gcc/testsuite/gcc.dg/Wstringop-overread-5.c

   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 }