clang/test/CXX/dcl.dcl/dcl.attr/dcl.align/p6.cpp

   1 // RUN: %clang_cc1 -std=c++11 -verify %s
   2
   3 alignas(4) extern int n1; // expected-note {{previous declaration}}
   4 alignas(8) int n1; // expected-error {{redeclaration has different alignment requirement (8 vs 4)}}
   5
   6 alignas(8) int n2; // expected-note {{previous declaration}}
   7 alignas(4) extern int n2; // expected-error {{different alignment requirement (4 vs 8)}}
   8
   9 alignas(8) extern int n3; // expected-note {{previous declaration}}
  10 alignas(4) extern int n3; // expected-error {{different alignment requirement (4 vs 8)}}
  11
  12 extern int n4;
  13 alignas(8) extern int n4;
  14
  15 alignas(8) extern int n5;
  16 extern int n5;
  17
  18 int n6; // expected-error {{'alignas' must be specified on definition if it is specified on any declaration}}
  19 alignas(8) extern int n6; // expected-note {{declared with 'alignas' attribute here}}
  20
  21 extern int n7;
  22 alignas(8) int n7;
  23
  24 alignas(8) extern int n8; // expected-note {{declared with 'alignas' attribute here}}
  25 int n8; // expected-error {{'alignas' must be specified on definition if it is specified on any declaration}}
  26
  27 int n9; // expected-error {{'alignas' must be specified on definition if it is specified on any declaration}}
  28 alignas(4) extern int n9; // expected-note {{declared with 'alignas' attribute here}}
  29
  30 struct S;
  31 struct alignas(16) S; // expected-note {{declared with 'alignas' attribute here}}
  32 struct S;
  33 struct S { int n; }; // expected-error {{'alignas' must be specified on definition if it is specified on any declaration}}
  34
  35 struct alignas(2) T;
  36 struct alignas(2) T { char c; }; // expected-note {{previous declaration is here}}
  37 struct T;
  38 struct alignas(4) T; // expected-error {{redeclaration has different alignment requirement (4 vs 2)}}
  39
  40 struct U;
  41 struct alignas(2) U {};
  42
  43 struct V {}; // expected-error {{'alignas' must be specified on definition if it is specified on any declaration}}
  44 struct alignas(1) V; // expected-note {{declared with 'alignas' attribute here}}
  45
  46 template<int M, int N> struct alignas(M) W;
  47 template<int M, int N> struct alignas(N) W {};
  48 W<4,4> w44; // ok
  49 // FIXME: We should reject this.
  50 W<1,2> w12;
  51 static_assert(alignof(W<4,4>) == 4, "");
  52
  53 template<int M, int N, int O, int P> struct X {
  54   alignas(M) alignas(N) static char Buffer[32]; // expected-note {{previous declaration is here}}
  55 };
  56 template<int M, int N, int O, int P>
  57 alignas(O) alignas(P) char X<M, N, O, P>::Buffer[32]; // expected-error {{redeclaration has different alignment requirement (8 vs 2)}}
  58 char *x1848 = X<1,8,4,8>::Buffer; // ok
  59 char *x1248 = X<1,2,4,8>::Buffer; // expected-note {{in instantiation of}}
  60
  61 // Don't crash here.
  62 alignas(4) struct Incomplete incomplete; // expected-error {{incomplete type}} expected-note {{forward declaration}}