clang/test/Sema/flexible-array-in-union.c

   1 // RUN: %clang_cc1 %s -verify=stock,c -fsyntax-only
   2 // RUN: %clang_cc1 %s -verify=stock,cpp -fsyntax-only -x c++
   3 // RUN: %clang_cc1 %s -verify=stock,cpp -fsyntax-only -fms-compatibility -x c++
   4 // RUN: %clang_cc1 %s -verify=stock,c,gnu -fsyntax-only -Wgnu-flexible-array-union-member -Wgnu-empty-struct
   5 // RUN: %clang_cc1 %s -verify=stock,c,microsoft -fsyntax-only -fms-compatibility -Wmicrosoft
   6
   7 // The test checks that an attempt to initialize union with flexible array
   8 // member with an initializer list doesn't crash clang.
   9
  10
  11 union { char x[]; } r = {0}; /* gnu-warning {{flexible array member 'x' in a union is a GNU extension}}
  12                                 microsoft-warning {{flexible array member 'x' in a union is a Microsoft extension}}
  13                               */
  14 struct _name1 {
  15   int a;
  16   union {
  17     int b;
  18     char x[]; /* gnu-warning {{flexible array member 'x' in a union is a GNU extension}}
  19                  microsoft-warning {{flexible array member 'x' in a union is a Microsoft extension}}
  20                */
  21   };
  22 } name1 = {
  23   10,
  24   42,        /* initializes "b" */
  25 };
  26
  27 struct _name1i {
  28   int a;
  29   union {
  30     int b;
  31     char x[]; /* gnu-warning {{flexible array member 'x' in a union is a GNU extension}}
  32                  microsoft-warning {{flexible array member 'x' in a union is a Microsoft extension}}
  33                */
  34   };
  35 } name1i = {
  36   .a = 10,
  37   .b = 42,
  38 };
  39
  40 /* Initialization of flexible array in a union is never allowed. */
  41 struct _name2 {
  42   int a;
  43   union {
  44     int b;
  45     char x[]; /* gnu-warning {{flexible array member 'x' in a union is a GNU extension}}
  46                  microsoft-warning {{flexible array member 'x' in a union is a Microsoft extension}}
  47                */
  48   };
  49 } name2 = {
  50   12,
  51   13,
  52   { 'c' },   /* c-warning {{excess elements in struct initializer}}
  53                 cpp-error {{excess elements in struct initializer}}
  54               */
  55 };
  56
  57 /* Initialization of flexible array in a union is never allowed. */
  58 struct _name2i {
  59   int a;
  60   union {
  61     int b;
  62     char x[]; /* gnu-warning {{flexible array member 'x' in a union is a GNU extension}}
  63                  microsoft-warning {{flexible array member 'x' in a union is a Microsoft extension}}
  64                  stock-note {{initialized flexible array member 'x' is here}}
  65                */
  66   };
  67 } name2i = {
  68   .a = 12,
  69   .b = 13,      /* stock-note {{previous initialization is here}} */
  70   .x = { 'c' }, /* stock-error {{initialization of flexible array member is not allowed}}
  71                    c-warning {{initializer overrides prior initialization of this subobject}}
  72                    cpp-error {{initializer partially overrides prior initialization of this subobject}}
  73                  */
  74 };
  75
  76 /* Flexible array initialization always allowed when not in a union,
  77    and when struct has another member.
  78  */
  79 struct _okay {
  80   int a;
  81   char x[];
  82 } okay = {
  83   22,
  84   { 'x', 'y', 'z' },
  85 };
  86
  87 struct _okayi {
  88   int a;
  89   char x[];
  90 } okayi = {
  91   .a = 22,
  92   .x = { 'x', 'y', 'z' },
  93 };
  94
  95 struct _okay0 {
  96   int a;
  97   char x[];
  98 } okay0 = { };
  99
 100 struct _flex_extension {
 101   char x[]; /* gnu-warning {{flexible array member 'x' in otherwise empty struct is a GNU extension}}
 102                microsoft-warning {{flexible array member 'x' in otherwise empty struct is a Microsoft extension}}
 103              */
 104 } flex_extension = {
 105   { 'x', 'y', 'z' },
 106 };
 107
 108 struct _flex_extensioni {
 109   char x[]; /* gnu-warning {{flexible array member 'x' in otherwise empty struct is a GNU extension}}
 110                microsoft-warning {{flexible array member 'x' in otherwise empty struct is a Microsoft extension}}
 111              */
 112 } flex_extensioni = {
 113   .x = { 'x', 'y', 'z' },
 114 };
 115
 116 struct already_hidden {
 117   int a;
 118   union {
 119     int b;
 120     struct {
 121       struct { } __empty;  // gnu-warning {{empty struct is a GNU extension}}
 122       char x[];
 123     };
 124   };
 125 };
 126
 127 struct still_zero_sized {
 128   struct { } __unused;  // gnu-warning {{empty struct is a GNU extension}}
 129   int x[];
 130 };
 131
 132 struct warn1 {
 133   int a;
 134   union {
 135     int b;
 136     char x[]; /* gnu-warning {{flexible array member 'x' in a union is a GNU extension}}
 137                  microsoft-warning {{flexible array member 'x' in a union is a Microsoft extension}}
 138                */
 139   };
 140 };
 141
 142 struct warn2 {
 143   int x[];  /* gnu-warning {{flexible array member 'x' in otherwise empty struct is a GNU extension}}
 144                microsoft-warning {{flexible array member 'x' in otherwise empty struct is a Microsoft extension}}
 145              */
 146 };
 147
 148 union warn3 {
 149   short x[];  /* gnu-warning {{flexible array member 'x' in a union is a GNU extension}}
 150                  microsoft-warning {{flexible array member 'x' in a union is a Microsoft extension}}
 151                */
 152 };
 153
 154 struct quiet1 {
 155   int a;
 156   short x[];
 157 };
 158
 159 struct _not_at_end {
 160   union { short x[]; }; /* stock-warning-re {{field '' with variable sized type '{{.*}}' not at the end of a struct or class is a GNU extension}}
 161                            gnu-warning {{flexible array member 'x' in a union is a GNU extension}}
 162                            microsoft-warning {{flexible array member 'x' in a union is a Microsoft extension}}
 163                          */
 164   int y;
 165 } not_at_end = {{}, 3};
 166
 167 struct _not_at_end_s {
 168   struct { int a; short x[]; }; /* stock-warning-re {{field '' with variable sized type '{{.*}}' not at the end of a struct or class is a GNU extension}} */
 169   int y;
 170 } not_at_end_s = {{}, 3};
 171
 172 struct {
 173   int a;
 174   union {      /* stock-warning-re {{field '' with variable sized type '{{.*}}' not at the end of a struct or class is a GNU extension}} */
 175     short x[]; /* stock-note {{initialized flexible array member 'x' is here}}
 176                   gnu-warning {{flexible array member 'x' in a union is a GNU extension}}
 177                   microsoft-warning {{flexible array member 'x' in a union is a Microsoft extension}}
 178                 */
 179     int b;
 180   };
 181   int c;
 182   int d;
 183 } i_f = { 4,
 184          {5},  /* stock-error {{initialization of flexible array member is not allowed}} */
 185          {},
 186           6};
 187
 188 // expected-no-diagnostics