clang/test/SemaCXX/alignof.cpp

   1 // RUN: %clang_cc1 -std=c++11 -fsyntax-only -verify %s
   2
   3 // rdar://13784901
   4
   5 struct S0 {
   6   int x;
   7   static const int test0 = __alignof__(x); // expected-error {{invalid application of 'alignof' to a field of a class still being defined}}
   8   static const int test1 = __alignof__(S0::x); // expected-error {{invalid application of 'alignof' to a field of a class still being defined}}
   9   auto test2() -> char(&)[__alignof__(x)]; // expected-error {{invalid application of 'alignof' to a field of a class still being defined}}
  10 };
  11
  12 struct S1; // expected-note 6 {{forward declaration}}
  13 extern S1 s1;
  14 const int test3 = __alignof__(s1); // expected-error {{invalid application of '__alignof' to an incomplete type 'S1'}}
  15
  16 struct S2 {
  17   S2();
  18   S1 &s;
  19   int x;
  20
  21   int test4 = __alignof__(x); // ok
  22   int test5 = __alignof__(s); // expected-error {{invalid application of '__alignof' to an incomplete type 'S1'}}
  23 };
  24
  25 const int test6 = __alignof__(S2::x);
  26 const int test7 = __alignof__(S2::s); // expected-error {{invalid application of '__alignof' to an incomplete type 'S1'}}
  27
  28 // Arguably, these should fail like the S1 cases do: the alignment of
  29 // 's2.x' should depend on the alignment of both x-within-S2 and
  30 // s2-within-S3 and thus require 'S3' to be complete.  If we start
  31 // doing the appropriate recursive walk to do that, we should make
  32 // sure that these cases don't explode.
  33 struct S3 {
  34   S2 s2;
  35
  36   static const int test8 = __alignof__(s2.x);
  37   static const int test9 = __alignof__(s2.s); // expected-error {{invalid application of '__alignof' to an incomplete type 'S1'}}
  38   auto test10() -> char(&)[__alignof__(s2.x)];
  39   static const int test11 = __alignof__(S3::s2.x);
  40   static const int test12 = __alignof__(S3::s2.s); // expected-error {{invalid application of '__alignof' to an incomplete type 'S1'}}
  41   auto test13() -> char(&)[__alignof__(s2.x)];
  42 };
  43
  44 // Same reasoning as S3.
  45 struct S4 {
  46   union {
  47     int x;
  48   };
  49   static const int test0 = __alignof__(x);
  50   static const int test1 = __alignof__(S0::x);
  51   auto test2() -> char(&)[__alignof__(x)];
  52 };
  53
  54 // Regression test for asking for the alignment of a field within an invalid
  55 // record.
  56 struct S5 {
  57   S1 s;  // expected-error {{incomplete type}}
  58   int x;
  59 };
  60 const int test8 = __alignof__(S5::x);
  61
  62 int test14[2];
  63
  64 static_assert(alignof(test14) == 4, "foo"); // expected-warning {{'alignof' applied to an expression is a GNU extension}}
  65
  66 // PR19992
  67 static_assert(alignof(int[]) == alignof(int), ""); // ok
  68
  69 namespace alignof_array_expr {
  70   alignas(32) extern int n[];
  71   static_assert(alignof(n) == 32, ""); // expected-warning {{GNU extension}}
  72
  73   template<int> struct S {
  74     static int a[];
  75   };
  76   template<int N> int S<N>::a[N];
  77   // ok, does not complete type of S<-1>::a
  78   static_assert(alignof(S<-1>::a) == alignof(int), ""); // expected-warning {{GNU extension}}
  79 }
  80
  81 template <typename T> void n(T) {
  82   alignas(T) int T1;
  83   char k[__alignof__(T1)];
  84   static_assert(sizeof(k) == alignof(long long), "");
  85 }
  86 template void n(long long);
  87
  88 namespace PR22042 {
  89 template <typename T>
  90 void Fun(T A) {
  91   typedef int __attribute__((__aligned__(A))) T1; // expected-error {{requested alignment is dependent but declaration is not dependent}}
  92   int k1[__alignof__(T1)];
  93 }
  94
  95 template <int N>
  96 struct S {
  97   typedef __attribute__((aligned(N))) int Field[sizeof(N)]; // expected-error {{requested alignment is dependent but declaration is not dependent}}
  98 };
  99 }
 100
 101 typedef int __attribute__((aligned(16))) aligned_int;
 102 template <typename>
 103 using template_alias = aligned_int;
 104 static_assert(alignof(template_alias<void>) == 16, "Expected alignment of 16" );
 105
 106 struct PR47138 {
 107   invalid_type a; // expected-error {{unknown type}}
 108 };
 109 static_assert(__alignof__(PR47138) == 1, ""); // Don't crash.