gcc/testsuite/c-c++-common/Wuse-after-free-5.c

   1 /* Verify -Wuse-after-free=2 triggers for conditional as well as
   2    unconditional uses but not for equality expressions.
   3    { dg-do compile }
   4    { dg-options "-O0 -Wall -Wuse-after-free=2" } */
   5
   6
   7 #if __cplusplus
   8 #  define EXTERN_C extern "C"
   9 #else
  10 #  define EXTERN_C extern
  11 #endif
  12
  13 EXTERN_C void free (void*);
  14
  15 void sink (void*);
  16
  17
  18 void warn_double_free (void *p)
  19 {
  20   free (p);
  21   free (p);         // { dg-warning "pointer 'p' used" }
  22 }
  23
  24 void warn_cond_double_free (void *p, int c)
  25 {
  26   free (p);
  27   if (c)
  28     free (p);       // { dg-warning "pointer 'p' may be used" }
  29 }
  30
  31 void warn_call_after_free (void *p)
  32 {
  33   free (p);
  34   sink (p);         // { dg-warning "pointer 'p' used" }
  35 }
  36
  37 void warn_cond_call_after_free (void *p, int c)
  38 {
  39   free (p);
  40   if (c)
  41     sink (p);       // { dg-warning "pointer 'p' may be used" }
  42 }
  43
  44 void* warn_return_after_free (void *p)
  45 {
  46   free (p);
  47   return p;         // { dg-warning "pointer 'p' used" }
  48 }
  49
  50 void* warn_cond_return_after_free (void *p, int c)
  51 {
  52   free (p);
  53   if (c)
  54     return p;       // { dg-warning "pointer 'p' may be used" }
  55   return 0;
  56 }
  57
  58 void warn_relational_after_free (char *p, char *q[])
  59 {
  60   free (p);
  61
  62   int a[] =
  63     {
  64      p < q[0],      // { dg-warning "pointer 'p' used" }
  65      p <= q[1],     // { dg-warning "pointer 'p' used" }
  66      p > q[2],      // { dg-warning "pointer 'p' used" }
  67      p >= q[3],     // { dg-warning "pointer 'p' used" }
  68      p == q[4],
  69      p != q[5]
  70     };
  71
  72   sink (a);
  73 }
  74
  75 void warn_cond_relational_after_free (char *p, char *q[], int c)
  76 {
  77   free (p);
  78
  79   int a[] =
  80     {
  81      c ? p < q[0] : q[0][0],  // { dg-warning "pointer 'p' may be used" }
  82      c ? p <= q[1] : q[1][1], // { dg-warning "pointer 'p' may be used" }
  83      c ? p > q[2] : q[2][2],  // { dg-warning "pointer 'p' may be used" }
  84      c ? p >= q[3] : q[3][3], // { dg-warning "pointer 'p' may be used" }
  85      c ? p == q[4] : q[4][4],
  86      c ? p != q[5] : q[5][5],
  87     };
  88
  89   sink (a);
  90 }
  91
  92
  93 // Verify warning for the example in the manual.
  94
  95 struct A { int refcount; void *data; };
  96
  97 void release (struct A *p)
  98 {
  99   int refcount = --p->refcount;
 100   free (p);
 101   if (refcount == 0)
 102     free (p->data); // { dg-warning "pointer 'p' may be used" }
 103 }