gcc/testsuite/c-c++-common/Wdangling-pointer-4.c

   1 /* PR middle-end/63272 - GCC should warn when using pointer to dead scoped
   2    variable within the same function
   3    Exercise -Wdangling-pointer for VLAs.
   4    { dg-do compile }
   5    { dg-options "-O0 -Wall -ftrack-macro-expansion=0" }
   6    { dg-require-effective-target alloca } */
   7
   8 void sink (void*, ...);
   9
  10 void nowarn_vla (int n)
  11 {
  12   {
  13     int vla1[n];
  14     int *p1 = vla1;
  15     sink (p1);
  16
  17     {
  18       int vla2[n];
  19       int *p2 = vla2;
  20       sink (p1, p2);
  21
  22       {
  23         int vla3[n];
  24         int *p3 = vla3;
  25         sink (p1, p2, p3);
  26       }
  27       sink (p1, p2);
  28     }
  29     sink (p1);
  30   }
  31 }
  32
  33 void warn_one_vla (int n)
  34 {
  35   int *p;
  36   {
  37     int vla[n];               // { dg-message "'vla' declared" "pr??????" { xfail *-*-* } }
  38     p = vla;
  39   }
  40   sink (p);                   // { dg-warning "using a dangling pointer to 'vla'" "vla" { xfail *-*-* } }
  41 }
  42
  43
  44 void warn_two_vlas_same_block (int n)
  45 {
  46   int *p, *q;
  47   {
  48     int vla1[n];              // { dg-message "'vla1' declared" "pr??????" { xfail *-*-* } }
  49     int vla2[n];              // { dg-message "'vla2' declared" "pr??????" { xfail *-*-* } }
  50     p = vla1;
  51     q = vla2;
  52   }
  53
  54   sink (p);                   // { dg-warning "using a dangling pointer to 'vla1'" "vla" { xfail *-*-* } }
  55   sink (q);                   // { dg-warning "using a dangling pointer to 'vla2'" "vla" { xfail *-*-* } }
  56 }
  57
  58
  59 void warn_two_vlas_in_series (int n)
  60 {
  61   int *p;
  62   {
  63     int vla1[n];              // { dg-message "'vla1' declared" "pr??????" { xfail *-*-* } }
  64     p = vla1;
  65   }
  66   sink (p);                   // { dg-warning "using a dangling pointer to 'vla1'" "vla" { xfail *-*-* } }
  67
  68   int *q;
  69   {
  70     int vla2[n];              // { dg-message "'vla2' declared" "pr??????" { xfail *-*-* } }
  71     q = vla2;
  72   }
  73   sink (q);                   // { dg-warning "using a dangling pointer to 'vla2'" "vla" { xfail *-*-* } }
  74 }