin_strlen (y);
      59    size_t sz = len_x + len_y; /* Forgetting to add space for the terminator.  */
      60    char *result = __builtin_malloc (sz); /* { dg-message "capacity: 'len_x \\+ len_y' bytes" } */
      61    if (!result)
      62      return NULL;
      63    __builtin_memcpy (result, x, len_x);
      64    __builtin_memcpy (result + len_x, y, len_y);
      65    result[len_x + len_y] = '\0'; /* { dg-warning "heap-based buffer overflow" } */
      66    return result;
      67  }