gcc/testsuite/gcc.dg/Wdangling-pointer.c

   1 /* Exercise basic C-only cases of -Wdangling-pointer.
   2    { dg-do compile }
   3    { dg-options "-O0 -Wall" }
   4    { dg-require-effective-target alloca } */
   5
   6 typedef __SIZE_TYPE__ size_t;
   7
   8 extern void* memchr (const void*, int, size_t);
   9 extern char* strchr (const char*, int);
  10
  11 void sink (const void*, ...);
  12
  13
  14 void nowarn_compound_literal (int i)
  15 {
  16   {
  17     int *p = (int[]){ 1, 2, 3 };
  18     sink (p);
  19   }
  20   {
  21     int *q = (int[]){ 1, 2, 3 };
  22     int *p = &q[1];
  23     sink (p);
  24   }
  25   {
  26     int *p = __builtin_memchr ((int[]){ 1, 2, 3 }, 2, 3 * sizeof *p);
  27     sink (p);
  28   }
  29   {
  30     int *p = __builtin_memchr ((int[]){ i, i + 1 }, 3, 2 * sizeof *p);
  31     sink (p);
  32   }
  33 }
  34
  35
  36 void warn_compound_literal (int i)
  37 {
  38   int *p;
  39   {
  40     p = (int[]){ 1, 2, 3 };   // { dg-message "unnamed temporary" },
  41   }
  42   sink (p);                   // { dg-warning "using dangling pointer 'p' to an unnamed temporary" }
  43
  44   {
  45     int *q =
  46       (int[]){ 1, 2, 3 };     // { dg-message "unnamed temporary" },
  47     p = &q[1];
  48   }
  49   sink (p);                   // { dg-warning "using dangling pointer 'p' to an unnamed temporary" }
  50   {
  51     p = (int*)memchr (
  52           (int[]){ 1, 2, 3 }, // { dg-message "unnamed temporary" }
  53           2, 3 * sizeof *p);
  54   }
  55   sink (p);                   // { dg-warning "using dangling pointer 'p' to an unnamed temporary" }
  56
  57   {
  58     p = (int*)memchr (
  59           (int[]){ i, i + 1 },// { dg-message "unnamed temporary" }
  60           3, 2 * sizeof *p);
  61   }
  62   sink (p);                   // { dg-warning "using dangling pointer 'p' to an unnamed temporary" }
  63 }
  64
  65
  66 void warn_store_compound_literal (int **p)
  67 {
  68   int *q = (int[]) { 1, 2, 3 };
  69   p[0] = q;                   // { dg-warning "storing the address" }
  70 }
  71
  72 void warn_store_vla (int n, int **p)
  73 {
  74   int a[n];
  75   p[1] = &a[1];               // { dg-warning "-Wdangling-pointer" "pr??????" { xfail *-*-* } }
  76 }