gcc/testsuite/c-c++-common/attr-nonstring-2.c

   1 /* Test to exercise attribute "nonstring".
   2    { dg-do compile }
   3    { dg-options "-O2 -Wattributes -Wstringop-truncation -ftrack-macro-expansion=0" }  */
   4
   5 #define ATTR(list) __attribute__ (list)
   6 #define NONSTR     ATTR ((nonstring))
   7 #define strncpy(d, s, n) (__builtin_strncpy ((d), (s), (n)), sink (d))
   8
   9 void sink (void*);
  10
  11 /* Global string with an unknown bound.  */
  12 extern char gsx[];
  13
  14 /* Global string with an known bound.  */
  15 extern char gs3[3];
  16
  17 /* Global non-strings with an unknown bound.  */
  18 extern NONSTR char gax_1[];
  19 extern char NONSTR gax_2[];
  20 extern char gax_3[] NONSTR;
  21
  22 /* Global non-strings with a known bound.  */
  23 NONSTR char gns3[3];
  24 char NONSTR gns4[4];
  25 char gns5[5] NONSTR;
  26
  27 /* Global string pointer.  */
  28 extern char *ps_1;
  29
  30 /* Global non-string pointers.  */
  31 extern NONSTR char *pns_1;
  32 extern char* NONSTR pns_2;
  33 extern char *pns_3 NONSTR;
  34
  35 struct MemArrays
  36 {
  37   NONSTR char ma3[3];
  38   char NONSTR ma4[4];
  39   char ma5[5] NONSTR;
  40   char max[] NONSTR;
  41 };
  42
  43
  44 void test_array (const char *s, unsigned n)
  45 {
  46   const char s7[] = "1234567";
  47
  48   strncpy (gs3, "", 0);           /* { dg-warning "destination unchanged after copying no bytes" } */
  49   strncpy (gs3, "a", 1);          /* { dg-warning "output truncated before terminating nul copying 1 byte from a string of the same length" } */
  50   strncpy (gs3, "a", 2);
  51   strncpy (gs3, "a", 3);
  52   strncpy (gs3, "ab", 3);
  53   strncpy (gs3, "abc", 3);        /* { dg-warning "output truncated before terminating nul copying 3 bytes from a string of the same length" } */
  54
  55   /* It might perhaps be helpful to diagnose certain truncation even
  56      for non-strings.  Then again, since the destination has been
  57      explicitly annotated as non-string, it might be viewed as a false
  58      positive.  A valid use case seen in Glibc goes something like this:
  59
  60      #if FOO
  61      # define S "1234"
  62      #else
  63      # define S "12345678"
  64      #endif
  65
  66      strncpy (d, S, 8);
  67   */
  68   strncpy (gax_3, s7, 3);
  69
  70   strncpy (gax_1, "a", 1);
  71   strncpy (gax_2, "ab", 2);
  72   strncpy (gax_3, "abc", 3);
  73   strncpy (gax_3, s7, 3);
  74
  75   strncpy (gax_1, s, 1);
  76   strncpy (gax_2, s, 1);
  77   strncpy (gax_3, s, 1);
  78
  79   strncpy (gax_1, s, n);
  80   strncpy (gax_2, s, n);
  81   strncpy (gax_3, s, n);
  82 }
  83
  84
  85 void test_pointer (const char *s, unsigned n)
  86 {
  87   const char s7[] = "1234567";
  88
  89   strncpy (pns_1, "a", 1);
  90   strncpy (pns_2, "ab", 2);
  91   strncpy (pns_3, "abc", 3);
  92   strncpy (pns_3, s7, 3);
  93
  94   strncpy (pns_1, s, 1);
  95   strncpy (pns_2, s, 1);
  96   strncpy (pns_3, s, 1);
  97
  98   strncpy (pns_1, s, n);
  99   strncpy (pns_2, s, n);
 100   strncpy (pns_3, s, n);
 101 }
 102
 103
 104 void test_member_array (struct MemArrays *p, const char *s, unsigned n)
 105 {
 106   const char s7[] = "1234567";
 107
 108   strncpy (p->ma3, "", 0);
 109   strncpy (p->ma3, "a", 1);
 110   strncpy (p->ma4, "ab", 2);
 111   strncpy (p->ma5, "abc", 3);
 112   strncpy (p->max, "abcd", 4);
 113   strncpy (p->max, s7, 5);
 114
 115   strncpy (p->ma3, s, 1);
 116   strncpy (p->ma4, s, 1);
 117   strncpy (p->ma5, s, 1);
 118   strncpy (p->max, s, 1);
 119
 120   strncpy (p->ma3, s7, n);
 121   strncpy (p->ma4, s7, n);
 122   strncpy (p->ma5, s7, n);
 123   strncpy (p->max, s7, n);
 124 }