gcc/testsuite/c-c++-common/attr-nonstring-7.c

   1 /* PR 85643 - attribute nonstring fails to squash -Wstringop-truncation
   2    warning
   3   { dg-do compile }
   4   { dg-options "-O2 -Wall -ftrack-macro-expansion=0" } */
   5
   6 #define strncpy   __builtin_strncpy
   7
   8 struct A {
   9   char a[16 + 1];
  10 };
  11
  12 struct B {
  13   char a[16] __attribute__ ((__nonstring__));
  14 };
  15
  16 struct B*
  17 test_memarray (const struct A *s)
  18 {
  19   static struct B b;
  20   strncpy (b.a, s->a, sizeof b.a);
  21   return &b;
  22 }
  23
  24 const char*
  25 test_array (const char *s)
  26 {
  27   static char a[80] __attribute__ ((__nonstring__));
  28   strncpy (a, s, sizeof a);
  29   return a;
  30 }
  31
  32 const char*
  33 test_array_idx (const char *s)
  34 {
  35   static char a[80]  __attribute__ ((__nonstring__));
  36   char *p __attribute__ ((__nonstring__)) = &a[20];
  37   strncpy (p, s, 60);   /* { dg-bogus "-Wstringop-truncation" } */
  38   return a;
  39 }
  40
  41 const char*
  42 test_array_off (const char *s)
  43 {
  44   static char a[80]  __attribute__ ((__nonstring__));
  45   char *p __attribute__ ((__nonstring__)) = a + 20;
  46   strncpy (p, s, 60);   /* { dg-bogus "-Wstringop-truncation" } */
  47   return a;
  48 }
  49
  50 struct B*
  51 test_memarray_cstidx_idx (const char *s)
  52 {
  53   static struct B b[2];
  54   char *p __attribute__ ((__nonstring__)) = &b[1].a[4];
  55
  56   /* The destination below is represented as &MEM[(void *)&a + 20B] and
  57      which (in general) doesn't make it possible to determine what member
  58      it refers to.  */
  59   strncpy (p, s, sizeof b[1].a - 4);   /* { dg-bogus "-Wstringop-truncation" "" { xfail *-*-*} } */
  60   return b;
  61 }
  62
  63 struct B*
  64 test_memarray_cstidx_off (const char *s)
  65 {
  66   static struct B b[2];
  67   char *p __attribute__ ((__nonstring__)) = b[1].a + 4;
  68
  69   /* Same as above.  */
  70   strncpy (p, s, sizeof b[1].a - 4);   /* { dg-bogus "-Wstringop-truncation" "" { xfail *-*-*} } */
  71   return b;
  72 }
  73
  74 struct B*
  75 test_memarray_varidx_idx (const char *s, int i)
  76 {
  77   static struct B b[3];
  78   char *p __attribute__ ((__nonstring__)) = &b[i].a[4];
  79   strncpy (p, s, sizeof b[i].a - 4);
  80   return b;
  81 }
  82
  83 struct B*
  84 test_memarray_varidx_off (const char *s, int i)
  85 {
  86   static struct B b[3];
  87   char *p __attribute__ ((__nonstring__)) = b[i].a + 4;
  88   strncpy (p, s, sizeof b[i].a - 4);
  89   return b;
  90 }