gcc/testsuite/gcc.dg/Wstringop-overflow-39.c

   1 /* PR middle-end/95667 - unintended warning for memset writing across multiple
   2    members
   3    { dg-do compile }
   4    { dg-options "-O2 -Wall" }
   5    { dg-require-effective-target alloca } */
   6
   7 extern void sink (void*);
   8
   9 struct S1 { char a[3], b[5]; };
  10
  11 void warn_strcpy_s1 (void)
  12 {
  13   struct S1 *p = __builtin_malloc (sizeof *p);
  14   char s[] = "1234567";
  15   __builtin_strcpy (p->a, s);         // { dg-warning "\\\[-Wstringop-overflow" }
  16   sink (p);
  17 }
  18
  19 void nowarn_memset_s1 (void)
  20 {
  21   struct S1 *p = __builtin_malloc (sizeof *p);
  22   __builtin_memset (p->a, 0, 8);      // { dg-bogus "\\\[-Wstringop-overflow" }
  23   sink (p);
  24 }
  25
  26 struct S2 { char a[2], b[2][2], c[3]; };
  27
  28 void nowarn_memset_s2 (void)
  29 {
  30   struct S2 *p = __builtin_malloc (sizeof *p);
  31
  32   __builtin_memset (p->a, 0, sizeof *p);
  33   sink (p);
  34
  35   __builtin_memset (p->b, 0, 7);
  36   sink (p);
  37
  38   __builtin_memset (&p->b[0], 0, 7);
  39   sink (p);
  40
  41   __builtin_memset (&p->b[1], 0, 5);
  42   sink (p);
  43
  44   __builtin_memset (&p->b[0][0], 0, 7);
  45   sink (p);
  46
  47   __builtin_memset (&p->b[0][1], 0, 6);
  48   sink (p);
  49
  50   __builtin_memset (&p->b[1][0], 0, 5);
  51   sink (p);
  52
  53   __builtin_memset (&p->b[1][1], 0, 4);
  54   sink (p);
  55 }
  56
  57 void warn_memset_s2 (void)
  58 {
  59   const unsigned n = sizeof (struct S2);
  60   struct S2 *p = __builtin_malloc (n);
  61
  62   /* These should trigger -Wstringop-overflow rather than -Warray-bounds
  63      but the main purpose of the test is to verify the absence of warnings
  64      above so the exact warning for these overflwing calls isn't important
  65      here.  */
  66
  67   __builtin_memset (p->a, 0, n + 1);  // { dg-warning "\\\[-Warray-bounds|-Wstringop-overflow" }
  68   sink (p);
  69
  70   __builtin_memset (p->b, 0, 8);      // { dg-warning "\\\[-Warray-bounds|-Wstringop-overflow" }
  71   sink (p);
  72
  73   __builtin_memset (&p->b[0], 0, 8);  // { dg-warning "\\\[-Warray-bounds|-Wstringop-overflow" }
  74   sink (p);
  75
  76   __builtin_memset (&p->b[0][0], 0, 8); // { dg-warning "\\\[-Warray-bounds|-Wstringop-overflow" }
  77   sink (p);
  78
  79   __builtin_memset (&p->b[1], 0, 6);  // { dg-warning "\\\[-Warray-bounds|-Wstringop-overflow" }
  80   sink (p);
  81
  82   __builtin_memset (&p->b[0][1], 0, 7); // { dg-warning "\\\[-Warray-bounds|-Wstringop-overflow" }
  83   sink (p);
  84 }
  85
  86 void nowarn_vl_struct (unsigned n)
  87 {
  88   if (n < 3 || 5 < n)
  89     n = 3;
  90
  91   struct V { char a[3], b[n], c[7]; } v;
  92
  93   __builtin_memset (v.a, 0, 15);
  94   sink (&v);
  95
  96   __builtin_memset (v.b, 0, 12);
  97   sink (&v);
  98
  99   __builtin_memset (v.c, 0, 7);
 100   sink (&v);
 101
 102   __builtin_memset (v.a, 0, 16);      // { dg-warning "\\\[-Warray-bounds|-Wstringop-overflow" }
 103   sink (&v);
 104
 105   __builtin_memset (v.b, 0, 13);      // { dg-warning "\\\[-Warray-bounds|-Wstringop-overflow" }
 106   sink (&v);
 107
 108   /* The &V.C argument is represented as a variable offset from
 109      the beginning of the allocated object and there's no good
 110      way to figure out from its variable offset that it's base
 111      is the C member:
 112        s.1_12 = __builtin_alloca_with_align (prephitmp_24, 8);
 113        _9 = s.1_12 + prephitmp_27;
 114        __builtin_memset (_9, 0, 2);
 115   */
 116
 117   __builtin_memset (v.c, 0, 8);       // { dg-warning "\\\[-Warray-bounds|-Wstringop-overflow" "pr?????" { xfail *-*-* } }
 118   sink (&v);
 119 }