clang/test/Sema/offsetof.c

   1 // RUN: %clang_cc1 -Wno-pointer-to-int-cast -fsyntax-only -verify %s
   2
   3 #define offsetof(TYPE, MEMBER) __builtin_offsetof (TYPE, MEMBER)
   4
   5 typedef struct P { int i; float f; } PT;
   6 struct external_sun3_core
   7 {
   8  unsigned c_regs;
   9
  10   PT  X[100];
  11
  12 };
  13
  14 // Ensure the builtin works as a constant expression
  15 int i = offsetof(PT, f);
  16
  17 void swap(void)
  18 {
  19   int x;
  20   x = offsetof(struct external_sun3_core, c_regs);
  21   x = __builtin_offsetof(struct external_sun3_core, X[42].f);
  22
  23   x = __builtin_offsetof(struct external_sun3_core, X[42].f2);  // expected-error {{no member named 'f2'}}
  24   x = __builtin_offsetof(int, X[42].f2);  // expected-error {{offsetof requires struct}}
  25
  26   int a[__builtin_offsetof(struct external_sun3_core, X) == 4 ? 1 : -1];
  27   int b[__builtin_offsetof(struct external_sun3_core, X[42]) == 340 ? 1 : -1];
  28   int c[__builtin_offsetof(struct external_sun3_core, X[42].f2) == 344 ? 1 : -1];  // expected-error {{no member named 'f2'}}
  29 }
  30
  31 extern int f(void);
  32
  33 struct s1 { int a; };
  34 int v1 = offsetof (struct s1, a) == 0 ? 0 : f();
  35
  36 struct s2 { int a; };
  37 int v2 = (int)(&((struct s2 *) 0)->a) == 0 ? 0 : f();
  38
  39 struct s3 { int a; };
  40 int v3 = __builtin_offsetof(struct s3, a) == 0 ? 0 : f();
  41
  42 // PR3396
  43 struct sockaddr_un {
  44  unsigned char sun_len;
  45  char sun_path[104];
  46 };
  47 int a(int len) {
  48 int a[__builtin_offsetof(struct sockaddr_un, sun_path[len+1])];
  49 }
  50
  51 // PR4079
  52 union x {struct {int x;};};
  53 int x[__builtin_offsetof(union x, x)];
  54
  55 struct incomplete; // expected-note 2 {{forward declaration of 'struct incomplete'}}
  56 int test1[__builtin_offsetof(struct incomplete, foo)]; // expected-error {{offsetof of incomplete type 'struct incomplete'}}
  57
  58 int test2[__builtin_offsetof(struct incomplete[10], [4].foo)]; // expected-error {{array has incomplete element type 'struct incomplete'}}
  59
  60 // Bitfields
  61 struct has_bitfields {
  62   int i : 7;
  63   int j : 12; // expected-note{{bit-field is declared here}}
  64 };
  65
  66 int test3 = __builtin_offsetof(struct has_bitfields, j); // expected-error{{cannot compute offset of bit-field 'j'}}
  67
  68 typedef struct Array { int array[1]; } Array;
  69 int test4 = __builtin_offsetof(Array, array);
  70
  71 int test5(void) {
  72   return __builtin_offsetof(Array, array[*(int*)0]); // expected-warning{{indirection of non-volatile null pointer}} expected-note{{__builtin_trap}}
  73 }
  74