1  /* Verify -Wstringop-overread with a source pointer pointing either
       2     before the beginning or past the end of an object.
       3     { dg-do compile }
       4     { dg-options "-O -Wall -Wno-array-bounds" } */
       5  
       6  typedef __SIZE_TYPE__ size_t;
       7  
       8  size_t strlen (const char *);
       9  
      10  void sink (void*, ...);
      11  
      12  void off_sz_or_1 (size_t i)
      13  {
      14    i |= 1;
      15  
      16    /* Verify the offset in the notes only mentions the meaningful lower
      17       bound and not a range with the excessive (and meaningless) upper
      18       bound like [2, 9223372036854775807].  */
      19    extern char a[1];
      20    // { dg-message "at offset 1 into source object 'a'" "note" { target *-*-* } .-1 }
      21    // { dg-message "at offset 2 " "note" { target *-*-* } .-2 }
      22  
      23    char *p1 = a + i;
      24    char *p2 = p1 + 1;
      25    char *p3 = p1 - 1;
      26  
      27    size_t n = 0;
      28    n += strlen (p1);     // { dg-warning "reading 1 or more bytes from a region of size 0" }
      29    n += strlen (p2);     // { dg-warning "reading 1 or more bytes from a region of size 0" }
      30    n += strlen (p3);
      31  
      32    sink (p1, p2, p3, n);
      33  }
      34  
      35  
      36  void off_sz_or_2 (size_t i)
      37  {
      38    i |= 2;
      39  
      40    extern char b[2];
      41    // { dg-message "at offset 2 " "note" { target *-*-* } .-1 }
      42    // { dg-message "at offset 3 " "note" { target *-*-* } .-2 }
      43  
      44    char *p1 = b + i;
      45    char *p2 = p1 + 1;
      46    char *p3 = p1 - 1;
      47  
      48    size_t n = 0;
      49    n += strlen (p1);     // { dg-warning "reading 1 or more bytes from a region of size 0" }
      50    n += strlen (p2);     // { dg-warning "reading 1 or more bytes from a region of size 0" }
      51    n += strlen (p3);
      52  
      53    sink (p1, p2, p3, n);
      54  }
      55  
      56  
      57  void off_sz_or_4 (size_t i)
      58  {
      59    i |= 4;
      60  
      61    extern char c[3];
      62    // { dg-message "at offset 4 " "note" { target *-*-* } .-1 }
      63    // { dg-message "at offset 5 " "note" { target *-*-* } .-2 }
      64    // { dg-message "at offset 3 " "note" { target *-*-* } .-3 }
      65  
      66    char *p1 = c + i;
      67    char *p2 = p1 + 1;
      68    char *p3 = p1 - 1;
      69  
      70    size_t n = 0;
      71    n += strlen (p1);     // { dg-warning "reading 1 or more bytes from a region of size 0" }
      72    n += strlen (p2);     // { dg-warning "reading 1 or more bytes from a region of size 0" }
      73    n += strlen (p3);     // { dg-warning "reading 1 or more bytes from a region of size 0" }
      74  
      75    sink (p1, p2, p3, n);
      76  }