gcc/testsuite/gcc.dg/uninit-42.c

   1 /* PR middle-end/101734 - missing warning reading from a write-only object
   2    Verify that reading objects pointed to by arguments
   3    declared with attribute access none or write-only is diagnosed by
   4    -Wmaybe-uninitialized.
   5    { dg-do compile }
   6    { dg-options "-Wall" } */
   7
   8 #define A(mode, ...) __attribute__ ((access (mode, __VA_ARGS__)))
   9
  10 void sink (void *, ...);
  11
  12
  13 A (write_only, 1, 2)
  14 int nowarn_wo_assign_r0 (int *p, int n)
  15 {
  16   *p = n;
  17   return *p;
  18 }
  19
  20 A (write_only, 1, 2)
  21 int nowarn_wo_sink_r0 (int *p, int n)
  22 {
  23   sink (p, p + 1, p + n);
  24   return *p;
  25 }
  26
  27 A (write_only, 1, 2)
  28 int warn_wo_r0 (int *p, int n)
  29 {
  30   return *p;        // { dg-warning "'\\*p' may be used uninitialized \\\[-Wmaybe-uninitialized" }
  31 }
  32
  33
  34 A (write_only, 1, 2)
  35 int nowarn_wo_w1_r1 (int *p, int n)
  36 {
  37   p[1] = n;
  38   return p[1];
  39 }
  40
  41 A (write_only, 1, 2)
  42 int warn_wo_r1 (int *p, int n)
  43 {
  44   return p[1];      // { dg-warning "'p\\\[1]' may be used uninitialized" }
  45 }
  46
  47
  48 A (write_only, 1, 2)
  49 int nowarn_wo_rwi_rj (int *p, int n, int i, int j)
  50 {
  51   p[i] = n;
  52   return p[j];
  53 }
  54
  55 A (write_only, 1, 2)
  56   int warn_wo_ri (int *p, int n, int i)
  57 {
  58   return p[i];      // { dg-warning " may be used uninitialized" }
  59 }
  60
  61
  62
  63 A (none, 1, 2)
  64 int* nowarn_none_sink_return (int *p, int n)
  65 {
  66   sink (p, p + 1, p + n);
  67   return p;
  68 }
  69
  70 A (none, 1, 2)
  71 int warn_none_r0 (int *p, int n)
  72 {
  73   (void)&n;
  74   return *p;        // { dg-warning "'\\*p' may be used uninitialized" }
  75 }
  76
  77 A (none, 1, 2)
  78 int warn_none_r1 (int *p, int n)
  79 {
  80   return p[1];      // { dg-warning "'p\\\[1]' may be used uninitialized" }
  81 }
  82
  83 A (write_only, 1, 2)
  84 int warn_none_ri (int *p, int n, int i)
  85 {
  86   return p[i];      // { dg-warning " may be used uninitialized" }
  87 }