gcc/testsuite/c-c++-common/analyzer/deref-before-check-2.c

   1 #include <stdio.h>
   2
   3 struct st
   4 {
   5   char *str;
   6   int i;
   7 };
   8
   9 int test_1 (struct st *p)
  10 {
  11   fprintf (stderr, "str: %s\n", p->str); /* { dg-message "pointer 'p' is dereferenced here" } */
  12   if (!p) /* { dg-warning "check of 'p' for NULL after already dereferencing it" } */
  13     return -1;
  14   return p->i;
  15 }
  16
  17 int test_2 (int flag_a, int flag_b, struct st *p)
  18 {
  19   if (flag_a)
  20     {
  21       int j = p->i; /* { dg-message "pointer 'p' is dereferenced here" } */
  22       if (flag_b && p) /* { dg-warning "check of 'p' for NULL after already dereferencing it" } */
  23         return 1;
  24       return j;
  25     }
  26   return 2;
  27 }
  28
  29 int test_3 (struct st *a, struct st *b)
  30 {
  31   if (!a)
  32     return b->i;
  33   if (!b)
  34     return a->i;
  35   return 0;
  36 }
  37
  38 int test_4 (struct st *p)
  39 {
  40   int *q = &p->i;
  41   if (!p)
  42     return -1;
  43   return *q;
  44 }
  45
  46 void test_check_after_strlen (const char *str)
  47 {
  48   size_t len_a = __builtin_strlen (str); /* { dg-message "pointer 'str' is dereferenced here" } */
  49   size_t len_b = str ? __builtin_strlen (str) : 0; /* { dg-warning "check of 'str' for NULL after already dereferencing it" } */
  50 }
  51
  52 void test_6 (struct st *a, struct st *b)
  53 {
  54   int diff = a->i - b->i; /* { dg-message "pointer 'b' is dereferenced here" } */
  55
  56   /* ... */
  57
  58   if (b) /* { dg-warning "check of 'b' for NULL after already dereferencing it" } */
  59     fprintf (stderr, "str: %s\n", b->str);
  60 }
  61
  62 void test_check_after_strcmp (const char *s1, const char *s2)
  63 {
  64   if (!__builtin_strcmp (s1, s2)) /* { dg-message "pointer 's1' is dereferenced here" } */
  65     return;
  66
  67   /* ... */
  68
  69   if (s1) /* { dg-warning "check of 's1' for NULL after already dereferencing it" } */
  70     return;
  71 }
  72
  73 void test_more_than_one_deref (struct st *p)
  74 {
  75   char *str = p->str; /* { dg-message "pointer 'p' is dereferenced here" } */
  76   int i = p->i;
  77
  78   /* ... */
  79
  80   if (p) /* { dg-warning "check of 'p' for NULL after already dereferencing it" } */
  81     return;
  82
  83   /* ... */
  84 }
  85
  86 void test_deref_under_another_name (struct st *p)
  87 {
  88   struct st *q = p;
  89   int i = q->i; /* { dg-message "pointer 'p' is dereferenced here" } */
  90
  91   /* ... */
  92
  93   if (p) /* { dg-warning "check of 'p' for NULL after already dereferencing it" } */
  94     return;
  95
  96   /* ... */
  97 }
  98
  99 void test_check_after_memcpy_src (struct st *dst, struct st *src)
 100 {
 101   __builtin_memcpy (dst, src, sizeof (struct st)); /* { dg-message "pointer 'src' is dereferenced here" } */
 102
 103   /* ... */
 104
 105   if (!src) /* { dg-warning "check of 'src' for NULL after already dereferencing it" } */
 106     return;
 107
 108   /* ... */
 109 }
 110
 111 void test_check_after_memcpy_dst (struct st *dst, struct st *src)
 112 {
 113   __builtin_memcpy (dst, src, sizeof (struct st)); /* { dg-message "pointer 'dst' is dereferenced here" } */
 114
 115   /* ... */
 116
 117   if (!dst) /* { dg-warning "check of 'dst' for NULL after already dereferencing it" } */
 118     return;
 119
 120   /* ... */
 121 }
 122
 123 void test_merger (int *p, int flag)
 124 {
 125   int x = *p;
 126   if (flag)
 127     __builtin_free (p);
 128   if (!flag)
 129     __builtin_free (p); /* { dg-bogus "double-'free'" } */
 130 }